Nervous tissue Flashcards
1
Q
what are myelinated axons surrounded by?
A
schwann cells
2
Q
where are unmyelinated axons found?
A
in the autonomic system and parts of the brain
3
Q
what does myelin allow?
A
impulses to travel faster acting as insulation and protection
4
Q
what is a nerve?
A
many neurons held together by connective tissue (neuroglia)
5
Q
what does neuroglia do?
A
- support neurons physically and metabolically
6
Q
what are astrocytes?
A
covers capillaries in brain and helps blood brain barrier
7
Q
what are oligodendrocytes?
A
peripheral nervous tissue
8
Q
what is microglia?
A
phagocytic cells, part of CNS defence system
9
Q
what is ependymal?
A
lining ventricles of brain and central canal of spinal cord
10
Q
what are three types of neuron?
A
- unipolar
- bipolar
- multipolar
11
Q
what forms grey matter?
A
cell bodies
12
Q
what forms white matter?
A
nerve fibre
13
Q
what are three classes of neurons?
A
- afferent
- efferent
- interneurons
14
Q
what does afferent mean?
A
- sensory - messages towards brain and spinal cord
15
Q
what does efferent mean?
A
- motor - messages away from brain and spinal cord
16
Q
what does interneurons mean?
A
- message transmission within brain and spinal cord
17
Q
what is a terminal button?
A
enlarged end of an axon which has lots of mitochondria
18
Q
what are the transmitter substances in the peripheral nervous system?
A
acetyl choline and nor-adrenalin
19
Q
what is the transmitter substance in the central nervous system?
A
acetyl choline
20
Q
what is the post-transmission period called?
A
refractory period
21
Q
what are the two components to the central nervous system?
A
brain and spinal cord
22
Q
what are the three main divisions of the brain?
A
- forebrain
- midbrain
- hindbrain
23
Q
what are the three ares of the forebrain?
A
- cerebrum
- thalamus
- hypothalamus
24
Q
what is the cerebrum and what does it do?
A
- 2 halves separated by longitudinal sulcus
- receive and process information
25
what are the folds in the cerebrum called?
gyri
26
how are gyri separated?
into areas by sulci and fissues
27
where is the thalamus found?
lies deep in brain tissue at the base of the cerebral hemisphere
28
what does the thalamus do?
relays info to and from cerebral cortex from sense organs
29
where is the hypothalamus found?
above pituitary gland
30
why is the hypothalamus important?
it links autonomic nervous and endocrine system
31
what is the optichiasma?
point where impulses from retinas cross over
32
where does the left cerebral hemisphere get information from?
- outer side of retina of left eye
- inner side of retina of right eye
33
what is the olfactory lobe?
- processes information regarding smells
34
what is the mid brain?
- connects fore and hind brain
- surrounds cerebral aquaduct which contains cerebral spine fluid
35
what does the cerebellum do?
- co ordinates muscular activity
- helps maintain posture and balacne
36
where is the cerebellum found?
in the hind brain
37
what does the medulla oblongata contain and do?
- contains origins of some cranial nerves
- controls basic functions such as respiration and cardiovascular
38
where is the medulla oblongata found?
in the hind brain
39
where is the pons found?
in the hindbrain between the mid brain and medulla oblongata
40
what does the pons do?
contains fibres which carry impulses within the brain
41
what happens if the brain is deprived of oxygen for 1min?
decreased activity
42
what happens if the brain is deprived of oxygen for 3min?
irreversible damage
43
what are the meninges?
they enclose and protect brain and spinal cord
44
what are the three layers of the meninges?
- dura mater (outermost, adheres to skull bones but not vertebrae)
- arachnoid mater (pressed against dura due to CSF pressure)
- pia mater (innermost, attached to actual brain and spinal cord)
45
what is cerebrospinal fluid?
- clear, colourless fluid
- formed in ventricles
- fills subarachnoid space and ventricles
46
where does the cerebrospinal fluid drain from?
- via veins in pia/arachnoid mater
47
where is cerebrospinal fluid secreted from?
- small arterioles and capillaries of pia/arachnoid mater
- choroid. plexus in the brain ventricles
48
what are the functions of cerebrospinal fluid?
- protection of brain and spinal cord against bone
- nutrition of brain and spinal tissue
- pressure maintainance
49
what are the 4 brain ventricles?
- 2 laterals
- 1 diencephalon
- 1 hindbrain
50
what are the function of the brain ventricles?
to help keep brain buoyant and cushioned
51
what is internal hydrocephallus?
foramina/apertures of ventricles obstructed
52
what is external hydrocephallus?
drainage of CSF obstructed
53
what is the peripheral nervous system made up of?
voluntary and involuntary (autonomic) branches
54
what are the voluntary branches of the PNS made up of?
12 pairs of cranial nerves and 38 pairs of spinal nerves
55
what are the involuntary branches of the PNS made up of?
sympathetic and parasympathetic nerves
56
what does the voluntary branches of the PNS control?
skeletal muscle movements
57
what does the involuntary branches of the PNS control?
smooth muscle, cardiac, and glands
58
how many cranial nerves are there?
12 pairs which are numbered rostrally to caudally
59
what is the vagus nerve?
- X
- atypical cranial nerve which is part of the parasympathetic nervous system and slows the heart
60
what does stimulation of the vagus nerve result in?
bradycardia
61
what nerve does injuries from intubation affect?
hypoglossal
62
what can damage to the hypoglossal nerve cause?
- dysphagia
- tongue deviation
63
what is a reflex arc?
nerve pathway from stimulation through spinal cord to effector site
64
what does dorsal root damage cause?
- lost sensation
- cannot feel stimulus
- no message sent
65
what does ventral root damage cause?
- sensation is felt and message transmitted
- no message sent to effector
- cannot initiate protective action
66
what is the sciatic nerve?
nerve found in caudal thigh that can cause temporary or permanent paralysis
67
what is the phrenic nerve?
controls diaphragm (contract/expand)
68
what is the autonomic nervous system?
- involuntary part of the PNS
69
what is the autonomic nervous system divided into?
- sympathetic (close to spinal cord)
- parasympathetic (in walls of affector organs)
70
what part of the autonomic nervous system is adrenalin and nor adrenalin associated with?
sympathetic
71
what part of the nervous system is acetyl choline associated with?
parasympathetic
72
what are some parts of a neuron?
- dendrite
- soma
- axon
- nodes of ranvier
- axon terminal
- schwann cell
- myelin sheath
- nucleus
73
what does a dendrite do?
receive impulses and carry then towards the cells body
74
what are the gaps between the schwann cells called which allow nutrients?
nodes of ranvier
75
what are some types of glial cells?
- astrocytes
- oligodendrocytes
- microglia
- ependymal
76
what is the synaptic cleft?
gap between 2 neurons
77
what are the 12 cranial nerves in order?
olfactory
optic
oculomotor
trochlear
trigeminal
abducens
facial
auditory
glossopharyngeal
vagus
spinal accessory
hypoglossal
78
what can sympathetic nerves be known as?
adrenergic nerves
79
what can parasympathetic nerves be known as?
cholinergic nerves
80
what nerves are associated with the fight or flight response?
sympathetic and parasympathetic
