How nerves work 1

Question 1

why does the nervous system exist

Answer 1

to send rapid signals throughout the body

Question 2

what does the peripheral nervous system (PNS) do?

Answer 2

carries info in and out of the CNS

Question 3

which type of information enters the spinal chord via the ventral root?

Answer 3

motor

Question 4

which type of information enters the spinal chord via the dorsal root?

Answer 4

sensory

Question 5

What is a ganglion

Answer 5

cluster of neurons (ganglion) where the cell bodies of sensory neurons are found
there is only a ganglion on the dorsal root of spinal nerve

Question 6

Where do motor neurons have their cell bodies?

Answer 6

in the ventral horn (inferior part of grey matter in spinal cord)

Question 7

what is a pseudoganglion

Answer 7

it looks like a ganglion, but only has nerve fibers and has no nerve cell bodies.

Question 8

how does sensory info enter the S.C?

Answer 8

Via the dorsal horn (posterior)

Question 9

how does motor info leave the S.C?

Answer 9

via the ventral horn (anterior)

Question 10

what happens at the spinal nerve?

Answer 10

the dorsal and ventral roots join and become mixed here. This then leaves the intervertebral foramen laterally and branches into dorsal and ventral rami.

Question 11

what does the ventral ramus supply

Answer 11

skin, muscles and bones of anterolateral sides of trunk as well as the entire upper and lower limbs

Question 12

what does the dorsal ramus supply?

Answer 12

posterior side of trunk only (don’t supply the limbs at all)

Question 13

what are dendrites?

Answer 13

they receive info (like the ears of cell)

Question 14

cell body (soma)

Answer 14

soma is effectively the nucleus- it makes things like proteins

Question 15

what is the axon hillock?

Answer 15

contains the machinery to fire an action potential to another neuron

Question 16

axon terminals

Answer 16

releases a neurotransmitter that binds to receptor on dendrites of other cells and tells them what to do

Question 17

what are the 3 main types of neurons?

Answer 17

afferent - responds to something in PNS and brings info into CNS (like pressure on skin, temp etc)

efferent- motor neurons- takes out of CNS and synapses onto an effector to make a response

inter-neuron- they look at sensory info and decide amongst themselves which motor neurons to turn on in CNS ie what to send out via efferent neuron

Question 18

what is glia? and give 3 examples of cell types

Answer 18

connective tissue of nervous system
Astrocytes
oligodendrocytes
microglia

Question 19

what are astrocytes and what do they do?

Answer 19

they are star shaped glia cell of CNS
they maintain external environment for neurones
they surround blood vessels + produce blood brain barrier

Question 20

what are oligodendrocytes and what do they do?

Answer 20

at type of glia cell

responsible for myelination of nerves in CNS- myelin helps insulate/ protect axons

Question 21

Schwaan cell’s role?

Answer 21

myelination in PNS

Question 22

what do microglia do?

Answer 22

help mop up infection if it occurs
act like a phagocytic hoover
carry out phagocytosis

Question 23

what is myelination?

Answer 23

form a myelin sheath around a nerve to allow the nerve impulses to move more quickly

Question 24

what are the 4 types of lobe in the cerebrum

Answer 24

frontal, temporal, parietal and occipital

Question 25

what is in the diencephalon

Answer 25

thalamus and hypothalamus

Question 26

what is inside the brainstem?

Answer 26

midbrain, pons, medulla oblongata

Question 27

how many spinal nerves are in the cervical region?

Answer 27

8