Q: Which equation best represents the movement of ions across the blood-brain barrier for polar molecules?

$$J = \text{Carrier-mediated transport}$$

Question 1

Which of the following best describes the role of Schwann cells in the peripheral nervous system (PNS)?

Accepted Answer

They produce myelin sheaths around axons and form a neurilemmal sheath in the PNS.

Question 2

A patient suffers a traumatic injury that severs axons in the peripheral nervous system. Which cellular process is most likely to support axonal regeneration?

Accepted Answer

Schwann cells form a regeneration tube and secrete neurotrophins.

Question 3

Which type of neuron is most abundant in the human nervous system and possesses several dendrites and one axon?

Accepted Answer

Multipolar neuron

Question 4

Which of the following statements about the blood-brain barrier is correct?

Accepted Answer

It restricts passage of ions and polar molecules, requiring channels or carriers for their transport.

Question 5

Which neuroglial cell type is responsible for producing cerebrospinal fluid (CSF) in the central nervous system?

Accepted Answer

Ependymal cells

Question 6

A researcher is studying the uptake of potassium ions ($$K^+) $$during neuronal action potentials. Which neuroglial cell is most involved in this process?

Accepted Answer

Astrocytes

Question 7

Which of the following best explains why regeneration of axons is limited in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes secrete inhibitory proteins such as Nogo, and a glial scar forms rapidly.

Question 8

Which of the following is a function of microglia in the CNS?

Accepted Answer

Detecting ATP released from damaged cells and becoming phagocytic

Question 9

Which equation best represents the movement of ions across the blood-brain barrier for polar molecules?

Accepted Answer

$$J = 	ext{Carrier-mediated transport}$$

Question 10

A neuron in the retina has two extensions, one at each end of the cell body. What type of neuron is this?

Accepted Answer

Bipolar neuron

Question 11

Which of the following best describes the direction of impulse travel in a typical neuron?

Accepted Answer

From the dendrites to the axon terminal

Question 12

Which neuroglial cell type is most abundant in the CNS and is involved in synapse maintenance and neurotransmitter uptake?

Accepted Answer

Astrocytes

Question 13

Which of the following is TRUE regarding myelination in the CNS?

Accepted Answer

Oligodendrocytes myelinate multiple axons, contributing to white matter.

Question 14

Which of the following is a consequence of astrocytic dysfunction in the CNS?

Accepted Answer

Alexander disease due to mutation in an astrocyte-specific protein

Question 15

Which of the following best describes the function of ependymal cells in the CNS?

Accepted Answer

They line the ventricles and central canal, producing and circulating cerebrospinal fluid.

Question 16

Which equation best describes the diffusion of nonpolar molecules such as $$O_2$$ across the blood-brain barrier?

Accepted Answer

$$J = P 	imes (C_{blood} - C_{brain})$$

Question 17

Which of the following is a function of astrocytes in the CNS?

Accepted Answer

Regulation of the extracellular environment, including $$K^+$$ and glucose uptake

Question 18

Which of the following best describes the difference between white matter and grey matter in the CNS?

Accepted Answer

White matter consists mainly of myelinated axons, while grey matter consists of cell bodies and dendrites.

Question 19

Which of the following is TRUE regarding the function of microglia in the CNS?

Accepted Answer

They are considered myeloid cells and are involved in immune defense and synaptic pruning.

Question 20

A patient is exposed to a neurotoxin that disrupts tight junctions in the brain capillaries. What is the most likely consequence?

Accepted Answer

Increased permeability of the blood-brain barrier, allowing harmful substances to enter the brain.

Physio: Overview of the Nervous System

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