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Medical Terminology and Anatomy and Physiology
Medical Terminology
Components of Medical Terms: Some medical words are compounds, or made up of two or more whole words (e.g., smallpox).
Roots are the foundations of words and are not used by themselves (e.g., therm). Combining form is when a vowel is added to the end
of the root to help it join with other words, roots, or suffixes (e.g., therm/o which can be combined with meter to make thermometer).
Prefixes are added to the beginning of roots or words to modify or qualify their meaning, using telling what kind of, where, in what
direction, or how many (e.g., dys-, intra-, quadri-) Suffixes are word parts added to the ends of roots or words to complete their
meaning (e.g., -iac, -itis, -iole)
Abbreviations and Acronyms: An acronym is an abbreviation made up of initials that can be pronounced as a word. Abbreviations
and acronyms can be helpful when completing documentation on a run or giving care to a patient (e.g., ABCs for airway, breathing,
and circulation). Be sure that the acronym or abbreviation that you are using is standard and accepted. Many services and regions have
policies regarding acceptable use of terms.
When and Where Not to Use Medical Terms: Avoid using any type of obscure medical terminology, jargon, abbreviations, or
acronyms when talking to patients or families. Resist the urge to use complex medical terminology when a simple, term will do.
Anatomy and Physiology: Anatomy, the study of body structure, will help you understand where organs and organ systems are
located and also how external injuries may impact internal systems. Physiology, the study of body function, will give you a baseline
idea of how the body should work normally. Anatomy and physiology will be helpful guides to decision making throughout your
experience as an EMT.
Anatomical Terms
Directional Terms: The directions left and right always refer to the patient’s left and right. Anatomical position is a person
standing, facing forward, with palms forward; use this position to describe locations on the body.
Planes: Slicing the body down the middle to create two side by side halves would create sagittal or median planes. Slicing the body
into two halves, front and back, would create frontal or coronal planes. Slicing the body into two halves, top and bottom, would create
transverse or horizontal planes. The midline of the body is created by drawing an imaginary line down the center of the body, dividing
the body into right and left halves. Medial—Refers to a position closer to the midline
Lateral—Refers to a position farther
away from the midline
Bilateral—Refers to both sides of anything
The mid-axillary line extends vertically from the mid-armpit to the ankle and divides the body into front and back halves.
Anterior or ventral—Refers to the front. Posterior or dorsal—Refers to the back. Superior means above. Inferior means below.
Proximal means closer to the torso, or trunk of the body. Distal means farther away from the torso. Palmar refers to the palm of the
hand. Plantar refers to the sole of the foot. The mid-clavicular lines (2) divide the chest into regions, running through the center of
each clavicle and extending inferiorly.
The abdomen is divided into four parts, or quadrants, by drawing horizontal and vertical lines through the naval.
Right upper quadrant (RUQ). Left upper quadrant (LUQ)
Right lower quadrant (RLQ)
Left lower quadrant (LLQ)
Positional Terms: A supine patient is lying on his back. A prone patient is lying on his abdomen. Recovery position is when a patient
is lying on his side. Preferred position for any unconscious non-trauma patient also referred to as lateral recumbent position. In the
Fowler position, the patient is seated (usually accomplished by raising the head of the stretcher so the body is at a 45 degree to 60
degree angle). If patient is leaning back in a semi-sitting position, this is sometimes called semi-Fowler. In a Fowler position, the legs
may be straight out or bent. In the Trendelenburg position, the patient is lying with his head slightly lower than his feet (now seldom
used).
Body Systems
Musculoskeletal System: Functions of the musculoskeletal system, Give the body shape, Protect vital internal organs, Provide for
body movement, interacting with the skeletal system are muscles, ligaments, and tendons.
Skull: Bony structure of the head Main function is to enclose and protect the brain. The face is the front of the skull. Mandible,
Lower jaw, Maxillae, Fused bones of the upper jaw, Nasal bones—Provide some of the structure of the nose, Orbits, Bones
surrounding the eyes, Zygomatic arches, Form the structures of the cheeks. The bones of the anterior cranium connect to facial bones.
Spinal column: Provides structure and support for the body and houses and protects the spinal cord Consists of 33 vertebrae in five
sections (cervical, thoracic, lumbar, sacral, and coccyx) The cervical and lumbar regions are the most easily injured areas.
Thorax: Bones of the thorax form an internal space called the thoracic cavity (chest). Protects vital organs such as heart, lungs, and
major blood vessels. Consists of 12 pairs of ribs that attach to the 12 thoracic vertebrae of the spine. Ten of these pairs are attached to
the sternum. Two are called floating ribs because they have no anterior attachment. Sternum (breastbone) is a flat bone divided into
the manubrium, the body, and the xiphoid process.
Pelvis: Contains bones that are fused together (sometimes confused with hip joint) Ilium is the superior bone that contains the iliac
crest. Ischium is the inferior, posterior portion of the pelvis. Pubis is formed by the joining of the bones of the anterior pubis. Pelvis is
joined posteriorly to the sacral spine. Hip joint consists of the acetabulum and the ball at the proximal end of the femur.
Lower extremities: Pelvis and hip may be considered part of the lower extremities. The femur is the largest long bone in the body
(thigh bone). The patella (kneecap) sits anterior to the knee joint. Tibia is the medial and larger bone of the lower leg (shin bone).
Fibula is the lateral and smaller bone of the lower leg. Ankle connects the tibia and fibula with the foot (lateral malleolus and medial
malleolus) and consists of bones called tarsals. Foot consists of foot bones (metatarsals), heel bone (calcaneus), and toe bones
(phalanges).
Upper extremities: Shoulder, Consists of the clavicle (collarbone) and scapula (shoulder blade) The acromion process of the scapula
is the highest portion of the shoulder and forms the acromioclavicular joint with the clavicle (common injury site). Upper arm and
forearm consists of the humerus, radius, and ulna., Wrist contains several bones called carpals. Bones of the hand are called
metacarpals. The finger bones are called phalanges.
Joints: Formed when bones connect to other bones. Types include ball-and-socket joints (hip) and hinge joints (elbow).
Muscles: Protect the body, give it shape, and allow for movement. Voluntary muscle (skeletal muscle) is under conscious control of
the brain via the nervous system. Attached to bones, forming major muscle mass of the body Can contract under voluntary command
of the individual Involuntary muscle (smooth muscle) is found in the gastrointestinal system, lungs, blood vessels, and urinary system
and controls the flow of materials through these structures. Responds automatically to orders from the brain Cannot be controlled by
the individual Does respond to stimuli such as stretching, heat, and cold Cardiac muscle is a specialized form of involuntary muscle
found only in the heart. Extremely sensitive to decreased oxygen supply Has its own blood supply through the coronary artery system
Has automaticity, or the ability to generate and conduct electrical impulses on its own (creating a heartbeat)
Respiratory System
Respiratory anatomy: Air enters through the mouth and nose. It moves through the oropharynx and the nasopharynx (pharynx is the
area that includes both of these). Epiglottis closes over the glottis to prevent food and foreign objects from entering the trachea. The
larynx (voice box) contains the vocal cords. The cricoid cartilage forms the lower portion of the larynx. The trachea is the tube that
carries inhaled air from the larynx toward the lungs. Splits into two branches called bronchi (one going to each lung) Air passages get
smaller and smaller ending at alveoli, small sacs within the lungs where gas exchange takes place with the bloodstream. Diaphragm
divides the chest cavity from the abdominal cavity and helps a person inhale and exhale.
Respiratory physiology Inhalation—Active process in which the muscles of the rib cage and the diaphragm contract. The expanding
size of the chest creates a negative pressure inside the chest cavity. The negative pressure pulls air into the lungs. Ventilation,
Movement of gases to and from the alveoli, Air is moved into the alveoli. Oxygen is transferred from the air inside the alveoli to the
bloodstream via the pulmonary capillaries. Carbon dioxide is moved from the bloodstream via the pulmonary capillaries into the
alveoli. Respiration—Process of moving gases (and other nutrients) between the cells and the blood. Oxygenated blood is carried from
the lungs to the heart. It travels through a branching series of arteries that connect to capillaries where gas exchange takes place.
Capillaries connect to veins, and veins return blood to the heart to get rid of carbon dioxide and pick up oxygen. Exhalation—Passive
process during which the intercostal muscles and the diaphragm relax The chest decreases in size and positive pressure builds inside
the chest cavity. This positive pressure pushes air out of the lungs. Breathing (process of inhaling and exhaling air) may be classified
as adequate (sustains life) or inadequate (does not sustain life).
Cardiovascular system
Anatomy of the heart: Two upper chambers called atria, Two lower chambers called ventricles. Blood circulation pathway through
heart. Right atrium: The superior vena cava and the inferior vena cava are two large veins that return blood to the heart and the site
of the right atrium. The right atrium sends blood to the right ventricle upon contraction. Right ventricle: Contracts to pump blood out
to the lungs via the pulmonary arteries. Carbon dioxide is excreted, and oxygen is obtained. Oxygen-rich blood then travels to the left
atrium via the pulmonary veins. Left atrium: Receives oxygen-rich blood from the lungs. Sends blood to the left ventricle upon
contraction Left ventricle: Contracts to send blood into the aorta, the body’s largest artery, for distribution throughout the body Most
muscular and strongest part of the heart Between each atrium and ventricle is a one-way valve that prevents blood in the ventricle
from being forced back up into the atrium. The pulmonary artery and the aorta also have one-way valves. The heart has a system of
specialized muscle tissues called cardiac conduction system that conduct electrical impulses and stimulate the heart to beat. Regulation
of rate, rhythm, and force of heartbeat comes partly from the cardiac control centers of the brain.
Circulation of the blood: Vessels that carry blood away from the heart are called arteries. Coronary arteries branch off from the aorta
and supply the heart muscle with blood. The aorta begins its attachment at the left ventricle and arches in front of the spine through the
thoracic and abdominal cavities. The pulmonary artery begins at the right ventricle and carries oxygen-poor blood to the lungs. The
carotid arteries are the major arteries in the neck and carry blood supply to the head; never palpate both at the same time during CPR
checks for adults and children. The femoral artery is the major artery of the thigh. The brachial artery is in the upper arm and checked
during infant CPR and when determining blood pressure without a blood pressure cuff and stethoscope. The radial artery travels
through and supplies the lower arm; it is checked when taking a pulse.The posterior tibial artery is often used when determining the
circulatory status of the lower extremity. The dorsalis pedis artery lies on the top of the foot, lateral to the large tendon of the big toe.
Arteries gradually branch to smaller and smaller vessels called arteriole (which lead to capillaries).Capillaries are tiny blood vessels
found throughout the body (where gases, nutrients, and waste products are exchanged between the body’s cells and the bloodstream).
Veins carry blood from the capillaries back to the heart (to the right atrium). Venules are the smallest veins that connect to the
capillaries and return blood to the heart. The superior vena cava collects blood that is returned from the head and upper body. The
inferior vena cava collects blood from the portions of the body below the heart. The pulmonary vein carries oxygenated blood from
the lungs to the left atrium of the heart.
Composition of the blood: Plasma is a watery, salty fluid that makes up over half the volume of blood and carries red blood cells,
white blood cells, and platelets. Red blood cells carry oxygen to the tissues and carbon dioxide away from the tissues; they provide the
red color to blood. White blood cells destroy microorganisms and produce antibodies to resist infection. Platelets are fragments of
specialized cells that release chemical clotting factors needed to form blood clots. Blood transports gases, fights infection, helps with
clotting, and regulates pH.
Pulse: Formed when the left ventricle contracts, sending a wave of blood through the arteries. The radial, brachial, posterior tibia, and
dorsalis pedis pulses are called peripheral pulses because they can be felt on the outer reaches of the body. The carotid and femoral
pulses are called central pulses because they can be felt in the central part of the body (even when peripheral pulses are too weak to be
felt).
Blood pressure: Blood pressure is the force blood exerts against the walls of blood vessels. The pressure created in the arteries by the
left ventricle contracting is the systolic blood pressure (reported first). When the left ventricle of the heart is relaxed and refilling, the
pressure remaining in the arteries is called the diastolic blood pressure (reported second).
Perfusion: The movement of blood through the heart and blood vessels is called circulation. The adequate supply of oxygen and
nutrients to the organs and tissues of the body, with the removal of waste products, is called perfusion. Hypo perfusion (inadequate
perfusion), or shock, means that there is inadequate circulation of blood through one or more organ structures; this is serious and can
lead to death.
Life Support Chain: The respiratory system and the cardiovascular system together make up the cardiopulmonary system. Oxygen
and glucose are necessary to cells. Oxygen helps convert glucose into adenosine triphosphate (energy) in a process called aerobic
metabolism. If oxygen is not present, the process shifts to anaerobic metabolism, producing less energy and more waste products such
as lactic acid. The coupling of a sufficient amount of air with a sufficient amount of blood is called a ventilation perfusion match and
abbreviated as a V/Q match. Consider anything that threatens the normal function of the cardiopulmonary system to be a threat to
quality perfusion.
Nervous System: The central nervous system consists of the brain, spinal cord, and nerve tissue. It transmits impulses that govern
sensation, movement, and thought, and controls the body’s voluntary and involuntary activity. The central nervous system consists of
the brain and spinal cord and controls consciousness (reticular activating system). The peripheral nervous system consists of sensory
and motor nerves. Sensory nerves pick up information from throughout the body and transmit it to the spinal cord and brain. The
motor nerves carry messages from the brain to the body. The autonomic nervous system is the division of the peripheral nervous
system that controls involuntary motor function and affects things such as digestion and heart rate. The sympathetic nervous system
function engages when the body is in crisis (“fight or flight”).The parasympathetic nervous system engages in times of relaxation and
is often referred to as the “feed or breed” response.
Digestive System: The digestive system provides the mechanisms by which food travels through the body and is digested, or broken
down into absorbable forms. Food enters the mouth and is broken down by both saliva and chewing. Food passes from the mouth
through the oropharynx and into the esophagus, where it is transported to the stomach. The stomach is a hollow organ in which acidic
gastric juices break down food into components that the body converts to energy. The small intestine is divided into three parts (the
duodenum, the jejunum, and the ileum) and continues to break down nutrients and absorb them through the way of the small intestine.
The large intestine removes water from waste products as they move toward elimination. Organs outside of the stomach-intestines
continuum assist in the food breakdown process. The liver produces bile which is excreted into the small intestines to break down fats.
It also detoxifies harmful substances, stores sugar, and assists in the production of blood products. The gallbladder serves as a storage
system for bile from the liver. The pancreas is involved in regulating sugar in the bloodstream and secretes juices that assist in
breaking down proteins, carbohydrates, and fat. The spleen filters out older blood cells. The appendix is often considered with the
digestive system because an infected appendix is a common cause of abdominal pain.
Integumentary System: The skin performs a variety of functions. Protection, Water balance, Temperature regulation, Excretion,
Shock (impact absorption) The skin has three major layers.: Epidermis—Composed of dead cells that are rubbed off or sloughed off
and replaced; contains no blood vessels or nerves. Dermis—Rich with blood vessels, nerves, and specialized structures such as sweat
glands, sebaceous (oil) glands, and hair follicles; once the dermis is opened to the outside world, contamination and infection become
major problems Subcutaneous layers—Major functions are shock absorption and insulation; problems of tissues and bloodstream
contamination, bleeding, and pain when these layers are injured or exposed.
Endocrine System: The endocrine system produces chemicals calls hormones that help to regulate many body activities and
functions. The pancreas secretes insulin which is critical to the body’s use of glucose. The adrenal glands secrete epinephrine
(adrenaline) and norepinephrine that serve as neurotransmitters and engage the sympathetic nervous system.
Renal System: The renal (urinary) system helps the body regulate fluid levels, filter chemicals, and adjust body pH. The kidneys filter
a waste product (urea) from the blood, provide fluid balance by regulating the uptake of sodium and excretion of urine, and produce
bicarbonate to regulate pH in the body. The bladder receives urine from the kidneys via small tubes called ureters. Urine is excreted
from the bladder to the outside world through a tube called the urethra.
Male reproductive system: The testes produce sperm and are housed outside of the body in the scrotum. The tested are connected to
the penis through a small tube called the epididymis. The penis is the external reproductive organ and is used for both sexual
intercourse and urination.
Female reproductive system: The ovaries are located bilaterally in the lower quadrants of a female’s abdomen and serve to produce
ova (eggs) for reproduction. The ovaries are connected to the uterus via the fallopian tubes (the site where sperm fertilizes the ovum).
The uterus is a muscular organ that contains the developing fetus through forty weeks of pregnancy; it expands and can be extremely
vascular. The uterus is connected to the vagina, or birth canal, which serves as the exit route to the fetus, the female reproductive
organ, and the site of sexual intercourse.