Nervous System Intro

Question 1

Name the parts of a neuron and their function

Answer 1

Soma - cell body, support metabolic and synthetic needs of the cell; nucleus is contained within the soma

Dendrites - Extensions of the cell membrane; receive information

Axon - information conduction

Axon Terminals - Distal end of axon filled with vesicles (neurotransmitters contained within vesicles)

Question 2

Name the Types of Neurons

Answer 2

Multipolar - many dendrites, single axon; 2 types:

• Pyramidal: 1 primary apicle dendrite, axon from base, send information long distances
• Stellate: Many dendrites no definitive axon, send information locally

Bipolar - one dendrite, one axon

Unipolar/Pseudounipolar - Single process that acts as axon and dendrite (sends and receives information); tend to be in the periphery; pseudounipolar start as bipolar and as they develop the axon and dendrite slide off to one side

Question 3

Describe Interneurons

Answer 3

Small neurons with all connections within a small area; CNS only; Tend to be multipolar; process information

Question 4

Projection neurons

Answer 4

Larger afferent neurons with long axons connecting different parts of the nervous system; CNS & PNS

• Sensory: Directly sensitive to various stimuli; carry ascending information in the spinal cord
• Motor: Efferent neurons that end directly on a muscle, gland, or autonomic neuron; carry descending information in the spinal cord

Question 5

Nuclei

Answer 5

Specific areas of functionally related cell bodies

Question 6

Cortex

Answer 6

Area where grey matter forms a layered surface that covers some parts of the CNS

Question 7

White Matter

Answer 7

Myelinated axons; subdivisions in axon bundles are called tracts, which are named for the parts that they connect

Question 8

Organelles of Neurons

Answer 8

Nucleus - DNA, Nucleolus (RRNA synthesized here)

Mitochondria - Produces ATP

Rough ER - protein synthesis

Golgi Apparatus - packages proteins before they are sent out

Question 9

Cytoskeleton Components

Answer 9

Microtubules - organelle and vesicle transport

Neurofilaments - mainly structural, regulate axon diameter

Microfilaments - helps with anchoring cells as well as acts as a shuttle to/from the membrane; also helps with cell movement from outside the cell

Question 10

Axon hillock

Answer 10

Attachment of axon to cell body; site of action potential initiation

Question 11

Kinesin

Answer 11

Anterograde transport away from cell; goes down to axon terminal

Question 12

Dynein

Answer 12

Retrograde transport towards the cell body; allows for organelles or vesicles to walk towards the cell body

Question 13

Astrocytes

Answer 13

Structural role; serve as electrical insulators; help provide blood brain barrier; help regulate ionic concentration gradient; absorb excess neurotransmitter; help form glial scar

Question 14

Microglia

Answer 14

Become macrophages when activated; part of immune/pathology response to remove pathogens and neuronal debris

Specialized immune system of the CNS

Question 15

Ependymal cells

Answer 15

Epithelial lining of ventricles; cover/form the choroid plexus for CSF production and circulation; help makes blood/CSF barrier

Question 16

Oligodendrocytes (Myelin CNS)

Answer 16

Single cell has many branches that encircle sections of axons

White matter for CNS

Question 17

Schwann Cells (Myelin PNS)

Answer 17

Single cell creates myelinated internode in PNS; allow axon regeneration

White matter in PNS

Question 18

Nodes of Ranvier

Answer 18

Areas between myelination along axons where ion channels reside