Better understanding through science: anatomy and physiology
back to basics
Having an understanding of what the body needs to function and thrive can give us a way to develop better eating habits. By starting at the basic level, in the cells (micro), and working our way up to the organ systems (macro), we can develop a better understanding on how what we eat has an effect on literally everything in our body.
Below is a very basic description of anatomy, physiology, and metabolism to help better understand how proper nutrition and exercise effects everything in the human body. Anatomy, physiology, and metabolism are very complex and detailed subjects, and the information below is just a very, very basic understanding/description of these topics.
This is not an all inclusive description. If you are looking for all inclusive, go get and read an anatomy and physiology textbook. A textbook will go into much more detail.
TOPICS ON THIS PAGE:
Below is a very basic description of anatomy, physiology, and metabolism to help better understand how proper nutrition and exercise effects everything in the human body. Anatomy, physiology, and metabolism are very complex and detailed subjects, and the information below is just a very, very basic understanding/description of these topics.
This is not an all inclusive description. If you are looking for all inclusive, go get and read an anatomy and physiology textbook. A textbook will go into much more detail.
TOPICS ON THIS PAGE:
- Cells: Basic building blocks
- Tissues
- Organs to Organ systems
Cells: Basic building blocks
Cells are the smallest and most basic structural unit in the body; they are often called the "building blocks of life."
Several cells make up tissues, several tissues make up organs, and several organs make up organ systems.
The body is a very complex functioning machine, and like any machine, it needs the proper fuel to run efficiently.
Each organ system has specific functions to keep the body at homeostasis.
Several cells make up tissues, several tissues make up organs, and several organs make up organ systems.
The body is a very complex functioning machine, and like any machine, it needs the proper fuel to run efficiently.
Each organ system has specific functions to keep the body at homeostasis.
There are roughly 200 different types of cells in the human body that carry out very specific and different functions.
A few examples of cells:
There are 3 types of muscle cells:
skeletal (biceps, triceps, quadriceps)
cardiac (heart)
smooth (digestive tract, vascular, reproductive tract, respiratory tract).
The pancreas has a large group of cells called the Islet of Langerhans, which consist of 4 main cell types:
alpha, which secrete glucagon (increases glucose in the blood)
beta, which secrete insulin (decreases glucose in the blood)
delta, which secrete somatostatin (regulates/stops alpha and beta cells)
PP cells or gamma cells, which secrete pancreatic polypeptides (self regulate pancreatic secretion activities)
A few examples of cells:
There are 3 types of muscle cells:
skeletal (biceps, triceps, quadriceps)
cardiac (heart)
smooth (digestive tract, vascular, reproductive tract, respiratory tract).
The pancreas has a large group of cells called the Islet of Langerhans, which consist of 4 main cell types:
alpha, which secrete glucagon (increases glucose in the blood)
beta, which secrete insulin (decreases glucose in the blood)
delta, which secrete somatostatin (regulates/stops alpha and beta cells)
PP cells or gamma cells, which secrete pancreatic polypeptides (self regulate pancreatic secretion activities)
Cells are responsible for every function of the body, both awake and asleep. You have to properly fuel the cells in order for the cells to function at their best. Many of our daily activities can inhibit, distort, or block some of these functions. Proper nutrition and activity can help, even enhance cellular function, which can lead to better performance and lifestyle.
Tissues
Tissues are groups or clusters of cells that perform a specific function in the body. There are 4 main types of tissues in the body.
Having a basic understanding and knowledge of tissues helps in understanding how exercise and nutrition effects the body as a whole.
- Epithelial
- Connective
- Muscle
- Nervous
Having a basic understanding and knowledge of tissues helps in understanding how exercise and nutrition effects the body as a whole.
This table shows all 8 types of epithelial tissues, their locations, and functions.
Main functions for epithelial tissue:
Main functions for epithelial tissue:
- Protection
- Sensory functions
- Secretion
- Absorption
- Excretion
This table shows the types of connective tissues and their locations.
Main functions of connective tissue:
Main functions of connective tissue:
- Connects
- Supports
- Transports
- Defends
This figure shows the 3 types of of muscle tissue, their locations, and functions.
Smooth muscle tissue is completely involuntary, meaning that we have no conscious control over this tissue; we can't tell our intestines move food/nutrient particles (process called peristalsis).
Cardiac muscle tissue is only found in the walls of the heart. They are involuntary and have a unique ability: they are the only types of cells and tissues that "self excite" with electrical impulses. (Totally cool, right?!)
Skeletal muscle tissue is voluntary, meaning that we have control over movement; this is part of how we are able to walk, pick up objects, and type.
Smooth muscle tissue is completely involuntary, meaning that we have no conscious control over this tissue; we can't tell our intestines move food/nutrient particles (process called peristalsis).
Cardiac muscle tissue is only found in the walls of the heart. They are involuntary and have a unique ability: they are the only types of cells and tissues that "self excite" with electrical impulses. (Totally cool, right?!)
Skeletal muscle tissue is voluntary, meaning that we have control over movement; this is part of how we are able to walk, pick up objects, and type.
This diagram shows how the nervous tissue functions in the body.
Nervous tissue is in the brain, spinal, cord, and the millions of neurons that are found all over the body.
Neurons are what carry the electrical signals from the brain and spinal cord to the body and back; this is how we move muscles, digest our food, fight or flight, breathe.
Nervous tissue is in the brain, spinal, cord, and the millions of neurons that are found all over the body.
Neurons are what carry the electrical signals from the brain and spinal cord to the body and back; this is how we move muscles, digest our food, fight or flight, breathe.
Organs to organ systems
Instead of going through all of the organs in a long drawn out lecture, we are going to jump to the organ systems. Again, this is a very basic overview of the organ systems and how they function.
There are 12 systems that work together to keep our body functioning.
There are 12 systems that work together to keep our body functioning.
- Circulatory/Cardiovascular System
- Lymphatic System
- Respiratory System
- Digestive System
- Endocrine System
- Integumentary System
- Muscular System
- Nervous System
- Reproductive System
- Skeletal System
- Excretory System
- Organs of Special Senses
Circulatory System
The human circulatory system is a closed system (contained within the body) that consists of the heart (cardiovascular), lungs (pulmonary), and arteries, veins, other vessels (systemic). This system is needed to transport blood, oxygen, nutrients, other gasses, hormones, cellular waste (through lymph), to and from cells. This system aids in immunity and homeostasis.
Blood consists of plasma, red blood cells, white blood cells, and platelets. The amount of blood in the body can vary depending on size. An average adult man has roughly 7-8 pints (5 liters) of blood; an average woman has roughly 5-6 pints (4 liters); a child around 2-5 pints (1-2 liters); a new born child 0.70-0.80 pints (0.35-0.40 liters).
Blood consists of plasma, red blood cells, white blood cells, and platelets. The amount of blood in the body can vary depending on size. An average adult man has roughly 7-8 pints (5 liters) of blood; an average woman has roughly 5-6 pints (4 liters); a child around 2-5 pints (1-2 liters); a new born child 0.70-0.80 pints (0.35-0.40 liters).
Lymphatic System
The lymphatic system works with the cardiovascular system as it circulates lymph fluid around the body. Lymph fluid is a clear, water-like fluid that is derived from blood proteins and electrolytes.
The lymphatic system plays a huge role in the body's defense (immune) system. The lymph fluid contains specialized white blood cells, called lymphocytes. Lymphocytes are crucial to the body's immune system; they attack and destroy micro organisms that are foreign, and potentially harmful to the body.
Lymph nodes are found throughout the body and filter the lymph fluid, this waste is then dumped into the veins for excretion. Lymph nodes are also important from a clinical stand point, where doctors can use these nodes for diagnosis and treatment for certain disease processes.
The lymphatic system plays a huge role in the body's defense (immune) system. The lymph fluid contains specialized white blood cells, called lymphocytes. Lymphocytes are crucial to the body's immune system; they attack and destroy micro organisms that are foreign, and potentially harmful to the body.
Lymph nodes are found throughout the body and filter the lymph fluid, this waste is then dumped into the veins for excretion. Lymph nodes are also important from a clinical stand point, where doctors can use these nodes for diagnosis and treatment for certain disease processes.
REspiratory System
"In and out, round and round" refers to air going in and out of the lungs and the blood going around the body.
The lungs supply the oxygen to the body.
Gas exchange occurs at the alveoli level.
Without a patent airway, oxygen can't get into the lungs and into the blood stream.
As babies, we breath from our bellies. As we grow older we begin to breathe from our chest. Reasoning behind the change from belly breathing to chest breathing is unclear, however some theories range from wanting to keep the belly flat, less concentration when chest breathing, stress, etc.
Ideally, adults should be breathing from their belly, focusing on the diaphragm. Diaphragm breathing is more efficient, forces better posture, is a good way to calm down and control breathing.
The lungs supply the oxygen to the body.
Gas exchange occurs at the alveoli level.
Without a patent airway, oxygen can't get into the lungs and into the blood stream.
As babies, we breath from our bellies. As we grow older we begin to breathe from our chest. Reasoning behind the change from belly breathing to chest breathing is unclear, however some theories range from wanting to keep the belly flat, less concentration when chest breathing, stress, etc.
Ideally, adults should be breathing from their belly, focusing on the diaphragm. Diaphragm breathing is more efficient, forces better posture, is a good way to calm down and control breathing.
Digestive system
Digestion is how the body takes the food and liquid that we eat and breaks it down into molecules that the cells can absorb and the body can use.
Digestion begins with chewing food and breaking it down into smaller pieces so it can be swallowed. While chewing, saliva helps lubricate the food for passage down the esophagus. Saliva also contains an enzyme, ptyalin that breaks down certain starches.
Food moves down the esophagus through a process called peristalsis. Peristalsis is an involuntary smooth muscle movement that moves food to the stomach.
The stomach is a muscular bag that functions as a reservoir for food while the break down of food takes place. The stomach contains gastric juices (hydrochloric acid, intrinsic factor, 3 enzymes: Renin, Pepsin, gastric lipase) that break down food for absorption into the intestine. The stomach releases broken down food into the intestine at intervals so that nutrients can be absorbed.
Nutrients are absorbed through the walls of the small intestine.
The colon or large intestine, receives all the liquefied contents or "left overs" from the small intestine and reabsorbs water. This forms a semi-solid waste which is then excreted as feces (poop).
The liver is a very important organ that does the following: detoxifies many different substances, secretes bile (bile aids in absorption of fats), stores several substances (iron, A, B12, and D), liver cells also aid in the metabolism of proteins, fats, and carbohydrates.
The gall bladder is the organ that stores and concentrates the bile.
The pancreas has several important functions: secretion of certain digestive enzymes, Beta cells of the pancreas secret insulin, Alpha cells of the pancreas secrete glucagon, and it has some endocrine functions.
Digestion begins with chewing food and breaking it down into smaller pieces so it can be swallowed. While chewing, saliva helps lubricate the food for passage down the esophagus. Saliva also contains an enzyme, ptyalin that breaks down certain starches.
Food moves down the esophagus through a process called peristalsis. Peristalsis is an involuntary smooth muscle movement that moves food to the stomach.
The stomach is a muscular bag that functions as a reservoir for food while the break down of food takes place. The stomach contains gastric juices (hydrochloric acid, intrinsic factor, 3 enzymes: Renin, Pepsin, gastric lipase) that break down food for absorption into the intestine. The stomach releases broken down food into the intestine at intervals so that nutrients can be absorbed.
Nutrients are absorbed through the walls of the small intestine.
The colon or large intestine, receives all the liquefied contents or "left overs" from the small intestine and reabsorbs water. This forms a semi-solid waste which is then excreted as feces (poop).
The liver is a very important organ that does the following: detoxifies many different substances, secretes bile (bile aids in absorption of fats), stores several substances (iron, A, B12, and D), liver cells also aid in the metabolism of proteins, fats, and carbohydrates.
The gall bladder is the organ that stores and concentrates the bile.
The pancreas has several important functions: secretion of certain digestive enzymes, Beta cells of the pancreas secret insulin, Alpha cells of the pancreas secrete glucagon, and it has some endocrine functions.
Endocrine system
The endocrine system works to regulate the body's internal homeostasis; this is done by the regulation of hormones. This figure shows all the endocrine organs.
Hormones are broken into 2 basic categories: steroid and non-steroid. The difference between the two is how the hormone is manufactured by the endocrine cell. Steroid hormones are derived from the cholesterol (lipid) molecule. Non-steroid hormones are derived mainly from amino acids (building blocks of proteins).
Main functions of the endocrine system hormones: response to stress and injury, absorption of nutrients, regulation of metabolism, growth and development, energy levels, water and electrolyte balance, reproductive hormones, birth, lactation.
Hormones are broken into 2 basic categories: steroid and non-steroid. The difference between the two is how the hormone is manufactured by the endocrine cell. Steroid hormones are derived from the cholesterol (lipid) molecule. Non-steroid hormones are derived mainly from amino acids (building blocks of proteins).
Main functions of the endocrine system hormones: response to stress and injury, absorption of nutrients, regulation of metabolism, growth and development, energy levels, water and electrolyte balance, reproductive hormones, birth, lactation.
Integumentary system
The integumentary system (skin) is the largest organ system of the body.
Functions of the skin:
Functions of the skin:
- Protection: the skin provides a barrier to the outside world from micro-organisms, and most harmful chemicals, reduces mechanical injury from day to day activities, protects from dehydration by preventing loss of internal body fluids, and keeping unwanted fluids from entering from the outside envrionment.
- Sensation: sensory receptors are located all over the body, throughout the skin. This helps the body to react as needed to internal and external envrionments.
- Flexibility: skin needs to be elasitc and supple to allow for growth and movment. Skin grows as we do.
- Exvretion: skin plays a small role in getting rid of bodily wastes such as uric acid, ammonia, and urea, through sweat.
- Vitamin D Production: when skin is exposed to UV light, certain chemical molecules begin the process of vitamin D production.
- Immunity: Skin aids in overall immune protection from certain disease
- Body Temperature Regulation: The skin helps to maintain body temperature. Main examples are sweating and shivering.
Muscular System
The human body has 3 types of muscle tissue: skeletal, smooth, and cardiac.
There are over 650 named skeletal muscles, however the number can reach as high as just over 800.
Main functions of skeletal muscle are
There are over 650 named skeletal muscles, however the number can reach as high as just over 800.
Main functions of skeletal muscle are
- Movement
- Heat production: muscles produce heat through catabolism (form of metabolism). Muscles also are a major component of body heat production.
- Posture: without muscle and muscle tone we would be a pile of mush on the ground
Smooth muscle tissue is completely involuntary, meaning that we have no conscious control over this tissue; we can't tell our intestines move food/nutrient particles (process called peristalsis).
Cardiac muscle tissue is only found in the walls of the heart. They are involuntary and have a unique ability: they are the only types of cells and tissues that "self excite" with electrical impulses. (Totally cool, right?!)
Skeletal muscle tissue is voluntary, meaning that we have control over movement; this is part of how we are able to walk, pick up objects, and type.
Cardiac muscle tissue is only found in the walls of the heart. They are involuntary and have a unique ability: they are the only types of cells and tissues that "self excite" with electrical impulses. (Totally cool, right?!)
Skeletal muscle tissue is voluntary, meaning that we have control over movement; this is part of how we are able to walk, pick up objects, and type.
Nervous system
Our nervous system is a very complex system that is, just awesome.. Its functions are to detect internal and external changes or stimuli, evaluate the stimulus, and respond appropriately to the stimulus through activation/deactivation of muscles and/or glands.
The next few pictures and diagrams help show the complexity, functions, and explanation of our nervous system.
The next few pictures and diagrams help show the complexity, functions, and explanation of our nervous system.
This is the spinal column, its vertebra, and the body parts that are controlled by the nerves.
This is a general break down of the human nervous system.
The Central Nervous System consists of the brain and spinal cord. It is the structural and functional center of the nervous system.
The Peripheral Nervous System that lie outside the brain and spinal cord, hence periphery. It is broken down further into the autonomic NS, the somatic NS, the sympathetic NS, and parasympathetic NS.
The Central Nervous System consists of the brain and spinal cord. It is the structural and functional center of the nervous system.
The Peripheral Nervous System that lie outside the brain and spinal cord, hence periphery. It is broken down further into the autonomic NS, the somatic NS, the sympathetic NS, and parasympathetic NS.
- The somatic NS carry information to skeletal muscles. The autonomic NS carry information to the smooth muscles, cardiac muscle, glands, adipose (fat) tissue and other involuntary tissues.
- The Sympathetic NS is the "Fight or Flight" response. This is the response that occurs when we sense we are in danger or there is a threat to survival. The Parasympathetic NS is the "Feed and Breed" or "Rest and Digest" response.
Example of innervation of spinal nerves and how they connect to the muscle and skin. (left)
What happens to the body during Sympathetic NS stimulation and Parasympathetic NS stimulation. (right) |
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Reproductive System
These are the male reproductive organs.
Primary sex characteristics are the development of of the gonads themselves through the release of sex hormones such as testosterone and estrogen. They come to mature during puberty; which can occur between ages of 10-18. During puberty, secondary sex characteristics such as skeletal changes (growth spurts), fat distribution, growth of pubic and body hair, and growth of the larynx, occur.
Primary sex characteristics are the development of of the gonads themselves through the release of sex hormones such as testosterone and estrogen. They come to mature during puberty; which can occur between ages of 10-18. During puberty, secondary sex characteristics such as skeletal changes (growth spurts), fat distribution, growth of pubic and body hair, and growth of the larynx, occur.
These are the female reproductive organs.
In females, during puberty, which begins between 10-16, breast begin to develop and menstruation begins. This is in addition to skeletal changes (growth spurts), fat distribution, growth of pubic and body hair.
In females, during puberty, which begins between 10-16, breast begin to develop and menstruation begins. This is in addition to skeletal changes (growth spurts), fat distribution, growth of pubic and body hair.
Skeletal system
The human body has roughly 206 bones. We are born with roughly 270 bones, but as we get older some bones fuse and we end up with roughly 206 bones.
The human skeletal system is broken down into the axial skeleton and the appendicular skeleton.
The axial skeleton consists the bones of the head, trunk, and vertebral column.
The appendicular skeleton consists of the the rest of the bones that are attached to the axial skeleton.
The skeletal system has the following functions:
The human skeletal system is broken down into the axial skeleton and the appendicular skeleton.
The axial skeleton consists the bones of the head, trunk, and vertebral column.
The appendicular skeleton consists of the the rest of the bones that are attached to the axial skeleton.
The skeletal system has the following functions:
- Support
- Movement
- Protection
- Production of blood cells
- Storage of ions
- Endocrine regulation
excretory system
The excretory system is a body system that removes wastes from the body to maintain homeostasis.
- The urinary system filters nitrogen compounds, toxins, water, and electrolytes through the kidneys.
- The integumentary system filters nitrogen compounds, electrolytes, and water through the sweat glands in the skin.
- The respiratory system filters carbon dioxide and water through the lungs; these products get expelled through breathing.
- The digestive system filters digestive wastes, bile pigments, and salts of heavy metals; this product is excreted as feces (poop).
Organs of the special senses
The body has sensory receptors all over to help us respond to internal and external stimuli. Being able to appropriately respond to the stimuli from the external and internal environments, is crucial to our survival.
Senses:
Senses:
- Vision/sight
- Smell (olfactory)
- Hearing (auditory)
- Taste (gustatory)
- Touch: pain (nociception), heat (thermoception), balance (equilibrioception), pressure (mechanoreception), Proprioception (knowing one's own perception of muscle strength needed in movements)