Which part of the endocrine system is sometimes called the "master gland"?

Correct Answer: C

Rationale: The pituitary gland is often referred to as the 'master gland' because it regulates the function of other endocrine glands by releasing hormones that control growth, metabolism, and reproduction. It is located at the base of the brain and is divided into the anterior and posterior lobes, each producing different hormones. The pituitary gland plays a central role in maintaining hormonal balance and overall bodily function.

Correct Answer: B

Rationale: Errorless learning is a training technique used to help individuals with amnesia acquire new skills or information without making mistakes. By minimizing errors during the learning process, this method enhances memory retention and reduces the likelihood of incorrect information being stored. Errorless learning is particularly effective for individuals with memory impairments, as it leverages their residual learning abilities and promotes successful skill acquisition.

Correct Answer: D

Rationale: Schwann cells are a type of neuroglial cell found in the peripheral nervous system (PNS). They are responsible for producing myelin, which insulates axons and enhances the speed of nerve impulse transmission. Other types of neuroglial cells include astrocytes, oligodendrocytes, and microglia, each of which supports and protects neurons in different ways. Schwann cells are essential for maintaining the health and function of peripheral neurons.

Correct Answer: A

Rationale: The refractory period is a brief time following an action potential during which a neuron is unable to fire another impulse. This period ensures that action potentials propagate in one direction and allows the neuron to reset its ion gradients. The refractory period is divided into the absolute refractory period, when no new action potentials can be generated, and the relative refractory period, when a stronger-than-usual stimulus is required to generate an action potential.

Correct Answer: D

Rationale: The brain is protected by multiple layers of defense, including the meninges (protective membranes), cerebrospinal fluid (a cushioning fluid), and the bony skull. The meninges consist of three layers—dura mater, arachnoid mater, and pia mater—that provide structural support and protection. Cerebrospinal fluid surrounds the brain and spinal cord, acting as a shock absorber. The skull provides a rigid barrier against physical injury. Together, these structures safeguard the brain from damage.