EXAM #1 Essay Q's

Question 1

be able to discuss the 6 different types of neuroglia and distinguish among them in terms of location, function, and special characteristics

Answer 1

CNS:
astrocytes - structure & support
microglia - microphage and vital check
ependymal - circulates CSF
oligodendrocytes - myelination

PNS:
Schwann cells - myelination
satellite cells - maintain environment of cell body

Question 2

action potential: be able to identify the stages of an action potential and describe what is occurring in each stage (i.e. which ion channels are opening and the direction of the ion current, why is it resulting in depolarization, repolarization, hyperpolarization, etc.) be able to describe the difference between graded and action potential

Answer 2

RMP
depolarization - VGSCs open
depolarization - VGSCs closed, K+ channels open
hyperpolarization - K+ channels fully close

graded potentials can be depolarizing or hyper polarizing

action potentials always lead to depolarization of membrane and reversal of the membrane potential.

Question 3

saltatory and continuous propagation: distinguish between the two and explain why saltatory results in faster nerve impulse transmission

Answer 3

saltatory:
fast
250mph
myelinated

continuous:
slow
2mph
unmyelinated
needs more ATP
info is retold every time down the axon

Question 4

spinal cord growth vs. vertebral bony column growth:

explain why the condensed spinal cord ends at about L2

the spinal roots from the cauda equina continue to grow after the rest of the spinal cord stops in order to maintain the spinal nerve relationship with their intervertebral foramens

explain the discrepancy between spinal cord growth and bony vertebral column growth is clinically relevant

Answer 4

the roots continue to grow to compensate for the continual growth of vertebrae

the spinal cord has simply stopped growing and that’s where it ends up in an adult granted its other end must remain attached to the brain

If the cauda equina didn’t grow, the filum terminale wouldn’t be able to anchor to the coccyx

Question 5

steps of reflex arc: list in order

Answer 5

sensory receptor

sensory neuron

integration center

motor neuron

effector (muscle / gland)

Question 6

spinal reflexes: describe what would happen reflexively if you stepped on a nail

explain how your body would be able to move your foot off the nail while still maintaining your balance

Answer 6

ipsilateral reflex of bringing foot off of nail

contralaterally crossed extensor reflex follows straightening other leg to compensate for balance

Question 7

cross section of spinal cord: be able to label the components including the visceral and somatic sensory and motor nuclei

be able to ID where motor/sensory conducts

Answer 7

OK

Question 8

cranial meninges: be able to ID the cranial meninges and their location relative to each other

the brain tissue and the skull

discuss their characteristics and explain what makes them unique compared to the spinal meninges

Answer 8

dura mater consists of two layers in skull:
periosteal
meningeal

arachnoid mater:
epidural space
filled with adipose, blood vessels

pia mater

Question 9

protection of the brain: be able to discuss the carious mechanisms that physically and biochemically protects the brain

Answer 9

cranial bones: contains brain

cranial meninges: hold brain position and protect from trauma

CSF: suspends brain and absorbs shock

BBB: isolates from systemic circulation of blood

Question 10

CSF: the brain holds an average of ~150ml/day

be able to discuss the production of CSF

how it enters the subarachnoid space

how we eliminate excess CSF

what is hydrocephalus

ID why and individual might develop hydrocephalus

Answer 10

CSF is produced by choroid plexus from plasma

CSF enters subarachnoid space via apertures in fourth ventricle

excess CSF is processed back into plasma, released by arachnoid granulations

hydrocephalus is a condition with excessive amounts of CSF

hydrocephalus can be caused due to: interruption in CSF flow; granulations not functioning; choroid plexus malfunctioning; apertures in 4th ventricle

Question 11

brain region function and damage: be able to ID the main functions of the areas of the brain discussed in lecture

how loss of function of the medulla oblongata, substantial nigra, thalamus, or cerebellum might affect an individual

Answer 11

medulla oblongata: loss of respiration, heartbeat, etc.

substantia nigra: loss of dopamine (Parkinson’s)

thalamus: loss of relaying sensory info to cortex (sleep, consciousness)
cerebellum: loss of coordinated movement(s)