Pathophysiology OA | Verified Q&A | 100% Correct | Pass
Guaranteed - A+ Graded
SECTION 1: CELLULAR BIOLOGY & PATHOPHYSIOLOGY
FOUNDATIONS (25 Questions)
Q1: A 68-year-old male with chronic heart failure presents with bilateral lower extremity
edema and decreased muscle mass. Histological examination of his gastrocnemius
muscle reveals reduced fiber size with preserved cell number. Which cellular adaptation
best describes these findings?
A. Hypertrophy, characterized by increased cell size due to increased protein synthesis
and organelle number
B. Hyperplasia, characterized by increased cell number through mitotic division
C. Atrophy, characterized by decreased cell size due to decreased protein synthesis and
increased autophagy [CORRECT]
D. Metaplasia, characterized by replacement of one differentiated cell type by another
Correct Answer: C
Rationale: Atrophy is a decrease in cell size resulting from decreased protein synthesis,
increased protein degradation via the ubiquitin-proteasome pathway, and increased
,autophagy. In this patient with chronic heart failure, disuse and malnutrition contribute
to skeletal muscle atrophy. The preserved cell number rules out hyperplasia.
Hypertrophy would show increased fiber size, not decreased. Metaplasia involves a
change in cell type, not size reduction.
Q2: A 55-year-old woman with a history of hypertension presents with left ventricular
hypertrophy on echocardiogram. The myocardial cells demonstrate increased size with
increased numbers of mitochondria and myofilaments. Which mechanism primarily
drives this cellular adaptation?
A. Activation of the ubiquitin-proteasome system leading to protein degradation
B. Increased workload triggering mTOR pathway activation and increased protein
synthesis [CORRECT]
C. Downregulation of growth hormone receptors and decreased IGF-1 signaling
D. Activation of caspase-3 leading to apoptotic cell death
Correct Answer: B
Rationale: Hypertrophy is driven by increased mechanical stress and neurohormonal
activation (angiotensin II, catecholamines), which activate the PI3K/Akt/mTOR pathway,
increasing protein synthesis and organelle biogenesis. The ubiquitin-proteasome
system causes atrophy, not hypertrophy. Growth hormone and IGF-1 promote, not
inhibit, hypertrophic signaling. Caspase-3 activation leads to apoptosis, which is distinct
from the adaptive hypertrophic response.
,Q3: A 42-year-old smoker presents with chronic bronchitis. Bronchial biopsy reveals
pseudostratified ciliated columnar epithelium replaced by stratified squamous
epithelium. This cellular adaptation is classified as:
A. Dysplasia, characterized by disordered cellular maturation and nuclear atypia
B. Metaplasia, characterized by reversible replacement of one mature cell type by
another [CORRECT]
C. Hyperplasia, characterized by increased cell number in response to chronic irritation
D. Anaplasia, characterized by loss of cellular differentiation and pleomorphism
Correct Answer: B
Rationale: Metaplasia is the reversible replacement of one differentiated cell type by
another, typically in response to chronic irritation. In this case, chronic smoking irritation
causes bronchial epithelium to transform to squamous epithelium (squamous
metaplasia), which is better suited to withstand irritants. Dysplasia involves disordered
maturation and is considered pre-neoplastic. Hyperplasia increases cell number without
changing cell type. Anaplasia indicates malignant loss of differentiation.
Q4: A 35-year-old woman with cervical dysplasia on Pap smear demonstrates
disordered maturation from basal to superficial layers, nuclear hyperchromasia, and
increased nuclear-to-cytoplasmic ratio. Which statement best describes the
pathophysiological significance of dysplasia?
A. Dysplasia is a fully reversible adaptive response with no malignant potential
B. Dysplasia represents a pre-neoplastic change with potential for progression to
carcinoma in situ or invasive cancer [CORRECT]
, C. Dysplasia is a normal physiological response to hormonal stimulation
D. Dysplasia indicates complete loss of cellular differentiation characteristic of invasive
malignancy
Correct Answer: B
Rationale: Dysplasia is a pre-neoplastic alteration characterized by disordered cellular
maturation, nuclear atypia, and loss of polarity. It represents a continuum from mild to
severe dysplasia/carcinoma in situ, with increasing risk of progression to invasive
carcinoma. While some mild dysplasias may regress, they are not "fully reversible with
no malignant potential." Dysplasia is pathological, not a normal response. Complete
loss of differentiation defines anaplasia, not dysplasia.
Q5: A patient with acute myocardial infarction presents 6 hours after symptom onset.
Cardiac troponins are elevated. Histological examination of the infarcted myocardium
reveals coagulative necrosis. Which pathophysiological sequence best explains this
type of cell death?
A. ATP depletion → loss of ion pump function → cellular swelling → enzyme
denaturation → protein coagulation with preserved tissue architecture [CORRECT]
B. Caspase activation → DNA fragmentation → apoptotic bodies → phagocytosis
without inflammation
C. Lipase activation → fat saponification → calcium soap formation → caseous
necrosis
D. Fibrinoid necrosis → immune complex deposition → vasculitis → tissue destruction