AANPCB AANPCB Pathophysiology 2 — Questions and Answers
Question 1: Which mechanism explains the development of compensatory polycythemia in patients with chronic obstructive pulmonary disease (COPD)?
- Increased iron absorption from the gut
- Hypoxia-stimulated erythropoietin release from the kidneys (Correct answer)
- Bone marrow hyperplasia due to infection
- Decreased plasma volume
Correct answer: Hypoxia-stimulated erythropoietin release from the kidneys
Chronic hypoxia in COPD stimulates the kidneys to release erythropoietin, which drives increased red blood cell production to improve oxygen-carrying capacity.
Question 2: In rheumatoid arthritis, what is the primary driver of joint destruction?
- Cartilage wear from repetitive mechanical stress
- Pannus formation from activated synovial fibroblasts and immune cells (Correct answer)
- Calcium crystal deposition in the joint space
- Bacterial infection of the synovium
Correct answer: Pannus formation from activated synovial fibroblasts and immune cells
RA joint destruction is driven by pannus, an invasive tissue formed by activated synoviocytes and infiltrating immune cells that erodes cartilage and bone.
Question 3: What pathophysiological mechanism explains why hypothyroidism causes hyperlipidemia?
- Increased dietary fat absorption
- Decreased LDL receptor expression leading to impaired LDL clearance (Correct answer)
- Overproduction of VLDL by the liver
- Reduced lipoprotein lipase activity in adipose tissue
Correct answer: Decreased LDL receptor expression leading to impaired LDL clearance
Thyroid hormone normally upregulates LDL receptors on hepatocytes; its deficiency reduces receptor expression and slows clearance of LDL from the bloodstream.
Question 4: Which pathophysiological process is central to the development of Alzheimer's disease?
- Dopamine depletion in the substantia nigra
- Amyloid-beta plaque accumulation and tau neurofibrillary tangles (Correct answer)
- Autoimmune demyelination of cortical neurons
- Ischemic neuronal death from microemboli
Correct answer: Amyloid-beta plaque accumulation and tau neurofibrillary tangles
Alzheimer's disease is characterized by extracellular amyloid-beta plaques and intracellular neurofibrillary tau tangles that disrupt neuronal function and lead to cell death.
Question 5: What is the underlying pathophysiology of peripheral edema in right-sided heart failure?
- Reduced oncotic pressure from hypoalbuminemia
- Elevated venous hydrostatic pressure due to impaired right ventricular output (Correct answer)
- Increased capillary permeability from infection
- Obstruction of lymphatic drainage by tumor
Correct answer: Elevated venous hydrostatic pressure due to impaired right ventricular output
Right ventricular failure raises systemic venous pressure, increasing hydrostatic force in capillaries and forcing fluid into the interstitial space of dependent tissues.
Question 6: In peptic ulcer disease, how does H. pylori infection contribute to mucosal injury?
- Directly secreting hydrochloric acid into the stomach
- Producing urease, disrupting the mucus layer, and triggering inflammation (Correct answer)
- Stimulating excess gastrin from the pylorus
- Blocking prostaglandin synthesis in the gastric mucosa
Correct answer: Producing urease, disrupting the mucus layer, and triggering inflammation
H. pylori produces urease that neutralizes gastric acid locally, disrupts the protective mucus layer, and induces an inflammatory response that damages the gastric epithelium.
AANPCB AANPCB Pathophysiology 2
Which mechanism explains the development of compensatory polycythemia in patients with chronic obstructive pulmonary disease (COPD)?