Question 1

Which of the following best describes the difference between direct and indirect cell-to-cell communication?

Accepted Answer

Direct communication uses cell junctions such as gap junctions for immediate exchange of ions and molecules, while indirect communication relies on chemical messengers released into the extracellular space.

Question 2

Which of the following is NOT a major mode of chemical messenger in the body?

Accepted Answer

Mechanical

Question 3

A patient is given a drug that acts as an antagonist to dopamine receptors. What is the expected effect?

Accepted Answer

The drug will block dopamine from binding to its receptors, reducing dopamine's physiological effects.

Question 4

Which equation is used to calculate the resting membrane potential of a neuron, considering multiple ions?

Accepted Answer

The Goldman-Hodgkin-Katz (GHK) equation: $$V_m = \frac{RT}{F} \ln \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}}$$

Question 5

Which of the following hormones is secreted by the posterior pituitary gland and acts on the kidneys to regulate water balance?

Accepted Answer

Antidiuretic hormone (ADH)

Question 6

Which of the following best describes a negative feedback loop in endocrine regulation?

Accepted Answer

A hormone inhibits the process that led to its secretion, maintaining homeostasis.

Question 7

Which of the following cell junctions is most effective for direct electrical signaling between adjacent cells?

Accepted Answer

Gap junctions

Question 8

A patient with hypothyroidism is found to have low levels of T3 and T4. Which gland is most likely underactive?

Accepted Answer

Thyroid gland

Question 9

Which neurotransmitter is primarily responsible for muscle contraction at the neuromuscular junction?

Accepted Answer

Acetylcholine

Question 10

Which of the following is a peptide hormone secreted by the anterior pituitary gland?

Accepted Answer

Growth hormone (GH)

Question 11

Which of the following best explains the permissive effect of hormones?

Accepted Answer

One hormone must be present for another hormone to exert its full effect.

Question 12

Which of the following is the correct pathway for the hypothalamic-pituitary-thyroid axis?

Accepted Answer

Hypothalamus → TRH → Anterior pituitary → TSH → Thyroid gland → T3/T4

Question 13

Which of the following is a major function of myelin sheaths in the nervous system?

Accepted Answer

To increase the speed of action potential conduction along axons

Question 14

Which of the following ions is most responsible for the rising phase of the neuronal action potential?

Accepted Answer

Sodium ($$Na^+)$$

Question 15

Which of the following best describes the difference between EPSPs and IPSPs?

Accepted Answer

EPSPs depolarize the postsynaptic membrane, increasing the likelihood of an action potential; IPSPs hyperpolarize the membrane, decreasing the likelihood of an action potential.

Question 16

Which of the following is a steroid hormone produced by the adrenal cortex?

Accepted Answer

Cortisol

Question 17

Which physiological activity is most likely to stimulate the DAG-IP3 pathway?

Accepted Answer

Activation of a G protein-coupled receptor by a hormone such as epinephrine

Question 18

Which of the following best describes saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

Question 19

Which of the following is a second messenger commonly used in signal transduction pathways?

Accepted Answer

cAMP ($$	ext{cAMP})$$

Comprehensive Study Notes: Chemical Messengers, Endocrine System, and Nervous System (Chapters 5-11)

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