Cellular Adaption, Injury and death

A client presents for a scheduled Papanicolaou (Pap) smear. The clinician who will interpret the smear will examine cell samples for evidence of: A) Changes in cell shape, size, and organization B) The presence of unexpected cell types C) Ischemic changes in cell samples D) Abnormally high numbers of cells in a specified field

Ans: A Feedback: A Pap smear is an example of a diagnostic procedure that tests for the presence of cell dysplasia, that is, deranged cell growth of a specific tissue that results in cells that vary in size, shape, and organization. Unexpected cell types are evidence of metaplasia, whereas ischemic changes are associated with cell hypertrophy. Increases in the number of cells are characterized as hyperplasia.

A client with diabetes has impaired sensation, circulation, and oxygenation of his feet. He steps on a piece of glass, the wound does not heal, and the tissue area becomes necrotic. The necrotic cell death is characterized by: A) Rapid apoptosis B) Cellular breakage C) Shrinkage and collapse D) Chronic inflammation

Ans: B Feedback: Apoptosis is a programmed cell death, unrelated to cell injury, and occurs in a controlled, organized manner. Necrosis is an unorganized death of cells that initiates the acute inflammatory response with intracellular swelling and resulting cellular breakage (rupture).

Hyperplasia

Increased workload causes normal cells to proliferate. (increase number of cells-normal cells)

Metaplasia

Preserves tissue function in harsh environment by changing type of normal cells. (replacement of 1 mature cell type that belongs there with another mature cell type that belong in different location)

Dysplasia

Tissue loses organization in harsh environment. (disorder growth)

Free radicals damage cells by: A) Destroying phospholipids in the cell membrane B) Altering the immune response of the cell C) Disrupting calcium storage in the cell D) Inactivation of enzymes and mitochondria

Ans: A Feedback: Free radicals are highly reactive and can damage cells in several ways. One way is by destroying lipids, which results in a loss of cell membrane integrity. Free radicals modify proteins but do not affect the immune function, calcium storage, or intracellular enzymes of cells.

Which body tissue exhibits the highest rate of turnover and renewal? A) The squamous epithelial cells of the skin B) The connective tissue supporting blood vessels C) The skeletal muscle that facilitates movement D) The nervous tissue that constitutes the central nervous system

Ans: A Feedback: Cells making up the epithelial tissues generally exhibit a high rate of turnover, which is related to their location and function. Renewal of connective and muscle tissue takes place at a much slower pace, whereas nervous tissue is incapable of postnatal regeneration.

When working with a client who has end-stage renal disease (ESRD) and is receiving peritoneal dialysis, the concept of diffusion can be explained by which of the following statements? A) ìIf your potassium level is high, then K+ particles will move from your peritoneal cavity into the dialysis solution, where the concentration of K+ is lower.î B) ìYou will need to give yourself a potent diuretic so that you can pull the potassium into your blood stream and filter the potassium out in your kidneys.î C) ìYour potassium molecules are lipid soluble and will dissolve in the lipid matrix of your cell membranes.î D) ìIf you can get very warm in a sauna, you will heat up your K+ particles, and the kinetic movement of the particles will increase and pass through the cell membranes faster.î

Ans: A Feedback: Diffusion refers to the passive process by which molecules and other particles in a solution become widely dispersed and reach a uniform concentration because of energy created by their spontaneous kinetic movements. In the process of reaching a uniform concentration, these molecules and particles move ìdownhillî from an area of higher to an area of lower concentration. Lipid-soluble molecules, such as oxygen, carbon dioxide, alcohol, and fatty acids (not K+), become dissolved in the lipid matrix of the cell membrane and diffuse through the membrane in the same manner that diffusion occurs in water. Diuretics are not very effective if a person has ESRD. The rate of diffusion depends on how many particles are available for diffusion, the kinetic movement of the particles, and the number and size of the openings in the membrane through which the molecules or ions can move. The environmental temperature does not play a role in this.

Ischemia and other toxic injuries increase the accumulation of intracellular calcium as a result of: A) Release of stored calcium from the mitochondria B) Improved intracellular volume regulation C) Decreased influx across the cell membrane D) Attraction of calcium to fatty infiltrates

Ans: A Feedback: Disruption of the normal intracellular functions causes the impaired mitochondria to release stored calcium. Cell injury disrupts intracellular volume regulation, allowing excessive influx of substances across the impaired cell membrane. Fatty infiltrate is an ominous sign of cell damage and does not interact with calcium.

Which of the following clients would be an example of cellular atrophy? A) A middle-aged female experiencing menopause due to loss of estrogen stimulation B) A postnephrectomy client whose remaining kidney enlarges to compensate for the loss C) A hypertensive, noncompliant client who has developed a progressive increase in left ventricular mass D) A female client with the change in uterine size as a result of pregnancy

Ans: A Feedback: In women, the loss of estrogen stimulation during menopause results in atrophic changes in the reproductive organs. Compensatory hypertrophy is the enlargement of a remaining organ or tissue after a portion has been surgically removed or rendered inactive. For instance, if one kidney is removed, the remaining kidney enlarges to compensate for the loss. In hypertension, for example, the increased workload required to pump blood against an elevated arterial pressure results in a progressive increase in left ventricular muscle mass and need for coronary blood flow. The pregnant uterus undergoes both hypertrophy and hyperplasia as a result of estrogen stimulation.

Which of the following processes associated with cellular injury is most likely to be reversible? A) Cell damage resulting from accumulation of fat in the cytoplasm B) Cellular changes as a result of ionizing radiation C) Cell damage resulting from accumulation of free radicals D) Apoptosis

Ans: A Feedback: Intracellular accumulation of fat leads to serious cell damage, but this is a potentially reversible effect. Ionizing radiation and damage from free radicals are more likely to be permanent, whereas apoptosis is defined as the permanent removal of injured and aged cells.

Which accurately explains the functions of the organelles lysosomes? They: A) Are sacs filled with enzymes that breakdown and remove foreign substances and worn-out cell parts B) Function in association with the endoplasmic reticulum to modify protein end products and package them into secretory granules or vesicles C) Are small particles of nucleoproteins that are involved in the synthesis of proteins that remain in the cell as cytoplasmic structural or functional elements D) Are a dynamic system of interconnected membranous tubes that functions as a tubular communication system for transporting various substances from one part of the cell to another

Ans: A Feedback: Lysosomes are sacs that are filled with hydrolytic enzymes that aid in the processing and removal of unwanted substances within the cytoplasm. The Golgi apparatus functions in association with the endoplasmic reticulum to modify and package substances in preparation for secretion, whereas ribosomes are small particles of nucleoproteins that are involved in the synthesis of proteins. The ER is a tubular communication system for transporting various substances from one part of the cell to another.

The process responsible for generating and conducting membrane potentials is: A) Diffusion of current-carrying ions B) Millivoltage of electrical potential C) Polarization of charged particles D) Ion channel neurotransmission

Ans: A Feedback: Membrane potentials rely on the permeability of the cell membrane and the diffusion of electrically charged ions. Charged particles are polarized (positive charge on one side of the membrane and negative charge on the opposite side of the membrane), but membrane potential exists when the charges are unbalanced on the two sides. Ion channel neurotransmitters are involved with opening protein channels for purposes of cell-to-cell communication.

Although the basic structure of the cell plasma membrane is formed by a lipid bilayer, most of the specific membrane functions are carried out by: A) Bound and transmembrane proteins B) Complex, long carbohydrate chains C) Surface antigens and hormone receptors D) A gating system of selective ion channels

Ans: A Feedback: The functions of plasma membrane depend on the presence of proteins that are bound in the lipid bilayer and some that have the ability to pass freely into and out of the cell. Carbohydrate chains form a cell coat that surrounds the membrane and that contain surface antigens and surface hormone receptors. Some ion channels are gated and open only when the membrane potential changes significantly.

A pregnant client is attending a nutrition class for first-time moms. During the class, the instructor stressed that they should avoid consumption of which food that may cause brain damage from methyl mercury exposure? A) Tuna B) Raw hamburger C) Fresh milk D) Beets

Ans: A Feedback: The main source of methyl mercury exposure is from consumption of long-lived fish, such as tuna and swordfish. Fish concentrate mercury from sediment in the water. Because the developing brain is more susceptible to mercury-induced damage, it is recommended that young children and pregnant and nursing women should avoid consumption of fish known to contain high mercury content. None of the other foods listed pose a threat of mercury toxicity.

A male client with a diagnosis of type 1 diabetes mellitus is experiencing hyperglycemia because he lacks sufficient insulin to increase the availability of glucose transporters in his cell membranes. Consequently, his cells lack intracellular glucose, and it accumulates in his blood. Which of the following processes would best allow glucose to cross his cell membranes? A) Facilitated diffusion B) Simple diffusion C) Secondary active transport D) Endocytosis

Ans: A Feedback: Transport molecules perform facilitated diffusion, in which one substance carries another substance across a cell membrane. Simple diffusion does not require a transport molecule. Glucose does not cross the cell membrane by secondary active transport or endocytosis.

With skeletal muscle contraction, what prevent the development of cross-bridges between the actin and myosin? Select all that apply. A) Tropomyosin attaches globular heads to the myosin filament. B) Troponin covers the tropomyosin-binding sites and prevents the formation of cross-bridges. C) ATP actually plays a role in the positioning of the myosin filaments and actin. D) The concentration of calcium around the myofibrils will prevent the cross-bridges from being formed.

Ans: A, B Feedback: Associated with each actin filament are the two regulatory proteins: tropomyosin and troponin. Tropomyosin, which lies in grooves of the actin strand, provides the site for attachment of the globular heads of the myosin filament. In the noncontracted state, troponin covers the tropomyosin-binding sites and prevents formation of cross-bridges between the actin and myosin. Energy from ATP is used to break the actin and myosin cross-bridges, stopping the muscle contraction. The binding of calcium to troponin uncovers the tropomyosin-binding sites such that the myosin heads can attach and form cross-bridges.

A person eating peanuts starts choking and collapses. His airway obstruction is partially cleared, but he remains hypoxic until he reaches the hospital. The health care providers will be assessing this client for which of the following physiological events? Select all that apply. A) Cerebral infarction B) Coagulation necrosis C) Rapid phagocytosis D) Protein p53 deficiency

Ans: A, B Feedback: Tissue infarction is caused by prolonged oxygen deprivation, and the resulting large group of dead cells coagulates in the damaged area. During coagulation necrosis, acidosis develops and denatures the enzymatic and structural proteins of the cell. Phagocytosis occurs rapidly during apoptosis, so it does not elicit an inflammatory response. Protein p53 activation initiates apoptosis.

Which of the following statements about how smooth muscle differs from skeletal or cardiac muscle are accurate? Smooth muscle: Select all that apply. A) Has dense bodies attached to actin filaments B) Contains sarcomeres between Z lines and M bands C) Contracts more rapidly than skeletal muscles D) Has one centrally located nucleus

Ans: A, D Feedback: Smooth muscle cells are spindle shaped and smaller than skeletal muscle fibers. Each smooth muscle cell has one centrally positioned nucleus. Smooth muscle contains dense bodies that are attached to the membrane, dispersed in the cell, and attached to actin filaments. Smooth muscle has slow contractions and no cross-striations. Sarcomeres are the functional units of cardiac and skeletal muscle only. The sarcomeres extend between Z lines and M bands.

Semen analysis indicates that the client's sperm have decreased motility. Which of the following cellular components may be defective within the client's sperm? A) Ribosomes B) Microtubules C) Mitochondria D) Microfilaments

Ans: B Feedback: Abnormalities in the structure and function of microtubules and consequent dysfunction of the flagella may contribute to impaired sperm motility. Ribosomes, microfilaments, and mitochondria do not directly contribute to movement in cells such as cilia and flagella.

Injured cells become very swollen as a result of: A) Increased cell protein synthesis B) Altered cell volume regulation C) Passive entry of potassium into the cell D) Bleb formation in the plasma membrane

Ans: B Feedback: Altered cell volume regulation, caused by the impaired permeability of the cell membrane, leads to sodium retention and substance accumulation within the cell. Sodium attracts water, and the cell swells even more. Protein synthesis is decreased in injured cells. Potassium has difficulty entering the cell and accumulates in the serum, due to loss of the ATPase sodium/potassium pump. Bleb formation occurs in the cell that is already swollen and ready to burst.

An elderly client has experienced some hypoxia as a result of chronic respiratory problems. Knowing that oxygen -deprived cells result in an accumulation of lactic acid in the cells, physiologically, the client may experience: A) An increase in fat load B) Altered cell membrane permeability C) Retention of lysosomal enzymes D) Cellular shrinkage and dehydration

Ans: B Feedback: Altered membrane permeability impairs the balance, allowing too much of some and not enough of other substances to flow in and out of the cell. The altered permeability, lack of ATP, and loss of functional surface receptors make it difficult for glucose to enter the cell. Excess fat accumulates because it is unable to move through the damaged membrane. Injury to the lysosomal membranes results in the leakage (not retention) of destructive lysosomal enzymes into the cytoplasm and enzymatic digestion of cell components.

The parents of a 4-year-old girl have sought care because their daughter has admitted to chewing and swallowing imported toy figurines that have been determined to be made of lead. Which of the following blood tests should the care team prioritize? A) White blood cell levels with differential B) Red blood cell levels and morphology C) Urea and creatinine levels D) Liver function panel

Ans: B Feedback: Anemia is a cardinal sign of lead toxicity. Consequently, assessment of the quantity and morphology of RBCs is paramount in cases of suspected lead toxicity. White blood cell and liver studies are not central to the care of this client. Lead is indeed nephrotoxic, and urea and creatinine levels are relevant to assessment, but the priority blood test is assessment of the RBCs.

While explaining to a postñsurgical knee client about the various forms and function of connective tissue, the nurse gives the example of the client's surgical repair of a torn anterior cruciate ligament (ACL), which is due to: A) A reticular fiber problem that interrupted the framework for capillaries B) A dense regular connective tissue tear that is usually rich in collagen fibers that allows ligaments to join bone to bone C) An irregular, dense connective tissue tear of loose connective tissue that is located in the perichondrium D) Irregular filling of spaces between tissues to facilitate keeping of joints and tendons in their proper place

Ans: B Feedback: Dense regular connective tissues are rich in collagen fibers and form the tendons and aponeuroses that join muscles to bone or other muscles and the ligaments that join bone to bone. Dense irregular connective tissue consists of the same components found in loose connective tissue but exhibits a predominance of collagen fibers and fewer cells. This type of tissue can be found in the fibrous sheaths of cartilage (i.e., perichondrium) and bone (i.e., periosteum). Fibroblasts, the most abundant loose connective tissue cells, synthesize the gel-like substance and collagen, elastin, and reticular fibers. Reticular fibers provide a fibrous framework for capillaries. Adipose tissue helps to fill spaces between tissues and keep organs in place.

Which of the following diseases would be considered to be caused by a lack of a specific vitamin or mineral? A) Anorexia nervosa B) Scurvy C) Sickle cell anemia D) Atherosclerosis

Ans: B Feedback: Dietary deficiencies can occur because of a selective deficiency of a single nutrient. Iron deficiency anemia, scurvy, beriberi, and pellagra are examples of injury caused by a lack of specific vitamins or minerals. Anorexia nervosa, sickle cell anemia, and atherosclerosis are not caused by lack of a vitamin/mineral.

The client is found to have liver disease, resulting in the removal of a lobe of his liver. Adaptation to the reduced size of the liver leads to which phenomenon in the remaining liver cells? A) Metaplasia B) Organ atrophy C) Compensatory hyperplasia D) Physiologic hypertrophy

Ans: C Feedback: Compensatory hyperplasia can be stimulated in response to loss of vital tissue that is capable of regeneration, such as liver cells. Metaplasia involves replacement of one existing cell type with another fully differentiated cell type. Organ atrophy is caused by irreversible loss of cells. Physiologic hypertrophy is increased size of existing cells resulting from increased workload.

An elderly client asks her health care provider if the reason she has developed aortic stenosis is because she drank so much milk as a child growing up on a farm. Which of the following responses is most accurate? A) ìDrinking lots of real milk as a child may have contributed to the damage in your valve.î B) ìAtherosclerosis is a long process that eventually results in calcification of heart valves.î C) ìThis calcification of your aortic valve is more than likely due to an undiagnosed thyroid problem.î D) ìMore than likely, calcium has left your bones and collected on your aortic valve.î

Ans: B Feedback: Dystrophic calcification represents the macroscopic deposition of calcium salts in injured tissue. Dystrophic calcification is commonly seen in atheromatous lesions of advanced atherosclerosis, in areas of injury in the aorta and large blood vessels, and in damaged heart valves. For example, calcification of the aortic valve is a frequent cause of aortic stenosis in the elderly. Drinking milk, undiagnosed thyroid problems, and calcium loss from bone causing osteoporosis do not cause damaged heart valves.

While caring for a client who has just been diagnosed with leukocyte adhesion deficiency (LAD), the client asks why he is always sick with an infection. The nurse responds, ìLAD is a rare autosomal recessive disorder that results in recurrent infections because of the lack of transmigration. This means: A) Your body doesn't make enough white blood cells.î B) Your white blood cells are not able to leave the blood vessels and move into the area of infection.î C) I don't really understand this, but it sounds like a good question to ask your physician.î D) Your bone marrow is damaged and can't put out enough white blood cells to fight off your infections.î

Ans: B Feedback: Leukocyte adhesion deficiency (LAD) is a rare autosomal recessive disorder characterized by immunodeficiency, resulting in recurrent infections. A WBC differential will reveal extremely elevated levels of neutrophils (on the order of 6ñ10 times normal) because they are unable to leave the blood vessels. Certain integrins play an important role in allowing white blood cells to pass through the vessel wall, a process called transmigration.

Which of the following facts underlies the concept of replicative senescence? A) Genes controlling longevity are present or absent in varying quantities among different individuals. B) Telomeres become progressively shorter in successive generations of a cell. C) The damaging influence of free radicals increases exponentially in later generations of a cell. D) Aging produces mutations in DNA and deficits in DNA repair.

Ans: B Feedback: Replicative senescence implies that cells have limited capacity for reproduction, largely as a result of the shortening of telomeres and consequent chromosomal damage. Genetic theories, the influence of free radicals, and DNA mutation are not central to the concept of replicative senescence.

A 70-year-old male client has been admitted to a hospital for the treatment of a recent hemorrhagic stroke that has left him with numerous motor and sensory deficits. These deficits are most likely the result of which of the following mechanisms of cell injury? A) Free radical injury B) Hypoxia and ATP depletion C) Interference with DNA synthesis D) Impaired calcium homeostasis

Ans: B Feedback: Stroke is characterized by impaired cerebral circulation and consequent death of neurons from cellular hypoxia. Free radical injury, abnormal DNA synthesis, and impaired calcium homeostasis are not direct consequences of lack of blood flow to body cells.

Which describes the function of the nucleus? A) It is basically the site of protein synthesis in the body. B) It contains the genetic code for the individual. C) It is the transformer of cellular energy. D) It initiates the process of aerobic metabolism.

Ans: B Feedback: The nucleus contains DNA, which contains the genetic code that contains the information that controls cells. Ribosomes synthesize protein. Mitochondria transform organic compounds into cellular energy. Mitochondria require oxygen for aerobic metabolism, using hydrogen and carbon combined with oxygen molecules to form carbon dioxide and water as energy is released.

When explaining the function of glycolysis as it relates to anaerobic metabolism, the faculty will mention which of the following key points? Select all that apply. A) Glycolysis requires the use of oxygen to begin the process. B) Glycolysis occurs in mitochondrion-lacking cells. C) Glycolysis provides the majority of the body's energy needs. D) Pyruvic acid is an end result from a series of reactions that converts glucose.

Ans: B, D Feedback: Glycolysis is the anaerobic process by which energy is liberated from glucose, and it is an important source of energy for cells that lack mitochondria. The process also provides a temporary source of energy for cells that are deprived of an adequate supply of oxygen. Glycolysis involves a sequence of reactions that converts glucose to pyruvic acid, with the concomitant production of ATP from ADP. It accounts for a small minority of the body's energy needs and results in NADH, hydrogen ions, ATP, and pyruvic acid.

A mother rushes her 4-year-old child to the emergency department after she found an empty Tylenol (acetaminophen) bottle beside her child. The nurse is trying to explain why it is so important to give the child Ipecac to induce vomiting in order to prevent: A) Renal failure B) Seizures C) Liver failure D) Hemorrhage

Ans: C Feedback: Acetaminophen, a commonly used over-the-counter analgesic drug, is detoxified in the liver, where small amounts of the drug are converted to a highly toxic metabolite. This metabolite is detoxified by a metabolic pathway that uses a substance normally present in the liver. When large amounts of the drug are ingested, this pathway becomes overwhelmed and toxic metabolites accumulate, causing massive liver necrosis.

A client has been diagnosed with a gram-negative bacillus in his blood cultures. The health care providers know these bacteria may produce clinical manifestations such as high temperature, high respiratory rate, and low blood pressure. These manifestations are primarily caused by: A) Disrupting the sodium/potassium ATPase pump B) Interrupting oxidative metabolism processes C) The outer layer of the bacterial membrane acting as an endotoxin D) The bacteria causing a decrease in protein synthesis and function

Ans: C Feedback: Bacteria and viruses can replicate within a cell, thus perpetuating the injuries. Gram-negative bacilli have unique characteristics in the structure of the outer membrane. The outer leaflet of the membrane has a lipid portion that acts as an endotoxin. If this bacillus enters the circulatory system, it causes a toxic reaction, with the sufferer developing a high temperature, high respiration rate, and low blood pressure. Other agents that are injurious to cells are unable to replicate in the cell, but they may disrupt the sodium/potassium pump, interrupt oxidative metabolism, or decrease protein synthesis.

A client has experienced significant decreases in mobility and stamina during a 3-week hospital stay for the treatment of a femoral head fracture. Which of the following phenomena most likely accounts for the client's decrease in muscle function? A) Impaired muscle cell metabolism resulting from metaplasia B) Dysplasia as a consequence of inflammation during bone remodeling C) Disuse atrophy of muscle cells during a prolonged period of immobility D) Ischemic atrophy resulting from vascular changes while on bedrest

Ans: C Feedback: Disuse atrophy frequently occurs as a consequence of prolonged periods of muscle inactivity. Metaplasia and dysplasia are not common consequences of immobility and muscle disuse. Similarly, infrequent muscle use does not typically cause vascular changes that result in ischemic atrophy.

A client with diabetes and severe peripheral vascular disease has developed signs of dry gangrene on the great toe of one foot. The client asks, ìHow this can happen?î Which of the following pathophysiologic processes should the nurse explain to this client? ìMore than likely, your gangrene is caused by: A) Inappropriate activation of apoptosis, which means death of your cells.î B) Bacterial invasion into the foot and toe.î C) Impaired arterial blood supply to your toe.î D) Metaplastic cellular changes in your toe.î

Ans: C Feedback: Dry gangrene is often a result of impaired arterial blood supply to the extremities. A bacterial etiology is more common in wet gangrene, whereas neither metaplasia nor activation of apoptosis is implicated in cases of dry gangrene.

Epithelial tissues are classified according to the shape of the cells and the number of layers. Which of the following is a correctly matched description and type of epithelial tissue? A) Simple epithelium: cells in contact with the intercellular matrix; some do not extend to surface. B) Stratified epithelium: single layer of cells; all cells rest on the basement membrane. C) Glandular epithelium: arises from surface epithelia and underlying connective tissue. D) Pseudostratified epithelium: multiple layers of cells; the deepest layer rests on the basement membrane.

Ans: C Feedback: Glandular epithelial tissue is formed by cells to produce fluid and arises from surface epithelium, involving connective tissue. Simple epithelium is a single layer of cells resting on the basement membrane; stratified epithelium has more than one layer, with the deepest layer resting on the basement membrane. Pseudostratified epithelium is in contact with the intercellular matrix and may not extend to the surface.

Exocytosis allows granular content to be released into extracellular fluid by: A) Engulfing and ingesting fluid and proteins for transport B) Killing, degrading, and dissolving harmful microorganisms C) Removing cellular debris and releasing synthesized substances like hormones D) Destruction of particles by lysosomal enzymes for secretion

Ans: C Feedback: In exocytosis, a secretory granule fuses to the inner cell membrane to form an opening, allowing granule contents to be released. The granule contains cellular debris and synthesized substances such as hormones, which it releases into the extracellular fluid. Phagocytosis and pinocytosisótypes of endocytosisófunction to engulf, kill, and present particles to lysosomal enzymes for degradation.

Although energy is not made in mitochondria, they are known as the ìpower plantsî of the cell because they: A) Contain RNA for protein synthesis B) Utilize glycolysis for oxidative energy C) Extract energy from organic compounds D) Store calcium bonds for muscle contractions

Ans: C Feedback: Mitochondria contain the enzymes needed for transforming organic compounds into energy that is easily accessible to the cell. Mitochondria contain their own DNA. Glycolysis is anaerobic metabolism and unrelated to oxidative energy. Mitochondria store phosphate bonds (such as in ATP) to power cellular functions.

Despite the low levels of radiation used in contemporary radiologic imaging, a radiology technician is aware of the need to minimize her exposure to ionizing radiation. What is the primary rationale for the technician's precautions? Radiation: A) Stimulates pathologic cell hypertrophy and hyperplasia B) Results in the accumulation of endogenous waste products in the cytoplasm C) Interferes with DNA synthesis and mitosis D) Decreases the action potential of rapidly dividing cells

Ans: C Feedback: Radiation has a damaging effect on DNA synthesis and mitosis, a process that is especially harmful to rapidly dividing cells. Radiation does not directly influence the action potential of cells or the accumulation of endogenous waste products. Cell changes such as hypertrophy or hyperplasia may result from radiation exposure, but such changes are secondary to interference with DNA synthesis and mitosis.

When performing an assessment on a school-aged child, the nurse notes that the mucous membranes along the gum margins have a noticeable blue-colored line. At this point, the nurse should ask the parents about possible: A) Liver problems as an infant B) Congenital heart problems C) Exposure to lead D) Second-hand smoke exposure

Ans: C Feedback: The formation of a blue lead line along the margins of the gum is one of the diagnostic features of lead poisoning. Liver problems are usually displayed as jaundice (yellowing of the skin/sclera). Congenital heart problems may exhibit cyanosis, but this would not be just in the gum margins. Second-hand smoke exposure may cause accumulation in the lungs.

Which of the following aspects of the function of the nucleus is performed by ribosomal RNA (rRNA)? A) Copying and carrying DNA instructions for protein synthesis B) Carrying amino acids to the site of protein synthesis C) Providing the site where protein synthesis occurs D) Regulating and controlling protein synthesis

Ans: C Feedback: There are three types of ribonucleic acid (messenger RNA, ribosomal RNA, and transfer RNA) that move to the cytoplasm and carry out the actual synthesis of proteins. Messenger RNA (mRNA) copies and carries the DNA instructions for protein synthesis to the cytoplasm; ribosomal RNA (rRNA) is the site of protein synthesis; and transfer RNA (tRNA) transports amino acids to the site of protein synthesis for incorporation into the protein being synthesized.

When exercising outside on an extremely warm day, the client can feel his heart pounding very rapidly. Thinking in terms of the ability of the aorta to stretch to accommodate more blood circulating during exercise and the warm environment, this is an example of the function of which fibrous protein? A) Collagen B) Reticular C) Elastin D) Ligaments

Ans: C Feedback: Three types of fibers are found in the extracellular space: collagen, elastin, and reticular fibers. Elastin acts like a rubber band; it can be stretched and then returns to its original form. Elastin fibers are abundant in structures subjected to frequent stretching, such as the aorta and some ligaments. Collagen is the most common protein in the body. It is a tough, nonliving, white fiber that serves as the structural framework for skin, ligaments, tendons, and many other structures. Reticular fibers are extremely thin fibers that create a flexible network in organs subjected to changes in form or volume, such as the spleen, liver, uterus, or intestinal muscle layer.

Which identifies correctly how the G proteinñlinked receptors are similar? A) Their cytosolic domain has intrinsic enzyme activity. B) Insulin is an example of the second messenger cAMP, which binds to an enzyme-linked receptor. C) These linked receptors are involved in rapid synaptic signaling between cardiac electrical cells. D) They have a ligand-binding extracellular receptor component, which causes changes that activate the G protein on the cytoplasmic side of the cell membrane.

Ans: D Feedback: Although there are differences among the G proteinñlinked receptors, all share a number of features. They all have a ligand-binding extracellular receptor component, which recognizes a specific ligand or first messenger. Upon ligand binding, they all undergo conformational changes that activate the G protein found on the cytoplasmic side of the cell membrane. Instead of having a cytosolic domain that associates with a G protein, enzyme-linked receptors have cytosolic domain either that has intrinsic enzyme activity or that associates directly with an enzyme. The binding of the hormone to a special transmembrane receptor results in activation of the enzyme adenylyl cyclase at the intracellular portion of the receptor. This enzyme then catalyzes the formation of the second messenger cAMP, which has multiple effects on cell function. Insulin, for example, acts by binding to an enzyme-linked receptor. Ion channelñlinked receptors are involved in the rapid synaptic signaling between electrically excitable cells.

A client with a pathophysiologic condition that affects the desmosomes is most likely to exhibit: A) Impaired contraction of skeletal and smooth muscle B) Weakness of the collagen and elastin fibers in the extracellular space C) Impaired communication between neurons and effector organs D) Separation at the junctions between epithelial cells

Ans: D Feedback: Desmosomes are a type of cell junction common in epithelium. Failure of epithelial desmosomes results in the inappropriate separation of adjacent cells. Desmosomes do not contribute to muscle contraction, communication between neurons and effector organs, or the structure of collagen and elastin.

A group of elderly residents were commenting on how many cell functions decline with age. One resident commented that many of his friends who lived under large electromagnetic towers seemed to experience aging at an accelerated rate in comparison with residents who lived nearby in lakefront housing. This observation is the basis for which theory on aging? A) Theories of genetic influences B) Programmed cell receptor theories C) Insufficient telomerase enzyme theory D) Error theory associated with DNA damage

Ans: D Feedback: Error theory suggests that aging results from DNA mutation or faulty repair. Another group of theories of aging focuses on programmed cell changes with genetic influences that systematically cause cell senescence. Elimination of receptor sites is not part of aging theory. Telomerase enzyme is thought to reduce the shortening of the chromosomes and loss of telomere DNA with each cell replication.

Which of the following pathophysiologic processes is most likely to result in metastatic calcification? A) Benign prostatic hyperplasia B) Liver cirrhosis C) Impaired glycogen metabolism D) Hyperparathyroidism

Ans: D Feedback: Metastatic calcification is a result of markedly increased serum calcium levels. Because the parathyroid gland is responsible for the regulation of serum calcium levels, hyperparathyroidism creates a risk for hypercalcemia and consequent metastatic calcification. Benign prostatic hypertrophy, cirrhosis, and impaired glycogen metabolism are not implicated in cases of metastatic calcification.

Impairment in the function of peroxisomes would result in: A) Inadequate sites for protein synthesis B) An inability to transport cellular products across the cell membrane C) Insufficient energy production within a cell D) Accumulation of free radicals in the cytoplasm

Ans: D Feedback: Peroxisomes function in the control of free radicals; unless degraded, these highly unstable chemical compounds damage other cytoplasmic molecules. Peroxisomes do not directly contribute to energy production, protein synthesis, or transport of cellular secretions.

The client asks the health care provider to explain phagocytosis. The provider will respond, ìPhagocytosis: A) Is a cotransport system that helps with the absorption of the medication.î B) Is the movement of particles from an area of higher concentration to one of lower concentration.î C) Uses proteins to form an open channel through which the drug can move into the cell.î D) Is a process where microorganisms are engulfed and subsequently degraded or killed.î

Ans: D Feedback: Phagocytosis, which means ìcell eating,î involves the engulfment and subsequent killing or degradation of microorganisms and other particulate matter. Certain cells, such as macrophages and neutrophils, are adept at engulfing and disposing of invading organisms, damaged cells, and unneeded extracellular constituents. An example of cotransport occurs in the intestine, where the absorption of glucose and amino acids is coupled with sodium transport. The process of diffusion describes particle movement from an area of higher concentration to an area of lower concentration, resulting in an equal distribution of permeable substances across the cell membrane. Ion channels are integral proteins that span the width of the membrane and are normally composed of several polypeptides or protein subunits that form a gating system. Specific stimuli cause the protein subunits to undergo conformational changes to form an open channel or gate through which the ions can move.

To effectively relay signals, cell-to-cell communication utilizes a chemical messenger system to: A) Displace surface receptor proteins B) Accumulate within cell gap junctions C) Bind to contractile microfilaments D) Release secretions into extracellular fluid

Ans: D Feedback: Signals are transmitted by releasing chemical secretions into extracellular fluid. Chemical signals move through cell-to-cell junctions to reach other cells and may attach to surface receptor proteins. The cytoplasmic contractile microfilaments are incapable of transmitting communication signals.

A student asks the instructor what it means when the book states, skeletal muscles are syncytial or multinucleated? The instructor responds: A) ìEach of the skeletal muscle cells has an apical, lateral, and basal surface.î B) ìThey are closely apposed and are joined by cell-to-cell adhesion molecules.î C) ìThis means that these muscles exhibit cross-striations formed by alternating segments of thick and thin protein filaments, with muscle cells having a branched appearance.î D) ìIf a skeletal muscle is injured and a portion dies, the adjacent sections of that same skeletal muscle fiber do not die because they have their own nuclear material.î

Ans: D Feedback: Skeletal muscles are syncytial or multinucleated structures, meaning there are no true cell boundaries within a skeletal muscle fiber. The multinucleated arrangement is important in pathologic states where focal necrosis (death) of a portion of skeletal muscle fibers does not result in necrosis death of the adjacent sections of that same skeletal muscle fiber, because those adjacent sections have their own nuclear material. Cardiac muscle exhibits cross-striations formed by alternating segments of thick and thin protein filaments. In contrast to skeletal muscle, cardiac muscle cells may be branched instead of linear and longitudinal. The other noted qualities are associated with epithelial, not skeletal muscle, cells.

A client has been diagnosed with gram-negative pneumonia of the lower lobe. Knowing that gram-negative bacteria have a lipopolysaccharide endotoxin on their outer cell membrane, the health care provider should be assessing the client for which pathophysiological end result? A) Damage to cellular mitochondria B) Increased ATP levels C) Activation of the p53 protein D) Apoptosis

Ans: D Feedback: The extrinsic pathway of apoptosis involves extracellular signaling proteins that bind to cell surface molecules called death receptors and trigger apoptosis. The end result includes activation of endonucleases that cause fragmentation of DNA and cell death. In addition to TNF and Fas ligand, primary signaling molecules known to activate the extrinsic pathway include TNF-related apoptosis-inducing ligand (TRAIL); the cytokine interleukin-1 (IL-1); and lipopolysaccharide (LPS), the endotoxin found in the outer cell membrane of gram-negative bacteria. DNA damage, activation of the p53 protein, and decreased ATP levels are associated with the intrinsic pathway.

Aerobic metabolism, also known as oxidative metabolism, provides energy to the body by: A) Removing the phosphate bonds from ATP B) Combining hydrogen and oxygen to form water C) Activating pyruvate stored in the cytoplasm D) Breaking down glucose to form lactic acid

Ans: b Feedback: Aerobic metabolism involves the combination of carbon ions from dietary nutrients, hydrogen ions, and oxygen. The result is carbon dioxide and water as energy is released, which is stored in ATP. Phosphate bonds are added (not removed from) to ADP to form ATP. Pyruvate is formed from glucose in the anaerobic process of glycolysis and is converted to lactic acid during anaerobic metabolism.

Hypertrophy

Increased workload triggers increased synthesis of normal cell components. (Increase cell size due to increase cellular component)

Atrophy

Reduction of workload or resources causes reduction in normal cell components. (Decrease cell size due to loss of cellular component)