SUNY Downstate Medical Center
NRMS 5190 – Pathophysiology
Exam 1 Questions and Answers| Latest Update
Q1. What is the difference between hypertrophy and hyperplasia?
Answer & Rationale: Hypertrophy is an increase in the size of individual cells without
cell division, leading to increased organ size (e.g., cardiac muscle in hypertension).
Hyperplasia is an increase in the number of cells through mitotic division, occurring
only in tissues capable of division (e.g., endometrial hyperplasia). Both are adaptive
responses to increased functional demand or hormonal stimulation.
Q2. What is atrophy and what are its common causes?
Answer & Rationale: Atrophy is a decrease in cell size and function due to a
reduction in cellular components, often as an adaptive response to decreased
workload, disuse, denervation, diminished blood supply, inadequate nutrition, loss of
hormonal stimulation, or aging. It reflects a reversible decrease in structural
components to match reduced metabolic demand.
Q3. Define metaplasia and explain why it occurs.
Answer & Rationale: Metaplasia is the reversible replacement of one differentiated
cell type with another, usually in response to chronic irritation or injury, allowing
cells better suited to withstand the adverse environment to survive. A classic
example is the conversion of ciliated columnar epithelium to squamous epithelium in
the bronchi of chronic smokers.
Q4. Why is metaplasia clinically significant even though it is an adaptive process?
Answer & Rationale: Although metaplasia itself is reversible and non-neoplastic, the
same stimuli that cause it can lead to dysplasia and eventually malignant
transformation if the injurious stimulus persists, because the replacing cells lose
some specialized protective functions of the original tissue.
Q5. Distinguish reversible from irreversible cell injury at the cellular level.
Answer & Rationale: Reversible injury involves functional and structural changes
(cellular swelling, fatty change) that resolve if the stressor is removed, characterized
by ATP depletion and mitochondrial swelling without membrane rupture. Irreversible
injury involves severe mitochondrial dysfunction, loss of membrane integrity, and
calcium influx that cannot be corrected, committing the cell to death.
,Q6. What is the role of calcium in irreversible cell injury?
Answer & Rationale: Loss of membrane integrity allows massive calcium influx into
the cytosol, activating destructive enzymes such as ATPases, phospholipases,
proteases, and endonucleases. This calcium-mediated enzyme activation degrades
membranes, cytoskeletal proteins, and DNA, driving the cell irreversibly toward
death.
Q7. Compare the mechanisms of hypoxic injury and ischemic injury.
Answer & Rationale: Hypoxic injury results from inadequate oxygen delivery (e.g.,
anemia, respiratory failure) but glycolysis can continue using anaerobic metabolism
to generate limited ATP. Ischemic injury results from reduced blood flow, depriving
cells of both oxygen and substrates for glycolysis, making it more rapid and severe
because anaerobic ATP production is also compromised.
Q8. Explain how free radicals cause cellular injury.
Answer & Rationale: Free radicals are unstable molecules with unpaired electrons
that react with cellular lipids, proteins, and DNA, causing lipid peroxidation of
membranes, protein cross-linking/fragmentation, and DNA strand breaks. This
oxidative damage disrupts membrane integrity, enzyme function, and genetic
stability, contributing to cell injury and aging.
Q9. What distinguishes necrosis from apoptosis in terms of mechanism and
consequence?
Answer & Rationale: Necrosis is an uncontrolled, passive form of cell death caused
by severe injury, characterized by cell swelling, membrane rupture, and release of
cellular contents that trigger inflammation. Apoptosis is a programmed, energy-
dependent process of cell deletion with cell shrinkage, chromatin condensation, and
formation of apoptotic bodies that are phagocytosed without eliciting inflammation.
Q10. Describe coagulative necrosis and the type of tissue in which it typically occurs.
Answer & Rationale: Coagulative necrosis is characterized by preservation of the
basic tissue architecture for several days due to denaturation of structural and
enzymatic proteins that blocks proteolysis. It is the hallmark of hypoxic death in solid
organs such as the heart, kidney, and adrenal gland, classically seen in myocardial
infarction.
Q11. Describe liquefactive necrosis and give a clinical example.
Answer & Rationale: Liquefactive necrosis occurs when dead cells are digested by
hydrolytic enzymes, transforming tissue into a liquid, viscous mass, typically due to
release of enzymes from neutrophils. It is characteristic of focal bacterial infections
, (abscess formation) and hypoxic death in the brain, which is enzyme-rich and lipid-
laden.
Q12. What is caseous necrosis and with which disease is it classically associated?
Answer & Rationale: Caseous necrosis is a distinctive form of coagulative necrosis in
which dead tissue appears as a friable, cheese-like white substance due to
incomplete degradation of lipid-rich cell membranes. It is classically associated with
tuberculosis, where the necrotic center is surrounded by a granulomatous
inflammatory border.
Section 2: Genetics and Genetic Disorders
Q13. What is the difference between a genotype and a phenotype?
Answer & Rationale: Genotype refers to an individual's actual genetic makeup or
specific allele combination at a locus, while phenotype is the observable physical,
biochemical, or physiologic expression of that genotype, which results from the
interaction of genes with each other and with the environment.
Q14. Explain the inheritance pattern of an autosomal dominant disorder.
Answer & Rationale: In autosomal dominant inheritance, a single copy of a mutant
allele on one of the 22 autosomes is sufficient to produce the disease phenotype, so
an affected heterozygous parent has a 50% chance of transmitting the disorder to
each offspring, and the trait appears in every generation without skipping.
Q15. Explain the inheritance pattern of an autosomal recessive disorder and why it
may skip generations.
Answer & Rationale: Autosomal recessive disorders require two copies of the
mutant allele (homozygosity) for the phenotype to be expressed; heterozygous
carriers are typically unaffected. Because carrier parents can each contribute one
mutant allele, affected children may be born to unaffected carrier parents, giving the
appearance of the trait skipping generations.
Q16. How does X-linked recessive inheritance explain why males are more frequently
affected than females?
Answer & Rationale: Because males have only one X chromosome, a single mutant
recessive allele on that X will be expressed since there is no second X allele to mask it.
Females, having two X chromosomes, generally need two mutant alleles to be
affected, so heterozygous females are typically unaffected carriers, making the
disease far more common in males.
NRMS 5190 – Pathophysiology
Exam 1 Questions and Answers| Latest Update
Q1. What is the difference between hypertrophy and hyperplasia?
Answer & Rationale: Hypertrophy is an increase in the size of individual cells without
cell division, leading to increased organ size (e.g., cardiac muscle in hypertension).
Hyperplasia is an increase in the number of cells through mitotic division, occurring
only in tissues capable of division (e.g., endometrial hyperplasia). Both are adaptive
responses to increased functional demand or hormonal stimulation.
Q2. What is atrophy and what are its common causes?
Answer & Rationale: Atrophy is a decrease in cell size and function due to a
reduction in cellular components, often as an adaptive response to decreased
workload, disuse, denervation, diminished blood supply, inadequate nutrition, loss of
hormonal stimulation, or aging. It reflects a reversible decrease in structural
components to match reduced metabolic demand.
Q3. Define metaplasia and explain why it occurs.
Answer & Rationale: Metaplasia is the reversible replacement of one differentiated
cell type with another, usually in response to chronic irritation or injury, allowing
cells better suited to withstand the adverse environment to survive. A classic
example is the conversion of ciliated columnar epithelium to squamous epithelium in
the bronchi of chronic smokers.
Q4. Why is metaplasia clinically significant even though it is an adaptive process?
Answer & Rationale: Although metaplasia itself is reversible and non-neoplastic, the
same stimuli that cause it can lead to dysplasia and eventually malignant
transformation if the injurious stimulus persists, because the replacing cells lose
some specialized protective functions of the original tissue.
Q5. Distinguish reversible from irreversible cell injury at the cellular level.
Answer & Rationale: Reversible injury involves functional and structural changes
(cellular swelling, fatty change) that resolve if the stressor is removed, characterized
by ATP depletion and mitochondrial swelling without membrane rupture. Irreversible
injury involves severe mitochondrial dysfunction, loss of membrane integrity, and
calcium influx that cannot be corrected, committing the cell to death.
,Q6. What is the role of calcium in irreversible cell injury?
Answer & Rationale: Loss of membrane integrity allows massive calcium influx into
the cytosol, activating destructive enzymes such as ATPases, phospholipases,
proteases, and endonucleases. This calcium-mediated enzyme activation degrades
membranes, cytoskeletal proteins, and DNA, driving the cell irreversibly toward
death.
Q7. Compare the mechanisms of hypoxic injury and ischemic injury.
Answer & Rationale: Hypoxic injury results from inadequate oxygen delivery (e.g.,
anemia, respiratory failure) but glycolysis can continue using anaerobic metabolism
to generate limited ATP. Ischemic injury results from reduced blood flow, depriving
cells of both oxygen and substrates for glycolysis, making it more rapid and severe
because anaerobic ATP production is also compromised.
Q8. Explain how free radicals cause cellular injury.
Answer & Rationale: Free radicals are unstable molecules with unpaired electrons
that react with cellular lipids, proteins, and DNA, causing lipid peroxidation of
membranes, protein cross-linking/fragmentation, and DNA strand breaks. This
oxidative damage disrupts membrane integrity, enzyme function, and genetic
stability, contributing to cell injury and aging.
Q9. What distinguishes necrosis from apoptosis in terms of mechanism and
consequence?
Answer & Rationale: Necrosis is an uncontrolled, passive form of cell death caused
by severe injury, characterized by cell swelling, membrane rupture, and release of
cellular contents that trigger inflammation. Apoptosis is a programmed, energy-
dependent process of cell deletion with cell shrinkage, chromatin condensation, and
formation of apoptotic bodies that are phagocytosed without eliciting inflammation.
Q10. Describe coagulative necrosis and the type of tissue in which it typically occurs.
Answer & Rationale: Coagulative necrosis is characterized by preservation of the
basic tissue architecture for several days due to denaturation of structural and
enzymatic proteins that blocks proteolysis. It is the hallmark of hypoxic death in solid
organs such as the heart, kidney, and adrenal gland, classically seen in myocardial
infarction.
Q11. Describe liquefactive necrosis and give a clinical example.
Answer & Rationale: Liquefactive necrosis occurs when dead cells are digested by
hydrolytic enzymes, transforming tissue into a liquid, viscous mass, typically due to
release of enzymes from neutrophils. It is characteristic of focal bacterial infections
, (abscess formation) and hypoxic death in the brain, which is enzyme-rich and lipid-
laden.
Q12. What is caseous necrosis and with which disease is it classically associated?
Answer & Rationale: Caseous necrosis is a distinctive form of coagulative necrosis in
which dead tissue appears as a friable, cheese-like white substance due to
incomplete degradation of lipid-rich cell membranes. It is classically associated with
tuberculosis, where the necrotic center is surrounded by a granulomatous
inflammatory border.
Section 2: Genetics and Genetic Disorders
Q13. What is the difference between a genotype and a phenotype?
Answer & Rationale: Genotype refers to an individual's actual genetic makeup or
specific allele combination at a locus, while phenotype is the observable physical,
biochemical, or physiologic expression of that genotype, which results from the
interaction of genes with each other and with the environment.
Q14. Explain the inheritance pattern of an autosomal dominant disorder.
Answer & Rationale: In autosomal dominant inheritance, a single copy of a mutant
allele on one of the 22 autosomes is sufficient to produce the disease phenotype, so
an affected heterozygous parent has a 50% chance of transmitting the disorder to
each offspring, and the trait appears in every generation without skipping.
Q15. Explain the inheritance pattern of an autosomal recessive disorder and why it
may skip generations.
Answer & Rationale: Autosomal recessive disorders require two copies of the
mutant allele (homozygosity) for the phenotype to be expressed; heterozygous
carriers are typically unaffected. Because carrier parents can each contribute one
mutant allele, affected children may be born to unaffected carrier parents, giving the
appearance of the trait skipping generations.
Q16. How does X-linked recessive inheritance explain why males are more frequently
affected than females?
Answer & Rationale: Because males have only one X chromosome, a single mutant
recessive allele on that X will be expressed since there is no second X allele to mask it.
Females, having two X chromosomes, generally need two mutant alleles to be
affected, so heterozygous females are typically unaffected carriers, making the
disease far more common in males.
