,1. A 65-year-old man with a history of hypertension and diabetes
mellitus presents to the emergency department with chest pain,
dyspnea, and diaphoresis. He is diagnosed with an acute myocardial
infarction (AMI) and is given thrombolytic therapy. Which of the
following statements best describes the pathophysiology of AMI?
a) The coronary arteries are narrowed by atherosclerosis and
become occluded by a thrombus, resulting in ischemia and necrosis
of the myocardium.
b) The coronary arteries are dilated by vasospasm and become
obstructed by a plaque, resulting in hypoxia and apoptosis of the
myocardium.
c) The coronary arteries are inflamed by infection and become
ruptured by an aneurysm, resulting in hemorrhage and infarction of
the myocardium.
d) The coronary arteries are calcified by aging and become eroded
by ulceration, resulting in perforation and abscess of the
myocardium.
*Answer: a) The coronary arteries are narrowed by atherosclerosis
and become occluded by a thrombus, resulting in ischemia and
necrosis of the myocardium.*
Rationale: Atherosclerosis is the most common cause of coronary
artery disease, which leads to AMI. Atherosclerosis is the
accumulation of lipids, fibrous tissue, calcium, and inflammatory
cells in the arterial wall, forming plaques that reduce the lumen
diameter and blood flow. A thrombus is a blood clot that forms on a
plaque due to platelet aggregation and activation of the coagulation
cascade. A thrombus can completely or partially block the coronary
artery, depriving the myocardium of oxygen and nutrients. Ischemia
is the inadequate blood supply to a tissue, which causes reversible
cellular injury. Necrosis is the irreversible death of cells due to
severe or prolonged ischemia.
2. A 25-year-old woman with a history of systemic lupus
erythematosus (SLE) presents to the rheumatology clinic with joint
,pain, skin rash, and fatigue. She is diagnosed with a flare-up of SLE
and is given corticosteroid therapy. Which of the following
statements best describes the pathophysiology of SLE?
a) SLE is an autoimmune disorder in which the immune system
produces antibodies against self-antigens, resulting in inflammation
and damage of various organs.
b) SLE is an infectious disorder in which the immune system is
invaded by microorganisms, resulting in infection and sepsis of
various organs.
c) SLE is a genetic disorder in which the immune system inherits
defective genes, resulting in mutation and malignancy of various
organs.
d) SLE is a metabolic disorder in which the immune system
accumulates toxic substances, resulting in intoxication and failure of
various organs.
*Answer: a) SLE is an autoimmune disorder in which the immune
system produces antibodies against self-antigens, resulting in
inflammation and damage of various organs.*
Rationale: Autoimmunity is the loss of self-tolerance, which means
that the immune system fails to distinguish between self-antigens
(normal components of the body) and foreign antigens (abnormal or
harmful substances). Autoimmunity results in the production of
autoantibodies, which are antibodies that target self-antigens.
Autoantibodies can form immune complexes with self-antigens,
which deposit in various tissues and trigger inflammation.
Inflammation is the body's response to injury or infection, which
involves vasodilation, increased vascular permeability, leukocyte
migration, cytokine release, and tissue repair. Inflammation can
cause damage to normal tissues if it is excessive or chronic. SLE is a
chronic inflammatory disorder that affects multiple organs, such as
skin, joints, kidneys, heart, lungs, brain, and blood.
3. A 45-year-old man with a history of chronic obstructive
pulmonary disease (COPD) presents to the pulmonology clinic with
cough, sputum production, and dyspnea. He is diagnosed with an
acute exacerbation of COPD and is given bronchodilator therapy.
, Which of the following statements best describes the
pathophysiology of COPD?
a) COPD is a respiratory disorder in which the airways are narrowed
by bronchoconstriction and mucus secretion, resulting in airflow
limitation and hyperinflation of the lungs.
b) COPD is a respiratory disorder in which the alveoli are destroyed
by emphysema and fibrosis, resulting in gas exchange impairment
and hypoxemia of the blood.
c) COPD is a respiratory disorder in which both airway narrowing
and alveolar destruction occur, resulting in a combination of airflow
limitation, gas exchange impairment, hyperinflation, and
hypoxemia.
d) COPD is a respiratory disorder in which neither airway narrowing
nor alveolar destruction occur, resulting in a normal lung function
and oxygenation of the blood.
*Answer: c) COPD is a respiratory disorder in which both airway
narrowing and alveolar destruction occur, resulting
PART B:
What are the main differences between fetal and adult
hemoglobin? How do they affect oxygen transport and affinity?
- Fetal hemoglobin (HbF) has a higher affinity for oxygen than adult
hemoglobin (HbA) because it has two gamma chains instead of two beta
chains. This allows HbF to bind oxygen more tightly and extract it from
maternal blood in the placenta. HbF also has a lower affinity for 2,3-
bisphosphoglycerate (2,3-BPG), a molecule that reduces oxygen affinity
in HbA. Therefore, HbF can maintain a high oxygen saturation even at
low partial pressures of oxygen.
1. Whatare the main factors that influence growth hormone secretion
throughout the life span? How do they affect growth and metabolism?
- Growth hormone (GH) secretion is influenced by several factors, such
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