Early symptoms of variant Creutzfeldt-Jakob Disease (vCJD) include changes in mood, temperament and behaviour followed by impairments in memory and concentration, and confused thinking. The infectious agent in vCJD is thought to be which of the following?

Correct Answer: B

Rationale: Prions are abnormal, infectious proteins that cause neurodegenerative diseases like variant Creutzfeldt-Jakob Disease (vCJD). These proteins induce the misfolding of normal cellular proteins in the brain, leading to brain damage and the characteristic symptoms of vCJD, such as mood changes, memory loss, and cognitive decline. Prion diseases are incurable and ultimately fatal, making early detection and prevention critical.

Correct Answer: A

Rationale: During the repolarization phase of an action potential, potassium ions move out of the axon, restoring the negative charge inside the neuron. This efflux of potassium ions helps return the membrane potential to its resting state after depolarization. The movement of potassium ions is facilitated by voltage-gated potassium channels, which open in response to the change in membrane potential.

Correct Answer: C

Rationale: The brain stem is responsible for regulating unconscious bodily functions, such as breathing, heart rate, and blood pressure. It includes structures like the medulla oblongata, pons, and midbrain. These areas control vital processes necessary for survival and maintain homeostasis. The brain stem also serves as a pathway for nerve signals traveling between the brain and the rest of the body, making it essential for basic life functions.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.