What do we call the layer of fatty tissue surrounding the axon of some neurons?

Correct Answer: B

Rationale: The myelin sheath is a layer of fatty tissue that surrounds the axons of some neurons, providing insulation and increasing the speed of electrical signal transmission. Myelin is produced by glial cells, such as oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. Damage to the myelin sheath, as seen in conditions like multiple sclerosis, can impair neural communication and lead to neurological symptoms.

Correct Answer: B

Rationale: Meningitis is an infection that causes inflammation of the meninges, the protective membranes covering the brain and spinal cord. Symptoms include fever, headache, neck stiffness, and cognitive impairments. The inflammation can lead to serious complications, such as brain damage or sepsis, if not treated promptly. Meningitis can be caused by bacterial, viral, or fungal infections, with bacterial meningitis being the most severe form.

Correct Answer: B

Rationale: Dendrites are specialized structures that receive nerve impulses from other neurons and conduct them toward the cell body. They are branched extensions that increase the surface area for receiving signals. The electrical signals generated by neurotransmitters binding to receptors on dendrites travel toward the cell body, where they are integrated to determine whether the neuron will fire an action potential. This directional flow is essential for neural communication.

Correct Answer: C

Rationale: The action potential involves a rapid change in membrane potential, typically ranging from -65mV (resting potential) to +40mV (peak depolarization). This change is driven by the influx of sodium ions and the subsequent efflux of potassium ions. The action potential is a key mechanism for transmitting information within the nervous system, enabling neurons to communicate over long distances.

Correct Answer: A

Rationale: Dendrites are the part of a neuron responsible for receiving nerve impulses from other neurons or sensory receptors. They are branched structures that extend from the cell body and contain receptors for neurotransmitters. When neurotransmitters bind to these receptors, they generate electrical signals that travel toward the cell body, initiating communication between neurons. Dendrites play a crucial role in integrating incoming signals and determining whether the neuron will fire an action potential.