Nervous System – Hacking Fitness

In the intestines there are around a hundred trillion microbes, reflecting 10,000 unique species, and contribute 150 times more genes than our own human genome.
Microbes help regulate several complex behaviors such as anxiety, learning and memory, appetite and satiety, mood and emotion, as well as other behaviors yet to be discovered.
One way that microbes are able to contribute to human behavior is by activating the vagus nerve, a nerve that runs from the gut lining to the brain stem.
Another way that microbes can effect the brain is by activating the gut endocrine system, producing neuroactive molecules.
Not only are we made up of a large amount of microbial cells, but that some of these cells can be truly mind altering; effecting our brain development, function, and behavior.

Aspartame

Aspartame is the artificial sweetener found in most diet sodas and drinks.
It can cause headaches/migraines.
Linked to depression and increased weight gain.
Classified as an excitotoxin.
Over stimulates brain cells, causing them to die.
Can change brain physiology and deplete your brain of serotonin, a mood regulator.

Washing Your Brain

The brain has two different functional states, one state being when we are awake and aware, the other being when we are asleep. The difference being, when we are awake the brain cells are working hard to process information, and when we are asleep the brain works hard to remove the waste that built-up while we were awake.
The glymphatic system functions like a garbage removal for the central nervous system. It accomplishes this by creating an influx of cerebrospinal fluid that is propelled between brain cells and flushes toxic waste products away.
A study of mice showed that cerebrospinal fluid had a higher influx during sleep states as opposed to waking states. This study also showed that spaces between cells had a 60% increase during sleep, theoretically causing a larger path for cerebrospinal fluid to clear toxic waste more efficiently.

Benefits of Sleep

Sleep is a critical function during which your body balances and regulates its vital systems, affecting respiration, and regulating everything from circulation to growth and immune response.
During sleep, a fifth of your circulatory blood gets channeled to your brain.
We normally forget 40% of new material within the first 20 minutes. But this loss can be prevented through memory consolidation, the process by which information is moved from short-term memory to long-term memory. One of the major factors contributing to memory consolidation is a good night’s sleep.

The Science of Sleep

Sleep is a periodic, natural, reversible, and near total loss of consciousness.
Some reasons why we sleep are for recuperation (allowing our neurons and other cells to rest and repair themselves), support growth (sleep is when our pituitary glands release growth hormones), and benefits for mental function (improving memory, giving the brain time to process the events of the day, and boosting creativity).
We experience 4 distinct stages of sleep, each defined by unique brainwave patterns. We go through all 4 stages about every 90 minutes or so.
Rapid Eye Movement (REM) is a recurring sleep stage during which vivid dreams commonly occur.
Lack of sleep is a predictor for depression and has been linked to things like weight gain, immune system suppression, and slowed reaction time.
The Information Processing theory proposes that our dreams help us sort out and process the day’s events and fix them into our memories.
The Physiological Function theory suggests that dreaming may promote neural development and preserve neural pathways by providing the brain with stimulation.

Meditation Benefits

During meditation, brain-scans see increased activity in regions directly correlated with decreased anxiety and depression along with increased pain tolerance.
The Default Mode Network is activated when one’s mind is at rest and not focusing on the outside world. This has been found to improve memory, self awareness, and goal setting.
Studies found that after 8 weeks of a meditation program, gray matter was more dense in areas associated with learning, memory processing, and emotion regulation. And the amygdala, which deals with stress, blood pressure, and fear, had decreased gray matter.
Meditation can not only lower blood pressure, but can also increase the variability of your heart rate (allowing for the proper transporting of oxygen and carbon dioxide throughout the body), and increase immune system function.
When cancer survivors completed a meditation program,their bodies showed significant increases in telomere (a protective protein complex at the end of your DNA) length. This helped to prevent damage to the DNA.

Iceman

Feeling is understanding.

Epigenetics

Basic genetics tells us that only DNA gets passed along to offspring; characteristics like memories, scars, or giant muscles can’t get passed on since acquiring them doesn’t alter the genetic code.
In every cell, biological machinery constantly translates DNA into the proteins needed to carry out vital processes. Chemical switches attached to the DNA turn genes on and off, telling the machinery which proteins to produce and in what quantities.
These switches, called “epigenetic tags” are why a kidney cell looks and acts differently than a skin or nerve cell, even though they all have identical DNA.
The switches in any one cell aren’t set in stone and can be influenced by external or environmental factors.

Cold Shower Therapy

Some benefits of cold showers:

helps to strengthen the immune system
deepens your breathing
increases blood circulation
healthy effects for your skin and hair
increases fertility in men
increases will power
has an anti-depressant effect
helps you sleep at night
improves lymphatic movement
increases metabolism

A Trip with Probiotics

More than half the world’s population have a bacteria called helicobacter pylori living in their stomach. They are pathogenic in nature, burrowing into the walls of the tissue and producing toxins that damage cells. Symptoms can manifest in the form of painful ulcers and cancer.
Certain probiotic bacteria may help in the reduction of helicon bacteria by attacking them with antibiotic-like weaponry or dislodging them from the stomach tissue.
Good bacteria in your intestines play critical roles to keep you healthy such as degrading food, counteracting bad bacteria, and modulating the immune response.

Stress As A Tool

By changing how you think about stress, you can change your body’s response to stress.
Instead of viewing physical changes due to the body’s stress response (faster heart beat, quickened breathing, and beginning to sweat) as signs of anxiety or inability to cope with the pressure, but rather as signs that your body was being energized and preparing you to meet a challenge, you can change the way stress effects your body.
By rethinking your stress response as helpful (a faster heart beat is preparing you for action and quickened breathing is getting more oxygen to your brain) you can feel less stressed out, less anxious, and more confident when placed in stressful situations.
In a typical stress response, your heart rate goes up and your blood vessels constrict; which is one of the reasons why chronic stress is sometimes associated with cardiovascular disease. But participants in a study who were told to view the stress response as helpful still had a quickened heart rate but their blood vessels stayed relaxed during stressful situations, similar to what happens during moments of joy and courage.
Oxytocin is a stress hormone released by the pituitary gland during the stress response. One of it’s roles is to protect your cardiovascular system from the effects of stress. It has the ability to help heart cells regenerate and heal from any stress-induced damage.
How you think and how you act can transform your experience of stress.
When you choose to view your stress response as helpful, you create the biology of courage.
When you choose to connect with others under stress, you can create resilience.

Stressing Your Body

Stress is a hardwired physical response that travels throughout your entire body. For short periods it can be advantageous, but when activated too often or too long, it not only changes your brain, but also damages many of the other organs and cells throughout your body.
Your adrenal gland releases the stress hormones cortisol, epinephrine (also known as adrenaline) , and norepinephrine.
Adrenaline causes your heart to beat faster and raises your blood pressure. Over time, this can lead to hypertension. Cortisol can cause the inner lining of blood vessels to not function normally. This is an early step in triggering the process of atherosclerosis, the build up of cholesterol plaque in your arteries. Together, these changes increase your chances of a heart attack or stroke.
The body’s stress response also can disturb the natural rhythmic contractions that move food through your gut, leading to irritable bowel syndrome, and can increase your gut sensitivity to acid, making you more likely to feel heartburn.
Stress can also change the composition and function of your gut bacteria, which may affect your digestive and overall health.
Cortisol can increase your appetite, telling your body to replenish energy stores with energy dense foods and carbs, causing you to crave comfort foods.
High levels of cortisol can cause you to put on those extra calories as visceral, or deep belly, fat. This type of fat actively releases hormones and immune system chemicals called cytokines that can increase your risk of developing chronic diseases such as heart disease and insulin resistance.
Stress hormones affect immune cells in a variety of ways. Initially, they help prepare to fight invaders and heal after injury, but chronic stress can dampen function of some immune cells, make you more susceptible to infections, and slow the rate you heal.
Chronic stress has also been associated with shortened telomeres, the end tips of chromosomes that measure a cell’s age. When telomeres become too short, a cell can no longer divide and it dies.
Chronic stress can also affect your health by causing acne, hair loss, sexual dysfunction, headaches, muscle tension, difficulty concentrating, fatigue, and irritability.
Although your life will always be filled with stressful situations, what matters to your brain and entire body is how you respond to that stress. If you can view those situations as challenges you can control and master, rather than as threats that are insurmountable, you will perform better in the short run and stay healthy in the long run.

Stressing Your Brain

The body’s stress response can be useful for an extra burst of energy and focus for when you are playing a competitive sport or when speaking in public. However, when it is continuous, it can begin to change your brain in negative ways.
Chronic stress can affect the brain’s size, structure, and how it functions.
When your brain detects a stressful situation, your HPA (hypothalamus-pituitary-adrenal) axis is instantly activated and releases a hormone called cortisol, which primes your body for instant action.
High levels of cortisol over long periods of time wreak havoc on your brain.
Chronic stress increases the activity level and number of neural connections in the amygdala, your brain’s fear center.
As levels of cortisol rise, electric signals in the part of your brain associated with learning, memories, and stress control known as the hippocampus begin to deteriorate.
The hippocampus also inhibits the activity of the HPA axis. So when it is weakened, your ability to control your stress is also weakened.
Cortisol can literally cause your brain to shrink in size. Too much cortisol can result in the loss of synaptic connections between neurons, and the shrinking of your prefrontal cortex, the part of your brain that regulates behaviors like concentration, decision-making, judgement, and social interaction.
Chronic stress also leads to fewer new brain cells being made in the hippocampus, meaning it might make it harder for you to learn and remember things, as well as setting the stage for more serious mental problems like depression and eventually Alzheimer’s disease.
There are many ways to reverse what cortisol does to your stressed brain, the most powerful being exercise and meditation, which involves breathing deeply and being aware and focused on your surroundings. Both activities decrease your stress and increase the size of your hippocampus, thereby improving your memory.
Get in control of your stress, before it takes control of you.

Stress

The sympathetic nervous system is the part of your nervous system that responds to stress by stimulating the “fight or flight ” response. It does this by diverting bodily resources from your digestion, reproduction, and immune systems and sending more energy to your brain, heart, and muscles.
Physiological responses to non-immediate stresses are largely the same as when you’re fighting for survival (your body doesn’t differentiate between life-threatening stress and life-annoying stress).
Since the body’s reaction to stress is a full body response, it can become very taxing over time, throwing parts of your body into overdrive while depriving others of blood and oxygen.
Encountering constant non-life threatening stressors can actually end up endangering your health in the long run because your body’s stress response is so effective.
The frequent activation of your sympathetic nervous system and hormonal stress response can have terrible consequences such as high blood pressure, digestive problems and the suppression of your immune system.

Planet You

There are 10 times more microorganism cells (bacteria, virus, fungi) than there are human cells in, and on, our body.
Our genes are outnumbered 100 to 1 by microbial genes.
The collection of microorganisms in and on the body is referred to as the human microbiome.
Microbes contribute in educating immune cells about the difference between the bad bacteria they should fight off because it might make us sick; and things that aren’t a threat like good microbes.
As we get older our body’s microbes become our first line of defense, fighting off germs that try to invade our bodies; protecting their turf while protecting our health.
Some microbes are able to create their own antibiotics to fight against bad bacteria.
The biggest, most important, and complex microbial community we have is in our gut.
Our gut microbiome assists in fighting off infection, controlling the immune system, and regulating our metabolism.
Changes in the gut microbiome caused by bad food we eat and certain medicines we take can lead to diseases such as colon cancer, colitis, and maybe even diabetes and obesity.
The loss of key gut microbes may be the cause of certain diseases.
Eating good bacteria, like probiotics, may help in treating and preventing some diseases.
Prebiotics are foods that good microbes like to eat, causing them to flourish in your gut.

Body Language

We tend to make judgement and inferences based on a person’s body language.
Our own thoughts, feeling and physiology can be influenced by our nonverbal expressions.
Nonverbal expressions of power and dominance is expanding your body to be big and stretched out, take up more space, and basically open up.
Humans sometimes display nonverbal expressions of power chronically or when they’re feeling powerful in the moment.
Nonverbal expressions of powerlessness involve closing up your body, making yourself smaller, and avoid bumping into people around you.
When people come together, they tend to compliment each other’s nonverbal expressions, not mirroring, but doing the opposite of each other.
Our nonverbals govern how other people think and feel about us.
Powerful people tend to be more assertive, more confident, more optimistic (feeling that they’re going to win even at games of chance), have an ability to think more abstractly, and take more risks.
Physiologically, there are two key hormones that govern power; testosterone, which is the dominance hormone that can give feelings of assertiveness, dominance and confidence, and cortisol, the stress hormone which makes people more stress reactive. High power people tend to have high levels of testosterone and low levels of cortisol.
People who perform a high power pose for two minutes have experienced about a 20% increase in testosterone levels and a 25% decrease in cortisol levels.
People who perform a low power pose for two minutes have experienced about a 10% decrease in testosterone levels and a 15% increase in cortisol levels.

Movement Complexity

Movement complexity deals with the wide range of distinctive movement that humans are able to perform.

Movement Mastery

Movement mastery is about mastering your bodies ability in movement, being aware of your bodies position in space, and maintaining balance in unique and rapidly switching positions.

Posture

Posture is the way you hold yourself when you are sitting or standing.
Posture is the foundation for every movement your body makes, and can determine how well your body adapts to the stresses placed on it; such as carrying weight or sitting awkwardly.
If your posture isn’t optimal, your muscles have to work harder to keep you upright and balanced.
With poor posture, some muscles will become tight and inflexible, while others will be inhibited.
Poor posture inflicts extra wear and tear on your joints and ligaments as well as cause changes in your mood and behavior.

Muscles

When using your muscles to complete a task, for instance opening a door, your brain sends signals to motor neurons inside your arm. When they receive this signal they fire, causing muscles to contract and relax. This pulls on the bone in your arm and generates the needed movement.
The bigger the challenge becomes, the larger the brain signals grows; rallying more motor units to achieve the task.
As muscles become exposed to stress, they experience microscopic damage which is then repaired by the body.
The cycle of damage and repair eventually makes muscles bigger and stronger.
In order to build new muscle, our cells need to be exposed to higher workloads than they are used to.
If you don’t expose your muscles to some form of resistance, they will shrink.
Proper nutrition, hormones, and rest are required to repair damaged muscle fibers.
Your body responds to the demands placed on it.
Meaningful growth requires challenge and stress.

Parasites

Parasites are organisms that live on or inside another host organism.
The host organism is harmed or killed by the parasite.
Parasites manipulate host behavior in order to transfer from one host to another.

Gluten

Gluten is a protein found in grains such as wheat, rye, and barley.
Gluten can cause problems with people who have wheat allergy, celiac disease, and non-celiac gluten sensitivity.
Wheat allergy is when eating gluten causes an immune response, leading to allergic reactions.
In people with celiac disease, gluten causes inflammation and damage to the lining of the small intestine. This leads to intestinal problems like belly pain, bloating, gas, diarrhea, weight loss, skin rash, bone problems, iron deficiency, small stature, infertility, fatigue, and depression.
Non-celiac gluten sensitivity has symptoms such as fatigue, brain fog, joint pain, or skin rashes.
Switching to a gluten-free diet and watching for improvements in these symptoms can let you know if you are sensitive to gluten.

Sugar

Sugar activates the release of dopamine, effecting the brain’s reward system.
Over activating this reward system can lead to loss of control,cravings, and increased tolerance to sugar.
Over consumption of sugar can have addictive effects on the brain.

Probiotics

A diverse community of microbes in your gut allows for the extraction of energy from our food.
Every person has a unique and diverse community of microbes and can process foods in different ways.
One person’s gut microbes may be capable of releasing a fraction of the energy that another’s gut microbes can extract.
The food we eat influence which microbes live in our gut.
Foods made of complex molecules like an apple requires a lof of different microbial workers to break it down.
Foods made of simple molecules, like a lollipop causes less microbial diversity.

Vitamins

Vitamins are organic compounds we need to ingest in small amounts to keep the body functioning.
Vitamins have a wide range of roles from helping to build muscle and bones, makeing use of nutrients, capturing and using energy, and healing wounds.
Our body cant produce vitamins so we have to acquire them from other sources.
Vitamins are either water -soluble or lipid-soluble.
Vitamin deficiency can cause a range of problems such as fatigue, nerve damage, heart disorders, or diseases such as rickets and scurvy.

Fat

The amount of fat we eat does not impact our weight, cholesterol levels, or our risk of heart disease nearly as much as what kind of fat we eat.
Fat is made up of molecules called triglycerides, which are made up of glycerol and fatty acids.
The subtle differences in the structure of chains of fatty acids is what determines whether a fat is solid or liquid, whether or not it goes rancid quickly, and how good or how bad it is for you.
There are many differences in the structure of fatty acids. They can be short, medium, or long chains and they can either be saturated or unsaturated.
How a fat will effect your health depends on where the molecule fits, where it doesn’t fit, and what pathways it interferes with.

Metabolism part 2

The molecules in your body are constantly changing shape, and renewing and rearranging themselves to either build things or to use energy.
Carbohydrates and facts can be directly oxidized into useable energy. Amino acids have to be converted into molecules that get broken down like carbs if you want to get energy out of them.
Excess carbs and fat can be stored in larger, polymer versions of their original forms. Amino acids on the other had have to be converted and then stored as fat or glycogen.
The law of conservation of energy states that energy can never be created or destroyed; it can only change forms.
The process of metabolism involves conversions of energy either through catabolizing reactions that release the energy stored in your food, or anabolizing reactions that use or store that energy.
Cellular respiration is how we derive energy from the food we eat. It breaks down nutrient molecules to generate ATP, the cellular currency of energy.
There are two nutritional states; the absorptive, or fed state, which is during or after eating, and the postabsorptive, or fasting state, when the GI tract is empty and the body is running off of stored supplies.
Basal metabolic rate is the number of daily calories your body needs to do business as usual. That rate can be influenced by your age, sex, and body or composition.

Metabolism

Metabolism is the process of breaking down big complex substances into molecular rubble and reassembling this rubble into different complex substances.
Anabolic reactions build structures and require energy. Catabolic reactions break down structures and release energy
Nutrients are the materials your body needs to build, maintain, and repair itself.
The 6 major nutrients are: water, vitamins, minerals, carbohydrates, lipids, and proteins.
Vitamins are not used for building blocks or energy, but are essential in helping the body make use of other nutrients.
Minerals have a wide range of functions to help you stay healthy.
Carbohydrates are a source of energy.
Lipids store energy and fat soluble-vitamins. They also form the myelin that insulates the neurons in your brain and throughout your body. Lipids such as cholesterol are the precursors to things such as testosterone and estrogen.
Proteins form the bulk of your muscle and connective tissue. They also make up enzymes which are responsible for every chemical reaction in your body.
Since all proteins are made up of just 20 amino acids, the difference between the thousands of unique proteins are in the sequence of these amino acids.

You Are What You Eat

Biological molecules are the molecules necessary for every living thing on earth to survive. They are carbohydrates, lipids, proteins, and nucleic acids.
Carbohydrates can be broken down to simple sugars, lipids into fatty acids, proteins into amino acids, and nucleic acid into nucleotides.
Carbohydrates are a short term source of energy.
Lipids are a long term source of energy and used in your body for different functions such as the cell membrane and lipid hormones.
Proteins can be formed into a wide variety of shapes, each having a unique function, from enzymes to antibodies.

Caffine

While awake, a chemical called adenosine accumulates in your brain.
When adenosine binds to receptors in the brain, it slows down brain activity causing you to feel tired.
Caffeine, similar in structure to adenosine, is able to bind to adenosine receptors.
When caffeine binds to adenosine receptors brain activity does not slow down.
Caffeine also stimulates the release of adrenaline, causing increased heart rate and blood flow.
Caffeine prevents the reabsorbtion of dopamine in the brain, causing feelings of happiness.

Resistant Starch

Your gut microbiome is nourished by a dietary fiber called resistant starch.
Resistant starch passes through your body undigested, becoming food for the bacteria in your gut.
As the bacteria eat the resistant starch for energy, small carbohydrate molecules are released. Other bacteria feed on these carbohydrate molecules and produce by-products such as butyrate, a short chain fatty acid.
Butyrate can be used by your body for energy, absorbed through the large intestine.
The presence of butyrate encourages blood flow to the large intestine, keeping it healthy.

Cellular Resiration

Cellular respiration is how we derive energy from the food we eat; specifically from glucose.
In order to turn glucose to energy, oxygen is needed.
Adenosine triphosphate (ATP) is the “currency” of biological energy.
In the absence of oxygen, energy can still be created through anarobic process. This produces a by-product called lactic acid.

Intelligence

Intelligence is the ability to learn from experience, solve problems, and use knowledge to adapt to new experiences.
An intelligence test is a method for assessing an individual’s mental aptitudes and comparing them with those of others, using numerical scores.
Factor analysis is a statistical procedure that identifies clusters of related items (called factors) on a test; used to identify different dimensions of performance that underlie a person’s total score.
L.L. Thurstone, an American pioneer of psychometrics, identified intelligence using seven clusters of mental abilities: spatial ability, verbal comprehension, word fluency perceptual speed, numerical ability, inductive reasoning, and memory.
Savant syndrome is a condition in which a person otherwise limited in mental ability has an exceptional specific skill such as in computation or drawing.
Psychologist Howard Gardner views intelligence as multiple abilities coming in different forms. He believed that we have eight intelligence: musical, mathematical, linguistic, naturalist, interpersonal, intrapersonal, spatial, and kinesthetic ability.
Psychologist Robert Sternberg boils down intelligence into three types: analytical (problem-solving), creative (ability to adapt to new situations), and practical (for everyday tasks).
Creativity is the ability to produce ideas that are both novel and valuable.
Expertise is a well-developed base of knowledge, basically knowing a lot about a lot. Expertise provides the mind with all sorts of data to work with and combine in new ways.
Imaginative thinking is the ability to see things in new ways, recognize patterns, and make connections.
A venturesome personality is a person who seeks new experiences, tolerates risk, and perseveres in overcoming obstacles.
Intrinsic motivation is performing an action or behavior because you enjoy the activity itself.
Emotional intelligence is the ability to perceive, understand, manage, and use emotions. Perceiving emotions is being able to recognize them in faces, and even in music, film, and stories. Understanding emotions is being able to predict them and how they might change. Managing emotion is knowing how to appropriately express yourself in various situations. Emotional intelligence also means using emotions to enable adaptive or creative thinking.

Emotions

Emotions can provide the energy and motivation necessary to meet our goals and needs.
Emotion is a mind and body’s integrated response to a stimulus of some kind.
Emotion involve physiological arousal, expressive behaviors, and conscious experience.
Arousal is an increase in reactivity or wakefulness that primes us for some kind of action.
Arousal spurs emotion, but cognition (how we think about the stimuli) directs it.
To emotion, there are two paths in which we can process sensory input. The slower high-road cortex route allows thinking about feeling, while the quick low-road shortcut allows instant emotional reaction.
Fear, anger, and sexual arousal often deliver some of the same biological signals.

Motivation

Motivation is the need or desire to do something Whether that need is biological, social, or emotional, motivation is what brings you to action.
Motivation is often viewed in one of four ways; an evolutionary perspective, drive-reduction, optimal arousal, and Maslow’s hierarchy of needs.
In the evolutionary perspective theory, motivation is viewed as an instinct, an innate “drive” to act a certain way.
The drive-reduction theory suggests that we are motivated by a physiological need, or drive, that simply compels us to reduce that need. Drive reduction involves maintaining your body’s homeostasis, the physiological balance of it’s systems.
An incentive is the positive or negative stimuli that either entice or repel us.
Optimal arousal theory suggest that rather than just reducing a drive or tension, like hunger, we’re motivated to maintain a balance between stimulation and relaxation. Additionally, that we’re motivated to avoid boredom and stress.
Maslow’s hierarchy of needs is a list of needs that motivate a person to action arranged in a pyramid. The bottom being the most basic needs working towards the top to higher level needs.The pyramid is arranged, from bottom to top; physiological (food, water, air, moderate temperature), safety, love and belonging, esteem and respect, and at the top is self-actualization and spiritual growth.
Most schools of psychological thought agree that we are driven by at least three big motivators: sex, hunger, and the need to belong.

Thinking

Cognition refers to our thoughts, perspectives, and expectations. This involves knowing, remembering, understanding, communicating, and, to a certain extent, learning.
Concepts are mental groupings of similar objects, people, ideas or events. It is one of the major ways in which our cognition uses to make sense of the world.
We often organize our concepts by forming prototypes. A prototype is a mental image or pinnacle example of a certain thing.
Concepts and prototypes speed up our thinking, but they can also box in our thinking and lead to prejudice if we see something that doesn’t fit our prototypes. This is why it is important to actively keep your mind open to make room for evolving concepts.
Our cognition works to our benefit through our ability to solve problems.
We approach problem-solving in different ways. Sometimes we value speed, while other times we value accuracy.
Some problems we figure out using trial and error, this involves repeating attempts to solve a problem using different methods until you become successful. This method is usually slow and deliberate.
Algorithms and heuristics are other methods we may use to solve problems. An algorithm is a logical, methodical, step-by-step procedure that eventually guarantees a solution, but may be slow to work through. A heuristic is a simple strategy that allows us to solve problems faster, although more error-prone than an algorithm.
Confirmation bias is the tendency to look for, and favor, evidence that confirms our ideas, while avoiding or ignoring contradictory evidence.
Belief perseverance is the tendency to cling to initial conceptions or beliefs despite proof to the contrary.
A mental set is a framework for thinking about a problem shaped by habit or desire. Mental sets can make it easy to solve a class of problem, but attachment to the wrong mental set can inhibit problem-solving and creativity.
People believe an event will be more likely to occur if they can conjure up examples or memories of it, especially if those examples are particularly vivid, scary, or awesome. The more mentally available these examples are the more it seems that it’s going to happen again. This is known as the availability heuristic.
Our thinking can be swayed by framing. Framing is how an issue is posed or presented. This can significantly affect decisions and judgments.

Remembering and Forgetting

Implicit memory is retention of information independent of conscious recollection such as how to talk or ride a bike. They are dealt with on a mostly automatic and non-conscious level.
Explicit memory is memory of facts and experiences that one can consciously know and “declare”. This often requires conscious, effortful work.
Retrieval cues are stimuli that help to retrieve a certain memory. They act like a trail leading back to a particular memory. The more retrieval cues you inadvertently, or intentionally, build along the way, the better you can backtrack and find the memory you are looking for.
Priming is the act of activating associations non-consciously. It is how memories that you didn’t know you had can awaken old associations.
Our states and emotions can also serve as retrieval cues.
We forget things usually in one of three different ways: failing to encode it, failing to retrieve it, or experience storage decay.
What we fail to notice, we tend not to encode, and thus don’t remember.
Retrieval failure can be caused by interference from other memories getting in the way, essentially cluttering the brain.
Proactive interference, a type of retrieval failure, is the disruptive effect of prior learning on the recall of new information. Retroactive interference is when new learning disrupts the recall of old information.
Storage decay is the natural forgetting over time.
Misinformation effect is incorporating misleading information into one’s memory of an event.
Source misattribution is forgetting or misrecalling the source of a memory.
Memory is both a reconstruction and a reproduction of past events

Memory

Memory is learning that has persisted over time- information that has been stored and, in many cases, can be recalled.
Memory can be accessed through three ways: recall, recognition, and relearning.
Recall is a measure of memory in which the person must retrieve information learned earlier.
Recognition is a measure of memory in which the person need only identify items previously learned.
Relearning is a measure of memory that assesses the amount of time saved when learning material again.
Memory formation occurs in three stages. First it is encoded into the brain’s working/short-term memory, then it is stored for future use in long-term memory, and then finally the information is retrieved.
Working memory is the conscious, active processing of incoming auditory and visual-spatial information, and of information retrieved from long-term memory.
Explicit memory is memory of facts and experiences that one can consciously know and “declare”.
Implicit memory is retention of information independent of conscious recollection.
Automatic processing is non-conscious encoding of incidental information, such as space, time, and frequency. and of well-learned information, such as word meanings.
Procedural memory refers to how we remember to do things such as riding a bike or reading.
Episodic memory is a type of long-term memory that is tied to specific episodes of your life.
Mnemonics are memory aids, especially those techniques that use vivid imagery and organizational devices.
Chunking is organizing items into familiar, manageable units. This often occurs automatically.
How much information you encode and remember depends on both the time you took to learn it and how you made it personally relevant to yourself.

Learning by Observing

Learning can occur through observing and imitating someone else’s behavior.
Species can more easily learn associations that help them thrive or survive, and not all associations are learned equally.
What humans learn don’t only influence our behavior, it also shapes our attitudes.
Our cognition (our thoughts, perspectives, and expectations) is important for learning as is our social context.
Sometimes we can think our way out of intended associations.
Latent learning involves gaining knowledge even though that learning is not immediately evident. It occurs without any obvious reinforcement of the behavior or associations that are learned. This shows that learning is not only about associating a response with a consequence but that thinking is involved.
Observational learning is learning by observing others or being influenced by them in other ways.
Modeling is the process of observing and imitating a specific behavior.
Social observation shapes behavior, especially in children.
Mirror neurons fire when performing certain actions or when observing another doing so.

Learning

Learning is the process of acquiring, through experience, new and relatively enduring information or behaviors.
Associative learning is when a subject links certain events, behaviors, or stimuli together in the process of conditioning.
Classical conditioning is a type of learning in which one learns to link two or more stimuli and anticipate events.
Classical conditioning shows how a process like learning can actually be studied through direct observation of behavior.
Operant conditioning is a type of learning in which we associate our own behaviors with consequences. The behavior is strengthened if followed by a reinforcer or diminished if followed by a punisher.
A positive reinforcer is a stimulus that, when presented after a response, strengthens the response.
A negative reinforcer is any stimulus that, when removed after a response, strengthens the response. Not to be confused with punishment, negative reinforcers remove the punishing event in order to strengthen the behavior.
Shading is an operant conditioning procedure in which reinforcers guide behaviors towards closer and closer approximations of the desired behavior.
Punishment is a change that occurs after a given behavior or response which reduces the likelihood of that behavior occurring again in the future. Unlike reinforcers that are used to increase behavior, punishment is used to decrease behavior.

Awareness

Consciousness is loosely defined as our awareness of ourselves and our environment. This awareness allows us to take in and organize information from many sources and senses at once.
Throughout our daily lives we experience different states of consciousness including waking, sleeping, and various altered states.Altered states can occur spontaneously such as dreaming, physiologically sparked like a drug induced hallucination, or be psychologically triggered through meditation or hypnosis.
Cognitive neuroscience is the study of how brain activity is linked with our mental processes including thinking, perception, memory, and language.
Dual processing is the principle that information is simultaneously processed on separate conscious and non-conscious tracks.
By some estimates all your different senses are gathering nearly 11 million bits of information every second, however you only consciously register about 40 bits at a time.
Selective attention is the focusing of conscious awareness on a particular stimulus or group of stimuli, while tuning out other incoming information.
Inattentional blindness is the event in which an individual fails to recognize an unexpected stimulus that is in plain sight due to their selective attention being focused elsewhere.
Change blindness is the psychological phenomenon in which we fail to notice changes in our environment.

Brain Areas

Different parts of the brain control specific aspects of our behavior.
The central nervous system (CNS) is composed of your brain and spinal cord. It is responsible for making big decisions concerning your body.
The peripheral nervous system (PNS) is made of sensory neurons. It’s role is to gather information about the environment and report it to the central nervous system.
Contrary to the popular belief that we only use 10% of our brain, nearly every region of the brain lights up during even simple tasks like walking and talking.
The brain requires 20% of the body’s energy.
The brain is composed of multiple systems of differing complexity.
The “old brain” is comprised of the brain stem, madulla, pons, thalamus, recticular formation, and cerebellum. They are mostly responsible for basic automatic functions such as controlling heart rate or processing sensory information.
The limbic system includes the amygdala, hypothalamus, and hippocampus. They are responsible for things such as learning, memory, and emotion. The hypothalamus helps govern the endocrine system which regulates a wide variety of body functions.
The two hemispheres of your cerebrum make up about 85% of your brain weight and oversees your ability to think, speak, and perceive.
Glial cells surround, insulate, and nourish your neurons.

The Biological Brain

Everything psychological is biological. So one way to understand how your mind works is to look at how the chemistry of your body influences how you think, sense, and feel about the world around you.
Neurons, or nerve cells, are the building blocks that comprise your nervous system and are able to communicate with each other through an electrochemical process. Your brain alone is made up of billions of neurons.
Some neurons are encased in a protective fatty tissue called the myelin sheath. This acts similar to insulation for electrical wires by speeding up the transmission of messages.
Neurons transmit signals when stimulated by sensory input or triggered by neighboring neurons with the use of neurotransmitters.
There are over 100 different kinds of neurotransmitters, some are excitatory while other are inhibitory.
Excititatory neurotransmitters rev neurons up. An example of this is norepinephrine which helps control alertness and arousal. Glutamate is another excitatory neuron that is involved in memory, but an oversupply of glutamate can cause seizures and migraines. This is why some people are sensitive to MSG, or monosodium glutamate, in their food.
Inhibitory neurotransmitters calm the neurons and make it less likely for them to fire an action potential. An example would be seratonin which effects your mood, hunger, and sleep. Low amounts of seratonin have been linked to depression.
There are other nerutransmitters such as acetylcholine and dopamine which are able to either excite or inhibit neurons based on the type of receptor that they encounter.

The Thyroid part 2

The thyroid’s role is to make sure that the cells in your body are working properly, it does this by delivering hormones to every cell in your body.
A critical job of thyroid hormone is to instruct every cell in the body when to consume oxygen and nutrients, which maintains the body’s metabolism and provides us with energy.
The thyroid is controlled by the pituitary gland which tells the thyroid when it is necessary to send out thyroid hormone.
The pituitary senses hormone levels in the blood and sends out or stops sending thyroid stimulating hormone based on those levels.
Certain diseases, growths, or chemical imbalances in the body can confuse the thyroid and cause it to no longer respond to the pituitary gland.
Hyperthyroidism is when the thyroid sends out too much hormones, causing the cells to be overactive. A person with hyperthyroidism experiences a higher metabolism, signaled by a faster heart beat, constant hunger, and rapid weight loss. They may also feel hot, sweaty, anxious, and find it difficult to sleep.
Hypothyroidism is when the thyroid sends out too few hormones, meaning the body’s cells don’t have as much messengers to guide them, causing a slower metabolism. People with hypothyroidism see symptoms in weight gain, sluggishness, sensitivity to cold, swollen joins, and depression.

The Thyroid

The thyroid is located at the base of your neck. The hormones it secretes regulate many aspects of your body’s homeostasis like body temperature, skin moisture, and your blood’s levels of oxygen, calcium, and cholesterol.
Thyroid hormone gets released during a hormone cascade known as the HPT axis. This occurs when the hypothalamus releases hormones to the pituitary which triggers the pituitary to release hormones that bind to the thyroid, causing the thyroid to release thyroid hormone to the rest of the body.
Thyroid hormone produce many effects like prompting your metabolism, maintaining blood pressure, promoting the growth of tissue, and triggering the secretion of digestive juices.
The hypothalamus and pituitary glands constantly monitor hormone levels in the blood. If there is too much thyroid hormone, they decrease their own hormone production to stop stimulating the thyroid to release thyroid hormone.
Thyroid disorders can be cause by lots of things including autoimmune dysfunction which produces abnormal antibodies that target the cells of your thyroid gland and bind to the thyroid’s receptors that are usually used by hormones from the pituitary gland. This causes the thyroid to no longer receive any negative feedback from the pituitary gland and will cause the thyroid to constantly release thyroid hormone.

The Endocrine System

The endocrine system produces, releases and reabsorbs chemical messengers called hormones. There are at least 50 different types of these chemical messengers at work in your body at any given time.
Hormones control and regulate reproduction, metabolism and energy balance, growth and development, body defenses, general homeostasis and water, nutrient, and electrolyte balance of the blood. They also regulate your sleep cycle and your response to stress.
While the nervous system sends quick electrical messages through neurons, the endocrine system sends chemical messages through the blood that produce widespread effects that last a lot longer than an action potential from the nervous system.
The endocrine system consists of organs and glands that are scattered throughout your body. A gland being any structure that makes and secretes a hormone.
The master gland is known as the pituitary gland. This is considered the master gland because it produces many hormones that signal other glands to make their own hormones.
A hormone can only trigger a reaction in specific cells, also known as target cells, that have the right receptors for them.
When a target cell is activated the hormone alters its activity by either increasing or decreasing some of its functions.
Some hormones just exist to control other hormones, which in turn control still more hormones. This is referred to as a hormone cascade.

The Parasympathetic Nervous System

The parasympathetic nervous system is known as the calming side of your nervous system, also referred to as the “rest and digest” or “feed and breed” response. It is responsible for calming you down after a stressful situation as well as allowing you to digest food, reproduce, excrete waste, and fight off infection.
The vagus nerve stretches from near the brain stem down to most of your visceral organs including your heart, lungs, and stomach. It has two-way communication sending sensory information from the peripheral nervous system to the brain and transmitting outgoing motor instructions from the brain to the rest of the body.
When food enters the stomach, it begins to digest the food, which is a parasympathetic response. This can trigger other parasympathetic responses throughout your body. This is why for some people eating is a way of reducing stress and anxiety.
During sex, the parasympathetic system is responsible for funneling blood away from your muscles and down to your genitals. This is why too much stress and anxiety can lead to sexual dysfunction.

The Sympathetic Nervous System

The sympathetic nervous system is the part of your nervous system that responds to stress by stimulating the “fight or flight ” response. It does this by diverting bodily resources from your digestion, reproduction, and immune systems and sending more energy to your brain, heart, and muscles.
Physiological responses to non-immediate stresses are largely the same as when you’re fighting for survival (your body doesn’t differentiate between life-threatening stress and life-annoying stress).
Since the body’s reaction to stress is a full body response, it can become very taxing over time, throwing parts of your body into overdrive while depriving others of blood and oxygen.
Encountering constant non-life threatening stressors can actually end up endangering your health in the long run because your body’s stress response is so effective.
The frequent activation of your sympathetic nervous system and hormonal stress response can have terrible consequences such as high blood pressure, digestive problems and the suppression of your immune system.

The Autonomic Nervous System

The autonomic nervous system is a branch of the peripheral nervous system that regulates the functions of your internal organs like your heart and stomach as well as control your smooth and cardiac muscles and glands.
The autonomic nervous system is constantly making involuntary fine tuned adjustments based on the signals that your body is picking up. This can include changing your body temperature, sending extra blood to a particular area, slowing your heartbeat, or tweaking your stomach secretions. It’s effects changing based on the situation you are in.
The autonomic nervous system is made up of two competing divisions that serve the same organs but create opposite effects in them, either to excite or subdue them.
The sympathetic nervous system is responsible for preparing you for activity, while the parasympathetic nervous system calms you down and relaxes you.

The Peripheral Nervous System

The peripheral nervous system puts your brain in touch with the physical environment, and allows it to respond. It does this through the use of sensory nerve receptors.
There are different types of sensory nerve receptors, each type responding to a different kind of stimuli. Thermoreceptors respond to changes in temperature, photoreceptors react to light, chemoreceptors pay attention to chemicals, and mechanoreceptors respond to pressure, touch, and vibration. There are also specialized nerve receptors called nociceptors that fire only to indicate pain.
Pain is used to help us protect us from ourselves and from the outside world. Physical pain is a signal to indicate that your body may be under stress, damaged, or in danger and that attention is required for a specific area.
We all have the same pain threshold (the point where a stimulus is intense enough to trigger an action potential in the nociceptors), but may differ in tolerances for discomfort.
When a receptor senses a stimulus (such as stepping on a sharp tack) the sensory neurons transmit the signal up the PNS to the CNS. The integration center decodes the signal and motor neurons sends directions back to the site of the stimulus. Effector cells at the site respond by contracting muscles (to lift the foot) or secreting hormones. This is known as a reflex arc.
Innate or intrinsic reflex action is a super fast motor response to a startling stimulus. These reflexes are so invested in your self-preservation that you actually can’t think about them before you respond.
Learned or acquired reflexes come from experience, such as dodging obstacles while riding a bike or driving a car. These reflexes are largely automatic but are learned over time.

The Central Nervous System

The central nervous system consists of the brain and spinal cord. It’s main functions are integrating to the sensory information that is received by the peripheral nervous system and responding to it by coordinating both conscious and unconscious activity.
The brain is responsible for sorting out and responding to the sensory information as well as carrying out more complex functions such as thinking, feeling and remembering.
The spinal cord conducts two-way signals between your brain and the rest of your body while also governing basic muscle reflexes and patterns that don’t need the brain to work.
Your brain is divided into specialized regions that may, or may not, interact with each other to produce a given action.

The Nervous System

All of your thoughts, actions, and emotions can be encapsulated into three simple functions: sensory input, integration, and motor output. For example, if a spider were to walk on your knee the sensory receptors on your skin would detect the spider(sensory input), your nervous system processes that input to decides what should be done about it (integration), and you brush away the spider with your hand (motor output).
There are two main parts to the nervous system, the central nervous system (CNS), consisting of your brain and spinal cord, and the peripheral nervous system (PNS), all the nerves that branch off from the brain and spine that allow your CNS to communicate with the rest of your body .
The peripheral nervous system is a two-way communication system. It is comprised of the sensory division, that picks up sensory stimuli, and the motor division, that sends directions from your brain to muscles and glands.
The motor division is comprised of two parts: the somatic nervous system, which controls your voluntary skeletal muscle movements, and the autonomic nervous system, that controls involuntary actions such as keeping your heart beating, lungs breathing, and stomach working.
The autonomic nervous system has two complementary components: the sympathetic division mobilizes the body into action while the parasympathetic division calms the body down.
All the different parts of your nervous system are mainly made up of nervous tissue. Nervous tissue contains neurons, which respond to stimuli and transmit signals, as well as glial cells, that surround and protect the neurons as well as provide support, nutrition, insulation, and help with signal transmission.
All neurons share three special characteristics: They are some of the longest-lived cells in your body, they are irreplaceable, and they have huge appetites (they have a huge metabolic rate and need a steady and abundant supply of glucose and oxygen; consuming about 25% of the calories that you take in every day)

The Lymphatic System

Your lymphatic system quietly plays a vital supporting role to both your cardiovascular and immune systems.
Structurally, the lymphatic system consists of three main parts: the lymph (a watery fluid that flows through your lymphatic system), a network of lymphatic vessels (that help to reabsorb fluid), and 600-700 lymph nodes (checkpoints that monitor and cleanse the lymph as it filters through).

Autoimmunity

T lymphocytes, or T cells, go after body cells that have been hijacked by things like viruses and bacteria or become cancerous.
T cells cause inflammation, activate macrophages, get other T cells fired up, and regulate much of the immune response.
All cells in your body with the exception of red blood cells have a MHC protein on the surface of their cell called class 1 MHC. This is used to signal to immune cells that the cell is healthy. If the cell is cancerous and making abnormal proteins which get affixed to the MHC, this alerts immune cells that there is a problem and will be destroyed.
A hyperactive immune system can cause mayhem by losing it’s ability to distinguish enemy from self, essentially turning on your own body.
Regulatory T cells release inhibiting cytokines that tell other immune cells to stand down once the initial threat has been handled. Without this regulation, the body may begin to start producing too many antibodies and cytotoxic cells that could damage or destroy it’s own tissues. This is what causes many autoimmune diseases such as multiple sclerosis (which eats away at the myelin sheaths around neurons) or type one diabetes (that tears up the pancreatic cells that make insulin).

The Immune Cells

The ability to remember specific pathogens is one of the key differences between the adaptive and innate defenses.
In order to recognize friend from foe, the immune system utilizes antigens. An antigen can be an invader from the outside world such as a bacterium, virus, fungus, or toxin or even your own diseased cell. Antigens are large signaling molecules not normally found in the body and act as flags for the immune system.
Antibodies are special protein receptors that are able to identify and bind to a specific kind of antigen.
Although antibodies cannot kill the antigens themselves, antibodies have numerous ways of debilitating antigens and signaling other cells to come and destroy the antigens.

The Immune System

The body’s very first line of defense is a simple physical barrier consisting of your skin and mucous membranes. The mucous membranes line any cavity that opens up to the outside world including your respiratory, digestive, urinary, and reproductive systems.
If the physical barrier has been breached, your internal innate defenses are utilized. Your body will take various actions such as starting a fever, releasing chemical signals, and causing inflammation to help identify and attack infectious invaders.
Phagocytes are one of the first responders to an infection. They will indiscriminately eat any intruders.
Natural killer cells patrol the blood and lymph looking for abnormal cells. They can kill your own cells if they are infected with viruses or have become cancerous.
In the event of an injury with potential infection, such as a cut, your body wants to prevent the spread of pathogens, clean up the mess, and heal as quickly as possible. In order to accomplish this it elicits an inflammatory response.
The inflammatory response generates redness, swelling, heat, and pain. All these features are signs of healing. The increase in temperature raises the nearby cell’s metabolic rate so they can repair quicker. Swelling is caused by an increase in resources that help to clot wounds and other tasks involved in healing.
When white blood cells encounter more foreign invaders than they can handle they trigger a systemic fever to essentially burn everything.

The Lungs

The respiratory system consists of your lungs, trachea, ribs, and diaphragm.
The respiratory system is set up to take full advantage of both bulk flow and simple diffusion.
Bulk flow moves a large number of molecules quickly. Your body uses this method to transport oxygen by way of your blood.
Simple diffusion is used in the lungs when oxygen molecules cross a thin layer of membranes from the lung cell into the blood.
The lungs do not have any contactable muscle tissue because they need to be able to expand. They require the help of the diaphragm in order to move.
The diaphragm is a set of muscles that separates your thorax from your abdomen. When your lungs empty, the diaphragm relaxes. When the diaphragm contracts and flattens, the pressure inside the lungs is lowered and outside air fills the lungs.

Red Blood Cells

Red blood cells are responsible for transporting oxygen to all your cells. Excluding water content, red blood cells are 95% hemoglobin, a molecule that easily binds to, and releases, oxygen.
Each individual red blood cell is capable of storing 1 billion molecules of oxygen.
The process of forming red blood cells takes place in red bone marrow.
Too many red blood cells will cause the blood to be too viscous making the blood difficult to pump. Too few red blood cells leads to oxygen derivation.
More red blood cells equals more oxygen being carried to your muscles, and therefore better physical performance. The extra oxygen doesn’t change your actual muscle strength, but the added aerobic capacity reduces muscle fatigue and enhanced endurance by allowing your muscles to work harder for longer.

The Blood

Blood is a type of connective tissue, made up of living cells suspended in a non-living matrix known as plasma.
Blood’s main roles are to transport and distribute oxygen, nutrients, waste products, and hormones. It also helps maintain and regulate body temperature, pH levels, and the volume of fluids in your body.
Besides the brain, your blood is the one component of your body that we haven’t figured out how to reproduce, synthesize, or imitate.
Whole blood contains formed elements (cells and cell fragments), water, and dissolved molecules.
The main components of blood are erythrocytes (red blood cells) that carry oxygen and carbon dioxide, leukocytes (white blood cells) that defend your body from toxins and foreign microbes, platelets that help with blood clotting, and plasma that is water filled with proteins, electrolytes, gases, hormones, and waste products.
Depending on the antigen that your red blood cells contain, you can be one of four different blood types: A, B, AB, or O.

Blood Pressure

Chronic high blood pressure, also known as hypertension, can cause serious damage to both the heart that creates the high pressure, and to the blood vessels that have to withstand that extra pressure.
Over time the extra force of blood against the arterial walls can cause them to stiffen, leak, or rupture.
The heart may begin to wear itself out from the extra work it is doing to keep blood moving.
Many factors can contribute to high blood pressure including: emotional stress, physical exertion, and dehydration.
Blood flow, also known as cardiac output, is the volume of blood flowing through any given vessel, or through the circulatory system as a whole, per minute.
One factor that can effect the rate of flow is resistance. Resistance is anything that hinders flow or creates friction.
In the case of your blood, resistance can be the result of increased viscosity (the thicker your blood is, the harder it is to move), increased vessel length (longer vessels are more resistant to flow), or most commonly vessel diameter (thinner blood vessels cause higher pressure).
An excess of LDL cholesterol in the blood can build up to form fatty plaque in the inside of your arteries, permanently increasing the resistance and hindering blood flow.
A long term method of controlling blood pressure is to alter the blood volume. The kidneys make hormones called renin and angiotensin. These help regulate levels of sodium and fluids in your body as well as expand and constrict blood vessels.
When blood pressure gets too high, the kidneys will try to reduce blood volume by getting rid of extra water.
Excess sodium in your diet causes the body to retain water. This causes higher blood volume and ultimately higher blood pressure.

Blood Vessels

Blood vessels are active, dynamic organs that are capable of contracting and expanding as they deliver oxygen and nutrients to cells, carry away waste products, and participate in maintaining blood pressure.
The three major types of blood vessels are the arteries (carry blood away from the heart), veins (carry blood towards the heart), and the capillaries (the transfer station between the arteries and veins. The two minor blood vessels are the arterioles (mini-arteries that branch out into the capillaries) and the venules (the smallest vein components that suck blood out of the capillaries).
All of your blood is contained within your heart and blood vessels at all time, unless you are bleeding.
Bleeding occurs when you cut open a blood vessel and blood flows out of the closed system. Bruising is internal bleeding, usually into loose connective tissue.
The elasticity of major arteries is important because it allows them to absorb pressure fluctuations as blood leaves the heart. This dampening of pressure ensures big surges don’t reach the smaller vessels where they can cause damage.
Muscular arteries distribute blood to specific body parts. These arteries are less elastic and more muscular.
Capillaries are thin vessels that allow for the exchange of oxygen and nutrients as well as carbon dioxide and waste between your blood and the cells of your body.
Capillaries form interweaving groups called capillary beds. They are responsible for exchanging nutrients, helping to regulate blood pressure, and play a role in thermoregulation.
When it is cold, smooth muscles that surround your vessels tighten up, forcing blood to bypass some of your capillaries, which means less blood is exposed to the cold, and you lose less heat. Conversely, when it is hot, the vessels become loose, which floods the capillary bed with blood to help disperse heat.
Veins contain venous valves which help keep blood from flowing backward. If these valves leak or the vein experiences too much pressure, the back flow of blood can stretch or twist the vein causing varicose veins or hemorrhoids.

How the Heart works

Unlike skeletal muscle tissue, cardiac muscle tissues are both physically and electrically connected with each other all of the time to ensure precise coordination.
Some heart cells, known as pacemaker cells, are able to generate their own electricity. They are what keep your heart beating at the correct rhythm and ensure that each cardiac muscle cell contracts in coordination with the others.
Uncoordinated contractions of the heart , also known as fibrillation, is a cause of cardiac arrest.
CPR can help prolong heart function during cardiac arrest by forcing a fibrillating heart to keep circulating oxygenated blood, but it usually can’t save a life without help from a defibrillator, which stops the heart to help reset the rhythm for correct coordination.

The Heart

The heart powers the entire circulatory system; transporting nutrients, oxygen, waste, heat, hormones, and immune cells throughout your whole body.
The heart is a pump whose main concern is to maintain the pressure of your circulatory system. It achieves this by generating high hydrostatic pressure to pump blood out of the heart, while also creating low pressure to bring it back in.
The heart is connected to the circulatory system by way of arteries and veins. Arteries carry blood away from the heart, and veins carry blood back towards the heart.
Blood travels in a cycle from the heart to the lungs (where it releases carbon dioxide and absorbs oxygen), then back to the heart and then to the body (where the oxygen is released and carbon dioxide is absorbed), then back to the heart again.
Blood pressure is a measure of the amount of strain your arteries feel as your heart moves your blood around. It is measured during peak pressure (systolic) and relaxed pressure (diastolic).
Prolonged high blood pressure can damage arterial walls, mess with your circulation and ultimately endanger your heart, lungs, brain, kidneys, and nearly every part of you.

Pancreas

The two main roles of the pancreas is to control sugar levels and produce pancreatic juice to release nutrients in your food.
Pancreatic juice is made of water, sodium bicarbonate, and digestive enzymes.
Sodium bicarbonate neutralizes the stomach’s natural acidity.
Some of the digestive enzymes the pancreas produces include: lipase (to break down fats), protease (to break down proteins), and amylase (to break down carbohydrates).
The pancreas controls the amount of sugar in your blood through the use of two hormones called insulin and glucagon.
If too much sugar is in the blood, the pancreas releases insulin which makes the excess sugar move into cells to be used as energy or stored for later use. Insulin also signals the liver to shut down sugar production.
If blood sugar is low, the pancreas releases glucagon which tells the cells and liver to release sugar into the blood stream.
If the pancreas is weakened by disease, it’s ability to control sugar levels is compromised and can lead to diabetes.
Without regular insulin release sugar will steadily build up in the blood. This hardens the blood vessels and can cause heart attacks, kidney failure, and strokes.
A lack of insulin also deprives the cells of sugars that they need for energy to function.

Growing Muscles

Muscles are this and that.
when this happens. muscles get stronger.

The Kidneys

The kidneys balance the amount of fluid in your body, detect waste in your blood, and regulates when you release the vitamins, minerals, and hormones you need to stay alive.
The main role of the kidneys is to dispose of waste products by converting it into urine.
The body’s 8 liter’s of blood pass through the kidneys about 20-25 times each day where it is filtered of waste product and monitored for nutrient content.
Waste is transported to the bladder to be discharged as urine.
If the kidney detects too much water in your blood, it sends the extra liquid to the bladder to be removed.
Kidneys also have the ability to activate vitamin D, secrete the hormone renin (that raises blood pressure), and secrete another hormone called erythropoietin (which increases red blood cell production).

The Digestive Organs

The small intestine continues the physical and chemical breakdown as well as the absorption of food.
The accessory digestive organs consist of the liver, gallbladder, and pancreas.
The liver processes and eliminates toxins and metabolic waste, stores glycogen and various vitamins and minerals, and produces different hormone, clotting, and plasma proteins.
The liver also produces bile which is essential for digesting fat. The bile is then stored and concentrated in the gallbladder, which will release the bile when signaled.
The pancreas brews up a powerful enzyme cocktail to help breakdown proteins, sugars, fats, and nucleic acids.
The large intestine absorbs the remaining water, stores feces until elimination, houses good bacteria and digest whatever remaining nutrients they release, and presides over defecation.

The Mouth to the Stomach

The mouth breaks down food through chewing and enzyme action found in your saliva.
The stomach is able to hold 2-4 liters of material at any given time.
The stomach secretes different types of chemicals that help to break down food and kill certain viruses and bacteria.
Stomach secretions occurs in three phases based on where the food is sensed; the brain, the stomach, and the small intestine.
The cephalic phase is ruled by the brain and occurs when you see, smell, taste, or even think about food.
When food enters the stomach it triggers the gastric phase. This increases the secretion of acid and enzymes and is monitored by the pH of the contents in your stomach.
The intestinal phase controls the rate in which your stomach is emptied so that the small intestines do not get overloaded with too much acid or broken down food.
There are only a small amount of things that are able to be absorbed through the stomach, such as caffeine and alcohol. The stomach is mostly used to decontaminate and break down the food you eat.

The Digestive System

The role of the digestive system is to break down food to the cellular level so it can be used by your body.
Food is deconstructed mechanically (teeth and muscle contractions) and chemically (acid and enzymes).
The organs of your digestive system are used to break down and absorb the right nutrients at the right time.
The gastrointestinal tract is one long continuous tube that runs from your mouth to your anus, acting as a barrier that allows for the selective movement of materials into your body.

The Liver

The liver is like a factory for your body.
It acts as a storehouse, a manufacturing hub, and as a processing plant.
Main function of liver is to filter the body’s blood. The two sources of blood are from the heart, containing oxygen, and the intestines, containing fats, carbohydrates, vitamins, and other nutrients.
The liver also filters the blood for useless substances and toxins, converting it to non-toxic substances, or isolating it and sending it to the kidneys or intestines to be excreted.
The liver manufactures bile, blood plasma proteins, cholesterol, and vitamin D.
Bile is responsible for breaking down fats,destroying microbes,neutralizing extra stomach acid,and transporting toxins out of the liver.
Cholesterol helps the body create hormones.