6. Nerve structure

Question 1

Where do neurones receive impulses

Answer 1

dendrites and cell body (perikaryon)

Question 2

what is a perikaryon

Answer 2

cell body surrounded by cytoplasm

Question 3

where do neurones send impulses through

Answer 3

axons

Question 4

specialised contact sites between nerve cells

Answer 4

synapse

terminal boutons of axons are in close contact to target cell

Question 5

how do neurones adapt

Answer 5

strengthening or weakening synpases
altering branching
allows us to learn and memorise

Question 6

what is between the terminal bouton of an axon and target cell

Answer 6

synaptic cleft

Question 7

what is stored in terminal boutons

Answer 7

vesicles containing NTs

Question 8

what happens at the post synaptic side

Answer 8

they have ion channels that open when NTs are bound to binding site
creates a mini current

Question 9

synaptic transmission is

Answer 9

unidirectional and highly specific

Question 10

synaptic junction in EM

Answer 10

electron dense layer on postsynaptic side

mitochondria provide ATP for vesicle recycling and NT synth

Question 11

afferent

Answer 11

neurone impulses along dendrite towards cell body

Question 12

efferent

Answer 12

neurones convey impulses away from cell body

Question 13

shapes of neurones

Answer 13

multipolar
bipolar
pseudo- unipolar (simple reflex- max speed)
very large SA:V

Question 14

Nissl bodies

Answer 14

dark dots in cytoplasm
aggregation of RER towards dendrite
- maintain large membrane area

Question 15

Why is the nucleus in nerve much larger than nuclei of surrounding nuclei but contain same amount of DNA?

Answer 15

a lot more space required for RNA processing

Question 16

transport system of neurones

Answer 16

rails: microtubuli and neurofilaments
vehicles: kinesis and dynein
axoplasmic flow

Question 17

oligodendrites

Answer 17

make myelin (40-50 sheaths) 
(myelin have saltatory conduction)

Question 18

myelin sheath

Answer 18

are eletrical insulators

formed by oligodendrites or schwann cells in PNS

Question 19

Glial cells

Answer 19

astrocytes
cover all surfaces of neurone that are not occupied by synapses or myelin
touch other glial cells, capillaries and neurones
take up nutrients from capillaries and provide to neurones
form BBB and seal on CNS surface
capable of mitosis: brain tumours usually glial origin
no cytoplasm

Question 20

function of glial cells

Answer 20

support neuronal architecture
aid in repair
support in functioning/ metabolism
defence

Question 21

Microglia cells

Answer 21

immune system of CNS
release cytokines if they detect infectious agents or dead cells
phagocytose and act as local APC
maintain and remodel CNS (eliminate under used synpases)

Question 22

PNS peripheral nerve

Answer 22

nerve fibre bundles: small nerves, one fasicle Epineurium: dense collagenous tissue holds large nerves together- several fascicles

Question 23

CNS: efferent neurones

Answer 23

perikarya in CNS, axons in PNS

Question 24

CNS: afferent neurones

Answer 24

cell bodies and dendrites in PNS

axons in CNS

Question 25

gangla

Answer 25

clusters of PNS perikarya

Question 26

clusters of CNS cell bodies

Answer 26

nuclei

Question 27

grey matter

Answer 27

clusters of neurones (perikarya and some glial)

Question 28

white matter

Answer 28

nerve connections (axons and dendrites), mostly myelinised

Question 29

PNS:Perineurium:

Answer 29

sheath with flat cells of epithelial character with collagen fibres between them. bundles axons into fasicles

Question 30

PNS: endoneurium

Answer 30

loose connective tissue between axon/ dendrite within a fasicle

Question 31

satellite (glial) cells

Answer 31

support cells for PNS ganglia

Question 32

PNS: anatomical nerves

Answer 32

bundles of nerve extensions (axons, dendrites), held together by epineurium, perineurium and endoneurium

Question 33

PNS: Functional nerve cells in vertebrates

Answer 33

are always fully covered by contacts to other neurons or glial cells. They cannot exist without them.

Question 34

schwann cells PNS

Answer 34

create one myelin sheath per cell

or wraps itself around unmyelinated nerve extensions