M1 - FINAL STUDY GUIDE

Question 1

Understand the shapes used to classify epithelial cells.

Answer 1

If classified according to shape, epithelial cells are identified as:
1. Squamous—flat and scalelike /ˈskwā-məs /
2. Cuboidal—cube shaped /kyü-ˈbȯi-dᵊl /
3. Columnar—taller than they are wide /kə-ˈləm-nər/
4. Transitional—varying shapes that can stretch
/ tran(t)-ˈzish-nəl /

Question 2

Understand the form elements of the blood.

Answer 2

Formed Elements
There are three main types and several subtypes of formed elements:
1. Red blood cells (RBCs), or erythrocytes 2. White blood cells (WBCs), or leukocytes a.** Granular** leukocytes (obvious granules in their cytoplasm are evident when stained) (1) Neutrophils (2) Eosinophils (3) Basophils
b. Agranular leukocytes (lack obvious granules in their cytoplasm when stained) (1) Lymphocytes (2) Monocytes
3. Platelets or thrombocytes

Question 3

Know the main parts of the cell.

Answer 3

A** plasma membrane** serves as the boundary of the cell; protein and carbohydrate molecules on the outer surface of the plasma membrane perform various functions such as serving as markers that identify cells of each individual. Cytoplasm-The living internal material of cells. It contains organelles necessary for the cells to survive. Nucleus-contains most of the cell’s genetic information, which ultimately controls every organelle in the cytoplasm. It contains DNA, which dictates protein synthesis. It controls cell reproduction.

Question 4

Describe the processes of passive transport passive.

Answer 4

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. Particles scatter themselves evenly throughout an available space. ** Filtration** is the movement of both water and small solute particles through a membrane because of a greater pushing force on one side of the membrane than on the other side. Movement is from an area of high pressure to an area of lower pressure. **Osmosis **is the movement of a fluid through a semipermeable membrane. When some of the solute cannot cross the membrane because there are no open channels or carriers for that solute.

Question 5

Know the anatomic nervous system’s two main division functions of the sympathetic and the parasympathetic division.
/ˌsim-pə-ˈthe-tik /

Answer 5

The ** sympathetic division**
accelerates heartbeat,
constricted blood vessels, dilates blood vessel, decrease per stylus,
inhibits defecation,
closes sphincter, i
nhibits relaxes bladder,
stimulate radial fibers-Dilation of pupils,
inhibits-accommodation for far vision,
stimulates-goose pimples,
increase epinephrine secretion,
increase sweat secretion,
decrease secretion of digestive juices.

The** parasympathetic division**
Slows heartbeat,
increase peristalsis, /ˌper-ə-ˈstȯl-səs/
inhibits-open sphincter for defecation,
stimulates- contracts bladder,
inhibits-Open sphincter for urination,
stimulates circular fibers-constriction of pupil,
stimulate-accommodation for near vision,
increase secretion of digestive juices.

Question 6

Know the chambers of the heart.

Answer 6

The two upper chambers are called atria (singular, atrium), and the two lower chambers are called ventricles. The atria are smaller than the ventricles, and their walls are thinner and less muscular. As you can see in Figure 14-1, both atria form an earlike outpouching called an auricle.

Question 7

Know the structures of the upper and the lower respiratory tract.

Answer 7

The upper respiratory tract is composed of the nose, pharynx, and larynx. The lower respiratory tract consists of the trachea, all segments of the bronchial tree, and the lungs.

Question 8

Know the sensory receptor cells and how they are classified functionally.

Answer 8

Sensory receptor cells are also classified functionally by the
types, or modes, of stimuli that activate them:
1. Photoreceptors—sensitive to change in intensity or color of light, as in vision
2. Chemoreceptors—sensitive to presence of certain chemicals, as in taste or smell
3. Pain receptors—sensitive to physical injury
4. Thermoreceptors—sensitive to changes in temperature
5. Mechanoreceptors—sensitive to mechanical stimuli that change their position or shape

Question 9

Review table 11-2 on page 299. Understand the sense organs and their senses of the eye, the ear. and the nose. Know the specific receptors of the sense organs.

Answer 9

TABLE 11-2 Special Sense Organs
SENSE ORGAN SPECIFIC RECEPTOR TYPE OF RECEPTOR SENSE
Eye Rods and cones Photoreceptor Vision
Ear Spiral organ Mechanoreceptor Hearing
(organ of Corti)
Crista ampullaris Dynamic equilibrium Maculae Static equilibrium
Nose Olfactory cells Chemoreceptor Smell
Taste buds Gustatory cells Taste

Question 10

Understand the process of hemostasis.

Answer 10

The story of how we stop bleeding when an injury occurs—a
process called hemostasis—is the story of a chain of rapid-fire reactions. All these reactions culminate in the formation of a blood clot.
When an injury occurs –> **vasoconstriction **
–> form prothrombin activator + clacium -> converting prothrombin (a protein in healthy blood) to thrombin + fibrinogen (a typical plasma protein) = a fibrous gel called fibrin
–>platelet plug

Question 11

Know the anatomical positions.

Answer 11

Anatomical position. The body is in an erect or standing posture with the arms at the sides and the palms forward. The head and feet also point for-ward. The dashed median line shows the axis of the body’s external bilateral symme-try, in which the right and left sides of the body are mirror images
of each other. The anatomical
compass rosette is ex-plained in a later section of this chapter.

Question 12

Know the meaning of inferior, superior, anterior, posterior, and lateral.

Answer 12

1. Superior and inferior (Figure 1-4). Superior means “to-ward the head,” and inferior means “toward the feet.” Su-perior also means “upper” or “above,” and inferior means
   “lower” or “below.” For example, the lungs are located superior to the diaphragm, whereas the stomach is lo-cated inferior to the diaphragm (refer to Figure 1-8 if you are not sure where these organs are located). The simple terms upper and lower are sometimes used in profes-sional language as well. For example, the term “upper respiratory tract” and “lower gastrointestinal tract” are used commonly by anatomists and health professionals.
2. Anterior and posterior (see Figure 1-4). Anterior means “front” or “in front of.” Posterior means “back” or “in back of.” For example, the nose is on the ante-rior surface of the body, and the shoulder blades are on its posterior surface.
3. Ventral and dorsal. In humans, who walk in an upright position, ventral (toward the belly) can be used in place of anterior, and dorsal (toward the back) can be used for posterior. These terms are sometimes helpful when the body is not in the ana-tomical position.
4. **Medial and lateral ** (see Figure 1-4). Medial means “toward the midline of the body.” Lateral means “to-ward the side of the body or away from its midline.” For example, the great toe is at the medial side of the foot, and the little toe is at its lateral side. The heart lies medial to the lungs, and the lungs lie lateral to the heart.
5. **Proximal and distal ** (see Figure 1-4). Proximal means “toward or nearest the trunk of the body, or nearest the point of origin of one of its parts.” Distal means “away from or farthest from the trunk or the point of ori-gin of a body part.” For example, the elbow lies at the proximal end of the forearm, whereas the hand lies at its distal end. Likewise, the distal portion of a kidney tubule is more distant from the tubule origin than is the proximal part of the kidney tubule.
6. Superficial and deep. Superficial means nearer the surface. Deep means farther away from the body sur-face. For example, the skin of the arm is superficial to the muscles below it, and the bone of the arm is deep to the muscles that surround and cover it.

Question 13

Planes of the Body

Answer 13

1. Sagittal plane —a sagittal cut or section that runs along a lengthwise plane running from anterior to posterior. It divides the body or any of its parts into right and left sides. The midsagittal plane shown in Figure 1-4 is a unique type of sagittal plane that divides the body into two equal halves.
2. Frontal plane —a frontal plane (coronal plane) is a lengthwise plane running from side to side. As you can see in Figure 1-4, a frontal plane divides the body or any of its parts into anterior and posterior (front and back) portions.
3. Transverse plane —a transverse plane is a crosswise or horizontal plane. Such a plane (see Figure 1-4) divides the body or any of its parts into superior and inferior portions.
4. oblique planes

Question 14

Know the organelles and their functions.

Answer 14

Plasma membrane
** Phospholipid** bilayer studded with proteins /ˌfäs-fō-ˈli-pəd/ /ˈstəd
Serves as the water-resistant boundary of the cell Protein and carbohydrate molecules on outer surface of plasma membrane perform various functions—for example, they serve as **[markers] **that identify cells as being from a particular individual, [receptor molecules] for certain hormones, or **[transporters] **to move substances through the membrane

** Cytoskeleton**
Complex internal network of microtubules, microfilaments, and intermediate filaments /ˌmī-krō-ˈtü-(ˌ)byül / /ˌmī-krō-ˈfi-lə-mənt /
Provides support and movement for the cell

Ribosomes /ˈrī-bə-ˌsōm/
Tiny particles, each made up of rRNA subunits
Synthesize proteins—a cell’s “protein factories” /ˈsin(t)-thə-ˌsīz /

Endoplasmic reticulum (ER) /ri-ˈti-kyə-ləm/
Membranous network of interconnected canals and sacs, some with ribosomes attached (rough ER) and some without attachments (smooth ER)
Rough ER receives and transports synthesized proteins (from ribosomes)
Smooth ER [synthesizes] lipids and certain carbohydrates

Golgi apparatus /ˈgȯl-(ˌ)jē/ /ˌa-pə-ˈra-təs/
Stack of flattened, membranous sacs
Chemically processes, then packages substances from the ER

Mitochondria /ˌmī-tə-ˈkän-drē-ən/
Membranous capsule containing a large, folded internal membrane embedded with enzymes; contains its own DNA molecule
Adenosine triphosphate (ATP) synthesis—a cell’s “power plant” or “battery charger” /ə-ˈde-nə-ˌsēn / /(ˌ)trī-ˈfäs-ˌfāt/ /ˈsin(t)-thə-səs

**Lysosome ** /ˈlī-sə-ˌsōm/
“Bubble” of hydrolysis enzymes encased by membrane /hī-ˈdrä-lə-səs/
A cell’s “digestive bag,” it breaks apart large molecules

**Centrosome **
Region of cytoplasm near nucleus containing the centrioles
Acts as a microtubule-organizing center, helping to move cell components

Centrioles /ˈsen-trē-ˌōl /
Pair of hollow cylinders at right angles to each other, each made up of tiny tubules within the centrosome
Help organize and move chromosomes during cell reproduction

Microvilli /ˌmī-krō-ˈvi-ˌlī/
Small, fingerlike projections of plasma membrane
Increase surface area for absorption

Cilia /ˈsi-lē-ə /
Hairlike cell surface extensions supported by an internal cylinder made of microtubules (longer than microvilli)
Sensory “antennae” to detect conditions outside the cell; some cilia also move substances over surface of the cell

Flagella /flə-ˈje-lə /
Long whiplike projection on the sperm; similar to a cilium but much longer
The only example in humans is the “tail” of a sperm cell, propelling the sperm through fluids

Nucleus /ˈnü-klē-əs /
Double-membraned, spherical envelope containing DNA strands
Contains DNA, which dictates protein synthesis, thereby playing an essential role in other cell activities such as transport, metabolism, growth, and heredity

**Nucleolus **
Dense region of the nucleus
Makes subunits that form ribosomes

Question 15

Know and describe the connective tissues.

Answer 15

Types of Connective Tissue The following list identifies several major types of connective tissue in the body. Notice that the list is organized by category. Photomicrographs of representative types are provided in the following pages.

A. Fibrous (connective tissue proper)
1. Loose fibrous (areolar)
2. Adipose (fat)
a. White
b. Brown
3. Reticular
4. Dense fibrous
a. Regular
b. Irregular

**B. Bone **
1. Compact
2. Cancellous

**C. Cartilage **
1. Hyaline
2. Fibrocartilage
3. Elastic

**D. Blood **

E. Hematopoietic tissue

Question 16

Review the different types of anemia.

Answer 16

Polycythemia is a serious blood condition characterized by dramatic increases in RBC numbers. /ˌpä-lē-(ˌ)sī-ˈthē-mē-ə/
**Hemorrhagic Anemia **
Hemorrhagic anemia is caused by an actual decrease in the number of circulating RBCs because of hemorrhage or bleed-ing. It is referred to as either acute blood-loss anemia resulting, for example, from extensive surgery or sudden trauma, or chronic blood-loss anemia caused by the slow but continuous loss of blood over time from diseases, such as cancer or ulcers.
Aplastic Anemia /(ˌ)ā-ˈpla-stik-/
Aplastic anemia is characterized by unusually low RBC counts and destruction of bone marrow. The cause is often related to high-dose exposure to certain toxic chemicals, such as benzene or mercury; irradiation; and in susceptible individuals, certain drugs including chloramphenicol.
**Deficiency Anemias **
Reduction of Healthy Hemoglobin
Deficiency anemias are caused by an inadequate supply of some substance, such as vitamin B12 or iron, required for RBC or hemoglobin production. In addition to adequate numbers of functioning RBCs, the amount and quality of hemoglobin are critical factors in maintaining the oxygen-carrying capac-ity of the blood. Typical hemoglobin levels range from 12 to 14 g per 100
milliliters (g/100 mL) of whole blood for typical adult females and 14 to 17 g/100 mL for typical adult males. A hemoglobin value less than 9 g/100 mL indicates anemia.
Pernicious Anemia /pər-ˈni-shəs/
Pernicious anemia results from a dietary deficiency of vitamin B12 or from the failure of the stomach lining to produce intrinsic factor—the substance that allows vitamin B12 to be absorbed. /in-ˈtrin-zik -ˈtrin(t)-sik /
**Folate Deficiency Anemia ** /ˈfō-ˌlāt /
Folate deficiency anemia is similar to pernicious anemia in that it develops from a vitamin deficiency, causes a decreased RBC count, and results in the formation of larger-than-typical RBCs. In this condition, *folic acid *(vitamin B9) is deficient.
**Iron Deficiency Anemia **
Iron deficiency anemia, as the name suggests, is caused by a deficiency of iron, a mineral required for hemoglobin synthe-sis. Although the body carefully protects its iron reserves, iron levels may be depleted through hemorrhage, low intake, or increased requirements, such as wound healing or pregnancy.

**Hemolytic Anemias ** /ˌhē-mə-ˈli-tik /
RBC Destruction
Hemolytic anemias as a group are all associated with a de-creased RBC lifespan caused by an increased rate of destruc-tion. Frequently, an atypical formation of hemoglobin will cause RBCs to become distorted and easily broken.
Sickle Cell Anemia
Sickle cell anemia is a genetic disease that results in the formation of limited amounts of a variant type of hemoglobin called sickle hemoglobin, or hemoglobin S (HbS). The ge-netic condition produces an amino acid sub-stitution in one of the beta (b) polypeptide chains (see Figure 13-4), causing the resulting HbS to be less stable and less soluble than typical hemoglobin. HbS forms crystals and causes the red cell to become fragile and as-sume a sickle (crescent) shape when the blood oxygen level is low (Figure 13-9).
Thalassemia /ˌtha-lə-ˈsē-mē-ə/
Thalassemia refers to a group of inherited hemolytic anemias. The most common type, which occurs most often in individu-als of Mediterranean descent, is characterized by production of atypical hemoglobin and inadequate numbers of small (mi-crocytic) and often oddly shaped RBCs that are short-lived.

**Hemolytic Disease of the Newborn **
Hemolytic disease of the newborn (HDN) = erythroblastosis fetalis

Question 17

Review the different types of heart sounds and the valve closure which they are associated with.

Answer 17

The first sound, or lub, is caused by vibrations that result
from the abrupt closure of the AV valves as the ventricles con-tract. Closure of the AV valves prevents blood from rushing back into the atria during ventricular contraction. This first sound is of longer duration and lower pitch than the second sound, or dup. The pause between the first and second sound is shorter than the pause between the second sound and the next lub dup of the next systole. The second heart sound is caused by the closing of both the semilunar valves when the ventricles undergo diastole (or relaxation) (see Figure 14-3). Atypical heart sounds called heart murmurs are often
caused by conditions of the valves. For example, incompetent valves may cause a swishing sound as a “lub” or “dup” ends. Stenosed valves, on the other hand, often cause swishing sounds just before a “lub” or “dup.”

Question 18

Review the different types of blood vessels, for example aneurysm, ischemia, and phlebitis.

Answer 18

Arteriosclerosis
If blood flow slows down too much,** ischemia** results.
Ischemia—or decreased blood supply to a tissue—eventually causes cell death and tissue necrosis. If a large section of tissue becomes necrotic, it may begin to decay. Necrosis that progresses to decay is called gangrene.
An** aneurysm** is a section of an artery that has become unusually widened because of a weakening of the arterial wall. Aneurysms sometimes form a saclike extension of the arterial wall. /ˈan-yə-ˌri-zəm /
cerebrovascular accident (CVA).

Conditions of Veins
**Varicose Veins **
Varicose veins are dilated, swollen, bulging veins in which
blood tends to pool rather than continue on toward the heart. Varicosities, also called varices (singular, varix), most com-monly occur in superficial veins near the surface of the body.
Hemorrhoids, or piles, are varicose veins in the rectum
or anus. Excessive straining during defecation can create pressures that cause hemorrhoids. Additionally, the unusual pressures associated with carrying a child during pregnancy predispose expectant mothers (ovum-parents) to hemorrhoids and other varicosities.
Phlebitis
Numerous factors can cause phlebitis, or vein inflammation. Irritation by an intravenous catheter, for example, is a common cause of vein inflammation. Thrombophlebitis is acute phlebitis caused by clot (thrombus) formation. Veins are more likely sites of thrombus formation than arteries because venous blood moves more slowly and is under less pressure than arterial blood. Thrombophlebi-tis is characterized by pain and discoloration of the surround-ing tissue.
If a piece of a clot breaks free, the resulting embolus can
travel and then lodge in another vessel. Pulmonary embolism, for example, results when an embolus lodges in the circulation of the lung (see Figure 13-19 on p. 375). Pulmonary embolism can lead to death quickly if too much blood flow is blocked.

Question 19

Review the different types of shocks, for example cardiogenic shock, hypovolemic shock, Anaphylactic shock and septic shock.

Answer 19

Cardiogenic Shock
Cardiogenic shock results from any type of heart failure, including severe myocardial infarction (heart attack), heart infections, and other heart conditions. The term cardiogenic literally means “produced by the heart.” Because the heart can no longer pump blood effectively
during heart failure, blood flow to body tissues decreases or stops.
Hypovolemic Shock
Hypovolemic shock results from a decrease in blood volume in the blood vessels. The term hypovolemia means “condition of low blood volume.” Reduced blood volume causes low blood pressure and re-duces the flow of blood to tissues. Hemorrhage is a common cause of blood volume loss that then leads to hypovolemic shock.
Hypovolemia can also be caused by loss of interstitial
fluid. When interstitial fluid levels are low, the relative in-crease in interstitial solute concentration will pull blood plasma out of blood vessels and into the tissue spaces. Loss of interstitial fluid is common in chronic diarrhea, vomiting, dehydration, intestinal blockage, severe or extensive burns, and various other conditions.
Neurogenic Shock
Neurogenic shock results from widespread dilation of blood vessels caused by an imbalance in autonomic stimulation of smooth muscles in vessel walls. The term neurogenic literally means “produced by nerves.” Recall from Chapter 10 that autonomic effectors such as smooth muscle tissues are controlled by a balance of stimula-tion between the sympathetic and parasympathetic divisions of the autonomic nervous system. In healthy situations, sym-pathetic stimulation maintains the muscle tone that keeps blood vessels at their usual diameter. If sympathetic stimula-tion is disrupted by an injury to the spinal cord, damage to the medulla, depressive drugs, emotional stress, or some other fac-tor, blood vessels dilate significantly. Widespread vasodilation reduces blood pressure, thus reducing blood flow.
Anaphylactic Shock /ˌa-nə-fə-ˈlak-tik /
Anaphylactic shock results from an acute allergic reaction called anaphylaxis. Like neurogenic shock, anaphylaxis causes systemic blood vessel dilation which leads to a rapid drop in blood pressure. /ˌa-nə-fə-ˈlak-səs /
Septic Shock
Septic shock results from complications of septicemia, a con-dition in which infectious agents release toxins into the blood. The toxins involved in septicemia often dilate blood vessels, thereby causing shock. The situation is usually worsened by the damaging effects
of the toxins on tissues combined with the increased cell activ-ity caused by the accompanying fever. One type of septic shock is toxic shock syndrome (TSS),
which usually results from staphylococcal infections that begin in the vagina during menstruation and spread to the blood (see Appendix A: Examples ofPathological Conditions at evolve.elsevier.com).

Question 20

know the function of B cells.

Answer 20

B cells function indirectly to produce humoral immunity. Recall that **humoral immunity **is resistance to disease organ-isms produced by the actions of antibodies binding to specific antigens while circulating in body fluids. Activated B cells develop into plasma B cells. Plasma B cells secrete antibodies into the blood—thus serving as the “antibody factories” of the body. These antibodies, like other proteins manufactured for extracellular use, are formed in the endoplasmic reticu-lum of the cell.

Question 21

Understand the process of breathing.

Answer 21

Pulmonary ventilation has two phases. Inspiration, or inhala-tion, moves air into the lungs, and expiration, or exhalation, moves air out of the lungs.
Inspiration
Inspiration occurs when the chest cavity enlarges. As the tho-rax enlarges, the lungs expand along with it, and air rushes into the alveoli. This happens because of a very important law of physics which states that the volume and pressure of a gas are inversely proportional.
Muscles that increase the volume of the thorax are classi-fied as inspiratory muscles. These include the diaphragm and the external intercostal muscles.
Expiration **
Quiet, resting expiration is ordinarily a passive process that
begins when the inspiratory muscles relax and return to their resting length.
During more forceful expiration, the expiratory muscles (internal intercostals and several abdominal muscles) contract.

Question 22

Differentiate between central nervous system and peripheral nervous system.

Answer 22

Interneurons
Interneurons conduct impulses within the CNS from sensory neurons to motor neurons. They also often connect with each other to form complex, central networks of nerve fibers. In-terneurons are sometimes called central or connecting neurons.

Central Glia Peripheral Glia
Schwann cells –>neurilemma

Tracts Nerves
bundles of axon axon endoneurium
in the CNS fascicles perineurium
white matter epineurium
(myelinated)
gray matter
(unmyelinated) A ganglion is a group of neuron cell bodies loated in the PNS

Question 23

Know the structures of the heart: the layers of the serous pericardium or the outside of the heart and the inside of the heart pg. 390.

Answer 23

The wall of each heart chamber is composed of cardiac muscle tissue usually referred to as the** myocardium. The septum between the atrial chambers is called the interatrial septum. The interventricular septum separates the ventricles. Each chamber of the heart is lined by a thin layer of very smooth tissue called the endocardium (see Figure 14-2). In-flammation of this lining is referred to as endocarditis. If in-flamed, the endocardial lining can become rough and abrasive to RBCs passing over its surface. Blood flowing over a rough surface is subject to clotting, which can promote formation of a thrombus, or clot (see Chapter 13).

Pericardium
Coverings of the Heart
The heart has its own special covering called the pericardium. It is a multilayered sac that consists of two main parts: a fibrous portion and a serous portion. The outer fibrous portion—the** fibrous pericardium**—is made of tough white fibrous connective tissue that forms a loose, inextensible, protective outer covering for the heart. Within the fibrous peri-cardium is a double layer of smooth, moist serous membrane called the serous pericardium. The inner layer of the serous pericardium is the visceral pericardium, or epicardium. It covers and adheres to the heart’s surface like an apple skin covers an apple. The outer layer of the serous pericardium is the parietal pericardium. It attaches to the inner lining of the fibrous pericardium. Between the visceral and parietal layers is a space filled with fluid that allows the two layers to glide over one another as the heart moves when it beats.

Question 24

Describe the different degrees of burns: first, second, third and 4th degree burns.

Answer 24

Partial-Thickness Burns
As the name suggests, a partial-thickness burn damages all or part of the epidermis, leaving the at least part of the der-mis intact. The least damaging partial-thickness burn is some-times called** a first-degree burn** (for example, a typical sunburn). These burns cause minor discomfort and some reddening of the skin. Although the surface layers of the epidermis may peel in 1 to 3 days, no blistering occurs, and actual tissue destruction is minimal.
A more serious partial-thickness burn is sometimes referred to as a second-degree burn (Figure 7-18, A) and involves the deep epidermal layers, and always causes injury to the upper layers of the dermis. Although deep second-degree burns damage sweat glands, hair follicles, and sebaceous glands, complete destruction of the dermis does not occur. Blisters, severe pain, generalized swelling, and fluid loss characterize this type of burn. Scarring is common.

Full-Thickness Burns
A full-thickness burn is characterized by complete destruction
of the epidermis and dermis. In addition, tissue death extends below the primary skin layers into the subcutaneous tissue. A third-degree burn is a type of full-thickness burn. One distinction between second-and third-degree burns is that third-degree lesions are insensitive to pain im-mediately after injury because of the destruction of nerve endings.

The term fourth-degree burn is used to de-scribe a full-thickness burn that extends below the subcutaneous tissue to reach muscle or bone.

Question 25

Review T cells and where they’re mature.

Answer 25

**Development of T Cells **
T cells are lymphocytes that have undergone their first stage of development in the thymus gland. Stem cells from the bone marrow seed the thymus, and shortly before and after birth, they develop into T cells. The newly formed T cells stream out of the thymus into the blood and migrate chiefly to the lymph nodes, where they take up residence.

Embedded in each T cell’s plasma membrane are protein molecules shaped to fit only one specific kind of antigen molecule.

The second stage of T-cell development takes place when
and if a T cell comes into contact with its specific antigen. If this happens, the antigen binds to the protein on the T cell’s surface, thereby changing the T cell into an activated T cell (Figure 16-18). As with B cells, T cells must also receive a chemical signal** (cytokine)** from another T cell to become activated. Likewise, activated T cells also produce a clone of identical cells, all able to react with this specific antigen.

Question 26

Know the disorders of the ear.

Answer 26

Hearing and Equilibrium Conditions
Hearing Conditions
conduction impairment and nerve impairment.

tinnitus, or “ringing in the ear”
–> **otosclerosis **( impairs conduction by causing structural irregularities in the stapes)
Temporary conduction impairment often results from ear
infection, or otitis.
Hearing loss caused by nerve impairment is common in
older adults. Called presbycusis, this progressive hearing loss associated with aging results from degeneration of nervous tissue of the inner ear and the vestibulocochlear nerve.
hearing loss

Equilibrium Conditions
Equilibrium conditions are often characterized by vertigo (sensation of spinning), disorientation, falling (or feeling of falling), dizziness, and/or lightheadedness.

Ménière disease is a chronic inner ear disease of unknown
cause. Ménière disease is characterized by tinnitus, progressive nerve deafness, and vertigo.

Question 27

Know the structures of the ear.

Answer 27

Ear
The ear is divided into the following anatomical areas (Figure 11-12):
1. External ear
2. Middle ear
3. Inner (internal) ear
External Ear
The external ear has two parts: the auricle, or pinna, and the external acoustic canal. The auricle is the appendage on the side of the head surrounding the opening of the external acoustic canal.
(Helix, Antihelix, Tragus, Antitragus, Lobule (earlobe))
Because it lies exposed against the bony surface of the skull, the auricle is frequently injured by blunt trauma. Bruising may then cause an accumulation of blood and tissue fluid between the skin and underlying cartilage. If left untreated, the classic swelling of “cauliflower ear” may develop and become perma-nent. The skin behind the ear is rich in sebaceous glands. And, if they become infected, painful cysts develop that must be drained.
In people who suffer from gout, small nodules made up of
urate crystals and called tophi often appear on the upper edge of the helix. Another type of nodule that may appear on the helix is called a Darwin tubercle. It is considered a variation and requires no treatment.

Middle Ear
The middle ear is a tiny and very thin epithelium-lined cavity hollowed out of the temporal bone (see Figure 11-12). It is an air-filled space housing three very small bones. The names of these ear bones, called ossicles, describe their shapes—malleus (hammer), **incus **(anvil), and stapes (stirrup).

A point worth mentioning, because it explains the frequent
spread of infection from the throat to the ear, is that a tube—the auditory tube, or eustachian tube—connects the throat with the middle ear (see Figure 11-12). The epithelial lining of the middle ears, auditory tubes, and throat are extensions of one continuous membrane. Consequently, infection caus-ing a sore throat may spread to produce a middle ear infection called otitis media (see Figure 11-13, C).

Inner Ear
Anatomically, the inner ear consists of three spaces in the
temporal bone, assembled in a complex maze called the bony labyrinth. This odd-shaped bony space is filled with a watery fluid called perilymph and is divided into the follow-ing parts: vestibule, semicircular canals, and cochlea. The vestibule is adjacent to the oval window between the semicir-cular canals and the cochlea (Figure 11-14).
Note in Figure 11-14 that a balloonlike membranous sac is suspended in the perilymph and follows the shape of the bony labyrinth much like a “tube within a tube.” This is the membranous labyrinth, and it is filled with a thicker fluid called endolymph.

Hearing
The vibration waves now travel through the fluid of the inner ear to the organ of hearing—the spiral organ (organ of Corti)—which lies within the curling, snail-shaped cochlea. The spiral organ is surrounded by en-dolymph, filling the membranous labyrinth within the bony cochlea. Ciliated “hair cells” on the spiral organ generate nerve impulses when they are bent by the movement of en-dolymph set in motion by sound waves.
his activation of these mechanoreceptors in the spiral or-gan inside the cochlea of the inner ear generates nerve im-pulses that travel through the cochlear nerve to the auditory area of the cerebral cortex and results in hearing.

Question 28

Understand the structure of the ear that controls equilibrium.

Answer 28

Equilibrium
The mechanoreceptors for our sense of balance, or equilibrium, are located in the saclike membranous labyrinth of the vesti-bule and the three semicircular canals of the inner ear.
Within the vestibule are two structures, each made up of a patch of sensory hairs coated with a thick glob of heavy gel.

Each of these mechanoreceptor structures is called a macula. When you bend your head, gravity acts on the heavy gel to pull it one way or the other (Figure 11-16). This, in turn, bends the cilia of the hair cells and thus produces a nerve impulse. This signal is interpreted by the brain as our “sense of gravity” or static equilibrium.

The three semicircular canals are half-circles oriented at
right angles to one another (Figure 11-17). Within each canal is a dilated area called the* ampulla* that contains a sensory struc-\ture called a** crista ampullaris**, which generates a nerve impulse when the speed or direction of movement of your head changes. This “sense of motion” is called dynamic equilibrium.
Nerves from mechanoreceptors in the vestibule join those
from the semicircular canals to form the vestibular nerve. The vestibular nerve then joins with the cochlear nerve to form the vestibulocochlear nerve (cranial nerve VIII) (see Figure 11-12). Eventually, nerve impulses passing through this nerve reach the cerebellum and medulla oblongata, ultimately reaching the cerebral cortex.

Question 29

Understand the type of neurons, sensory, motor, and interneurons.

Question 30

Know the disorders of the eyes, for example, cataracts, conjunctivitis, glaucoma etc.

Answer 30

Refraction Conditions
Common Focusing Problems
If our eyeballs are elongated, the
image focuses somewhere in front of the retina rather than directly on it. The retina receives only a fuzzy image. This con-dition, called** myopia** or nearsightedness, can be corrected with refractive eye surgery or by using contact lenses or glasses.
If our eyeballs are shorter (as measured from anterior to
posterior) than typical, the image focuses behind the retina, also producing a fuzzy image. This condition, called** hyperopia** or *farsightedness *also can be corrected by eye surgery or lenses.
An irregularity (unequal curvature) in the cornea or lens, a
condition called** astigmatism** that distorts vision, also can be corrected with glasses or contact lenses.
Presbyopia, literally “old-sightedness,” is the name for this condition.

Cataracts
Unfortunately, in some individuals, longtime exposure to ultraviolet (UV) radiation in sunlight may cause the lens to become hard, lose its transparency, and have regions that be-come “milky” in appearance. This condition is called a cataract (Figure 11-8). Cataracts often interfere with focusing.
Conjunctivitis
Most eye infections start out in the conjunctiva, producing an inflammation response known as “pink eye” or conjunctivitis. You may recall from Chapter 6 that a variety of different pathogens can cause conjunctivitis. For example, the bacterium Chlamydia trachomatis that commonly infects the reproductive tract can cause a chronic infection called chlamydial conjunctivitis or** trachoma**.
Highly contagious acute bacterial conjunctivitis, characterized by drainage of a mucous pus (Figure 11-9), is most commonly caused by bacteria such as Staphylococcus and Haemophilus.

Strabismus
If the positioning of the eyes cannot be coordinated, a
condition called strabismus or “squint” results. In some cases, the eyes may diverge outward to the side, a condition called divergent squint. If one or both eyes converge toward the nose, the condition is called convergent squint or “cross-eye.”

Conditions of the Retina
Retinal Detachment
For example, in a condition called retinal detachment, part of the retina falls away from the tissue supporting it (see Figure 11-5, C).
**Diabetic Retinopathy **
Diabetes mellitus, a disorder involving the hormone insulin, may cause a condition known as diabetic retinopathy. In this situation, diabetes causes small hemorrhages in retinal blood vessels that disrupt the oxygen supply to the photoreceptors (see Figure 11-5, D).

Glaucoma
Another common condition that can damage the ret-ina is glaucoma. Recall that glaucoma is excessive intraocular pressure caused by excess accumulation of aque-ous humor. As fluid pressure against the retina increases, blood flow through the retina slows. Reduced blood flow causes de-generation of the retina cells and thus a loss of vision.

Retinal Degeneration
Degeneration of the retina can cause difficulty seeing at night
or in dim light. This condition is called **nyctalopia **or “night blindness.”

he leading cause of permanent blindness in older adults
is progressive degeneration of the central part of the retina. Called age-related macular degeneration (AMD), this con-dition affects the part of the retina that is most essential to good vision—the central region called the macula.

Question 31

Know the respiratory disorders.

Question 32

Know the lymphatic disorders.

Answer 32

**Lymphedema **
Lymphedema is a condition in which tissues exhibit swelling (edema) because of the accumulation of lymph. Lymph may accumulate in tissue when the lymphatic vessels are partially blocked (Figure 16-3). This may result from a congenital condi-tion or a specific injury or blockage of lymphatic drainage. Lymphedema also may result from lymphangitis, that is,
lymphatic vessel inflammation. Lymphangitis is characterized by thin, red streaks extending from an infected region. The in-fectious agent that causes lymphangitis may eventually spread to the bloodstream, causing septicemia (“blood poisoning”) and possibly death from septic shock (Figure 16-4). Rarely, lymphedema may be caused by small parasitic worms
that infest the lymphatic vessels. When such infestation blocks the flow of lymph, edema of the tissues drained by the affect-ed vessels occurs. In severe cases, as you can see in Figure 16-5, the tissues swell so much that the limbs look as if they belong to an elephant! For this reason, the condition is often called elephantiasis—literally “condition of being like an elephant.”

rtant in clinical medicine. For example, a school nurse monitoring the progress of a child with an infected fin-ger will watch the elbow and axillary regions for swelling and tenderness of the lymph nodes—a condition called lymphadenitis.

The tonsils serve as the first line of defense from the exterior and, as such, are subject to chronic infection or tonsillitis.

Splenomegaly, or enlargement of the spleen, is observed
in a variety of conditions. For example, infectious conditions such as scarlet fever, syphilis, and typhoid fever, are charac-terized by splenomegaly. Spleen enlargement sometimes ac-companies hypertension or mononucleosis with its increase in monocytes. Splenomegaly also accompanies some forms of hemolytic anemia in which red blood cells appear to be bro-ken apart at a faster than typical rate. Surgical removal of the spleen often cures such cases.

Lymphoma
As you may recall from Chapter 6, lymphoma is a term that refers
to lymphatic tumors. Lymphomas are most often
malignant but, in rare cases, can be benign. The two principal categories of lymphoma are Hodgkin disease and non-Hodgkin lymphoma.

Question 33

Know the autoimmune disorders.

Answer 33

Hypersensitivity of the Immune System
Hypersensitivity is an inappropriate or excessive response of the immune system. There are three main types: allergy, auto-immunity, and alloimmunity.

Allergy
The term allergy is used to describe hypersensitivity of the immune system to relatively harmless environmental antigens. Antigens that trigger an allergic response are often called allergens. One in six Americans has a genetic predisposition to exhibiting an allergy of some kind.
Delayed allergic responses, on the other hand, involve
cell-mediated immunity. In contact dermatitis, for example, T cells trigger events that lead to local skin inflammation a few hours or days after initial exposure to an antigen. Expo-sure to poison ivy, soaps, and certain cosmetics may cause con-tact dermatitis in this manner (Figure 16-20). Hypersensitive individuals may use hypoallergenic products (products without common allergens) to avoid such allergic reactions.
**Autoimmunity **
Autoimmunity is an inappropriate and excessive response to self-antigens. Conditions that result from autoimmune re-sponses are called autoimmune diseases. Examples of autoim-mune diseases are given in Table 9 of Appendix A: Examples of Pathological Conditions at evolve.elsevier.com.

A common autoimmune disease is systemic lupus erythematosus (SLE), or simply lupus. Lupus is a chronic inflam-matory disease that affects many tissues in the body: joints, blood vessels, kidneys, nervous system, and skin.

**Alloimmunity **
Alloimmunity is an excessive reaction of the immune system to antigens from a different individual of the same species. It
is important in relation to pregnancy and tissue transplants. Alloimmunity is also sometimes called isoimmunity.

The antigens most commonly involved in transplant rejec-tion are called human leukocyte antigens (HLAs).
Rejection of grafted tissues can occur in two ways. One
is called host-versus-graft rejection because the recipient’s im-mune system recognizes foreign HLAs and attacks them, destroying the donated tissue. The other is graft-versus-host rejection because the donated tissue (for example, bone mar-row) attacks the recipient’s HLAs, destroying tissue throughout the recipient’s body. Graft-versus-host rejection may lead to death.

Immune System Deficiency
Immune deficiency, or immunodeficiency, is the failure of im-mune system mechanisms in defending against pathogens. Immune system failure usually results from disruption of lym-phocyte (B cell or T cell) function.

Congenital Immune Deficiency **
Congenital immune deficiency, which is rare, results from im-proper lymphocyte development before birth. Depending on the stage of stem cell development (B cells or T cells) during which it occurs, different diseases can result. For example, improper B-cell development can cause insufficiency or the absence of antibodies in the blood. If stem cells are disrupted, a condition called severe combined immune de-ficiency (SCID)** results. In most forms of SCID, humoral im-munity and cell-mediated immunity do not function properly.

Acquired Immune Deficiency
Acquired immune deficiency develops after birth and is not related to genetic conditions. A number of factors can con-tribute to acquired immune deficiency: nutritional deficien-cies, immunosuppressive drugs or other medical treatments, trauma, stress, and viral infection. One of the best-known examples of acquired immune deficiency is acquired immunodeficiency syndrome (AIDS). This syndrome (collection of symptoms) is caused by the human immunodeficiency virus or HIV.

HIV can also be a perinatal infection, that is, an infection passing from parent to infant during birth.

Question 34

Understand the sinuses in the skull.

Question 35

Understand cardiovascular disorders.

Answer 35

Pericarditis
If the pericardium becomes inflamed, a condition called pericarditis results. Pericarditis has various causes, includ-ing trauma, viral or bacterial infection, tumors, and other factors.
Pericardial fluid, pus, or blood (in the case of an injury) may accumulate in the space be-tween the two pericardial layers and impair the pumping ac-tion of the heart. Called pericardial effusion, this condition may develop into a serious compression of the heart called cardiac tamponade.

Valve Conditions
Conditions of the cardiac valves can have several effects. For
example, a congenital variation in valve structure can result in mild to severe pumping inefficiency. Incompetent valves leak, allowing some blood to flow back into the chamber from which it came. Stenosed valves are valves that are narrower than typical, slowing blood flow from a heart chamber (Figure 14-4).
Rheumatic heart disease is cardiac damage resulting
from a delayed inflammatory response to streptococcal in-fection that occurs most often in children. A few weeks after an untreated or improperly treated streptococcal infection, the cardiac valves and other tissues in the body may become inflamed—a condition called rheumatic fever. If severe, the in-flammation can result in stenosis or other deformities of the valves, chordae tendineae, or myocardium.

Mitral valve prolapse (MVP) is a condition affecting the left AV valve (mitral valve). Some people are born with a genetic predisposition for developing this condition, but other factors, including rheumatic fever, can cause it. During contraction of the heart, the flaps of a prolapsed mitral valve extend back into the left atrium which prevents the flaps from fully or evenly clos-ing (Figure 14-5). This causes incompetence, or leaking, through the valve which allows blood to flow back into the left atrium.

Atypical heart sounds called heart murmurs are often
caused by conditions of the valves. For example, incompetent valves may cause a swishing sound as a “lub” or “dup” ends. Stenosed valves, on the other hand, often cause swishing sounds just before a “lub” or “dup.”

Blood Supply to Heart Muscle
In both coronary thrombosis and coronary embolism, a
blood clot occludes or blocks some part of a coronary artery. Blood cannot pass through the occluded vessel and so cannot reach the heart muscle cells it usually supplies. Deprived of oxygen, these cells die. In medical terms, myocardial infarc-tion (MI), or “cardiac muscle tissue death,” occurs. An MI, also referred to as a “heart attack,” is a common
cause of death during middle and late adulthood.
Coronary arteries may also become blocked as a result of
atherosclerosis, a type of “hardening of the arteries” in which lipids and other substances accumulate on the inside of blood vessel walls. Mechanisms of** atherosclerosis** are discussed fur-ther in Chapter 15.

Cardiac Dysrhythmia
The term dysrhythmia refers to an unusual variation of heart rhythm. The term *arrhythmia *is also some-times used to refer to unusual rhythm variations.

** Heart Block**
A **heart block **is an example of a dysrhythmia. In an AV node block, impulses are prevented—or “blocked”—from getting to the ventricular myocardium, which causes the ventricles to contract at a much slower rate than usual. On an ECG, there may be a large distance between the peak of the P wave and the peak of the QRS complex (at “R”). **Complete heart block **occurs when the P waves do not match up with the QRS com-plexes at all—as in an ECG that shows two or more P waves for every one QRS complex (Figure 14-13, B).

Bradycardia
Bradycardia is a slow heart rhythm—less than 60 beats per minute (Figure 14-13, C). Slight bradycardia is typical during sleep and in conditioned athletes while they are awake but at rest. Atypical bradycardia can result from a damaged SA node. When the SA node fails to work properly, the AV node often takes over as the pacemaker of the heart. The AV node fires at a much slower rate than the SA node, which results in 40 to 60 heartbeats per minute. Atypical bradycardia can also result from improper autonomic nervous control of the heart.

Tachycardia
Tachycardia is a rapid heart rhythm—more than 100 beats per minute (Figure 14-13, D). Tachycardia is typical during the stress response and both
during and after exercise. Atypical tachycardia can result from improper autonomic control of the heart, excessive blood loss or shock, fever, the action of drugs and toxins, as well as other factors.

Sinus Dysrhythmia
Sinus dysrhythmia (or sinus arrhythmia) is a variation in heart rate during the breathing cycle (Figure 14-13, E) where the heart rate increases during inspiration and decreases dur-ing expiration. The causes of sinus dysrhythmia are not clear. This phenomenon is common in young, healthy people and does not require treatment.

Premature Contractions
Premature contractions, or extrasystoles, are contractions that occur before the next expected contraction in a series of car-diac cycles. For example, premature atrial contractions (PACs) may occur shortly after the ventricles contract and are indi-cated by an early P wave on the ECG. Premature ventricular contractions (PVCs) occur when the electrical signal begins in the ventricle rather than in the SA node (Figure 14-13, F).

Fibrillation
Frequent premature contractions can lead to fibrillation, a condition in which cardiac muscle fibers contract chaotically, irregularly, and out of sync with one another.
Atrial fibrillation (AF or A-fib) occurs commonly in those with mitral stenosis, rheumatic heart disease, and infarction of the atrial myocardium. Figure 14-13, G, shows an example of atrial fibrillation in an ECG strip. Symptoms of atrial fibril-lation quite often come and go, but if they persist, they might require treatment.
Ventricular fibrillation (VF or V-fib) is an immediately
life-threatening condition. In V-fib, the ventricular contrac-tions are more like “flutters” that are too weak to effectively pump blood out of the ventricles and into their connected vessels. This ineffective ventricular pumping decreases the flow of blood to body tissues, essentially depriving the tissues of oxygen. Unless ventricular fibrillation is corrected immedi-ately by defibrillation or some other method, death may occur within minutes. Figure 14-13, H, shows how ventricular fibrilla-tion looks on an ECG strip.

Heart Failure
Heart failure, often referred to as congestive heart failure or CHF, is the inability of the heart to pump enough blood to sustain life. It can affect the right, left, or both sides of the heart, but most individuals with heart failure have symptoms due to impaired functioning of the left side. Ineffective pump-ing of the left ventricle then results in a significant drop in cardiac output. Heart failure can result from many different heart diseases.
Valve conditions can reduce the pumping efficiency of the heart enough to cause heart failure. Cardiomyopathy, or disease of the myocardial tissue, may reduce pumping effectiveness.

Right heart failure can also be caused by lung conditions
that obstruct healthy pulmonary blood flow and thus overload the right side of the heart—a condition called cor pulmonale (Figure 14-16).

The more common left-sided heart failure—which involves the inability of the left ventricle to pump blood effectively—most often results from myocardial infarction caused by coro-nary artery disease. As stated earlier, left heart failure causes congestion of blood in the pulmonary circulation, termed pulmonary edema, which can possibly lead to right heart failure.

Question 36

Understand the cranial nerves and functions. /ˈkrā-nē-əl/

Question 37

Know the structures of the eyes, for example the optic nerve.