NBSS (neuroscience) Cellular Structure of the Nervous System

Question 1

how can neurons be described?

Answer 1

polarised (morphologically and functionally)

Question 2

what are neurons made up of?

Answer 2

axon terminal, dendrites, soma

Question 3

what does polarised mean?

Answer 3

information carried via electrical charges as sodium ions are pushed out of cell and potassium ions in

Question 4

what is the resting potential?

Answer 4

-70mv

Question 5

how much of the brains energy is consumed to maintain resting potential?

Answer 5

60%

Question 6

over how many mm does the dendritic signal decay?

Answer 6

1-2mm

Question 7

where is voltage gated sodium channel activated at

Answer 7

-50mV

Question 8

what 4 things describes how information is carried in axon hillock?

Answer 8

unidirectional

all-or-nothing principle

non-decaying

carried at same amplitude

Question 9

what type of neurones have two firing modes?

Answer 9

thalamocortical

Question 10

what is an electrical synapse?

Answer 10

formed by gap junctions where current carried by ion transfer directly through channels - ‘coupled’

minimal delay

bidirectional

Question 11

what is a chemical synapse?

Answer 11

Physical gap between two junctions, presynaptic neurotransmitters diffuse across to postsynaptic receptors

unidirectional

delay of 0.3-0.5mSec

Question 12

what are 3 neurotransmitter types?

Answer 12

• biogenic amines
• amino acids
• peptides

Question 13

what are examples of biogenic amines neurotransmitters?

Answer 13

• acetylcholine
• noradrenaline
• adrenaline
• dopamine
• serotonin

Question 13

what are examples of amino acid neutransmitters?

Answer 13

• glutamate
• aspartate
• g-aminobutyric acid
• glycine INHIBITIORS VIA HYPERPOLARISATION

Question 13

what are example of peptide neurotransmitters?

Answer 13

• somatostatin
• endorphins
• dynorphins
• bradykinin
• enkephalins
• substance P

Question 14

what are other examples of neurotransmitters?

Answer 14

• ATP
• nitric oxide

Question 15

what does axosomatic mean

Answer 15

cell body

Question 16

what does axodendritic mean

Answer 16

dendrite

Question 17

what is axoaxonic

Answer 17

single axon terminal

Question 18

where are motor neurones found

Answer 18

motor neurons are in ventral
(anterior) “horn”

Question 19

motor neurons control what? and what are they described as being

Answer 19

motor control our muscles and are
efferent

Question 20

sensory cells project into what?

Answer 20

Sensory cells project into dorsal (posterior) ”horn” from ganglia

Question 21

how are sensroy neurons described as

Answer 21

afferent

Question 22

how many layers of cortex are there?

Answer 22

5

Question 23

which layer has the largest cell bodies?

Answer 23

5

Question 24

how do motor axons exit the CNS?

Answer 24

efferently - moves away from

Question 25

how do peripheral sensory neurons exit the CNS?

Answer 25

afferently - moves towards

Question 26

pre ganglionic neurones control what?

Answer 26

post-ganglionic
neurons

Question 27

what do autonomic ganglion do?

Answer 27

efferently transmit sensory signals in both the parasympathetic and sympathetic nervous system controlling acitivty of smooth muscle contractions and secretions

Question 28

what speeds up neurone communication?

Answer 28

myelination

Question 29

how does myelination speed up communication?

Answer 29

myelin layers wrapped around axons acting as layer of insulation for action potential transmission across nodes of ranvier with voltage gated sodium ion channels = saltatory conduction

Question 30

what does damage to myelination do? what is this called?

Answer 30

conduction speed slows down or is prevented

demyelinating disease: multiple sclerosis, extreme = paralysis

Question 31

what are white matter filled with?

Answer 31

myelinated axons

Question 32

what are grey matter filled with?

Answer 32

cell bodies, dendrites, axons

Question 33

what is the difference in grey and white matter in brain and spinal cord?

Answer 33

• brain: grey matter external, white matter internal
• spinal cord: white matter external, grey matter internal

Question 34

what are the 5 glial cell types

Answer 34

oligodendrocytes (CNS)
Schwann cells (PNS)
microglia
astrocytes
radial glia

Question 35

whats the function of:

oligodendrocytes (CNS)
Schwann cells (PNS)

Answer 35

Deposit myelin

Question 36

what are microglia described as being

Answer 36

phagocytic

Question 37

what is the function of astrocytes

Answer 37

• homeostatic function: blood vessel/brain interface linking metabolism to function
• refine signalling: remove excess K+ at mylein gaps, remove synaptic neurotransmitter and insulate synapse

Question 38

what is the function of radial glia

Answer 38

they are long and thin, stretching from brain surface to inner luminal surface - structural support of adult nervous system and development of NS

Question 39

where are cells born?

Answer 39

inner ventricular suface

Question 40

where do CNS cell types migrate to?

Answer 40

overlying mantle

Question 41

where are motor neurons formed?

Answer 41

ventral

Question 42

where are sensory neurons formed?

Answer 42

dorsal

Question 43

what is the nerual tube formed by?

Answer 43

dorsal closure

Question 44

what does cell type made depend on?

Answer 44

where in the neural tube they are positioned: dorsoventral position gives types

Question 45

what is the origin of peripheral nervous system (PNS) neurons?

Answer 45

nerual crest populates PNS

Question 46

what is an example of a neuronal defect

Answer 46

Neurulation defects range from spinabifida to a complete loss of head (anencephaly)