Question 1

Refer to the first image. Which structure is labeled 'A' and what is its primary function in compact bone?

Accepted Answer

A: Osteon; function: structural unit providing strength and support

Question 2

In the first image, what is the structure labeled 'B' and what is its significance?

Accepted Answer

B: Perforating (Volkmann's) canal; connects blood and nerve supply of periosteum to those in the central canals

Question 3

What is the function of the structure labeled 'C' in the first image?

Accepted Answer

C: Lamella; provides tensile strength and resists torsion

Question 4

In the first image, what is the role of the structure labeled 'D'?

Accepted Answer

D: Canaliculi; allow for communication and nutrient/waste exchange between osteocytes

Question 5

Which structure is labeled 'E' in the first image, and what is its function?

Accepted Answer

E: Lacuna; houses osteocytes

Question 6

Refer to the second image (action potential graph). What event is occurring at point 'A'?

Accepted Answer

A: Resting membrane potential, maintained by Na+/K+ pump

Question 7

What is happening at point 'B' on the action potential graph?

Accepted Answer

B: Depolarization due to Na+ influx

Question 8

At point 'C' on the action potential graph, which ion channels are primarily open?

Accepted Answer

C: Voltage-gated Na+ channels

Question 9

What process is occurring at point 'D' on the action potential graph?

Accepted Answer

D: Repolarization due to K+ efflux

Question 10

What does point 'E' on the action potential graph represent?

Accepted Answer

E: Hyperpolarization due to slow closing of K+ channels

Question 11

Which equation best describes the Nernst potential for potassium ($$K^+) $$across a membrane?

Accepted Answer

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

Question 12

If a mutation caused voltage-gated Na+ channels to remain open longer than normal, which part of the action potential graph would be most affected?

Accepted Answer

The peak (C) would be higher and broader

Question 13

A drug that blocks voltage-gated K+ channels would have what effect on the action potential graph?

Accepted Answer

It would prolong the repolarization phase (D)

Question 14

Which phase of the action potential is responsible for the absolute refractory period?

Accepted Answer

Repolarization (C to D)

Question 15

If extracellular $$K^+$$ concentration increases, what happens to the resting membrane potential?

Accepted Answer

It becomes less negative (depolarizes)

Question 16

Which structure in compact bone allows for the passage of nutrients and waste between osteocytes?

Accepted Answer

Canaliculi

Question 17

Which labeled structure in the first image is most responsible for resisting torsional (twisting) stress in bone?

Accepted Answer

C: Lamellae

Question 18

During which phase of the action potential (second image) are voltage-gated Na+ channels inactivated and voltage-gated K+ channels open?

Accepted Answer

D: Repolarization

Question 19

Which labeled phase in the action potential graph (second image) corresponds to the relative refractory period?

Accepted Answer

E: Hyperpolarization

ANP Study Guide: Key Concepts and Step-by-Step Guidance

Study Guide - Practice Questions