2. Components of MedicalComponents of Medical
TermsTerms
O Words made from parts
O Root: pnea, arthr
O Root with combining form: therm-o + meter
= thermometer
O Prefix: dys-pnea, tachy-pnea
O Suffix: arthr-itis, hemophil-iac
O Compounds of two or more words:
smallpox
4. Word Component ExampleWord Component Example
hemo (blood) thorax (chest)
hemothorax (blood in chest cavity)
5. Word Component ExampleWord Component Example
cardio
(heart)
ology
(study of)
ist
(specialist)
cardiologist
(doctor specializing in cardiac care)
6. Acronyms and AbbreviationsAcronyms and Abbreviations
O Acronym: abbreviation made up of initials
that can be pronounced as a word
O CPAP (see-pap): Continuous Positive
Airway Pressure
O Abbreviation: letters or symbols used in
place of words or phrases
O DNR: Do Not Resuscitate
11. Planes of the Body
O Coronal (frontal)
O Front and back
O Sagittal (median)
O Split body into right
and left
O Transverse or axial
(horizontal)
O Top and bottom
12. Abdominal QuadrantsAbdominal Quadrants
O Horizontal and vertical
lines through navel
O Right upper quadrant
(RUQ)
O Left upper quadrant
(LUQ)
O Right lower quadrant
(RLQ)
O Left lower quadrant
(LLQ)
20. Skeletal System
O Extends into all
parts of body
O Consists of skull
and spine, ribs and
sternum, shoulders
and upper
extremities, pelvis
and lower
extremities
31. Respiratory PhysiologyRespiratory Physiology
O Inhalation (active process)
O Diaphragm and intercostal muscles
contract; diaphragm moves downward
O Negative pressure pulls air into lungs
O Exhalation (passive process)
O Diaphragm and intercostal muscles relax
O Positive pressure pushes air out of lungs
33. Ventilation and RespirationVentilation and Respiration
O Ventilation: movement of gases to and
from alveoli
O Respiration: exchange of gases between
cells and bloodstream
continued
34. Ventilation and RespirationVentilation and Respiration
O Oxygenated blood travels from lungs to
heart, then is pumped to rest of the body
O At capillary level, oxygen (O2) is
exchanged with cells for waste carbon
dioxide (CO2)
O Deoxygenated blood returns to the heart,
then to lungs to exchange waste CO2 for
O2
41. Composition of the BloodComposition of the Blood
O Plasma
O More than half of blood’s volume
O Red blood cells
O RBCs, erythrocytes, red corpuscles
O White blood cells
O WBCs, leukocytes, white corpuscles
O Platelets
O Help with clotting
42. PulsePulse
O Wave of blood flowing down an artery
when the left ventricle contracts
O Can be felt when an artery is near the
surface of the skin and over a bone
43. Peripheral and Central PulsesPeripheral and Central Pulses
O Peripheral (outer parts of body)
O Radial
O Brachial
O Posterior tibial
O Dorsalis pedis
O Central (core of body)
O Carotid
O Femoral
44. Central PulsesCentral Pulses
O Pulses near the center or core of the body
O Carotid
O Femoral
O Carotid pulse should be used to determine
pulselessness rather than a peripheral
pulse
50. Blood PressureBlood Pressure
O Pressure inside
arteries
O Systolic (upper
reading)—arterial
pressure when left
ventricle contracts
O Diastolic (lower
reading)—pressure
when left ventricle
refills
55. Autonomic Nervous System
O Division of peripheral nervous system that controls
involuntary motor functions
O Sympathetic (fight or flight)
O Body response –stimulation of sympathetic tone
O Lungs breath deeper, heart beats faster, vessels
constrict
O Parasympathetic (feed or breed)
O Digestive and reproductive system
O Directs blood to required areas
O Normal body functions
57. IntegumentaryIntegumentary
System—FunctionsSystem—Functions
O Protection
O Serves as barrier to keep out microorganisms, debris,
and unwanted chemicals
O Preserves chemical balance of body fluids and tissue
O Water Balance
O Prevent water loss and stops environmental water from
entering
O Temperature Regulation
O Blood vessels dilate or constrict to radiate heat or
prevent heat loss
O Sweat glands help cool body
63. continued
Chapter ReviewChapter Review
O Medicine has a language of its own. You
will frequently communicate with medical
professionals who speak this language.
O Medical terms generally consist of a root
with a prefix and/or suffix.
64. Chapter ReviewChapter Review
O Your knowledge of the anatomy, or
structure, and the functions, or physiology,
of the body will be important in allowing
you to assess your patient and
communicate your findings with other
EMS personnel and hospital staff
accurately and efficiently.
continued
65. Chapter ReviewChapter Review
O Major body systems with which you
should be familiar are musculoskeletal,
respiratory, cardiovascular, nervous,
digestive, integumentary, endocrine,
renal, and reproductive.
66. RememberRemember
O Medical terminology is the language of
health care. Roots, prefixes, and suffixes
can lend clues to the meaning of many
terms.
O Understanding anatomy and physiology is
like reviewing the owner’s manual for the
body.
continued
67. RememberRemember
O Anatomical terminology brings precision
and accuracy to descriptions.
O Understanding an overview and the basic
function of body systems will improve both
assessment and treatment of patients.
68. Questions to ConsiderQuestions to Consider
O Is my use of medical terms accurate and
descriptive?
O Can I identify critical organs and
structures that reside in an area where a
patient has a complaint or traumatic
injury?
69. Critical ThinkingCritical Thinking
O You respond to a teenage boy who has
taken a hard fall from his dirt bike. He has
a deep gash on the outside of his left arm
halfway between shoulder and elbow and
another on the inside of his right arm just
above the wrist. His left leg is bent at a
funny angle about halfway between hip
and knee.
continued
70. Critical ThinkingCritical Thinking
O When you cut away his pants leg, you see
a bone sticking out of a wound on the
front side. How will you describe your
patient’s injuries over the radio to the
hospital staff?
Editor's Notes
Advance Preparation
Prepare lists of medical terms, including prefixes, roots, and suffixes.
Prepare lists of common abbreviations and acronyms.
Prepare anatomical models.
Invite a model to demonstrate directional and positional terminology.
Talking Points: When a vowel (such as o) is added to end of the root, it becomes a combining form which can be joined with other words or roots or suffixes. For example, therm/o and meter combine to form thermometer, an instrument for measuring heat or temperature. Prefixes modify the root’s meaning, usually telling what kind, where, in what direction, or how many. For example, the root pnea relates to breathing. Adding the prefix dys- (painful; difficult) makes dyspnea, or difficult breathing. Adding the prefix tachy- (rapid; fast) creates tachypnea, or rapid breathing. A number of suffixes have specialized meanings. The suffix -itis means “inflammation” and the root arthr refers to a joint; thus, arthritis is inflammation of a joint. The suffix -iac forms a noun indicating a person afflicted with a certain disease: for example, a hemophiliac is a patient suffering from the bleeding disorder hemophilia. Sometimes medical words are compounds, made up of two or more whole words. For example, the word small is joined with the word pox to form the medical term smallpox, the name of a disease.
Discussion Topics: Explain how knowing various common roots, prefixes, and suffixes can help you identify unknown medical terms. List and define common medical roots, prefixes, and suffixes.
Class Activity: Everyone in the class must use medical terminology from this point forward. This activity will continue throughout the length of the entire course. Have students practice using the terminology.
Point to Emphasize: Many medical terms can be broken down into roots, prefixes, and suffixes to identify their meaning.
Point to Emphasize: Learning to recognize common roots, prefixes, and suffixes will aid comprehension of unknown terms.
Knowledge Application: Assign homework. Provide students with a list of medical terms as well as a list of common roots, prefixes, and suffixes. Have students, using only these lists, define the medical terms. Discuss the results in class.
Point to Emphasize: Abbreviations and acronyms can be helpful, but they often lead to ambiguity and imprecision.
Talking Points: Avoid using obscure medical terminology, jargon, abbreviations, or acronyms when talking to patients and families. For example, if you ask if a patient has ever had an “MI” (myocardial infarction, or heart attack), the patient might not be able to provide the correct answer because of the unfamiliar terminology. Resist the urge to use complex medical terminology—even correctly—when a simple, accurate term will do. The language of medicine, like any other language, must be applied appropriately and practically in any given situation.
Discussion Topic: Discuss why abbreviations and acronyms might lead to imprecise documentation.
Critical Thinking: Present two situations. First, describe a situation in which using precise medical terminology may not be the best course of action. Next, describe a situation in which the precision of medical terminology (compared to common language) might be necessary.
Knowledge Application: Use random and unknown abbreviations and acronyms in the instructions for a homework assignment. Discuss the ensuing confusion.
Talking Points: A working knowledge of anatomy will help you understand where organs and organ systems are located and also how external injuries may impact internal systems. Knowing physiology will give you a baseline idea of how the body should work normally. Understanding this will help you identify abnormal function and predict the impact of challenges to normal function.
Discussion Topic: Define anatomy and physiology.
Critical Thinking: Why is understanding normal functions of the body so important? What help does it give us as EMTs?
Knowledge Application: Explain why knowledge of anatomy and physiology might be helpful to you as an EMT in the areas of assessment and of treatment of your patients.
Points to Emphasize: Directional terms allow for precision of description. Anatomical position is the universal reference for directional terminology.
Talking Points: All descriptions of the body use anatomical position as their starting point. When describing locations on the body, use anatomical position as a reference even if the patient is not in this position. For example, the patient’s face is referred to as anterior (at the front) because the face is anterior in anatomical position, even if the patient is lying face down. The importance of always using this standardized position is that all health care providers will use the same anatomical starting point and will understand each other’s references.
Discussion Topic: Discuss how a possessing a knowledge of external anatomy might assist you in locating internal structures.
Talking Points: For directional and spatial relationships, the body is divided into planes. A plane is a flat surface that would be formed if you sliced straight through an imaginary human body. Cutting from top to bottom, you could slice the body into right and left halves (sagittal or median planes) or into front and back halves (frontal or coronal planes). Slicing the body into top and bottom halves creates transverse or horizontal planes.
Discussion Topic: Discuss how using directional terms makes your descriptions more precise.
Knowledge Application: Have students work in small groups. Ask each group to provide directions for a simple task, using only anatomical directional terms. For example, one group might provide directions on how to walk to the bathroom; another might explain how to drink water from a cup.
Talking Points: It is important for the EMT to learn what organs are located in each quadrant to help in the assessment and treatment of the patient.
Discussion Topic: Discuss how possessing a knowledge of external anatomy might assist you in locating internal structures.
Class Activity: Have students, working with tape and a marker, use anatomical terms to label the student sitting next to them. (Do not allow this exercise to get out of hand or become inappropriate.)
Critical Thinking: How might using medical directional terms be confusing to your patient?
Knowledge Application: Use a skeleton or other anatomical model to demonstrate how external anatomy helps to identify internal structures.
Point to Emphasize: Positional terms allow for precise and universal description of the patient’s position.
Talking Points: This is the preferred position for the unconscious non-trauma patient, as it allows vomitus and secretions to drain from the mouth and reduces the risk of aspiration. It is also referred to as either left or right lateral recumbent, depending on which side the patient is on. This position is also used for the transport of women in late stages of pregnancy.
Talking Points: This is usually accomplished by raising the head end of the stretcher so the body is at a 45°–60° angle. The patient may be sitting straight up or leaning slightly back. If 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.
Discussion Topic: Explain the following positional terms: supine, prone, semi-Fowler, lateral recumbent.
Talking Points: In the Trendelenburg position, the patient is lying with the head slightly lower than the feet. This may be accomplished by having the patient lie flat and elevating the legs a few inches. This position is now seldom used. It was once used for patients with suspected shock without suspected spine injury, but is no longer recommended for shock.
Knowledge Application: Have a model assume various positions. Ask students to label those positions, using positional terms.
Point to Emphasize: The musculoskeletal system has three main functions: to give the body shape; to protect vital internal organs, and to provide for body movement.
Class Activities: Have small groups, using household items (bags, funnels, tubing, rubber bands, and so on), design models of a body system. Have them present and explain functions. Assign anatomical diagrams to be filled out as homework.
Knowledge Application: Conduct an A&P research project. Assign each student a specific body system. Have them research that body system and present their findings to the class.
Point to Emphasize: The skeleton consists of the skull and spine, ribs and sternum, shoulders and upper extremities, and pelvis and lower extremities. Interacting with the skeletal system are muscles, ligaments, and tendons.
Talking Points: Interacting with the skeletal system are muscles, ligaments (which connect bone to bone), and tendons (which connect muscle to bone).
Knowledge Application: Assign a disease or injury (such as asthma) to each student. Have students research the disorder and then report on its relationship to the affected body system. How does the disorder interrupt function?
Talking Points: The skull is the bony structure of the head. A main function is to enclose and protect the brain. (If the brain is injured and begins to swell, there is little room inside the skull to expand. This can result in a serious situation for the patient.) The cranium consists of the top, back, and sides of the skull. The face is the front of the skull. The bones of the anterior cranium connect to facial bones, including the mandible, maxillae (fused bones of the upper jaw), and the nasal bones (which provide some of the structure of the nose). These bones form the facial structures. Some of these structures consist of multiple bones, such as the orbits, which surround the eyes, and the zygomatic arches, which form the structure of the cheeks.
Talking Points: Like building blocks, vertebrae are stacked one upon the other to form the spinal column. Vertebrae are open in the middle, somewhat like donuts, creating a hollow center for the spinal cord. Since the spinal cord is essential for movement, sensation, and vital functions, injuries to the spine have the potential to damage the cord, possibly resulting in paralysis or death. For this reason, you will see references to “taking spinal precautions” for some patients. The areas most commonly injured are the cervical and lumbar areas, since these have no supporting structure (like the ribs and pelvis) and so absorb more force in a traumatic injury.
Talking Points: The thorax is the chest. The bones of the thorax form an internal space called the thoracic cavity. This cavity contains the heart, lungs, and major blood vessels. An important function of the thorax is to protect these vital organs. This is accomplished by the 12 pairs of ribs that attach to the 12 thoracic vertebrae of the spine. In the front, 10 of these pairs of ribs are attached to the sternum (breastbone) and two are called floating ribs since they have no anterior attachment. The sternum is a flat bone divided into three sections: manubrium (superior portion), body (center portion), and xiphoid process (inferior tip).
Class Activity: Assign an online scavenger hunt. Ask each student to find video graphics on a particular body system and present their findings to the class.
Talking Points: The pelvis is sometimes called the hip, although the hip is actually the joint where the femur (thigh bone) and pelvis join. The pelvis contains bones that are fused together. The ilium is the superior bone that contains the iliac crest, which is the wide bony wing that can be felt near the waist. The ischium is the inferior, posterior portion of the pelvis. The pubis is formed by the joining of the bones of the anterior pubis. The pelvis is joined posteriorly to the sacral spine. The hip joint consists of the acetabulum (the socket of the hip joint) and the ball at the proximal end of the femur.
Talking Points: The pelvis and hip joint are part of the lower extremities. Moving downward from the hip, the large thigh bone is the femur. (It is the largest long bone in the body.) It has a slight bend at its proximal end where it attaches to the pelvis. This is a frequent site of fractures and is commonly involved when a patient “breaks a hip.” Progressing down the leg, the patella, or kneecap, sits anterior to the knee joint. The knee connects with the femur superiorly and with the bones of the lower leg, the tibia and fibula, inferiorly. The tibia (shin bone) is the medial and larger bone of the lower leg. The fibula is the lateral and smaller bone of the lower leg. The ankle connects the tibia and fibula with the foot. Two distinct landmarks are the malleolus at each side of the ankle: the lateral malleolus (lower end of the fibula), and the medial malleolus (lower end of the tibia). These are the protrusions seen on the lateral and medial aspects of the ankles. The ankle consists of bones called tarsals. The foot bones are metatarsals, the heel bone is the calcaneus, and the toe bones are phalanges.
Talking Points: Each shoulder consists of several bones: clavicle (collarbone), scapula (shoulder blade), and proximal humerus. The clavicle is located anteriorly; the scapula is located posteriorly. The acromion process of the scapula is the highest portion of the shoulder. It forms the acromioclavicular joint with the clavicle and is a frequent area of shoulder injury. The upper arm and forearm consist of three bones connected at the elbow: the humerus (between the shoulder and the elbow) and the radius and ulna (between the elbow and the hand). The radius is the lateral bone of the forearm. It is always aligned with the thumb. (The radial pulse is taken over the radius.) The ulna is the medial forearm bone. The wrist consists of several bones called carpals. The bones of the hand are the metacarpals. The finger bones, like the toe bones, are phalanges.
Talking Points: Joints are formed when bones connect to other bones. There are several types of joints, including ball-and-socket joints and hinge joints. The hip is an example of a ball-and-socket joint, in which the ball of the femur rotates in a round socket in the pelvis. The elbow is an example of a hinge joint in which the angle between the humerus and ulna—which are connected by ligaments—bends and straightens, as the name suggests, like a hinge.
Talking Points: Attached to the bones, voluntary muscles form the major muscle mass of the body. Voluntary muscle can contract upon voluntary command. For example, if you want to, you can reach to pick up an item or walk away. Involuntary muscles respond automatically to orders from the brain. They are found in the GI system, lungs, blood vessels, and urinary system. You do not have to consciously think about using them to breathe, digest food, or perform other functions that occur under their control. In fact, you have no direct control over involuntary muscles. Involuntary muscles do respond to stimuli such as stretching, heat, and cold. Cardiac muscle is a specialized form of involuntary muscle found only in the heart. Cardiac muscle is extremely sensitive to decreased oxygen supply and can tolerate interruption of blood supply for only very short periods. The heart muscle has its own blood supply through the coronary artery system. The heart also has a property called automaticity: it has the ability to generate and conduct electrical impulses. The heartbeat (contraction) is controlled by these electrical impulses.
Point to Emphasize: The purposes of the respiratory system are ventilation and oxygenation. Oxygen is moved into the bloodstream through inhalation, and carbon dioxide is picked up by the blood and excreted through exhalation.
Talking Points: Air enters the body through the mouth and nose. It moves through the pharynx, which includes the oropharynx (posterior to the mouth) and the nasopharynx (posterior to the nose). From the pharynx, air moves on a path to the lungs. A leaf-shaped structure called the epiglottis closes over the glottis, the opening to the trachea, to prevent foods and foreign objects from entering the trachea during swallowing. The larynx (voice box), contains the vocal cords. The ring-shaped cricoid cartilage forms the lower portion of the larynx. The trachea (windpipe) carries air from the larynx down to the lungs. This tube is formed and protected by 16 C-shaped (incomplete) rings of cartilage. The trachea splits (bifurcates) into two bronchi. One “mainstem” bronchus goes to each lung. Inside each lung, the bronchi branch and split (the branches are called bronchioles) and the passages get smaller. Each branch ends at a group of alveoli, the small sacs where gas exchange with the bloodstream takes place. The diaphragm divides the chest cavity from the abdominal cavity. It is a large muscle primarily controlled by the phrenic nerve. The diaphragm and other parts of the body allow the body to inhale and exhale.
Point to Emphasize: Respiratory physiology is an important concept that will be valuable in later discussions. Provide an early emphasis to improve ongoing comprehension.
Talking Points: During inhalation, air is moved through the airway and into the alveoli. Each single alveolus is surrounded by pulmonary capillaries. The pulmonary capillaries bring circulating blood to the outside of the alveoli. Through the very thin walls of the alveoli and the capillaries, oxygen is transferred from the air inside the alveoli to the bloodstream and carbon dioxide is moved from the bloodstream into the air within the alveoli. This movement of gases to and from the alveoli is called ventilation. Some respiratory diseases interfere with this process, making exhalation an active process as well.
Knowledge Application: Have students work in small groups. Assign each group a system. Have them research that system and then work with other groups to identify how their systems might overlap and work together. Discuss findings.
Points to Emphasize: Circulation and perfusion are concepts that also will continue to be important. Take time now to assist future lessons. The cardiovascular system consists of the heart, the blood, and the blood vessels. It is also called the circulatory system. The respiratory system and the cardiovascular system together make up the cardiopulmonary system. The interaction of these two systems is essential to life.
Knowledge Application: Have students work in small groups. Assign the task of designing a body system assessment (acknowledging that you have not yet taught patient assessment). Discuss.
Talking Points: The heart has four chambers: two upper chambers (atria) and two lower chambers (ventricles). The venae cavae (superior and inferior) are the two large veins that return deoxygenated blood to the heart. The right atrium receives this blood and, upon contraction, sends it to the right ventricle. When the right ventricle contracts, it pumps this blood out to the lungs via the pulmonary arteries. In the lungs, carbon dioxide is excreted (taken out of the blood), and oxygen is obtained (taken into the blood). The oxygen-rich blood is returned to the left atrium via the pulmonary veins. When the left atrium contracts, it sends this blood to the left ventricle. When the left ventricle contracts, it pumps this blood into the aorta, the body’s largest artery, for distribution to the entire body. The left ventricle is the most muscular and strongest part of the heart. Between each atrium and ventricle is a one-way valve that prevents blood from being forced back up into the atrium when the ventricle contracts. The pulmonary artery has a one-way valve so that blood in the artery does not return to the right ventricle. The aorta also has a one-way valve to prevent backflow to the left ventricle. This system of one-way valves keeps the blood moving in the correct direction along the path of circulation.
Talking Points: The contraction, or beating, of the heart is an automatic, involuntary process. The heart has its own natural “pacemaker” and a system of specialized muscle tissues that conduct electrical impulses that stimulate the heart to beat. This network is called the cardiac conduction system. Regulation of rate, rhythm, and force of heartbeat comes, in part, from the cardiac control centers of the brain. Nerve impulses from these centers are sent to the pacemaker and conduction system of the heart. These nerve impulses and chemicals (epinephrine, for example), released into the blood, control the heart’s rate and strength of contractions.
Talking Points: The heart receives no oxygenation from the blood that is pumped through the chambers. It is oxygenated by the coronary arteries that branch off the base of the aorta. If a blockage of blood flow occurs in these arteries, it may result in an acute myocardial infarction (AMI), or heart attack.
Talking Points: Blood vessels are described by their function, location, and whether they carry blood away from or to the heart. Arteries carry blood away from the heart and begin with large vessels, like the aorta. They gradually branch to smaller and smaller vessels. The smallest branch of an artery is called an arteriole. These small vessels lead to the capillaries. Capillaries are tiny blood vessels found throughout the body. The capillaries are where gases, nutrients, and waste products are exchanged between the body’s cells and the bloodstream. From the capillaries the blood begins its return journey to the heart by entering the smallest veins. The blood travels from the smaller to the larger vessels on its return trip to the heart. Immediately after leaving the capillaries, the blood enters venules, the smallest veins. From the venules, the veins get gradually larger, eventually reaching the venae cavae. The pulmonary artery carries deoxygenated blood from the heart to the lungs, while the pulmonary vein carries oxygenated blood from the lungs to the heart.
Discussion Topic: Define perfusion. Describe the necessary requirements to create perfusion.
Talking Points: The red and white blood cells and platelets are carried in the plasma. The primary function of red blood cells is to carry oxygen to the tissues and carbon dioxide away from the tissues. These cells also provide the red color to the blood. White blood cells are involved in destroying microorganisms (germs) and producing substances called antibodies, which help the body resist infection. Platelets are membrane-enclosed fragments of specialized cells. When these fragments are activated, they release chemical clotting factors needed to form blood clots.
Talking Points: The carotid pulse, rather than a peripheral pulse, should be used to determine pulselessness.
Points to Emphasize: Glucose is converted by the cells into energy in the form of adenosine triphosphate (ATP). Oxygen is a necessary component of this conversion process. When oxygen is present, glucose is converted in a process called aerobic metabolism. This process produces sufficient amounts of energy and minimal waste products. If oxygen is not present in sufficient supply, the process will shift to anaerobic metabolism. The movement of oxygen from the blood into the cells, coupled with the removal of waste products, is referred to as perfusion. In order for cells to be oxygenated and carbon dioxide to be removed, air must be reaching the alveoli, and it must be matched up with a sufficient supply of blood in the pulmonary capillaries.
Talking Points: Hypo is the medical prefix meaning “low.”
Discussion Topics: Describe the elements required for the production of adenosine triphosphate. Compare and contrast aerobic metabolism with anaerobic metabolism. Why is aerobic metabolism better for the body system?
Points to Emphasize: The nervous system consists of the brain, spinal cord, and nerve tissue. It transmits impulses that govern sensation, movement, and thought. It also controls the body’s voluntary and involuntary activity. The central nervous system is composed of the brain and the spinal cord.
Talking Points: The brain is like a powerful computer that receives information from the body and, in turn, sends impulses to different areas to respond to internal and external changes. The spinal cord rests within the spinal column and stretches from the brain to the lumbar vertebrae. Nerves branch from each part of the cord and reach throughout the body. A key function of the central nervous system is consciousness. The reticular activating system is a series of nervous pathways in the brain and is essentially responsible for keeping you awake. The brain and spinal cord are quite fragile. They have a consistency not unlike a ripe banana. This is why they are protected by the skull and spinal vertebrae. Once damaged, brain and spinal tissue will not regenerate and cannot be repaired.
Critical Thinking: Your patient has been stabbed and is losing blood rapidly. Discuss the changes that might occur in each of the following systems in response to blood loss: circulatory system, respiratory system, nervous system.
Points to Emphasize: Discussion of the autonomic/sympathetic nervous system in terms of the “fight or flight” response will help students understand compensation. The peripheral nervous system consists of two types of nerves: sensory and motor. Sensory nerves transmit this to the spinal cord and brain so immediate action may be taken. The motor nerves carry messages from the brain to the body.
Talking Points: The autonomic nervous system is the division of the peripheral nervous system that controls involuntary motor functions and affects such things as digestion and heart rate. It can be further broken down into the sympathetic and parasympathetic nervous systems. The sympathetic function is often referred to as the “fight or flight” response. This system is engaged when the body is in crisis. Stimulation of sympathetic tone causes the heart to beat faster, the lungs to breathe deeper, and the blood vessels to constrict. The parasympathetic asserts an opposite effect. It is engaged in times of relaxation and is often referred to as the “feed or breed” response. Parasympathetic tone causes increased blood flow to the digestive tract and to the reproductive organs. It also can cause the heart to slow down and the blood vessels to dilate.
Discussion Topics: Describe the basic function of each of the following systems: skeletal, respiratory, cardiovascular, and nervous. Describe the roles of the autonomic and the peripheral nervous systems. How do their functions differ?
Talking Points: The digestive system provides mechanisms by which food travels through the body and is digested. Food enters the mouth and is broken down by saliva and chewing. The food passes from the mouth through the oropharynx and into the esophagus, where it is transported to the stomach. Except for the mouth and the esophagus, all of the organs of digestion are contained in the abdominal cavity. The stomach fills with food. Acidic gastric juices begin to break food down into components that the body will be able to convert into energy. The small intestine has three parts: duodenum, jejunum, and ileum. It continues to break food down for absorption through the wall of the small intestine. The large intestine removes water from waste products as they move toward elimination from the body. Several organs located outside of the stomach–intestines continually assist in the food breakdown process. The liver produces bile, which helps break down fats. The liver also detoxifies harmful substances, stores sugar, and helps produce blood products. The gallbladder stores bile. The pancreas secretes juices that help break down proteins, carbohydrates, and fat. Acting as a blood filtration system, the spleen filters out older blood cells. The appendix is made of lymphatic tissue. Its exact function is not well understood, but an infected appendix (appendicitis) is a common cause of abdominal pain.
Talking Points: The skin has three major layers. The outer layer (epidermis) is composed of four layers (except at palms of hands and soles of feet, which have five layers). The pigment granules of the skin and living cells are found in the deeper layers. The cells of the innermost layer actively divide, replacing the dead cells of the outer layers. The epidermis contains no blood vessels or nerves. Injuries of the epidermis present few problems in EMT-level care. The layer below the epidermis is the dermis, which is rich with blood vessels, nerves, and specialized structures such as sweat glands, sebaceous (oil) glands, and hair follicles. Specialized nerve endings are also found in the dermis. Once the dermis is opened to the outside world, contamination and infection become major problems. These wounds can be serious, accompanied by profuse bleeding and intense pain. The layers of fat and soft tissue below the dermis are the subcutaneous layers. Shock absorption and insulation are major functions. Again, there are the problems of tissue and bloodstream contamination, bleeding, and pain when these layers are injured or exposed.
Talking Points: The endocrine system produces chemicals called hormones that help to regulate many body activities and functions. The pancreas is a key organ of the endocrine system. Among other functions it secretes the hormone insulin. Insulin is critical to the body’s use of glucose, a sugar that fuels the body. The adrenal glands are also an essential component of the endocrine system. They secrete epinephrine (adrenaline) and norepinephrine. These chemicals are neurotransmitters (chemical messengers) and engage the sympathetic nervous system through a series of chemical receptors located in specific organ systems. For example, when the fight or flight response is engaged, norepinephrine is released. It activates receptors in the lungs (beta 2 receptors) which stimulate the bronchioles to dilate and move more air. Receptors in the heart (beta 1 receptors) are activated to increase heart rate and the force of contraction. The endocrine system is a complex system of chemical messaging that interacts with many other body systems.
Talking Points: The renal system, also called the urinary system, helps the body regulate fluid levels, filter chemicals, and adjust body pH. Fluid balance is essential to a healthy body. An average adult excretes roughly 1.5 liters of urine per day. The renal system can adjust this fluid movement to account for changes in fluid intake or fluid loss such as bleeding. The kidneys are the principal organs of the renal system. They help filter a waste product called urea from the blood and provide fluid balance by regulating the uptake of sodium and the excretion of urine. The kidneys also assist the buffer system with the production of bicarbonate for the blood. Bicarbonate is an essential substance used to help regulate acidity or pH in the body. The renal system also includes the bladder and its connecting passages. The bladder is a round, hollow sac that serves as a fluid reservoir for urine. It 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. In males, the urethra passes through the penis. In females, the urethra is shorter and emerges from the body just above the vaginal opening.
Talking Points: These questions point up the importance of this A&P chapter. Being fluent with the language and being knowledgeable about the subject of the chapter will help EMTs not only assess and care for patients, but also relay information about the patient to other medical personnel and enable them to read medical records documenting the patient’s medical condition.
Talking Points: Remind students of the need to be precise in their language as well as to keep unnecessary words out of the radio message.
