Question 1

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

Accepted Answer

Direct communication occurs via physical contact between cells, such as through gap junctions, whereas indirect communication uses chemical messengers released into the extracellular space.

Question 2

Which equation describes the resting membrane potential of a neuron according to the Nernst equation?

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 3

Which of the following is NOT a major class of chemical messenger?

Accepted Answer

Glycogen

Question 4

A patient presents with muscle weakness and fatigue. Lab results show low levels of acetylcholine. What is the most likely cellular effect?

Accepted Answer

Decreased activation of postsynaptic sodium channels, leading to reduced action potential generation.

Question 5

Which of the following hormones is secreted from the posterior pituitary gland and acts primarily on the kidneys?

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 release of another hormone, reducing the initial stimulus.

Question 7

Which of the following is a permissive effect of hormones?

Accepted Answer

One hormone allows another hormone to exert its full effect.

Question 8

Which of the following cell types is responsible for secreting growth hormone in the anterior pituitary gland?

Accepted Answer

Somatotrophs

Question 9

Which of the following best explains the role of myelin sheaths in nerve conduction?

Accepted Answer

They insulate the axon, allowing action potentials to jump between nodes of Ranvier, increasing conduction speed.

Question 10

Which of the following is the correct formula for Ohm's Law as it applies to membrane potential?

Accepted Answer

$$V = IR$$

Question 11

Which neurotransmitter is primarily involved in the regulation of mood and is known as one of the 'Happy Hormones'?

Accepted Answer

Serotonin

Question 12

Which of the following best describes the function of the hypothalamic portal system?

Accepted Answer

It allows hormones from the hypothalamus to reach the anterior pituitary directly, bypassing the general circulation.

Question 13

Which of the following is a characteristic of steroid hormones?

Accepted Answer

They are hydrophobic, derived from cholesterol, and typically act on intracellular receptors.

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 graded potentials and action potentials?

Accepted Answer

Graded potentials decrease in strength as they spread, while action potentials maintain their strength over distance.

Question 16

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

Accepted Answer

cAMP (cyclic adenosine monophosphate)

Question 17

Which of the following is a function of the adrenal medulla?

Accepted Answer

Release of epinephrine and norepinephrine during stress

Question 18

Which of the following best describes the role of the sodium-potassium pump in maintaining membrane potential?

Accepted Answer

It actively transports 3 sodium ions out and 2 potassium ions in, maintaining the negative resting membrane potential.

Question 19

Which of the following is a major effect of parathyroid hormone (PTH) on calcium homeostasis?

Accepted Answer

It increases calcium reabsorption in the kidneys and stimulates bone resorption.

Comprehensive Study Notes: Chemical Messengers, Endocrine System, and Nervous System in Anatomy & Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard