Question 1

Which of the following best describes the difference between hydrophilic and lipophilic hormones in terms of their mechanism of action?

Accepted Answer

Hydrophilic hormones bind to cell surface receptors and typically activate second messenger systems, while lipophilic hormones diffuse through the cell membrane and bind to intracellular receptors to alter gene transcription.

Question 2

A patient is given a drug that blocks the activity of adenylyl cyclase. Which hormone signaling pathway would be most directly affected?

Accepted Answer

cAMP second messenger pathway

Question 3

Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential ($E_{ion}$) of an ion across a membrane?

Accepted Answer

$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$

Question 4

Which of the following is NOT a characteristic of graded potentials?

Accepted Answer

They are all-or-none events.

Question 5

A mutation causes the voltage-gated sodium channels in a neuron to remain open longer than normal. What effect would this have on the action potential?

Accepted Answer

It would prolong the depolarization phase, potentially increasing the amplitude of the action potential.

Question 6

Which of the following hormones is released from the posterior pituitary and is involved in water reabsorption in the kidneys?

Accepted Answer

Antidiuretic hormone (ADH)

Question 7

A patient presents with symptoms of hypothyroidism. Which hormone would you expect to be decreased in their blood?

Accepted Answer

Thyroxine ($T_4$)

Question 8

Which of the following best explains why steroid hormones typically have longer-lasting effects than peptide hormones?

Accepted Answer

Steroid hormones alter gene transcription, leading to changes in protein synthesis that persist after the hormone is gone.

Question 9

Which of the following is a correct sequence of events at a chemical synapse when an action potential arrives at the axon terminal?

Accepted Answer

Calcium ions enter the axon terminal, neurotransmitter vesicles fuse with the membrane, neurotransmitter is released into the synaptic cleft.

Question 10

Which of the following best describes the role of the axon hillock in neuronal signaling?

Accepted Answer

It is the region where summation of graded potentials occurs and the action potential is initiated if threshold is reached.

Question 11

Which of the following statements about the absolute refractory period is correct?

Accepted Answer

It is the period during which voltage-gated sodium channels are inactivated and no action potential can be generated.

Question 12

Which of the following is a function of tropic hormones?

Accepted Answer

They regulate the activity of other endocrine glands.

Question 13

A patient with hyperparathyroidism would most likely exhibit which of the following symptoms?

Accepted Answer

High blood calcium levels

Question 14

Which of the following best describes the effect of an EPSP (excitatory postsynaptic potential) on a postsynaptic neuron?

Accepted Answer

It depolarizes the postsynaptic membrane, increasing the likelihood of reaching threshold for an action potential.

Question 15

Which of the following is a correct description of the signal transduction mechanism for G protein-coupled receptors (GPCRs)?

Accepted Answer

Ligand binding activates a G protein, which then activates an effector enzyme such as adenylyl cyclase, leading to the production of a second messenger.

Question 16

Which of the following pituitary hormones is primarily responsible for stimulating milk production in the mammary glands?

Accepted Answer

Prolactin

Question 17

Which of the following best explains the effect of myelination on the speed of action potential propagation?

Accepted Answer

Myelination allows action potentials to jump between nodes of Ranvier, increasing conduction velocity.

Question 18

Which of the following is a direct effect of insulin on target cells?

Accepted Answer

Increased uptake of glucose from the blood

Question 19

Which of the following best describes the role of the hypothalamic-pituitary-adrenal (HPA) axis?

Accepted Answer

It controls the body's response to stress by regulating cortisol secretion.

Question 20

Which of the following is a correct statement about the maintenance of the resting membrane potential (RMP) in neurons?

Accepted Answer

The RMP is maintained by the activity of the Na	extsuperscript{+}/K	extsuperscript{+} ATPase pump, which moves 3 Na	extsuperscript{+} out and 2 K	extsuperscript{+} in per ATP hydrolyzed.

Cellular Communication, Hormones, and Neural Signaling: Study Notes for Anatomy & Physiology

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