Chapter 3: Neurophysiology

Question 1

what are the three types of macroglia?

Answer 1

astrocytes, oligodendrocytes, and schwann cells

Question 2

what do astrocytes do?

Answer 2

provide a structural matrix for neurons and contribute to the blood-brain barrier which prevents toxins in the blood from entering the brain, they also help transfer nutrients to neurons

Question 3

what do oligodendrocytes do?

Answer 3

provide myelin covering that insulate axons in the CNS with one oligodendrocyte able to myelinate up to 15 axons

Question 4

what do schwann cells do?

Answer 4

supply myelin in the PNS and guide regrowth of damaged axons

Question 5

what do microglia do?

Answer 5

clean up dead brain cells that might interfere with brain function, also remove inactive synapses

Question 6

what are the three types of fibers in neurons?

Answer 6

1. microtubules: transport material within the neuron
2. neurofilaments: provide structural support
3. microfilaments: involved with structural changes associated with development and learning

Question 7

what is the state of the cell membrane at rest?

Answer 7

the intracellular space is more negative at rest

Question 8

what are the 4 basic steps of an action potential?

Answer 8

1. once threshold is reached sodium channels open and Na+ rushes in causing cell to depolarize
2. near the peak potassium channels open and K+ starts to leave cell
3. at peak sodium channels close and cell hyperpolarizes
4. once hyperpolarized potassium channels close and resting potential is restored

Question 9

what takes place at gap junctions?

Answer 9

cells directly stimulate other adjacent cells through electrical communication

Question 10

what takes place at the synapse?

Answer 10

chemical communication takes place when neurotransmitters are released and bind to the postsynaptic receptor sites

Question 11

what is calcium channel dysregulation associated with?

Answer 11

neurological, retinal, cardiac, and muscular disease such as epilepsy

Question 12

what are the two types of post-synaptic receptors and what do they do?

Answer 12

ionotropic: in charge of fast reactions, recognition site is directly on the ion channel
metabotropic: recognition site does not have direct control over the ion channel, instead G proteins act as the messenger between the recognition site and ion channel

Question 13

in what three ways are neurotransmitters deactivated?

Answer 13

1. diffusion away from the synapse
2. degradation by enzymes
3. reuptake