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BIOL251 Human Anatomy & Physiology I with Lab
Module 9 Exam Actual Exam 2026/2027 – Complete
Exam-Style Questions with Detailed Rationales | 100%
Verified – Pass Guaranteed – A+ Graded
Endocrine System Overview & Hormone Chemistry
Q1: While comparing notes before the exam, a student asks you to distinguish between an
endocrine and an exocrine gland. Which explanation is most accurate?
A. Endocrine glands secrete hormones into ducts that lead to specific body surfaces, whereas
exocrine glands release hormones directly into the bloodstream.
B. Endocrine glands are ductless and release hormones into the blood, while exocrine glands
secrete substances into ducts that lead to epithelial surfaces.
C. Exocrine glands regulate long-term processes like metabolism, while endocrine glands
primarily secrete enzymes for digestion.
D. The primary difference is that endocrine glands only contain epithelial tissue, whereas
exocrine glands are composed entirely of connective tissue.
Correct Answer: B
Rationale: The best answer is B because it correctly identifies the defining structural difference:
endocrine glands are ductless and secrete hormones into the bloodstream for systemic
distribution, whereas exocrine glands use ducts to transport secretions to a specific surface.
Q2: A researcher is studying a molecule that is derived from cholesterol and can easily diffuse
across the plasma membrane of target cells. Which chemical class of hormones does this
molecule belong to?
A. Peptide hormones
B. Amino acid-derived hormones (amines)
C. Steroid hormones
D. Eicosanoids
Correct Answer: C
,2
Rationale: This choice is correct because steroid hormones (such as cortisol and testosterone) are
lipid-soluble molecules synthesized from cholesterol, allowing them to diffuse directly across the
cell membrane.
Q3: Why do peptide hormones, such as insulin or growth hormone, require a "second
messenger" system to exert their effects on a target cell?
A. They are too large to enter the nucleus, so they must send a signal inside the cell via
intermediate molecules.
B. They are water-soluble and cannot cross the plasma membrane, so they bind to surface
receptors to trigger internal changes.
C. They are derived from amino acids and must be converted into a steroid form before they can
be effective.
D. They act on the DNA directly but need a co-factor to ensure the correct gene is activated.
Correct Answer: B
Rationale: This matches the principle that peptide hormones are hydrophilic (water-soluble) and
cannot diffuse through the hydrophobic lipid bilayer of the cell membrane, so they must bind to
receptors on the cell surface to activate second messenger cascades inside.
Q4: During a clinical case study, a patient exhibits symptoms of low blood calcium. A hormone
is administered that binds to receptors on the surface of osteoclasts to stimulate bone resorption.
Based on the mechanism of action, this hormone is likely:
A. A steroid hormone because it alters gene transcription directly.
B. A catecholamine because it causes a "fight or flight" response.
C. A peptide hormone because it utilizes a surface receptor to activate bone cells.
D. A thyroid hormone because it regulates basal metabolic rate.
Correct Answer: C
Rationale: The best answer is C because the hormone described acts on surface receptors of
osteoclasts (bone cells) to trigger a rapid response, characteristic of water-soluble peptide
hormones like PTH, rather than entering the cell to act on the nucleus like a steroid.
,3
Q5: An anatomy student is confused about "target cell specificity." You explain that a hormone
only affects certain cells. What determines whether a cell responds to a particular hormone?
A. The size of the cell; larger cells absorb more hormones from the blood.
B. The location of the cell; only cells near the gland are affected.
C. The presence of specific receptors for that hormone on or in the cell.
D. The blood flow to that specific tissue; cells with high blood flow respond to all hormones.
Correct Answer: C
Rationale: This choice is correct because target cell specificity is determined solely by the
presence of specific receptors that recognize and bind to that hormone; if a cell lacks the
receptor, the hormone has no effect.
Q6: Which of the following correctly pairs a hormone with its chemical classification?
A. Insulin – Steroid
B. Estrogen – Peptide
C. Epinephrine – Amino acid derivative (Amine)
D. Cortisol – Protein
Correct Answer: C
Rationale: This aligns with the module objectives as epinephrine is derived from the amino acid
tyrosine (making it an amine), whereas insulin is a peptide, estrogen is a steroid, and cortisol is a
steroid.
Q7: In a laboratory experiment, a hormone is added to a cell culture, and the rate of protein
synthesis increases significantly within minutes. However, when the nucleus is removed from the
cells, this effect stops immediately. Which class of hormone was likely added?
A. A steroid hormone
B. A peptide hormone
C. A water-soluble hormone
D. A hormone utilizing cAMP as a second messenger
Correct Answer: A
, 4
Rationale: The best answer is A because steroid hormones enter the cell and bind to intracellular
receptors, directly influencing gene transcription (DNA) to synthesize new proteins, a process
that requires the nucleus.
Q8: A patient is prescribed a replacement therapy for a hormone deficiency. The medication is
taken orally, yet the patient still experiences low hormonal effects. Considering hormone
chemistry, why might this oral administration be failing for a peptide hormone?
A. Peptide hormones are easily digested by proteolytic enzymes in the stomach and small
intestine before they can be absorbed.
B. Peptide hormones are unable to pass through the intestinal lining because they are too large.
C. Steroid hormones are the only type that can be absorbed through the skin, not the mouth.
D. The patient's liver is filtering out the hormone too quickly before it reaches the target tissue.
Correct Answer: A
Rationale: This choice is correct because peptide hormones are proteins that are typically broken
down by digestive enzymes if taken orally, which is why they must usually be injected, unlike
steroid hormones which can survive digestion.
Q9: A hormone binds to a G-protein coupled receptor on a target cell. This binding activates
adenylate cyclase, which then converts ATP to cAMP. In this specific signaling pathway, what
role does cAMP play?
A. It acts as the first messenger.
B. It acts as the second messenger.
C. It acts as the hormone precursor.
D. It acts as the receptor antagonist.
Correct Answer: B
Rationale: The best answer is B because cAMP (cyclic AMP) is the classic intracellular signaling
molecule, or "second messenger," that relays the signal from the surface receptor to the inside of
the cell to elicit a response.
Q10: When comparing the duration of action between steroid and peptide hormones, which
statement is generally true?
BIOL251 Human Anatomy & Physiology I with Lab
Module 9 Exam Actual Exam 2026/2027 – Complete
Exam-Style Questions with Detailed Rationales | 100%
Verified – Pass Guaranteed – A+ Graded
Endocrine System Overview & Hormone Chemistry
Q1: While comparing notes before the exam, a student asks you to distinguish between an
endocrine and an exocrine gland. Which explanation is most accurate?
A. Endocrine glands secrete hormones into ducts that lead to specific body surfaces, whereas
exocrine glands release hormones directly into the bloodstream.
B. Endocrine glands are ductless and release hormones into the blood, while exocrine glands
secrete substances into ducts that lead to epithelial surfaces.
C. Exocrine glands regulate long-term processes like metabolism, while endocrine glands
primarily secrete enzymes for digestion.
D. The primary difference is that endocrine glands only contain epithelial tissue, whereas
exocrine glands are composed entirely of connective tissue.
Correct Answer: B
Rationale: The best answer is B because it correctly identifies the defining structural difference:
endocrine glands are ductless and secrete hormones into the bloodstream for systemic
distribution, whereas exocrine glands use ducts to transport secretions to a specific surface.
Q2: A researcher is studying a molecule that is derived from cholesterol and can easily diffuse
across the plasma membrane of target cells. Which chemical class of hormones does this
molecule belong to?
A. Peptide hormones
B. Amino acid-derived hormones (amines)
C. Steroid hormones
D. Eicosanoids
Correct Answer: C
,2
Rationale: This choice is correct because steroid hormones (such as cortisol and testosterone) are
lipid-soluble molecules synthesized from cholesterol, allowing them to diffuse directly across the
cell membrane.
Q3: Why do peptide hormones, such as insulin or growth hormone, require a "second
messenger" system to exert their effects on a target cell?
A. They are too large to enter the nucleus, so they must send a signal inside the cell via
intermediate molecules.
B. They are water-soluble and cannot cross the plasma membrane, so they bind to surface
receptors to trigger internal changes.
C. They are derived from amino acids and must be converted into a steroid form before they can
be effective.
D. They act on the DNA directly but need a co-factor to ensure the correct gene is activated.
Correct Answer: B
Rationale: This matches the principle that peptide hormones are hydrophilic (water-soluble) and
cannot diffuse through the hydrophobic lipid bilayer of the cell membrane, so they must bind to
receptors on the cell surface to activate second messenger cascades inside.
Q4: During a clinical case study, a patient exhibits symptoms of low blood calcium. A hormone
is administered that binds to receptors on the surface of osteoclasts to stimulate bone resorption.
Based on the mechanism of action, this hormone is likely:
A. A steroid hormone because it alters gene transcription directly.
B. A catecholamine because it causes a "fight or flight" response.
C. A peptide hormone because it utilizes a surface receptor to activate bone cells.
D. A thyroid hormone because it regulates basal metabolic rate.
Correct Answer: C
Rationale: The best answer is C because the hormone described acts on surface receptors of
osteoclasts (bone cells) to trigger a rapid response, characteristic of water-soluble peptide
hormones like PTH, rather than entering the cell to act on the nucleus like a steroid.
,3
Q5: An anatomy student is confused about "target cell specificity." You explain that a hormone
only affects certain cells. What determines whether a cell responds to a particular hormone?
A. The size of the cell; larger cells absorb more hormones from the blood.
B. The location of the cell; only cells near the gland are affected.
C. The presence of specific receptors for that hormone on or in the cell.
D. The blood flow to that specific tissue; cells with high blood flow respond to all hormones.
Correct Answer: C
Rationale: This choice is correct because target cell specificity is determined solely by the
presence of specific receptors that recognize and bind to that hormone; if a cell lacks the
receptor, the hormone has no effect.
Q6: Which of the following correctly pairs a hormone with its chemical classification?
A. Insulin – Steroid
B. Estrogen – Peptide
C. Epinephrine – Amino acid derivative (Amine)
D. Cortisol – Protein
Correct Answer: C
Rationale: This aligns with the module objectives as epinephrine is derived from the amino acid
tyrosine (making it an amine), whereas insulin is a peptide, estrogen is a steroid, and cortisol is a
steroid.
Q7: In a laboratory experiment, a hormone is added to a cell culture, and the rate of protein
synthesis increases significantly within minutes. However, when the nucleus is removed from the
cells, this effect stops immediately. Which class of hormone was likely added?
A. A steroid hormone
B. A peptide hormone
C. A water-soluble hormone
D. A hormone utilizing cAMP as a second messenger
Correct Answer: A
, 4
Rationale: The best answer is A because steroid hormones enter the cell and bind to intracellular
receptors, directly influencing gene transcription (DNA) to synthesize new proteins, a process
that requires the nucleus.
Q8: A patient is prescribed a replacement therapy for a hormone deficiency. The medication is
taken orally, yet the patient still experiences low hormonal effects. Considering hormone
chemistry, why might this oral administration be failing for a peptide hormone?
A. Peptide hormones are easily digested by proteolytic enzymes in the stomach and small
intestine before they can be absorbed.
B. Peptide hormones are unable to pass through the intestinal lining because they are too large.
C. Steroid hormones are the only type that can be absorbed through the skin, not the mouth.
D. The patient's liver is filtering out the hormone too quickly before it reaches the target tissue.
Correct Answer: A
Rationale: This choice is correct because peptide hormones are proteins that are typically broken
down by digestive enzymes if taken orally, which is why they must usually be injected, unlike
steroid hormones which can survive digestion.
Q9: A hormone binds to a G-protein coupled receptor on a target cell. This binding activates
adenylate cyclase, which then converts ATP to cAMP. In this specific signaling pathway, what
role does cAMP play?
A. It acts as the first messenger.
B. It acts as the second messenger.
C. It acts as the hormone precursor.
D. It acts as the receptor antagonist.
Correct Answer: B
Rationale: The best answer is B because cAMP (cyclic AMP) is the classic intracellular signaling
molecule, or "second messenger," that relays the signal from the surface receptor to the inside of
the cell to elicit a response.
Q10: When comparing the duration of action between steroid and peptide hormones, which
statement is generally true?
