Question 1

Which of the following best describes the process of signal amplification in a biological signal transduction pathway?

Accepted Answer

A single ligand binding to a receptor stimulates the production of many second messenger molecules inside the cell.

Question 2

A patient is given a drug that acts as an antagonist to a specific neurotransmitter receptor. What is the most likely effect of this drug on signal transduction?

Accepted Answer

It will block the receptor and prevent the normal cellular response to the neurotransmitter.

Question 3

Which of the following is a characteristic of neural control compared to endocrine control in homeostatic reflex pathways?

Accepted Answer

Neural control is faster and more specific than endocrine control.

Question 4

During a homeostatic reflex pathway, which component is responsible for comparing incoming information to a setpoint and initiating an output signal?

Accepted Answer

Integration center

Question 5

A neuron is exposed to a neurotransmitter that opens potassium ($$K^+) $$channels. What is the most likely effect on the neuron's membrane potential?

Accepted Answer

The neuron will become hyperpolarized.

Question 6

Which of the following best explains why action potentials are conducted in only one direction along an axon?

Accepted Answer

Voltage-gated sodium ($$Na^+) $$channels become inactivated after opening, preventing backward propagation.

Question 7

Which of the following statements about graded potentials is TRUE?

Accepted Answer

Graded potentials lose strength as they move through the cell due to current leak and cytoplasmic resistance.

Question 8

A patient with hyperkalemia (elevated plasma $$K^+) is at $$risk for which of the following changes in neuronal excitability?

Accepted Answer

The resting membrane potential becomes less negative, making neurons more likely to depolarize.

Question 9

Which of the following best describes the role of myelin in action potential conduction?

Accepted Answer

Myelin increases the speed of action potential conduction by reducing ion leakage and allowing saltatory conduction.

Question 10

Which of the following is an example of agonistic control in homeostatic regulation?

Accepted Answer

The sympathetic and parasympathetic nervous systems sending signals that have opposite effects on heart rate.

Question 11

During the rising phase of the action potential, which of the following occurs?

Accepted Answer

Sodium ($$Na^+) $$moves into the cell down both its concentration and electrical gradients.

Question 12

Which of the following is TRUE regarding the specificity of neural versus endocrine control systems?

Accepted Answer

Neural control is more specific because each neuron terminates on a single or limited number of target cells.

Question 13

A ligand binds to a receptor and causes a rapid change in ion flow through a channel. This type of signal pathway is most likely found in which type of cell?

Accepted Answer

Neuron

Question 14

Which of the following best describes the function of the axon hillock in a neuron?

Accepted Answer

It is the site where action potentials are initiated if the graded potential reaches threshold.

Question 15

Which of the following statements about the refractory period of an action potential is correct?

Accepted Answer

During the absolute refractory period, no new action potential can be generated because $$Na^+$$ channels are inactivated.

Question 16

A researcher observes that a cell increases the number of receptors on its surface in response to a low concentration of a signaling molecule. This process is known as:

Accepted Answer

Up-regulation

Question 17

Which of the following is a correct statement about the movement of ions during the repolarization phase of an action potential?

Accepted Answer

$$K^+$$ exits the neuron to the extracellular fluid (ECF).

Question 18

Which of the following best explains why graded potentials decrease in strength as they move away from the site of origin?

Accepted Answer

Current leak and cytoplasmic resistance cause the loss of signal strength.

Question 19

Which of the following is TRUE regarding the effect of a strong stimulus on action potential conduction?

Accepted Answer

A strong stimulus increases the frequency of action potentials, not their speed or amplitude.

Exam Reflection and Critical Thinking Assignments in Anatomy & Physiology

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