STRAIGHTERLINE A&P FINAL REVIEW 2026/2027 | 100%
Correct Answers with Complete Solutions | Human Anatomy
& Physiology II | Comprehensive Final Review | Clinical
Correlations | Pass Guaranteed - A+ Graded
Domain 1: Endocrine System (15 Questions)
Q1: A 45-year-old female patient presents with weight gain, fatigue, cold intolerance, and
a goiter. Laboratory studies reveal elevated TSH and decreased free T4. Which
endocrine disorder and underlying pathophysiology best explains these findings?
A. Graves' disease with TSH receptor antibodies stimulating excessive thyroid hormone
production
B. Hashimoto's thyroiditis with autoimmune destruction of thyroid tissue leading to
hypothyroidism
C. Thyroid storm due to acute release of thyroid hormones causing hypermetabolic
state
D. Iodine deficiency causing compensatory thyroid enlargement with normal hormone
levels
Correct Answer: B [CORRECT]
Rationale: The clinical presentation of weight gain, fatigue, cold intolerance, elevated
TSH, and decreased free T4 is classic for primary hypothyroidism. Hashimoto's
thyroiditis (autoimmune thyroiditis) is the most common cause of hypothyroidism in
developed countries. The autoimmune destruction of thyroid follicular cells reduces
thyroid hormone production (low T4), which removes negative feedback on the anterior
,pituitary, causing compensatory TSH elevation. The goiter develops due to chronic TSH
stimulation of thyroid tissue.
● A is incorrect: Graves' disease causes hyperthyroidism (weight loss, heat
intolerance, low TSH, high T4), the opposite of this presentation.
● C is incorrect: Thyroid storm is a life-threatening hypermetabolic emergency with
fever, tachycardia, and agitation, not hypothyroid symptoms.
● D is incorrect: While iodine deficiency causes goiter, it typically results in
euthyroid or sometimes hyperthyroid states (Jod-Basedow phenomenon), not the
pronounced hypothyroidism with elevated TSH seen here.
Q2: A patient with Cushing's syndrome undergoes a dexamethasone suppression test.
Administration of low-dose dexamethasone fails to suppress cortisol levels, but
high-dose dexamethasone causes suppression. Which source of excess cortisol is
most likely?
A. Ectopic ACTH-producing small cell lung carcinoma
B. Adrenal cortical adenoma secreting cortisol autonomously
C. Pituitary adenoma (Cushing's disease) with ACTH hypersecretion
D. Iatrogenic corticosteroid administration from chronic prednisone use
Correct Answer: C [CORRECT]
Rationale: The dexamethasone suppression test distinguishes ACTH-dependent from
ACTH-independent Cushing's syndrome. High-dose dexamethasone suppresses cortisol
in pituitary ACTH hypersecretion (Cushing's disease) because pituitary corticotrophs
retain partial negative feedback sensitivity, albeit at higher thresholds. The pituitary
adenoma responds to high-dose (but not low-dose) glucocorticoid negative feedback by
reducing ACTH secretion, thereby lowering cortisol.
, ● A is incorrect: Ectopic ACTH production (e.g., small cell lung cancer) is typically
high-volume and autonomous; high-dose dexamethasone rarely suppresses
cortisol because the ectopic source lacks normal feedback mechanisms.
● B is incorrect: Adrenal adenomas produce cortisol autonomously without ACTH
stimulation; dexamethasone cannot suppress cortisol regardless of dose
because the adrenal source is independent of ACTH.
● D is incorrect: Iatrogenic Cushing's syndrome would show suppressed ACTH and
failure of dexamethasone to suppress cortisol at any dose due to exogenous
steroid feedback, but the test results here indicate endogenous ACTH-dependent
pathology.
Q3: Which hormone is correctly paired with its mechanism of action and primary target
tissue?
A. Insulin → Binds nuclear receptors → Stimulates gluconeogenesis in liver
B. Aldosterone → Binds cell surface receptors → Increases sodium reabsorption in
kidney
C. Epinephrine → Binds G-protein coupled receptors → Increases glycogenolysis in liver
D. Testosterone → Binds tyrosine kinase receptors → Stimulates protein synthesis in
muscle
Correct Answer: C [CORRECT]
Rationale: Epinephrine binds to α and β adrenergic receptors, which are G-protein
coupled receptors (GPCRs). In the liver, epinephrine stimulates glycogenolysis
(breakdown of glycogen to glucose) through a cAMP-PKA signaling cascade, providing
rapid glucose mobilization during stress or exercise.
● A is incorrect: Insulin binds to tyrosine kinase receptors (insulin receptor
substrate pathway), not nuclear receptors. Insulin inhibits gluconeogenesis and
promotes glycogen synthesis, opposite to the stated action.
, ● B is incorrect: Aldosterone is a steroid hormone that diffuses into cells and binds
nuclear mineralocorticoid receptors, not cell surface receptors. The
receptor-hormone complex acts as a transcription factor to induce sodium
channel and Na+/K+-ATPase synthesis.
● D is incorrect: Testosterone is a steroid hormone that binds intracellular
androgen receptors (nuclear receptors), not tyrosine kinase receptors. The
hormone-receptor complex translocates to the nucleus to stimulate protein
synthesis gene expression.
Q4: A 28-year-old male presents with polyuria, polydipsia, and dehydration. His fasting
glucose is normal (92 mg/dL), but urine specific gravity is inappropriately low (1.002). A
water deprivation test shows no increase in urine osmolality, but administration of
desmopressin (ADH analog) corrects the urine concentration. Which diagnosis and
anatomical lesion location is correct?
A. Diabetes mellitus with destruction of pancreatic beta cells
B. Diabetes insipidus with lesion in supraoptic or paraventricular hypothalamic nuclei
C. Syndrome of inappropriate ADH (SIADH) with ectopic ADH production from lung
cancer
D. Primary polydipsia with psychogenic water intoxication causing dilutional
hyponatremia
Correct Answer: B [CORRECT]
Rationale: The presentation of polyuria with dilute urine despite dehydration, normal
glucose, and response to desmopressin indicates central diabetes insipidus (DI). ADH
(vasopressin) is synthesized in the supraoptic and paraventricular nuclei of the
hypothalamus, transported via axons to the posterior pituitary, and released into
circulation. Lesions in these hypothalamic nuclei (tumors, trauma, surgery, infiltrative
diseases) disrupt ADH synthesis, causing inability to concentrate urine.
Correct Answers with Complete Solutions | Human Anatomy
& Physiology II | Comprehensive Final Review | Clinical
Correlations | Pass Guaranteed - A+ Graded
Domain 1: Endocrine System (15 Questions)
Q1: A 45-year-old female patient presents with weight gain, fatigue, cold intolerance, and
a goiter. Laboratory studies reveal elevated TSH and decreased free T4. Which
endocrine disorder and underlying pathophysiology best explains these findings?
A. Graves' disease with TSH receptor antibodies stimulating excessive thyroid hormone
production
B. Hashimoto's thyroiditis with autoimmune destruction of thyroid tissue leading to
hypothyroidism
C. Thyroid storm due to acute release of thyroid hormones causing hypermetabolic
state
D. Iodine deficiency causing compensatory thyroid enlargement with normal hormone
levels
Correct Answer: B [CORRECT]
Rationale: The clinical presentation of weight gain, fatigue, cold intolerance, elevated
TSH, and decreased free T4 is classic for primary hypothyroidism. Hashimoto's
thyroiditis (autoimmune thyroiditis) is the most common cause of hypothyroidism in
developed countries. The autoimmune destruction of thyroid follicular cells reduces
thyroid hormone production (low T4), which removes negative feedback on the anterior
,pituitary, causing compensatory TSH elevation. The goiter develops due to chronic TSH
stimulation of thyroid tissue.
● A is incorrect: Graves' disease causes hyperthyroidism (weight loss, heat
intolerance, low TSH, high T4), the opposite of this presentation.
● C is incorrect: Thyroid storm is a life-threatening hypermetabolic emergency with
fever, tachycardia, and agitation, not hypothyroid symptoms.
● D is incorrect: While iodine deficiency causes goiter, it typically results in
euthyroid or sometimes hyperthyroid states (Jod-Basedow phenomenon), not the
pronounced hypothyroidism with elevated TSH seen here.
Q2: A patient with Cushing's syndrome undergoes a dexamethasone suppression test.
Administration of low-dose dexamethasone fails to suppress cortisol levels, but
high-dose dexamethasone causes suppression. Which source of excess cortisol is
most likely?
A. Ectopic ACTH-producing small cell lung carcinoma
B. Adrenal cortical adenoma secreting cortisol autonomously
C. Pituitary adenoma (Cushing's disease) with ACTH hypersecretion
D. Iatrogenic corticosteroid administration from chronic prednisone use
Correct Answer: C [CORRECT]
Rationale: The dexamethasone suppression test distinguishes ACTH-dependent from
ACTH-independent Cushing's syndrome. High-dose dexamethasone suppresses cortisol
in pituitary ACTH hypersecretion (Cushing's disease) because pituitary corticotrophs
retain partial negative feedback sensitivity, albeit at higher thresholds. The pituitary
adenoma responds to high-dose (but not low-dose) glucocorticoid negative feedback by
reducing ACTH secretion, thereby lowering cortisol.
, ● A is incorrect: Ectopic ACTH production (e.g., small cell lung cancer) is typically
high-volume and autonomous; high-dose dexamethasone rarely suppresses
cortisol because the ectopic source lacks normal feedback mechanisms.
● B is incorrect: Adrenal adenomas produce cortisol autonomously without ACTH
stimulation; dexamethasone cannot suppress cortisol regardless of dose
because the adrenal source is independent of ACTH.
● D is incorrect: Iatrogenic Cushing's syndrome would show suppressed ACTH and
failure of dexamethasone to suppress cortisol at any dose due to exogenous
steroid feedback, but the test results here indicate endogenous ACTH-dependent
pathology.
Q3: Which hormone is correctly paired with its mechanism of action and primary target
tissue?
A. Insulin → Binds nuclear receptors → Stimulates gluconeogenesis in liver
B. Aldosterone → Binds cell surface receptors → Increases sodium reabsorption in
kidney
C. Epinephrine → Binds G-protein coupled receptors → Increases glycogenolysis in liver
D. Testosterone → Binds tyrosine kinase receptors → Stimulates protein synthesis in
muscle
Correct Answer: C [CORRECT]
Rationale: Epinephrine binds to α and β adrenergic receptors, which are G-protein
coupled receptors (GPCRs). In the liver, epinephrine stimulates glycogenolysis
(breakdown of glycogen to glucose) through a cAMP-PKA signaling cascade, providing
rapid glucose mobilization during stress or exercise.
● A is incorrect: Insulin binds to tyrosine kinase receptors (insulin receptor
substrate pathway), not nuclear receptors. Insulin inhibits gluconeogenesis and
promotes glycogen synthesis, opposite to the stated action.
, ● B is incorrect: Aldosterone is a steroid hormone that diffuses into cells and binds
nuclear mineralocorticoid receptors, not cell surface receptors. The
receptor-hormone complex acts as a transcription factor to induce sodium
channel and Na+/K+-ATPase synthesis.
● D is incorrect: Testosterone is a steroid hormone that binds intracellular
androgen receptors (nuclear receptors), not tyrosine kinase receptors. The
hormone-receptor complex translocates to the nucleus to stimulate protein
synthesis gene expression.
Q4: A 28-year-old male presents with polyuria, polydipsia, and dehydration. His fasting
glucose is normal (92 mg/dL), but urine specific gravity is inappropriately low (1.002). A
water deprivation test shows no increase in urine osmolality, but administration of
desmopressin (ADH analog) corrects the urine concentration. Which diagnosis and
anatomical lesion location is correct?
A. Diabetes mellitus with destruction of pancreatic beta cells
B. Diabetes insipidus with lesion in supraoptic or paraventricular hypothalamic nuclei
C. Syndrome of inappropriate ADH (SIADH) with ectopic ADH production from lung
cancer
D. Primary polydipsia with psychogenic water intoxication causing dilutional
hyponatremia
Correct Answer: B [CORRECT]
Rationale: The presentation of polyuria with dilute urine despite dehydration, normal
glucose, and response to desmopressin indicates central diabetes insipidus (DI). ADH
(vasopressin) is synthesized in the supraoptic and paraventricular nuclei of the
hypothalamus, transported via axons to the posterior pituitary, and released into
circulation. Lesions in these hypothalamic nuclei (tumors, trauma, surgery, infiltrative
diseases) disrupt ADH synthesis, causing inability to concentrate urine.
