Lecture 16: Cells Of The Nervous System

Front 1

What are the two systems of the nervous system

Back 1

CNS - brain and the spinal cord

PNS - peripheral nerves and everything else

both composed of neurons and glia

Front 2

Describe the structure of the Input zone

Back 2

-dendrites, cell body

- receives chemical signals from other neurons

Front 3

Describe the structure of the summation zone

Back 3

decisions to transmit signals further at the axon hillock

Front 4

Describe the structure of the conduction zone

Back 4

- axon

- carry electrical signals between brain areas to and from the spinal cord or to and from peripheral sensory receptors

Front 5

Describe the structure of the output zone

Back 5

- axon terminals

- contact with input zone of other neurones

- release of neurotransmitter = chemical signal

Front 6

Describe the structure of the myelin sheath

Back 6

- multiple schwa cells in a line

- increases conduction velocity

Front 7

Describe the structure of the nodes of ranvier

multi - polar

bi - polar

uni - polar

Back 7

gaps between myelin, increases conduction;

Multipolar= many processes that emanate from the cell body

Bipolar= two processes emanate from the cell body

unipolar= one process, branches into dendrite and axon

Front 8

Name the five main types of glial cells

Back 8

CNS glia;

Astrocytes (star)

Microglia

Ependymal

Oligodendrocytes

PNS glia;

Schwaan

Front 9

Describe the function of the CNS glial cell Astrocytes (star):

Back 9

Astrocytes (star):

- supply nutrient to neurone

-ensheath blood capillaries

-transmit information

The blood supply that comes into the system needs to be regulated so the astrocytes for sheaths around the capillaries to help regulate this

Front 10

Describe the function of the CNS glial cell Microglia:

Back 10

Immune cell;

-engulf microorganisms and debris (dead cells)

Front 11

Describe the function of the CNS glial cell Ependymal:

Back 11

Lines fluid filled spaces of the brain and spinal cord

- have cilia (hair-like processes) circulate CSF

Front 12

Describe the function of the CNS glial cell Oligodendrocytes:

Back 12

support nerve fibres

-ensheath them with myelin

Front 13

Describe the function of the PNS glial - schwaan cell:

Back 13

support peripheral nerve fibres.

- ensheath them with myelin

- similar to oligodendrocytes

- it takes its cell membrane and wraps itself around the shaft of an axon to form the myelin sheath cross sectional structure.

- ensheath (wraps around)

- myelin is lipid (fat) wrapped around the axon > electrically insulates axon > increases conduction velocity

- fats are good electrical conductors

-electrical insulation prevents electricity leaving axon

Front 14

Describe the CNS and the targeted effector organs;

Back 14

cell bodies are segregated from axons

axons are grouped into tracts (a major passage)

-groups of cell bodies are grouped into nuclei.

special case: cerebral cortex

- cell bodies grouped into grey matter

- axons grouped into white matter

Front 15

Describe the PNS and the targeted effector organs

Back 15

cell bodies are segregated from axons

- cell bodies grouped into ganglia (swelling)

- axons are grouped into nerves (only found in the PNS)

Front 16

describe how Electrical nerve impulses change to chemical signals

Back 16

Synapse

pre-synaptic neurone

post-synaptic neuron

signal transduction at the synapse