nervous tissue structure and function - why we need a nervous system Flashcards

1
Q

what is grey matter and where is it located

A

grey matter contains dendrites, cell bodies, axon terminals, non myelinated axons and all support cells. located in centre of spinal chord and on edge of brain

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2
Q

what is white matter and where is it located

A

contains axons and myelinated material. is located on the outside of the spinal chord and in the centre of the brain. it is white because the myelinated material contains lots of lipids

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3
Q

what produces the myelin sheath

A

in CNS= produced by oligodendriytes and in PNS= by shcwann cells

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4
Q

structure of neurone

A

draw with dendrites, cell body, axon and end plate labelled. cell body and dendrites are located in the CNS

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5
Q

variations of neurone structure in the CNS

A

pyramiding and purkinje neurones both have very extensive dendrite network. their function is to collate information and they the sub type of neurone called integrative

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6
Q

types of neurone in the PNS (variations)

A

multipolar- 1 axon and multiple dendrites (cell body at the end)
unipolar- look at pic but cell body then dendrites and axon
bipolar- 1 axon and 1 dendrite with cell body in the middle
psuedounipolar - cell body coming off in the middle

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7
Q

what are nissil bodies

A

A Nissl body, also known as Nissl substance and Nissl material, is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis

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8
Q

how is information passed so quickly along neurone

A

atugrade and retrograde use microtubules to shuttle from the soma (cell body) to the synapse

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9
Q

how is neurotransmitter synthesised

A

vesicles are transported using microtubules. each vesicle contains just 1 enzyme and as it travels the length of the axon it starts to synthesis its neurotransmitter. vesicles without neurotransmitter will be transported back to the cell body or lost to the neurolemma

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10
Q

structure of a nerve

A

epineurium- covers outside holding the fascicles together
perineurium - on the outside of a fascicle (paraneurium)
endoneurium covers the outside of a nerve fibre
within each fascicle there are the same type of nerve e.g myelinated or non myelinated

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11
Q

how to recognise nerves with myelin on a microscope slide

A

toluidine blue stains fat and if there is a large blue ring around the nerve = myelin

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12
Q

difference between myelinated and unmyelinated structure

A

in unmyelinated multiple nerve fibres are surrounded by a Schwann cell. here the impulse will travel along the outer edge. whereas in myelinated each nerve fibre is surrounded by a myelin sheath, here the impulse will travel down the centre. look at pics

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13
Q

how does myelination occur

A

axon is sitting in grove surrounded by Schwann cell. the mesaxon membrane surrounds axon and wraps itself around it forming multiple layer. the cytoplasm is extorted from between the layers and it becomes compact to form myelin

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14
Q

what is an oligodendrocyte

A

does the same thing as a Schwann cell but in the CNS however it wraps more the 1 axon simultaneously

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15
Q

what is an astrocyte

A

star like structure. Have perineural diet which contain gap junctions. regulate nerve impulses by releasing glutamate and contribute to blood brain barrier

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16
Q

what is a microglial cell

A

large cell with elongated nucleus acting as a resident macrophage removing damaged nerve cells and acting as an immune cell

17
Q

what is an ependymal cell

A

they line the spinal chord and ventricles of brain producing cerebral fluid which is moved with their villi. microvilli absorb the cerebral fluid for the removal of pathogens. look at pic of them

18
Q

what is multiple sclerosis

A

autoimmune degradation of myelin = loss of conduction velocity and therefore symptoms such as fatigue, vision problems, slurred speech, numbness/tingling and mobility issues

19
Q

name the support cells of the CNS

A

oligodendrocytes, astrocytes, microglial cell and ependymal cell

20
Q

what is myelin and what does it do

A

many layers of plasma membrane without the cytoplasm. acts as an insulating material preventing action potentials from being generated. speed up rate of conduction by saltatory conduction

21
Q

what are satellite/glial cells and where are they found

A

Found in the PNS they cover the cell bodies in the ganglia

22
Q

glial cells?

A

cell present in the CNS

23
Q

nerves that carry impulses towards CNS and away from CNS

A
towards= sensory or afferent 
away = motor or efferent
24
Q

what is a ganglion

A

an accumulation of neurone cell bodies outside the CNS

25
Q

why do we need a nervous system

A

can’t rely on diffusion alone for communication

26
Q

how can the motor output of nervous system be divided

A

somatic (voluntary) and autonomic (involuntary). And then autonomic is divided into sympathetic (fight or flight, affects whole body) or parasympathetic (rest and digest, selectively targets cells/organs)

27
Q

where are the parasympathetic spinal chord segments found and the sympathetic spinal chord segments found

A

para- top and bottom

sympa- in the middle

28
Q

draw myosynaptic reflex arc

A

draw?

29
Q

difference between structure of para and sympathetic

A

both have 2 chains of neurones and a synapse between them at the autonomic ganglion. sympathetic has short axon and long dendron whereas para has a long axon and a ganglia found in the wall of target organ with therefore a short axon

30
Q

how spinal chord communicates with autonomic NS

A

draw it

31
Q

how does the sympathetic nervous system supply the skin - 1 spinal chord doesn’t add up to 1 dermatome?

A

from the entry level segment it will ascend and descend the chain and the impulse will be sent out from the spinal chord

32
Q

how are the viscera supplied by the sympathetic nervous system because this dermatome lines up to the parasympathetic spinal chord segment

A

go straight through chain and the no the aorta where there are specialised ganglion called splachic nerves. This is the example with the heart as a part of the viscera. can also be for other organs in viscera

33
Q

targets of the parasympathetic nervous system

A

supplies visera via vagus nerve and the head also has 4 specialised ganglia found in the target organs - cilary to eye, pterygopalatine to facial nerves and lacrimal gland in eye, submandibular to salivary gland and otic to parotid gland