Nervous System

Question 1

What is the axon hillock exactly?

Answer 1

Its the intial segment, the region where a soma generates an action potential and conducts it away from the soma by way of the axon.

Question 2

What is the term for ribosomes and RER in the perikaryon?

Answer 2

Nissl bodies

Question 3

Is there a difference between myelin sheaths in the CNS and PNS?

Answer 3

Yes, in the CNS myelin sheaths are created by the oligodendorocytes (blankets). In the PNS, sheaths are created by the

Question 4

What is the structure that the axon terminals are connected to (before the axon)?

Answer 4

Telodendria

Question 5

What chemical to astrocytes secrete to help guide neuron growth (embryonic)?

Answer 5

Neurotropic factors

Question 6

What is metabolism?

Answer 6

All of the chemical processes to sustain life via breaking down molecules and reforming molecules for energy. Ex. Body breaking down “sun energy” stored in plants releases energy we can use.

Question 7

What is catabolism?

Answer 7

A form of metabolism in which large molecules are broken down to release energy. “Cata”=break).

Question 8

What is anabolism?

Answer 8

A form of metabolism in which simple molecules are used to form larger molecules using energy. (“Ana”=upwards)

Question 9

Are ganglion found in the CNS?

Answer 9

No, this is the name for a collection of cell bodies OUTSIDE the CNS. Within the CNS they are called nuclei.

Question 10

What are nuclei within the nervous system?

Answer 10

This is the term for groups of cell bodies (or centers) within the CNS ONLY, within anatomical boundaries.

Question 11

What are centers within the nervous system?

Answer 11

These are collections of cell bodies within the CNS only.(no anatomical boundaries, but they all have similar functions.

Question 12

Branches off of the axon are called____?

Answer 12

Collaterals

Question 13

What is axoplasmic transport?

Answer 13

The movement of organells, nutrient/wastes, etc from the cell body and down the axons to the axon terminals. This process uses energy and relies on neurofibrils.

Question 14

Where will you find bipolar neurons? Why do you think that is?

Answer 14

Bipolar neurons have a long dendrite on one side of the cell body and an axon on the other. This allows it to have increased sensory function. Therefore, it is found acting as a receptor for smell, sight, hearing, taste,and vestibular functions (balance/spatial). Bipolar neurons are rare, Mostly found in olfactory epithelium and in the retina of the eye.

Question 15

What exactly is an interoreceptor?

Answer 15

It is a type of neuron that monitors sensations from the inner organs, deep pressure, deep pain, and taste, then sends information on any changes to
Ex. Change in BP, chemicals, blood O2, etc.

Question 16

Describe what must happen in order for a sensation to be passed to the CNS for processing.

Answer 16

Processing atthe Receptor Level

1. ) The receptormust have specificityforthe stimulus energy.
2. ) The receptor’s receptive field must be stimulated
3. ) Stimulus energymust be converted into a graded potential.
4. ) Ageneratorpotential in the associated sensoryneuron must reach threshold ( )

Question 17

Where are neurotransmitters synthesized and stored?

Answer 17

Neurotransmitters are synthesized in the cell bodies and tranported by axonal transport to the axon terminals where they are stored. Some are synthesized in the terminals themselves.

Question 18

What is epineurium?

Answer 18

This is the covering for each individual peripheral nerve.

Question 19

What is the filum terminale?

Answer 19

It is a strand of connective tissue that connects the conus medullaris to the first coccygeal vertebra.

Question 20

What is the cauda equina?

Answer 20

Just another term for the area containing the filum terminale and the dorsal and ventral roots that sort of hang down from the conus medullaris.

Question 21

What is the difference between a bipolar neuron and a unipolar neuron?

Answer 21

Well, both are sensory neurons, but a pseudounipolar neuron’s single axon runs from tissue to spinal cord.

Question 22

What is the difference between a bipolar neuron and a unipolar neuron?

Answer 22

Well, both are sensory neurons, but a pseudounipolar neuron’s single axon runs from tissue to spinal cord. it’s cell body is stored in the dorsal root ganglion near the spinal cord.

Question 23

What is the cervical enlargement and where is it?

Answer 23

This is an enlarged area of the spinal cord between C4-T1, it is where the cervical plexus emerges from.

Question 24

Where is the lumbosacral enlargement of the spinal cord?

Answer 24

This is between L1-S3. The lumbosacral plexus emerges from here.

Question 25

Name the locations of each type of neuronal cell body in the spinal cord. And are they multipolar, pseudounipolar, or bipolar neurons?

Answer 25

Visceral efferent(1&2) = Grey matter (1)/ Autonomic ganglion(2), multipolar
Visceral afferent = Dorsal root ganglion*, pseudounipolar
Somatic efferent = Ventral horn of grey matter, multipolar
Somatic afferent = Dorsal root ganglion*, pseudounipolar 
*difference btwn sensory nuclei all in gray matter, versus soma's in DRG?

Question 26

What is special about the route of the visceral motor neuron?

Answer 26

It leaves the cord through the ventral root, and leaves the root through the white ramus (preganglionic), then goes through and exits (postganglionic) the grey ramus, headed to it’s effector or back through the ventral root to

Question 27

What causes an action potential?

Answer 27

A change in the membrane resting potential created by a stimulus. It has to be an adequate stimulus (threshhold stimulus) and the right stimulus for that particular receptor to generate an AP, a

Question 28

What causes an action potential?

Answer 28

A change in the membrane potential (excitable) created by a stimulus. It has to be an adequate stimulus (threshhold stimulus) and the right stimulus for that particular receptor to generate an AP in it’s soma’s plasma membrane. Once generated it will travel down the axon and hope to synapse with another neuron (via its dendrites, soma, or axon).

Question 29

Where all can a synapse happen?

Answer 29

From one cells axon terminals to anothers cell body (axosomatic), dendrites (axodendritic), or axon (axoaxonic).

Question 30

Is a neurotransmitter just “accepted” once it reaches a synapse?

Answer 30

1) No, it has to bind to receptor proteins on the postsynaptic membrane, which changes that cells membrane potential.
2) The change doesn’t last for long though, and that cell can’t send a message back.
3) If the neurotransmitter is excitatory, it causes another AP to be generated. If it’s inhibitory, it squashes the potential for another AP.