Porth’s Essentials of Pathophysiology 5th Edition Test Bank
Porth’s Essentials of Pathophysiology 5th Edition Test Bank
1. Chapter 1
Although the
... [Show More] 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.
2. 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.
3. 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.
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4. 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.
5. 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.
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6. Although energy is not made in mitochondria, they are known as the “power plants” 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.
7. 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.
8. 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.
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9. 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.
10. 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.
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11. Which identifies correctly how the G protein–linked 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 protein–linked 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 channel–linked receptors
are involved in the rapid synaptic signaling between electrically excitable cells.
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12. 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) “If 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.”
B) “You 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.”
C) “Your potassium molecules are lipid soluble and will dissolve in the lipid matrix
of your cell membranes.”
D) “If 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.”
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 “downhill” 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.
13. 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.
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14. The client asks the health care provider to explain phagocytosis. The provider will
respond, “Phagocytosis:
A) Is a cotransport system that helps with the absorption of the medication.”
B) Is the movement of particles from an area of higher concentration to one of lower
concentration.”
C) Uses proteins to form an open channel through which the drug can move into the
cell.”
D) Is a process where microorganisms are engulfed and subsequently degraded or
killed.”
Ans: D
Feedback:
Phagocytosis, which means “cell eating,” 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.
15. 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 pinocytosis—types of endocytosis—function to engulf, kill, and
present particles to lysosomal enzymes for degradation.
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16. 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.
17. 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.
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18. 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.
19. While explaining to a post–surgical 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.
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20. A student asks the instructor what it means when the book states, skeletal muscles are
syncytial or multinucleated? The instructor responds:
A) “Each of the skeletal muscle cells has an apical, lateral, and basal surface.”
B) “They are closely apposed and are joined by cell-to-cell adhesion molecules.”
C) “This means that these muscles exhibit cross-striations formed by alternating
segments of thick and thin protein filaments, with muscle cells having a branched
appearance.”
D) “If 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.”
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.
21. 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.
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22. 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.
23. 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.
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24. 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.
25. 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, “LAD 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.”
B) Your white blood cells are not able to leave the blood vessels and move into the
area of infection.”
C) I don't really understand this, but it sounds like a good question to ask your
physician.”
D) Your bone marrow is damaged and can't put out enough white blood cells to fight
off your infections.”
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 6–10
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.
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1. Chapter 2
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 [Show Less]