Anatomy & Physiology Week 2 Flashcards
Organ Systems
Integumentary. Muscular. Skeletal. Nervous. Endocrine. Cardiovascular. Lymphatic. Digestive. Respiratory. Urinary. Reproductive.
Integumentary System
Contains largest organ in the body - the skin
Functions to protect our body by keeping microbes and harmful materials out, keeping body fluids in, and helping to control our body temperature
Integumentary made up of what structures
Epidermis
Dermis
Hypodermis
Nails
Hair
Sweat glands
Epidermis
Epidermis - outside layer of skin. Elastic and constantly being regenerated
Dermis
Dermis - inner layer of skin. connective tossie that is thick, fibrous structure made up of collagen, elastic tissue, nerve endings, hair follicles, vasculature, and glands
Hypodermis
Hypodermis, or subcutaneous later, lies below the dermis and consists largely of adipose and connective tissue. Main structural support for skin and insulates the body from the cold. also assists in shock absorption, interlaced with blood vessels and nerves, connects skin to muscle and bones
Nails
Nails - specialized epithelial cells grow from the nail bed, which divide and harden through keratinization
Hair
Hair - develops from hair follicles originating in the dermis, serves function of temperature regulation and acts as protection for skin. Helps increase sensory function within body. Sebaceous glands, often associated with hair follicles, secrete an oily substance called sebum to keep hair and skin soft
Sweat glands
if body temperature rises, nerve impulses stimulate activity in the sweat glands, releasing sweat onto skin surface. As sweat evaporates, heat is carried away, cooling the skin
Vitamin D
fat soluble vitamin
essential for bone health due to its role in calcium absorption and maintenance of calcium and phosphate concentrations. influence on immune system, blood sugar regulation, cell growth and differentiation
Skeletal system
support structure within the body. he skeletal system gives the body its shape and facilitates movement by providing a connection point for muscles. In addition, the skeletal system makes blood cells and stores and releases minerals and fats. It also provides protection for organs through its structure.
Bones
Cartilage
Joints
Tendons
Ligaments
Bones
Bones - hard, mineralized connective tissue. provide shape and support for body and protect internal organs. also serve as storage site for minerals and house the medium for development of red blood cells (marrow)
Cartilage
Cartilage - smooth, resilient connective tissue that reduces friction between bones. Composed of collagen and water, helps to absorb impact from movement and disperse body weight
Joints
Joints - made of flexible connective tissue and are found at points in the body where two or more bones meet. may bind bones together, like fibrous joints in our skull, while many allow movement through their hinging and rotating abilities
Tendons
Tendons - cords of strong flexible tissue attached to both muscle and bone and serve to move the bone or structure
Ligaments
Ligaments - fibrous connective tissue that attach bone to another bone, to stabilize connections at a joint. keep muscle and bone stable in place
Skeletal system and mineral supply
The skeleton contains 99% of the body’s calcium, as well as roughly 85% of the body’s phosphorus, and lesser amounts of potassium, sulfur, sodium, and magnesium.
Bone Remodeling
Bone is a living tissue and is continuously being broken down, repaired, and rebuilt
First, we have osteoclasts, osteo- meaning bone and -clast meaning to break apart. These bone cells break down bone and dissolve its minerals, leaving behind small cavities. This part of the process is known as resorption. Working to rebuild, we have osteoblasts, which are newly formed cells that build and compact to create new bone matrix. The creation of new bone matrix in this fashion is called ossification.
There are organs and hormones involved in promoting or inhibiting the activity of the cells responsible for bone remodeling and calcium homeostasis.
* The parathyroid glands, four small glands that regulate blood calcium levels, are located on the back of the thyroid gland in the neck
* Parathyroid hormone, or PTH, is the hormone produced by the parathyroid glands that has the effect of raising blood calcium. PTH accomplishes this by stimulating osteoclastic activity, which releases calcium from bone. It also increases calcium reabsorption from the urine by the kidneys - meaning that the kidneys recycle calcium to keep it in the body, and it increases calcium absorption from gastrointestinal tract. All of these processes lead to increased calcium in the blood.
* Calcitonin, a hormone secreted by the thyroid gland, has the effect of lowering blood calcium. Calcitonin inhibits osteoclastic activity, thereby stopping the breakdown of bone. It also decreases calcium reabsorption from kidneys (so more calcium will be removed via the urine), further contributing to decreased serum calcium levels.
Calcium Homeostasis
Calcium homeostasis maintains a specific calcium level in our blood at all times. tightly controlled process, and works quickly to regulate itself as blood calcium levels play a vital role in many human life activities, such as maintenance of the skeleton, regulation of hormonal secretion, and transmission of nerve impulses.
If the calcium level increases, the thyroid gland will release calcitonin. If the calcium level decreases, the parathyroid glands will release parathyroid hormone.
Bone health
Dietary and lifestyle strategies that support healthy bones include regular intake of nutrient dense foods rich in calcium, avoiding cigarettes and excessive alcohol intake, and including weight-bearing and resistance movements as appropriate. One should also make note of any ongoing medication use that may interfere with calcium absorption to have a full understanding of possible impact on calcium status.
Muscular system
Muscle cells build muscle tissue. Three types of muscle tissue:
skeletal
smooth
cardiac
Skeletal muscles
voluntary muscles of the body, allow us to walk and talk. composed of muscle tissue, nervous tissue, connective tissue, and blood. work with skeletal system to facilitate movement. skeletal muscles are striated meaning they have alternating bands of light and dark protein structures that would be visible under magnification
Smooth muscle contraction
Smooth muscle contraction is similar to skeletal muscle, with the notable difference of being contracted involuntarily, as their actions are regulated by neurotransmitters and hormones.
slower to contract and relax, and can maintain a more forceful contraction for a greater period of time.
also have the ability to change length without influencing tautness, meaning they can stretch while maintaining consistent pressure, an important feature for organs like our stomach and small intestine.
found in the walls of hollow organs, like the stomach and intestine, as well as our blood vessels.
Cardiac muscle
Cardiac muscle is found only in the heart and is also under involuntary control. Its mechanism of contraction is self-exciting, meaning that the electrical signal to contract originates in the heart itself. As the impulse travels through the various parts of the heart, the whole structure contacts as a unit. This process repeats itself rhythmically, in what we know as the heartbeat.
Anabolism
Anabolism describes metabolic reactions in which energy is used to build larger, more complex structures from smaller molecules
Anabolic exercise, typically short-duration, weight-bearing movements, utilizes little cellular energy in the moment, but has the effect of stressing muscle fibers leading to subsequent repair and growth.
Catabolism
catabolism is the breakdown of large molecules into smaller components, thereby releasing energy.
Catabolic activity, commonly called aerobic or cardiovascular exercise, has the opposite effect; it requires high use of oxygen and energy during the active period. While aerobic exercise is beneficial for cardiovascular function and endurance, one should consider frequency and duration with respect to muscle catabolism. Balancing cardiovascular exercise with weight-bearing movement, ensuring adequate protein intake, and allowing for rest and recovery will all work to limit muscle breakdown and support overall muscle health.
Nervous system
Nervous system is command center of the human body
Central nervous system (CNS) - consists of the brain which is the nervous tissue located within the skull, and the vertebral column, or spinal cord, which is enclosed by the bones of the spine, called vertebrae. Both the brain and spinal cord contain millions of neurons, also known as nerve cells.
Peripheral nervous system (PNS). branches peripherally from the brain and spinal cord, connecting to other areas of head, neck, and trunk of the body. From the base of the brain, twelve pairs of cranial nerves extend to specific points in the body; for example, the optic nerve connects to the back of the eye and is responsible for transferring visual information from the retina to the brain.
Spinal nerves
Originating in the spinal cord, there are 31 pairs of spinal nerves which provide communication between the spinal cord and parts of the neck, truck, and limbs. These nerves are not named individually, but are grouped according to the point of origin along the spine; starting at the neck, there are 8 pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and finally one pair of coccygeal nerves.
The peripheral nervous system also includes sensory receptors, specialized cells which receive information from our internal and external environment, and ganglia, clusters of neurons, or nervous tissue, that carry nerve signals to and from other parts of the body.
Nervous system - Sensory function
touch, temperature, sound, and light, as well as internal signals such as changes in blood pressure or hormone levels
Nervous system - Integrative function
make decisions, plan and carry out movements, and respond to changes in our environment
Nervous system - Motor function
can initiate motor output, sending signals to muscles and glands to carry out specific actions
Autonomic nervous system - Sympathetic
fight or flight. this is the branch of our nervous system that prepares the body for physical activity and stress
Sympathetic:
dilate pupils. inhibit salivation. relax airways. increase heartbeat. inhibit activity of stomach. stimulate release of glucose. inhibit gallbladder. inhibit activity of intestines. secrete epinephrine and norepinephrine. relax bladder. promote ejaculation and vaginal contractions.
enteric: neural activity within our intestines
Autonomic nervous system - Parasympathetic
rest & digest. works to return the body to a state of relaxation to maintain mental and physical health.
constrict pupils. stimulate saliva. constrict airways. slow heartbeat. stimulate activity of stomach. inhibit release of glucose. stimulate gallbladder. stimulate activity of intestines. contract bladder. promote erection of genitals
Vagus Nerve
The Vagus nerve, also called the tenth cranial nerve or cranial nerve X, extends downward from the brainstem through the neck and into the chest and abdomen, providing a communication highway between the brain and several important organs, including our heart, lungs, liver, and intestines. The Vagus nerve is the primary neural connection for our parasympathetic nervous system, and it helps regulate several critical physiological responses, like heart rate, blood pressure, digestive function and hormonal response.
Endocrine System
The endocrine system is also involved in daily cell-to-cell communication, and this system includes the cells, tissues, organs (collectively referred to as the endocrine glands) which utilize chemical signaling via substances called hormones. Differing from the immediate nature of neural communication, hormones are transported through the blood stream to arrive at an intended target cell-receptor site.
The hormones produced by the endocrine system regulate life processes from the moment we’re born, and are involved in growth, development, metabolism, energy production and storage, sleep, sexual function and reproduction, blood pressure, mineral balance, and more.
Major Glands of Endocrine system
hypothalamus
pituitary gland
pineal gland
thyroid gland
parathyroid glands
adrenal glands
pancreas
gonads (testes and ovaries)
Hypothalamus
The hypothalamus works in tandem with the pituitary gland; you can think of them as the conductors of the endocrine system. The hypothalamus, a small region of the brain, oversees the entire system, receiving feedback from all glands involved, constantly assessing hormonal balance in efforts to maintain homeostasis. If the hypothalamus is the master conductor, the pituitary is second in command, receiving instruction from the hypothalamus and using that information to direct the function of rest of the endocrine glands.
Adrenal Glands
The adrenal glands, small cap-shaped glands located at the top of each kidney (-renal meaning kidney), are responsible for producing critical hormones that maintain multiple body processes. Each adrenal gland consists of the outer adrenal cortex and the inner adrenal medulla, with each region producing unique hormones.
The adrenal medulla secretes two closely related hormones, epinephrine (also known as adrenaline) and norepinephrine (or noradrenaline). These hormones are associated with the sympathetic nervous system and the state we refer to as “fight or flight”, and work to increase heart rate, improve blood flow, dilate air passages, and increase blood glucose levels to provide immediate energy.
Aldosterone
ldosterone is our major mineralocorticoid, so named for the influence on regulating mineral homeostasis. The main function of aldosterone is to increase sodium and water reabsorption in the kidneys while concurrently increasing potassium excretion via urine. The net effect of these two actions yields an increase in blood volume and blood pressure.
Cortisol
Cortisol is a glucocorticoid hormone, so called for its effect on glucose metabolism produced in the intermediate zone of the adrenal cortex.
The cells of the inner zone of the adrenal cortex produce a small amount of androgen hormones that serve as precursors to more potent steroid hormones. During puberty and into adulthood, these precursor hormones can be converted by the testes and ovaries into active sex hormones.
Thyroid Gland
The thyroid gland is a butterfly shaped structure located in the lower, anterior section of the neck. The thyroid is most known for its primary role in regulating metabolism and energy production. This function can also affect the rate at which we breathe and digest our food, our body temperature and weight, serum lipid levels, menstrual cycle, and more.
Pancreas
The pancreas is an elongated glandular organ located in the abdomen, posterior to the stomach. In its role as an endocrine gland, it is responsible for the creation of the hormones glucagon and insulin, which play key roles in maintaining blood glucose levels.
Gonads
Gonads include the testes and ovaries, which produce sperm and eggs respectively, as well as the body’s sex hormones. These glands produce steroid hormones that affect growth and development and regulate reproductive cycles and behaviors. Examples of gonadal steroids are estrogen, progesterone, and testosterone, which will be discussed later in the module.
Pineal Gland
The pineal gland, found deep within the brain, is responsible for synthesizing the hormone melatonin, which plays an important role in regulating sleep cycles and maintaining our inherent circadian rhythm. Melatonin production will peak in the nighttime, promoting physiological responses that support sleep, and naturally taper in the morning, being inhibited by light.
Endocrine Axis. HPA Axis
Hypothalamus –> Anterior Pituitary –> Adrenal Cortex
While the adrenal axis may receive the spotlight, other endocrine organs function within a similar framework; the hypothalamus-pituitary complex also coordinates hormone signaling for the thyroid gland, the gonads (testes and ovaries), and the pancreas with respect to its endocrine function.
hypothalamus-pituitary-thyroid (HPT) axis example
If the hypothalamus receives information that the level of thyroid hormone is low, it will produce thyroid releasing hormone (TRH), which in turn prompts the pituitary to secrete thyroid stimulating hormone (TSH). TSH travels to receptors in the cells of the thyroid gland, directing the gland to produce more thyroid hormones. As serum hormone levels increase and return to the optimal range, this inhibits the production of TRH by the hypothalamus, in what we refer to as a “negative feedback loop”. Should thyroid hormone levels decline, the “negative feedback” ceases, triggering a return to action by the hypothalamus and pituitary to once again increase hormone levels.
Cardiovascular system (circulatory system)
Responsible for pumping blood through the closed circulatory loop throughout the body.
Carries oxygen, nutrients, and hormones to the body’s cells while also removing carbon dioxide and other metabolic waste.
Plays an assisting role in immune function; blood is the liquid transport by which white blood cells and antibodies are moved throughout the body. Also helps regulate blood pressure and body temperature.
Cardiovascular system Structures
Heart
Blood vessels:
arteries
aterioles
capillaries
venules
veins
Heart
The heart is a hollow organ consisting of four distinct chambers, located in the thoracic cavity, bordered laterally by the lungs. There are two upper chambers, called atria, which receive blood returning to the heart, and two lower chambers, the ventricles, which by both gravity and contraction, receive the blood from the atria.
Blood Vessels
Blood vessels are a circuit of tubes that carry the blood from the heart to cells throughout the body. There are five distinct types of blood vessels: arteries, arterioles, capillaries, venules, and veins.
Arteries
Arteries are thick-walled blood vessels that carry blood away from the heart under high pressure. As these arteries branch and divide, they taper into smaller tubes called arterioles, a vast network of vessels which gradually thin to the finest channels, known as capillaries.
Capillaries
Capillaries have the smallest diameter of all blood vessels and connect the smallest arteries to the smallest veins. Capillaries are also an active site of exchange, where gases, nutrients, and metabolic biproducts move between the blood and surrounding tissue through processes known as filtration and reabsorption.
From the capillary network, we begin to work back up in vessel size. Venules are extremely small vessels that gradually grow and merge to form veins. Veins carry deoxygenated blood back to the heart.
Circulatory paths of blood
The pulmonary circuit involves the heart and lungs. If we begin with the heart, deoxygenated blood moves to the lungs. Once oxygenated, blood moves from the lungs back to the heart.
the systemic circuit involves the supply of oxygenated blood system- wide, to all cells of the body, and then the return of deoxygenated blood back to the heart, through the pathways of arteries and veins described earlier.
Blood Pressure
Systolic is the top number, it’s the reading of pressure against your artery walls at the moment that your heart beats.
Diastolic, the bottom number, indicates pressure between beats, or when the heart is resting.
An example of one blood pressure reading would be “120/80”.
Hypertension
Hypertension can be defined as a chronic elevation in blood pressure. Over time, elevated blood pressure can lead to damage within the blood vessels, contributing to the buildup of plaque formation along vascular walls.
Inflammation
Inflammation is your body’s natural response to an irritant such as illness, injury, or infection. When damage occurs in our organs, tissues, or cells, an immune response is triggered. White blood cells will be sent to the injured area of the body in an effort to protect and repair those tissues.
For short term, or acute, situations, inflammation is part of a critical cascade of events to defend and repair tissue. But when inflammation becomes chronically activated and sustained over time, this can lead to progressive tissue injury and increased likelihood of dysfunction and disease. Chronic, systemic inflammation is correlated with increased risk for a variety of disease states, including a notable risk for cardiovascular events.
Connection of inflammation and atherosclerosis
Research has consistently confirmed the connection between inflammation and atherosclerosis, the term used to describe the thickening and stiffening of the walls of the blood vessels. Chronically sustained levels of inflammation can irritate and damage the delicate walls of our blood vessels, prompting the development of arterial plaque. Arterial plaques are formed from lipids, fibrous tissue, cellular waste, and calcium, in response to injury of the arterial wall. Plaques can grow and accumulate, leading to impaired blood flow to other tissues and organs, including blood returning back to the heart, or they can rupture, causing a blood clot, referred to as thrombosis, which can block the artery entirely, leading to heart attack or stroke.
Common vascular irritants include highly processed and refined foods, chronically elevated insulin levels, stress, poor sleep, smoking, lack of exercise, and routine exposure to environmental toxins.
Any efforts we make to reduce sources of inflammation will benefit the cardiovascular system. This includes removing or reducing inflammatory foods, implementing stress management techniques, and taking in a wide variety of healthy fats and foods rich in antioxidants.
Lymphatic System
The lymphatic system is a network of organs, vessels, and cells that transport fluids from body tissues and return them to the bloodstream.
The three main functions of this system are to maintain fluid levels in the body, absorb and transport digested dietary lipids and fat-soluble vitamins, and to support immune function through the production and transportation of immune cells and filtration of pathogens from the blood.
Lymph organs
The lymphatic system includes all lymphatic vessels and lymphoid organs such as the spleen, thymus, lymph nodes, and lymphatic tissue in the small intestine and throat.
Lymph is the watery interstitial fluid that flows through this system.
The lymphatic vessels are an extensive system of vessels and capillaries that transport lymph throughout the body. Originating with the smallest of vessels, fluid flows into lymphatic capillaries, moving lymph in one direction through increasingly larger vessels, upward toward the neck, before connecting to one of two main collecting ducts, then the subclavian veins, and finally draining back into the blood stream. As lymph makes its journey through the vessels, active filtration occurs along the way.
Lymph nodes are small glands or clusters of glands found within the system of lymphatic vessels. They vary in size, shape and location, and are responsible for filtering substances through the lymph fluid before it is returned to the bloodstream. Lymph nodes also contain lymphocytes, or white blood cells that help fight infection and disease.
Spleen
The spleen is the largest of our lymphatic organs. Located in the upper left portion of the abdominal cavity, it is a lobed structure containing tissues composed of white and red blood cells. The spleen plays a major role in filtering the blood to remove microbes and waste materials, and also stores and releases specific immune cells.
Thymus Gland
The thymus gland, which lies between the lungs, posterior to the sternum, secretes hormones that differentiate immature immune cells into specialized types of white blood cells. The thymus is the largest when we are young, and roughly at the time of puberty this gland begins to shrink in size, also decreasing in activity.
Tonsils, or adenoids
Tonsils, or adenoids, are lymphatic nodules in the throat which help stop bacteria and other pathogens from entering the body on the food we eat or the air we breathe. Small masses of lymphatic nodules in the small intestine are known as Peyer’s patches, and they play an important role in immune function specific to the gut. They monitor bacterial population of the small intestine and help keep the growth of pathogenic bacteria at bay.
How does lymph move
the flow of lymph relies on general movement of the body and the contraction of muscles.
As skeletal muscles contract, they exert pressure on the walls of the lymph vessels, propelling the lymph onward. Smooth muscles adjacent to lymph vessels also contribute to further movement, as demonstrated by the act of deep breathing and the subsequent expansion of the lungs and contraction of the diaphragm within the thoracic cavity – the abdomen is a notable site for lymphatic flow.
How lymph is connected to immune system
The lymphatic system is an integral part of our immune system. In addition to filtering bodily fluids, the lymphatic system produces, houses, and transports white blood cells, or leukocytes. The immune system is a collection of organs, cells, and chemicals involved in protecting the body from exposure to pathogens and preventing or limiting infection that could lead to damage, disease, or death.
Immune system
Our immune system is highly organized, with several complex mechanisms working together to support whole-body health. Here we will present an overview of key players and functions to better understand what happens when we encounter an immune challenge.
Within our immune defenses we have two branches of functional division, innate and adaptive immunity. Innate immunity is all about protecting the body from anything deemed to be “non- self” – non-specific mechanisms are not directed toward a specific type of microbe, but collectively work to block or destroy foreign particles. Specific, or adaptive, responses are precise, targeting certain pathogens in a coordinated defense.
Innate immune system
Innate immune system, the first line of defense: physical and chemical barriers. This includes several different non-specific organs, substances, and actions that work continuously to prevent entry of bacteria and microbes.
The largest of our physical barriers is our skin, specifically the epidermis, which when intact, provides a highly effective barrier against microbes at the skin’s surface. Additionally, hair, cilia, mucosal tissue and mucus all work to prevent entry by filtering or trapping potential pathogens.
There are also several bodily fluids that work to flush possible pathogens from delicate tissues, like tears and urine. We also produce substances like enzymes and hydrochloric acid, which can break down and destroy bacteria.
And lastly, there are mechanical actions that propel potential microbes away from or out of the body: sneezing, coughing, vomiting, urination, and defecation.
(innate defense: barriers - skin, hair, mucus, tears, urine, stomach acid, enzymes, sneezing, coughing, vomiting)
Second line of innate immune defense
inflammation and fever are both part of the body’s second line of defense. Fever prompts an uptick in certain immune cells, while simultaneously telling the liver to sequester iron, which reduces bacterial proliferation as body temperature rises. Inflammation is known for effects like swelling, redness, and heat, all of which result from dilation of blood vessels and increased blood volume at the site of injury or infection, allowing for greater delivery of white blood cells.
Phagocytes
Phagocytes are a subset of white blood cells that can engulf another cell and ingest it – the root word “phago-” meaning to eat. Neutrophils are the most common type of phagocyte in circulation, and often the first to arrive at the site of infection. Neutrophils may perform a variety of roles to help suppress or eliminate the pathogen; they can ingest foreign particles and pathogens, or they can degranulate, releasing chemicals into the environment that lead to cell death.
Monocytes
Although slower to arrive on-site, monocytes are white blood cells waiting in reserve to support the innate immune response. They can develop into active cells called macrophages (meaning “big eater”) which are highly efficient at ingesting microbes as well as cellular debris that may remain after the infection. Some monocytes will develop into dendritic cells; these cells do not actively ingest other cells, but specialize in the important step of antigen presentation, whereby information about the pathogenic cells is presented to the adaptive immune cells to create a more sophisticated response.
Natural Killer (NK) Cells
Natural killer cells, or NK cells - main function is to destroy microbes as well as host cells that have been infected in order to stop the proliferation of disease. This is accomplished by secreting proteins that destroy the pathogen’s cell membrane.
Adaptive immune system (third line of defense)
The specific, adaptive response. These white blood cells have specialized function and are referred to as lymphocytes, so named for their established presence within the lymphatic system. There are two main types of lymphocytes, B cells and T cells, both originating from stem cells developed in bone marrow.
B Cells
B cells, which also mature within the bone marrow before heading to the lymphatic system, are most recognized for their ability to synthesize and secrete antibodies, also known as immunoglobulins. Antibodies are protein-based structures that help other cells in the immune system to identify foreign substances, which are collectively referred to as antigens.
T Cells
Different types of T cells have distinct roles in the adaptive immune response.
Helper T helper certainly live up to their name; they assist with the overall adaptive immune response by producing proteins that activate and increase production of other T cells, B cells, and NK cells.
Cytotoxic, or killer T cells, are similar to NK cells – they also kill damaged or infected cells, but differ in that they have the ability to recognize and target an infected cell thanks to specialized receptors.
Memory T cells are a specific set of helper T cells; these long-living cells remain in the lymph system and can recognize a specific prior antigen exposure. They can be quickly converted into active cytotoxic T cells should the same antigen reinfect the body, creating a highly efficient response to a subsequent exposure.
Regulatory T cells (aka “T regs”) have a distinct and essential role in the third line of defense. Their actions suppress the activity of other immune cells, calming the immune system once the active threat is no longer a concern. This helps the body return to a state of homeostasis and prevents ongoing or excessive tissue damage.
Digestive system
The digestive system consists of two parts, the alimentary canal, which begins with the mouth, includes the entire digestive tract ending with the anus, and the accessory digestive organs, which include the salivary glands, liver, gallbladder, and pancreas.
Core functions of digestive process
The six core functions of the digestive process are:
ingestion- in mouth as we consume food or liquid
secretion- as we mix the food with saliva through chewing
mixing and propulsion- ctions that mix food and secretions together and keep contents moving southward through the rest of the digestive system. For example, when we swallow, the tongue pushes food into the esophagus, physically moving the food through the early part of the digestive tract. From here on out, food will progress without our voluntary efforts thanks to a process called peristalsis, a sequence of wavelike contractions that will continue movement throughout the entire GI tract.
digestion- goal is to break food down into smaller molecules, so that it can be used by the body. Digestion may be mechanical, like the grinding of food by teeth, or chemical, where substances like enzymes and stomach acid work to break down the chemical structures in food into even smaller particles.
absorption- The primary site of nutrient absorption is the small intestine, where broken-down food particles pass into the blood and lymph to be further circulated throughout the body.
defecation- Any remaining wastes products or undigestible particles pass into the large intestine to be compacted into feces and eliminated through the anus in the final process, defecation.
Respiratory system
In a process known as respiration, the respiratory system facilitates an exchange of gases from our internal and external environments, bringing oxygen to tissues and cells and removing carbon dioxide and other waste products. Every cell in the body requires oxygen to produce the energy it needs to stay alive and function optimally.
Organs of the respiratory system
The organs of the respiratory system are found in the thoracic cavity, also called the chest cavity, and can be divided into two groups, the upper respiratory tract and the lower respiratory tract.
The upper respiratory tract includes the nose, nasal cavity and the pharynx.
The lower respiratory tract consists of the larynx, trachea, bronchi and the lungs.
Respiratory system organ functions
The nose, through which we take in and expel air to and from the body, provides the entrance to the nasal cavity, a hollow space behind the nose where air is warmed and moistened.
From here, air travels through the pharynx, (FAR-inks) what we commonly call the throat, then moves further on to the larynx.
The larynx is a short, cartilaginous structure that connects the pharynx to the trachea. It helps to regulate the volume of air that enters the lungs, prevent food and other particles from getting into the trachea, and houses our vocal cords – a lot of important functions for this little organ!
The trachea, also referred to as the windpipe, is a cylindrical tube that extends downward from the larynx before branching into the bronchi.
Housed within the lungs, a branching arrangement of bronchial tubes, referred to as the bronchial tree based on its shape, consists of airways leading from the trachea to the structures of gas exchange. These tubes create a network of intricate passages that supply the lungs with air, beginning with the largest, the primary bronchi, which divide into the secondary and tertiary bronchi, then to smaller bronchioles, then terminal bronchioles, and finally, they further divide to become the very small tubes called alveolar ducts. These ducts lead to alveolar sacs, and finally, microscopic alveoli – the site of active exchange of oxygen and carbon dioxide.
The lungs are large, spongy organs that occupy most of the space within the thoracic cavity. The lungs house the multiple air passages and alveoli described above, as well as numerous blood vessels, lymphatic vessels, connective tissue, and nerves.
In an assisting role, we have the diaphragm, a dome shaped muscle that separates the thoracic cavity from the abdominal cavity in the trunk of the body. As we inhale, the diaphragm contracts and flattens, expanding the cavity of the chest, creating a vacuum effect that assists in pulling air into the lungs. On the exhale, the diaphragm relaxes and curves upward, helping to push air out of the lungs.
Nose breathing
As humans, we’re designed to breathe air in though our nose, and there are notable benefits to breathing nasally.
The insides of our nostrils are lined with fine hairs and cilia (slender, hairlike strands) that act as tiny filters for any particles that may tag along in the air we inhale. Think of all the dust, pollen, and bacteria that we may be exposed to when we take a breath… the nose helps to filter those airborne particles to protect our respiratory system.
Nose breathing also channels air through the nasal passages which adjust for temperature and humidity. Our lungs prefer air that’s close to our internal body temperature, and the nasal canal warms the incoming air as it passes through.
Similarly, the nasal passages will humidify, or moisten, the air when we breathe in, further preventing irritation to the respiratory tract and lungs.
Nose breathing increases the amount of oxygen in the blood, which is essential to nearly every cell in the body, and also produces a special molecule called nitric oxide. Nitric oxide, a beneficial vasodilator, is dramatically increased when we breathe through the nose. It relaxes and dilates the blood vessels allowing for improved circulation and greater delivery of nutrients and oxygen to cells, thereby reducing blood pressure, and supporting immune response, physical performance, and brain function.
Chronic mouth breathing can result in more unfiltered particles entering the body, drying of the mouth and oral cavity, and an increase in the risk of gum inflammation and tooth decay.
Urinary system
commonly known for its role in eliminating liquid waste, but there are several other important functions this organ system is involved in. The four main structures in the urinary system are the kidneys, ureters, urinary bladder and urethra.
Kidneys
The kidneys are smooth, bean-shaped organs that lie against the deep muscles of the lower back on either side of the vertebrae. Their primary function is to filter blood supplied from the renal arteries to remove metabolic wastes and dilute them with water and electrolytes to create urine, which will eventually be excreted from the body. Healthy adult kidneys filter nearly half a cup of blood per minute through millions of tiny structures called nephrons in order to maintain the balance of water, salts, and minerals.
Ureter
After urine is formed, it is passed through a funnel-shaped section of the kidney, called the renal pelvis, which tapers to a long, thin tube called a ureter. Ureters connect the kidneys to the urinary bladder. Urine drains from each kidney through the ureters and into the bladder.
Urinary bladder
The urinary bladder is a hollow, muscular organ that provides a holding space for urine. As the bladder begins to fill with urine, receptors in the bladder wall send a signal to relax the internal sphincter; it is through our learned, voluntary control of the external urethral sphincter that we are able to hold urine until we can use the bathroom.
Urethra
The urethra is the tube by which urine is excreted from the body.
More info on kidneys
Kidneys control the pH, or acid balance, of the blood, have influence on the circulatory system, produce hormones that stimulate the creation of red blood cells, and play a role in the synthesis of vitamin D.
involved in maintaining homeostasis in the body by regulating blood volume, pressure, and pH balance. The kidneys regulate blood volume by conserving or eliminating water; they conserve water if your urine becomes concentrated and eliminate water if your urine is diluted.
The body’s blood pH is tightly regulated to stay within a narrow range of 7.35 to 7.45 to maintain appropriate metabolic function. Through the filtering process of the kidneys, excess acids are removed and excreted in the urine.
Additionally, the kidneys can resorb bicarbonate ions, passing them back into the blood to help buffer pH.
The kidneys also produce and secrete a hormone which helps to regulate the rate at which new red blood cells are created. And lastly, the kidneys are the site of a chemical reaction that transforms vitamin D into the active, or usable form, called calcitriol.
From a nutritional standpoint, with respect to the urinary system, hydration is necessary for optimal function of the kidneys. Adequate hydration allows the kidneys to clear waste products, including sodium and urea, from the body. Adequate water intake also reduces the risk of kidney stones, hard deposits of minerals that can form within the renal pelvis and collecting ducts.
Reproductive systems
The reproductive system is a collection of organs and glands that produce sex hormones and gametes, which are reproductive sex cells.
The male reproductive system produces sperm, while the female reproductive system produces oocytes, or eggs. Gametes are haploid cells, meaning that they carry a single set of chromosomes.
During fertilization, the sperm meets the oocyte, combining to form a single diploid cell, called a zygote, which contains two complete sets of chromosomes.
During pregnancy, the zygote will divide to become an embryo, develop further into a fetus, and eventually be delivered as a new human being.
Major organs of male reproductive system
The major organs of the male reproductive system are the testes, scrotum, epididymis, vas deferens, seminal vesicles, prostate gland and the penis.
The paired testes, or testicles, are oval-shaped glands supported by the scrotum, an external pouch of loose skin and tissue that hangs posterior to the penis. This location outside the abdomen is important as a main function of the testes is to produce sperm, which is optimized at a temperature just below core body temperature. Testes are also responsible for producing the sex hormone testosterone.
The epididymis is a coiled tube attached to the testes, and the site of maturation and storage for newly formed sperm.
The vas deferens, also called the ductus deferens, is a long tube that connects the epididymis to pelvic cavity. The vas deferens is also a storage site for mature sperm, and also conveys the sperm toward the urethra.
The seminal vesicles are sac-like structures found near the base of the bladder. These glands produce an alkaline fluid that neutralizes any potentially acidic environment in order to ensure the survival of sperm.
The function of the prostate gland, a small gland located below the bladder and surrounding the urethra, is to secrete prostate fluid which nourishes and helps transport sperm.
The penis is the organ responsible for conveying urine, and seminal fluid and sperm, from the body.
major organs of the female reproductive system
The major organs of the female reproductive system include the ovaries, uterine tubes, uterus, and vagina.
The ovaries, small oval-shaped glands located in the pelvic cavity on either side of the uterus, are the main reproductive organs and they produce and store ovum, or eggs. They are also responsible for the production of estrogen and progesterone during the reproductive years.
The uterine tubes, or Fallopian tubes, are hollow ducts that extend from the uterus laterally toward the ovaries, curving and expanding to create a funnel shaped enclosure around the ovary without directly attaching. Fringed structures at the end of these tubes function to sweep the oocyte into the tube for travel to the uterus. Uterine tubes are also the usual site of fertilization.
The uterus, a hollow, muscular organ roughly the size and shape of an inverted pear, provides an open space that can receive a fertilized ovum and sustain its development during pregnancy.
The lower portion of the uterus, known as the cervix, narrows and extends downward, connecting to the upper portion of the vagina.
The vagina is a muscular canal with nerves and mucous membranes that connect the uterus and cervix to the outside of the body. The vagina allows passage for uterine fluids to the external environment and is the delivery channel for a baby during childbirth.
Several additional accessory glands and external organs function to protect the internal environment and ovum, provide lubrication, and assist in the production of breastmilk during lactation.
Reproductive hormones
Reproductive hormones are a group of hormones that regulate the reproductive system; they are responsible for the development and maintenance of reproductive organs and the production of gametes (sperm and eggs).
Connection of reproductive system and endocrine system
Gonadotropin-Releasing Hormone (GnRH) is produced by the hypothalamus and stimulates the pituitary gland to release the gonadotropins, follicle-stimulating hormone and luteinizing hormone.
Follicle-Stimulating Hormone (FSH) is then produced by the pituitary gland. FSH stimulates the growth and development of ovarian follicles in females and the production of sperm in males.
Also produced by the pituitary gland, Luteinizing Hormone (LH) triggers ovulation in females and stimulates the production of testosterone in males.
FSH and LH act on the gonads (the testes and ovaries) to stimulate the production of sex hormones.
Estrogen, progesterone and testosterone are all classified as steroid hormones; they are derived from cholesterol and produced in the ovaries and testes.
Estrogen and testosterone are responsible for the development of secondary sexual characteristics during puberty.
Progesterone helps to regulate menstrual cycle and has a key role in preparing the uterus for pregnancy.
Body Systems
integumentary
muscular
skeletal
nervous
endocrine
cardiovascular
lymphatic
digestive
respiratory
urinary
reproductive
Neurons
Soma
Dendrite
Axon
Myelin Sheath
Afferent neurons - sensory
Efferent neurons - motor
Blood brain barrier
protective, three layer wall made up of different types of cells and linked by tight junctions. designed to prevent any leaking of fluid between cells.
central nervous system
brain
spinal cord
peripheral nervous system
autonomic nervous system
somatic nervous system
autonomic nervous system
sympathetic nervous system
parasympathetic nervous system
somatic nervous system
sensory
motor
Cranial nerves
oculamotor (III)
olfactory (I)
optic (II)
vestibulocochlear (VIII)
glossopharyngeal (IX)
Vagus (X)
hypoglossal (XII)
Accessory (XI)
abducens (VI)
facial (VII)
trigeminal (V)
Trochlear (IV)
Spinal nerves
cervical
thoracic
lumbar
sacral
coccygeal
