BIOS 252 COMP Exam Study Guide 2025/2026 | BIOS 252
Comprehensive Exam Practice Questions with Detailed Answers
1. Which of the following best describes the fundamental difference between endocrine and exocrine
glands?
A) Endocrine glands have ducts; exocrine glands are ductless
B) Endocrine glands secrete hormones into the bloodstream; exocrine glands secrete through ducts
C) Endocrine glands produce enzymes; exocrine glands produce hormones
D) Endocrine glands are found only in the brain; exocrine glands are found throughout the body
Correct Answer: B) Endocrine glands secrete hormones into the bloodstream; exocrine glands
secrete through ducts
Rationale: Endocrine glands are ductless and release hormones directly into the interstitial fluid and
blood. Exocrine glands secrete their products through ducts onto epithelial surfaces.
2. The "master gland" that regulates many other endocrine glands and is itself controlled by the
hypothalamus is the:
A) Thyroid gland
B) Adrenal gland
C) Pituitary gland
D) Pineal gland
Correct Answer: C) Pituitary gland
Rationale: The pituitary gland is often called the "master gland" because its hormones control other
endocrine glands. It is regulated by the hypothalamus.
3. Which hormones are released from the posterior pituitary?
A) TSH and ACTH
B) FSH and LH
C) Oxytocin and ADH
D) Growth hormone and prolactin
Correct Answer: C) Oxytocin and ADH
Rationale: The posterior pituitary stores and releases oxytocin and antidiuretic hormone (ADH),
which are produced by the hypothalamus.
4. Which mechanism of hormone action involves the hormone entering the target cell to bind to
intracellular receptors and directly influence gene transcription?
A) Second messenger mechanism
B) Steroid hormone mechanism
,C) Tyrosine kinase mechanism
D) G-protein coupled receptor mechanism
Correct Answer: B) Steroid hormone mechanism
Rationale: Steroid hormones are lipid-soluble, allowing them to diffuse through the plasma
membrane and bind to intracellular receptors, which then affect gene transcription.
5. A 58-year-old patient with a history of head trauma presents with polyuria, polydipsia, and dilute
urine. Which hormone deficiency is most likely responsible?
A) Aldosterone
B) Cortisol
C) Antidiuretic hormone (ADH)
D) Thyroid hormone
Correct Answer: C) Antidiuretic hormone (ADH)
Rationale: Head trauma can damage the hypothalamus or posterior pituitary, causing decreased ADH
secretion. Without ADH, the kidneys cannot concentrate urine, leading to diabetes insipidus with
polyuria and polydipsia.
6. The primary target organ for parathyroid hormone (PTH) is:
A) Thyroid gland
B) Bone
C) Liver
D) Kidneys
Correct Answer: B) Bone
Rationale: PTH acts on bone to stimulate osteoclasts, which release calcium into the blood. It also
acts on the kidneys and intestine, but bone is the primary target.
7. A patient presents with signs of hypothyroidism. Laboratory results reveal elevated TSH and low
T3/T4 levels. Which of the following best explains the elevated TSH?
A) The anterior pituitary is producing excess TSH independently of feedback mechanisms
B) The thyroid gland is not producing adequate T3/T4, so negative feedback on the pituitary is reduced
C) The hypothalamus is producing excess TRH
D) The thyroid gland is producing excess T3/T4
Correct Answer: B) The thyroid gland is not producing adequate T3/T4, so negative feedback on the
pituitary is reduced
Rationale: In primary hypothyroidism, the thyroid cannot produce sufficient T3/T4. Low T3/T4 levels
reduce negative feedback on the anterior pituitary, causing elevated TSH secretion.
,8. Which hormone is produced by the anterior pituitary gland and stimulates the release of thyroid
hormones?
A) TRH (thyrotropin-releasing hormone)
B) TSH (thyroid-stimulating hormone)
C) ACTH (adrenocorticotropic hormone)
D) FSH (follicle-stimulating hormone)
Correct Answer: B) TSH (thyroid-stimulating hormone)
Rationale: TSH is produced by the anterior pituitary and stimulates the thyroid gland to produce and
release T3 and T4. TRH comes from the hypothalamus.
9. Which of the following hormones is classified as a steroid hormone?
A) Insulin
B) Epinephrine
C) Cortisol
D) Glucagon
Correct Answer: C) Cortisol
Rationale: Cortisol is a steroid hormone produced by the adrenal cortex. Insulin, epinephrine, and
glucagon are amino acid-derived hormones.
10. Which hormone is responsible for the "fight-or-flight" response?
A) Insulin
B) Cortisol
C) Epinephrine
D) Aldosterone
Correct Answer: C) Epinephrine
Rationale: Epinephrine (adrenaline) is released from the adrenal medulla and mediates the rapid
fight-or-flight response.
11. The most abundant plasma protein, primarily responsible for maintaining colloid osmotic pressure,
is:
A) Fibrinogen
B) Gamma globulin
C) Albumin
D) Prothrombin
Correct Answer: C) Albumin
Rationale: Albumin makes up about 60% of plasma proteins and maintains colloid osmotic pressure,
preventing edema.
, 12. A patient with Type A+ blood can safely receive a transfusion from which of the following donors?
A) Type B+
B) Type AB+
C) Type O-
D) Type AB-
Correct Answer: C) Type O-
Rationale: Type O- is the universal donor. A Type A+ patient has anti-B antibodies and cannot receive
B or AB blood.
13. Which leukocyte is the first to arrive at the site of an acute bacterial infection and performs
phagocytosis?
A) Basophil
B) Eosinophil
C) Monocyte
D) Neutrophil
Correct Answer: D) Neutrophil
Rationale: Neutrophils are the most numerous WBCs and act as "first responders" to bacterial
invasion through phagocytosis.
14. Which stage of hemostasis involves the conversion of soluble fibrinogen into insoluble fibrin
strands?
A) Vascular spasm
B) Platelet plug formation
C) Coagulation
D) Clot retraction
Correct Answer: C) Coagulation
Rationale: Coagulation is the third stage of hemostasis, where thrombin converts fibrinogen to fibrin
to form a mesh that traps blood cells.
15. Erythropoietin (EPO) is a hormone released by the in response to:
A) Liver; high blood pressure
B) Kidneys; low blood oxygen (hypoxia)
C) Bone marrow; high iron levels
D) Spleen; bacterial infection
Correct Answer: B) Kidneys; low blood oxygen (hypoxia)
Comprehensive Exam Practice Questions with Detailed Answers
1. Which of the following best describes the fundamental difference between endocrine and exocrine
glands?
A) Endocrine glands have ducts; exocrine glands are ductless
B) Endocrine glands secrete hormones into the bloodstream; exocrine glands secrete through ducts
C) Endocrine glands produce enzymes; exocrine glands produce hormones
D) Endocrine glands are found only in the brain; exocrine glands are found throughout the body
Correct Answer: B) Endocrine glands secrete hormones into the bloodstream; exocrine glands
secrete through ducts
Rationale: Endocrine glands are ductless and release hormones directly into the interstitial fluid and
blood. Exocrine glands secrete their products through ducts onto epithelial surfaces.
2. The "master gland" that regulates many other endocrine glands and is itself controlled by the
hypothalamus is the:
A) Thyroid gland
B) Adrenal gland
C) Pituitary gland
D) Pineal gland
Correct Answer: C) Pituitary gland
Rationale: The pituitary gland is often called the "master gland" because its hormones control other
endocrine glands. It is regulated by the hypothalamus.
3. Which hormones are released from the posterior pituitary?
A) TSH and ACTH
B) FSH and LH
C) Oxytocin and ADH
D) Growth hormone and prolactin
Correct Answer: C) Oxytocin and ADH
Rationale: The posterior pituitary stores and releases oxytocin and antidiuretic hormone (ADH),
which are produced by the hypothalamus.
4. Which mechanism of hormone action involves the hormone entering the target cell to bind to
intracellular receptors and directly influence gene transcription?
A) Second messenger mechanism
B) Steroid hormone mechanism
,C) Tyrosine kinase mechanism
D) G-protein coupled receptor mechanism
Correct Answer: B) Steroid hormone mechanism
Rationale: Steroid hormones are lipid-soluble, allowing them to diffuse through the plasma
membrane and bind to intracellular receptors, which then affect gene transcription.
5. A 58-year-old patient with a history of head trauma presents with polyuria, polydipsia, and dilute
urine. Which hormone deficiency is most likely responsible?
A) Aldosterone
B) Cortisol
C) Antidiuretic hormone (ADH)
D) Thyroid hormone
Correct Answer: C) Antidiuretic hormone (ADH)
Rationale: Head trauma can damage the hypothalamus or posterior pituitary, causing decreased ADH
secretion. Without ADH, the kidneys cannot concentrate urine, leading to diabetes insipidus with
polyuria and polydipsia.
6. The primary target organ for parathyroid hormone (PTH) is:
A) Thyroid gland
B) Bone
C) Liver
D) Kidneys
Correct Answer: B) Bone
Rationale: PTH acts on bone to stimulate osteoclasts, which release calcium into the blood. It also
acts on the kidneys and intestine, but bone is the primary target.
7. A patient presents with signs of hypothyroidism. Laboratory results reveal elevated TSH and low
T3/T4 levels. Which of the following best explains the elevated TSH?
A) The anterior pituitary is producing excess TSH independently of feedback mechanisms
B) The thyroid gland is not producing adequate T3/T4, so negative feedback on the pituitary is reduced
C) The hypothalamus is producing excess TRH
D) The thyroid gland is producing excess T3/T4
Correct Answer: B) The thyroid gland is not producing adequate T3/T4, so negative feedback on the
pituitary is reduced
Rationale: In primary hypothyroidism, the thyroid cannot produce sufficient T3/T4. Low T3/T4 levels
reduce negative feedback on the anterior pituitary, causing elevated TSH secretion.
,8. Which hormone is produced by the anterior pituitary gland and stimulates the release of thyroid
hormones?
A) TRH (thyrotropin-releasing hormone)
B) TSH (thyroid-stimulating hormone)
C) ACTH (adrenocorticotropic hormone)
D) FSH (follicle-stimulating hormone)
Correct Answer: B) TSH (thyroid-stimulating hormone)
Rationale: TSH is produced by the anterior pituitary and stimulates the thyroid gland to produce and
release T3 and T4. TRH comes from the hypothalamus.
9. Which of the following hormones is classified as a steroid hormone?
A) Insulin
B) Epinephrine
C) Cortisol
D) Glucagon
Correct Answer: C) Cortisol
Rationale: Cortisol is a steroid hormone produced by the adrenal cortex. Insulin, epinephrine, and
glucagon are amino acid-derived hormones.
10. Which hormone is responsible for the "fight-or-flight" response?
A) Insulin
B) Cortisol
C) Epinephrine
D) Aldosterone
Correct Answer: C) Epinephrine
Rationale: Epinephrine (adrenaline) is released from the adrenal medulla and mediates the rapid
fight-or-flight response.
11. The most abundant plasma protein, primarily responsible for maintaining colloid osmotic pressure,
is:
A) Fibrinogen
B) Gamma globulin
C) Albumin
D) Prothrombin
Correct Answer: C) Albumin
Rationale: Albumin makes up about 60% of plasma proteins and maintains colloid osmotic pressure,
preventing edema.
, 12. A patient with Type A+ blood can safely receive a transfusion from which of the following donors?
A) Type B+
B) Type AB+
C) Type O-
D) Type AB-
Correct Answer: C) Type O-
Rationale: Type O- is the universal donor. A Type A+ patient has anti-B antibodies and cannot receive
B or AB blood.
13. Which leukocyte is the first to arrive at the site of an acute bacterial infection and performs
phagocytosis?
A) Basophil
B) Eosinophil
C) Monocyte
D) Neutrophil
Correct Answer: D) Neutrophil
Rationale: Neutrophils are the most numerous WBCs and act as "first responders" to bacterial
invasion through phagocytosis.
14. Which stage of hemostasis involves the conversion of soluble fibrinogen into insoluble fibrin
strands?
A) Vascular spasm
B) Platelet plug formation
C) Coagulation
D) Clot retraction
Correct Answer: C) Coagulation
Rationale: Coagulation is the third stage of hemostasis, where thrombin converts fibrinogen to fibrin
to form a mesh that traps blood cells.
15. Erythropoietin (EPO) is a hormone released by the in response to:
A) Liver; high blood pressure
B) Kidneys; low blood oxygen (hypoxia)
C) Bone marrow; high iron levels
D) Spleen; bacterial infection
Correct Answer: B) Kidneys; low blood oxygen (hypoxia)
