BIOS 256 Final Exam Actual Exam 2026/2027 –
Comprehensive A&P IV Assessment with Detailed Rationales
| 100% Verified | Pass Guaranteed – A+ Graded
Section A: Endocrine System & Hormonal Regulation
Q1: A 42-year-old female presents with heat intolerance, weight loss, tachycardia, and
exophthalmos. Laboratory studies show elevated free T4 and suppressed TSH. Which
hormone is primarily responsible for the negative feedback inhibition of TSH secretion
in this patient?
A. Thyrotropin-releasing hormone (TRH)
B. Thyroid-stimulating hormone (TSH)
C. Thyroxine (T4) and triiodothyronine (T3)
D. Calcitonin
Correct Answer: C
Rationale: Thyroid hormones (T3/T4) exert negative feedback on both the
hypothalamus (reducing TRH) and the anterior pituitary (reducing TSH secretion). In
Graves' disease, elevated T4/T3 suppress TSH. Option A (TRH) stimulates TSH release;
Option B (TSH) stimulates the thyroid; Option D (calcitonin) regulates calcium and has
no effect on TSH.
Q2: A patient with a pituitary adenoma develops diabetes insipidus. Which hormone
deficiency is responsible for the polyuria and polydipsia?
A. Aldosterone
,B. Antidiuretic hormone (ADH)
C. Oxytocin
D. Atrial natriuretic peptide (ANP)
Correct Answer: B
Rationale: ADH (vasopressin) is synthesized in the hypothalamus and released from the
posterior pituitary; it promotes water reabsorption in the collecting ducts. Deficiency
causes diabetes insipidus with dilute polyuria. Option A (aldosterone) regulates sodium;
Option C (oxytocin) regulates uterine contraction and milk ejection; Option D (ANP)
promotes natriuresis and diuresis but is not the cause of central diabetes insipidus.
Q3: Cortisol is classified as which type of hormone, and which receptor mechanism
does it primarily use?
A. Peptide hormone; cell surface receptor with cAMP second messenger
B. Steroid hormone; intracellular receptor with genomic effects
C. Amine hormone; G-protein coupled receptor
D. Eicosanoid; tyrosine kinase receptor
Correct Answer: B
Rationale: Cortisol is a steroid hormone synthesized from cholesterol; being
lipid-soluble, it crosses cell membranes and binds intracellular receptors that act as
transcription factors to alter gene expression. Option A describes peptide hormones like
ACTH; Option C describes catecholamines and thyroid hormone; Option D describes
prostaglandins and leukotrienes.
, Q4: During the stress response, the hypothalamus releases CRH, stimulating the
anterior pituitary to release ACTH, which stimulates the adrenal cortex to release
cortisol. Cortisol then inhibits further CRH and ACTH release. This is an example of:
A. Positive feedback
B. Negative feedback
C. Feed-forward regulation
D. Neural regulation
Correct Answer: B
Rationale: This is classic negative feedback: the end product (cortisol) inhibits
upstream regulators (CRH, ACTH) to maintain homeostasis. Option A (positive
feedback) amplifies the response (e.g., oxytocin during labor); Option C anticipates a
change; Option D involves direct neural control rather than hormonal feedback.
Q5: A patient with Addison's disease presents with hypotension, hyperkalemia, and
hyponatremia. Which hormone deficiency is primarily responsible for the electrolyte
abnormalities?
A. Cortisol
B. Aldosterone
C. Epinephrine
D. Androstenedione
Correct Answer: B
Comprehensive A&P IV Assessment with Detailed Rationales
| 100% Verified | Pass Guaranteed – A+ Graded
Section A: Endocrine System & Hormonal Regulation
Q1: A 42-year-old female presents with heat intolerance, weight loss, tachycardia, and
exophthalmos. Laboratory studies show elevated free T4 and suppressed TSH. Which
hormone is primarily responsible for the negative feedback inhibition of TSH secretion
in this patient?
A. Thyrotropin-releasing hormone (TRH)
B. Thyroid-stimulating hormone (TSH)
C. Thyroxine (T4) and triiodothyronine (T3)
D. Calcitonin
Correct Answer: C
Rationale: Thyroid hormones (T3/T4) exert negative feedback on both the
hypothalamus (reducing TRH) and the anterior pituitary (reducing TSH secretion). In
Graves' disease, elevated T4/T3 suppress TSH. Option A (TRH) stimulates TSH release;
Option B (TSH) stimulates the thyroid; Option D (calcitonin) regulates calcium and has
no effect on TSH.
Q2: A patient with a pituitary adenoma develops diabetes insipidus. Which hormone
deficiency is responsible for the polyuria and polydipsia?
A. Aldosterone
,B. Antidiuretic hormone (ADH)
C. Oxytocin
D. Atrial natriuretic peptide (ANP)
Correct Answer: B
Rationale: ADH (vasopressin) is synthesized in the hypothalamus and released from the
posterior pituitary; it promotes water reabsorption in the collecting ducts. Deficiency
causes diabetes insipidus with dilute polyuria. Option A (aldosterone) regulates sodium;
Option C (oxytocin) regulates uterine contraction and milk ejection; Option D (ANP)
promotes natriuresis and diuresis but is not the cause of central diabetes insipidus.
Q3: Cortisol is classified as which type of hormone, and which receptor mechanism
does it primarily use?
A. Peptide hormone; cell surface receptor with cAMP second messenger
B. Steroid hormone; intracellular receptor with genomic effects
C. Amine hormone; G-protein coupled receptor
D. Eicosanoid; tyrosine kinase receptor
Correct Answer: B
Rationale: Cortisol is a steroid hormone synthesized from cholesterol; being
lipid-soluble, it crosses cell membranes and binds intracellular receptors that act as
transcription factors to alter gene expression. Option A describes peptide hormones like
ACTH; Option C describes catecholamines and thyroid hormone; Option D describes
prostaglandins and leukotrienes.
, Q4: During the stress response, the hypothalamus releases CRH, stimulating the
anterior pituitary to release ACTH, which stimulates the adrenal cortex to release
cortisol. Cortisol then inhibits further CRH and ACTH release. This is an example of:
A. Positive feedback
B. Negative feedback
C. Feed-forward regulation
D. Neural regulation
Correct Answer: B
Rationale: This is classic negative feedback: the end product (cortisol) inhibits
upstream regulators (CRH, ACTH) to maintain homeostasis. Option A (positive
feedback) amplifies the response (e.g., oxytocin during labor); Option C anticipates a
change; Option D involves direct neural control rather than hormonal feedback.
Q5: A patient with Addison's disease presents with hypotension, hyperkalemia, and
hyponatremia. Which hormone deficiency is primarily responsible for the electrolyte
abnormalities?
A. Cortisol
B. Aldosterone
C. Epinephrine
D. Androstenedione
Correct Answer: B
