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What is Anatomy and PHYSIOLOGY?
What is Anatomy and PHYSIOLOGY?
Human anatomy and physiology is the study of the body's systems and structures and how they interact. Anatomy focuses on the physical parts of the body. Physiology studies functions of the body with a detailed look at cells, tissues, and organs. Although a phlebotomist primarily works with veins (a part of the circulatory system) you will soon discover how interconnected all the body systems are. You will need to be aware of much more than just the veins and blood when working with your patients. In this section, we will do a basic review of the major body systems; the musculoskeletal system, the nervous system, the digestive system, the urinary system, the respiratory system, and the integumentary system. What about the circulatory system? Yes, that is also a major system. We will dedicate the whole next section to it, to go over in more detail.
Nervous system
Nervous system
The nervous system controls and regulates the entire body by sending messages through nerve fibers to muscles, organs, and glands. Returning information travels to the spinal cord and brain to allow it to make decisions. Neurons are nerve cells and have several parts; dendrites that receive signals, axons that transmit them, and the cell body which maintains the nerve cell. The nervous system is composed of two parts, the peripheral nervous system and the central nervous system.
Central Nervous System (CNS)- is made up of the brain and spinal cord. These structures are made up of a large number of neurons and support cells, with both large blood vessels and capillaries supplying the large amount of energy the neurons require. Both the brain and spinal cord are encased in bone (the skull and vertebral column) for extra protection.
Peripheral Nervous System (PNS)- consists of nerves. It is extensive as it covers all areas of the body. Nerves have many functions including controlling body movement, controlling the function of the organs, and returning sensory information from the entire body back to the spinal cord and brain. Nerves branch out from the spinal cord to the body, although there are some cranial nerves that branch out directly from the brain.
The physiology of the nervous system explains the ability of nerves to transfer signals. They do this through "action potentials" which allow signals to transfer down the axon of the nerve and to receptors at the end. The action potentials or "signals" that neurons send are created by the opening and closing of voltage-sensitive ion channels on the surface of the neuron (nerve cell). This results in a "wave" of electrical energy which travels down the neuron. Neurotransmitters at the end of the neuron are transferred at the synaptic or axon terminals and the message is "delivered." Neurons always fire at full strength and on average are firing about 200 times per second.
Anything done automatically by the nervous system without any intentional thinking is a part of the autonomic nervous system. The autonomic nervous system consist of two parts- the sympathetic and parasympathetic nervous system. The sympathetic nervous system activates the fight or flight response during a threat or perceived danger, and the parasympathetic nervous system restores the body to a state of calm.
How does this relate to phlebotomy?
When drawing blood you need to be aware of where the nerves run and avoid hitting them with your needle. You also need to be aware of how the nervous systems work when it comes to parasympathetic responses, such as fainting (vasovagal syncope).
musculoskeletal system
musculoskeletal system
The musculoskeletal system provides structure, allows movement and protects other body systems. When looking at the anatomy of the musculoskeletal system, it's easier to look at it in two systems, the muscular (made up of muscles) and the skeletal (made up of bones).
The skeletal system has 5 major areas the 206 bones in our bodies can be categorized under.
The Skull- The skull is made up of flat bones that protect the brain and create structure for the face. It has attachment points for muscles that allow for movement of the head, neck and face.
The Spine- Contains multiple interlocking vertebrae with a central channel protecting the spinal cord. The spinal column has exit points for nerves to branch out to the body systems. It also has attachment points for muscles and ribs.
Thoracic Cage (Rib Cage)- The rib cage is vital to the respiratory system as it protects the lungs and also allows for movement (expansion and contraction).
Pelvic Girdle- The pelvic girdle transfers the weight of the upper body to the legs. It connects various large muscle groups of the trunk and legs at attachment points.
Limbs- The limbs (or arm and legs) contain many bones and joints with many muscle attachment points for precise movement.
The muscular system consists of three different kinds of muscles. Muscles are made up of bundles of smaller fibers (myofibrils):
Skeletal Muscle- voluntary muscles that attach to the skeletal system (bones) and enable us to move. The movements occur due to us thinking to move (or through the nervous system).
Smooth Muscle- involuntary muscle that makes it possible for movement of our internal organs. Smooth muscle is controlled through the nervous system as well, but not voluntarily like skeletal muscles.
Cardiac Muscle- striated muscle that makes up the heart. It is unique as it is the only muscle fiber that consists of branching fibers. Cardiac muscle functions involuntarily. Cardiac muscle is not controlled by the nervous system, it acts entirely autonomously.
How does this relate to phlebotomy?
When drawing blood you will be finding veins that run over muscles. Injections are usually into the muscle, but blood draws are the opposite, you don't want to be going that deep. Learn the anatomy of the arm and other draw sites to be sure you are putting your needle in appropriately. We'll go over this more in a later section.
Digestive system
Digestive system
The digestive system breaks down and absorbs ingested food and liquids to be used for energy and the creation of new cells within the body.
The digestive system begins at the mouth. The teeth masticate (chew) the food. Saliva helps moisten the food and break it down to create a bolus (a mass of food ready to be swallowed). The food is swallowed with aid from the tongue down the esophagus (a tube that connects the mouth to the stomach). The stomach both physically grinds up food and chemically digests it with acid. The intestines then absorb the nutrients and water from the food with help from liver bile and pancreatic enzymes. Any waste then exits via the urinary system for liquids and the anus for solids.
The liver serves two purposes: producing bile, which helps with the absorption of fats by the intestines, and with detoxification of the blood. The gallbladder stores bile used for digestion. The pancreas, like the liver, has a dual role. It produces enzymes that break down protein and hormones which balance the blood glucose.
How does this relate to phlebotomy?
When doing lab work and drawing blood, sometimes you will be collecting samples other than blood. Learning about digestive disorders and diseases will help you when reading a lab order. Some people can get nauseous when getting blood drawn. Be sure to always check your patients comfort level with the blood draw experience so that you can be prepared to help them.
Urinary system
Urinary system
The Urinary System is responsible for maintaining the volumes of bodily fluids, helping regulate blood pressure, controlling the levels of electrolytes and metabolites, and regulating blood pH. The kidneys filter the blood and make urine (liquid waste-by-product) from extra components found in and removed from the blood. The urine travels down the ureters and to the bladder where it is stored for release. When released it exits through the urethra.
How does this relate to phlebotomy?
Like the digestive system sometimes you will be getting collections of samples other than blood, such as urine samples.
REspiratory system
REspiratory system
The respiratory system is responsible for getting oxygen to the body through the blood. It is divided into the upper and lower respiratory tract. The division occurs at the larynx. The upper respiratory tract consists of the nasopharynx and oropharynx. The lower respiratory tract is made up of the trachea, bronchi, bronchioles, and lungs. Movement of air through the system provided by the diaphragm.
The upper respiratory tract is responsible for the initial cleaning and warming of air before it is transmitted to the lower airways. It is also instrumental in the production of speech. The larynx is a "box" of cartilage that divides the digestive and respiratory systems. The epiglottis is a physical flap that protects the airway from food and fluids. The rest of the larynx is specialized to allow for the production of speech. The vocal cords and various cartilages can change shape to allow air passing over them to create speech.
The lower respiratory tract transfers air through a branching made up of the trachea, bronchi, and bronchioles. Once it reaches the alveoli (microscopic sacks with thin walls that are covered in thin capillaries) oxygen is transferred to the blood.
The diaphragm is a sheet of muscle at the base of the lungs that pulls air into the airways by creating negative pressure in the chest. When the diaphragm contracts, air is drawn into the chest (inspiration), and when it relaxes, air is forced out (expiration).
How does this relate to phlebotomy?
The respiratory system is very important to the circulatory system. That is how blood is oxygenated. In lab work you may also be collecting samples that are related to the respiratory system such as throat and nasal swabs or phlegm collections.
Integumentary system
Integumentary system
The integumentary system, or the skin, is the largest organ and provides a physical barrier between the inner body and the outside world. It is vital to the regulation of the body's internal environment, holding in fluids, keeping out bacteria. It also regenerates and prevents permanent damage to the more fragile cells of the body.
It has three main layers, the epidermis, dermis, and subcutaneous layers. The epidermis is a thick layer of dead cells. It does not have any active blood supply to it. This layer is the barrier for the body that protects it from invasion of germs.
The dermis is the living skin layer with cells that continuously multiply and divide. It holds nerves, blood vessels, sweat glands, and oil glands. It does have an active blood supply. It also contains dense connective tissue made of collagen fibers that give the skin its elasticity.
The subcutaneous layer is one of the main areas of fat (adipose tissue) storage, also acting as a significant insulating layer for the body. It helps maintain body temperature and protect organs beneath the skin.
How does this relate to phlebotomy?
You will be puncturing down right though all these layers to the blood vessel protected by adipose tissue. Patients with veins that are deep can be challenging as adipose tissue can sometimes feel like a vein. Learning the difference will mean a lot to your patients! Accurately finding the vein that bounces back will be the key.
RETURN TO THE GOOGLE CLASSROOM AND DO THE PRACTICE WORKSHEET.
For more information and references on the reading material found in Section 12: Basic Human Anatomy and Physiology, click the link below. Test questions will be based on the reading in the sections and not from more information found in external references and website links.
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