Overview of the nervous system

Question 1

what is the function of the NS

Answer 1

controls and coordinates functions throughout the body, and responds to internal and external stimuli.

Question 2

What is the NS responsible for?

Answer 2

It can detect changes within and round the brain
Respond to external changes
Receive and interpret sensory information.

Question 3

what is the NS derived from?

Answer 3

from the ectoderm

Question 4

What is neurlation?

Answer 4

formation of of the neural plate (ectoderm) , closure of the neural tube and early development of the NS

Question 5

what is the CNS ccomposed off?

Answer 5

Brain
Spinal Cord

Question 6

What is the PNS composed off? (peripheral NS)

Answer 6

Afferent info (input)
Efferent input (output)

Question 7

What are the 4 cells of the CNS

Answer 7

Neurons
Gila= atrocyte
oligodendrocytes
Ependymal cells

Question 8

where does the cell bodies of neurons live

Answer 8

grey metter

Question 9

where can we find myleinated axons

Answer 9

white matter

Question 10

where are gilal cells found

Answer 10

grey and white matter

Question 11

what are the 5 componets of a neuron?

Answer 11

soma
dendrites
Axon
axon hillock
axon terminal

Question 12

what happens in the soma

Answer 12

contains nucleus and most of the organelles

Question 13

what happens in the dendrites

Answer 13

reception of incoming info

Question 14

what happens in the axon

Answer 14

transmits eletrical impulses called AP

Question 15

what happens in the axon hillock

Answer 15

where axon orginates and AP iniated

Question 16

what happens in the axon temrinal

Answer 16

releases neurotransmitter

Question 17

what is a snyapse

Answer 17

Site of communication between two neurons

Question 19

what is an afferent neuron?

Answer 19

orininagte in the periphery with sensory or visceral receptors

Question 20

efferent neurons?

Answer 20

originate in the CNS where the cell body and dendrites recieve synpatic communication from other neurons

Question 21

interneurons

Answer 21

within the cns and can communicate with afferent neurons, efferent neruons and other interneruons

Question 22

what are glial cells

Answer 22

90% of all cells in the nervous system
Do not function as signal cells
Provide structure and integrity to the nervous system

Question 23

examples of gilal cells

Answer 23

Astrocytes
Microglia
Schwann Cells

Question 24

what are astrocytes involved in

Answer 24

Development of neural connections
Development of blood-brain barrier
Protect neurons against toxic substances & oxidative stress

Question 25

what is microglia

Answer 25

Protect CNS from foreign matter through phagocytosis Protect CNS from oxidative stress

Question 26

what are the 2 mylein forming cells>

Answer 26

schawn cells- oligodendorcytes

Question 27

what is the differnece between schwann cells and oloigendrndorcytes?

Answer 27

O cells cover CNS where as schwan cells cover PNS O cells have many myekin sheath whereas schwan have one mylein sheath

Question 28

Describe meylin?

Answer 28

Insulating wrap around the axons Enables neurons to transmit action potentials more efficiently Reduce leakage of ions across the cell membrane

Question 29

describe myelination?

Answer 29

Schwann cells myelinate peripheral nerves

Question 30

The myelin sheath surrounding nerve fibres in the spinal cord is from where?

Answer 30

oligodendroglial cells

Question 31

what is cerbrospinalfluid?

Answer 31

clear watery extracelluar fluid bathing the CNS

Question 32

the CSF summarised

Answer 32

Recycled 3 times/day Secreted by ependymal cells of the choroid plexus Circulates through ventricles to subarachnoid space Reabsorbed by arachnoid villi Total volume of CSF = 125 – 150 mL

Question 33

what are the functions of the CSF?

Answer 33

cushions the brain and mantains a stable interstilala fluid envionment

Question 34

how does CSF provide interstidals envrionment

Answer 34

provides neruons nd gilal cells with essentail nuterins and removes waste products

Question 35

blood supply to the CNS

Answer 35

High metabolic rate Brain uses 20% of oxygen consumed by body at rest Brain uses 50% of glucose consumed by body at rest

Question 36

blood brain barrier?

Answer 36

Special anatomy consisting of CNS capillaries that limit exchange

Question 37

describe the capillaries in the blood brain barrier

Answer 37

Sites of exchange between blood & interstitial fluid Thin: single layer of endothelial cells Diffusion