Which of the Following Situations Occurs in Electrically Excitable Cells

question 141

Multiple Choice

Which of the following situations occurs in electrically excitable cells?

• A) When Na⁺ ion channels open, K⁺ ion channels close.
• B) The sodium-potassium pump moves sodium into the cell.
• C) Depolarization causes voltage-gated sodium ion channels to open.
• D) Sodium ion channels are opened by high extracellular calcium levels.
• E) The opening and closing of ligand-gated channels cause depolarization.

---

Definitions:

External Intercostals

Muscles found between the ribs that aid in the mechanics of breathing by elevating the ribcage.

Olecranon Process

The prominent, pointed bone at the proximal end of the ulna, around which the elbow joint is formed.

Extension

A movement that increases the angle between two body parts, such as straightening a flexed knee.

Flexion

A movement decreasing the angle between two body parts, such as bending the arm at the elbow or the knee.