FIS2603
ASSIGNMENT 2 SEMESTER 1 2025
UNIQUE NO. 739210
DUE DATE: 17 APRIL 2025
, FIS2603
Assignment 2 Semester 1 2025
Unique No. 739210
Due Date: 17 April 2025
Physiological Defence Mechanisms
Question 1
1.1 Factors that Hyperpolarize and Depolarize the Membrane (7)
The membrane potential of a cell is influenced by various factors that either
hyperpolarize (make the inside of the cell more negative) or depolarize (make the inside
of the cell less negative or more positive).
Factors that hyperpolarize the membrane:
1. Opening of potassium (K⁺) channels – Increases K⁺ efflux, making the inside
more negative.
2. Opening of chloride (Cl⁻) channels – Cl⁻ influx increases negativity inside the
cell.
3. Inhibition of sodium (Na⁺) channels – Prevents Na⁺ from entering, maintaining
a negative charge.
Factors that depolarize the membrane:
4. Opening of sodium (Na⁺) channels – Na⁺ influx makes the inside more positive.
5. Opening of calcium (Ca²⁺) channels – Ca²⁺ influx also contributes to depolarization.
6. Closure of potassium (K⁺) channels – Reduces K⁺ efflux, making the inside less
negative.
7. Neurotransmitters (e.g., acetylcholine and glutamate) – These can trigger ion
channel openings leading to depolarization.
ASSIGNMENT 2 SEMESTER 1 2025
UNIQUE NO. 739210
DUE DATE: 17 APRIL 2025
, FIS2603
Assignment 2 Semester 1 2025
Unique No. 739210
Due Date: 17 April 2025
Physiological Defence Mechanisms
Question 1
1.1 Factors that Hyperpolarize and Depolarize the Membrane (7)
The membrane potential of a cell is influenced by various factors that either
hyperpolarize (make the inside of the cell more negative) or depolarize (make the inside
of the cell less negative or more positive).
Factors that hyperpolarize the membrane:
1. Opening of potassium (K⁺) channels – Increases K⁺ efflux, making the inside
more negative.
2. Opening of chloride (Cl⁻) channels – Cl⁻ influx increases negativity inside the
cell.
3. Inhibition of sodium (Na⁺) channels – Prevents Na⁺ from entering, maintaining
a negative charge.
Factors that depolarize the membrane:
4. Opening of sodium (Na⁺) channels – Na⁺ influx makes the inside more positive.
5. Opening of calcium (Ca²⁺) channels – Ca²⁺ influx also contributes to depolarization.
6. Closure of potassium (K⁺) channels – Reduces K⁺ efflux, making the inside less
negative.
7. Neurotransmitters (e.g., acetylcholine and glutamate) – These can trigger ion
channel openings leading to depolarization.
