structure and function of CNS Flashcards
1
Q
what makes up the CNS?
A
spinal cord and brain
2
Q
what makes up the peripheral nervous system?
A
spinal nerves, cranial nerves
3
Q
what cell types are found In the CNS?
A
neurons
glial cells
astrocytes
Schwann cells
oligodendrocytes
ependymal cells
microglia
4
Q
function of astrocytes?
A
give structural support, form blood brain barrier, nourish, nutrient supply to neurons in the CNS
5
Q
function of ependymal cells?
A
found in ventricles of brain, promote circulation of cerebrospinal fluid
6
Q
function of microglial cells?
A
immune protection, defence role ; phagocytic
7
Q
function of oligodendrocyte and Schwann cells?
A
enables fast signalling (myelination) and neural support
8
Q
what promotes myelination?
A
CNS - glial cells, oligodendrocytes
PNS - Schwann cells
9
Q
what makes the tissue more white?
A
more axons (myelinated), more glial cells (oligodendrocytes),; blood vessels
10
Q
what makes the tissue more grey?
A
more cell bodies, dendrites, axon terminals, glial cells (astrocytes) ; blood vessels
11
Q
what are sulci?
A
grooves (central sulcus and lateral sulcus)
12
Q
what are gyri?
A
ridges (pre central gyrus and post central gyrus)
13
Q
what are the lobes of the brain?
A
-frontal
-parietal
-temporal
-occipital
14
Q
what is the function of the brain stem?
A
consciousness, breathing and heart rate
15
Q
what is the function of the cerebellum?
A
balance/posture
coordination of movement
16
Q
what is the function of the cerebrum?
A
speech, judgments, emotions, learning act
17
Q
what are the 3 parts of the brain stem?
A
midbrain
pons
medulla oblongata
18
Q
where do most of the cranial nerves emerge from?
A
the brain stem
19
Q
what is the function of prefrontal cortex?
A
problem solving, high level of thinking, personality, moods, behaviours
20
Q
what is the function of the primary motor cortex?
A
controlling voluntary movement
21
Q
what is the function of the primary somatosensory cortex?
A
sensation and touch
22
Q
which part of the brain controls hearing?
A
temporal lobe
23
Q
which part of the brain controls speech?
A
brocas area (in the frontal lobe)
24
Q
which part of the brain controls language and reading?
A
wernicke’s area (temporal lobe)
25
what is the limbic system?
emotions and emotional behaviour (amygdala) ; learning and memory (hippocampus)
26
what is the basal ganglia?
control of movement
27
what is the hypothalamus?
temp regulation; other homeostasis
28
what is the thalamus?
sensory relay centre between spinal cord and cerebral cortex
29
what is a white matter tract?
communication between brain parts
30
which hemisphere is language production and comprehension in?
the left (97% of people)
31
what is the spinal cord?
a direct extension of the brainstem downwards
32
how are the spinal nerves named?
after the vertebrae that they exit
33
what are nerves C1-C5 involved in?
breathing
34
what are nerves L3-S1 involved in?
knee and foot movement
35
where is the sympathetic tone?
T1-T12
36
where is the parasympathetic?
cranial nerves & S4
37
where is the motor output?
spinal nerve on the anterior side
38
where is the sensory input?
spinal nerve on dorsal side
39
what are tracts?
bundles of nerve fibres that run up/down the spinal cord. some are ascending and descending
40
what is the spinothalamic tract?
ascending, sensory, pain and temp
41
what is the corticospinal tract?
descending, motor, voluntary movement
42
what are the three membranes that surround the brain and spinal cord (meninges)?
-dura mater (hard/tough)
-arachnoid mater (spider)
-pia mater (gentle)
43
what is the dura mater?
fibrous connective tissue
43
what is the arachnoid mater?
membrane, does not pass into the sulk and presses against dura
44
what is the Pia mater?
innermost layer of meninges, allows blood vessels to pass through brainmembrane
45
what is the epidural (extradural) potential space?
middle meningeal arteries supply dura : rupture > haematoma
46
what is the subdural potential space?
bridging veins connecting to venous sinuses : rupture > haematoma
47
what is the subarachnoid space?
CSF, cerebral arteries/veins, arachnoid trabeculae (connective)
48
what is meningitis?
inflammation of the meninges, usually a viral or bacterial infection. can lead to brain damage; cerebral oedema, raised inter cranial pressure can cause herniation
49
what is the cerebrospinal fluid?
fills the ventricles of the brain and subarachnoid space of the meninges, usually have about 125-150ml total
50
what is the function of CSF?
cushions brain against impact/movement and own weight.
provides stable chemical environment for brain
nutrient and waste exchange between nervous tissue and blood
aging: reduced CSF turnover, metabolic waste build ups may contribute to neurodegenerative diseases
51
where is the CSF produced?
choroid plexus in lateral and 4th ventricles
reabsorbed into venous system via arachnoid granulations
52
what is hydrocephalus?
flow obstruction of CSF and build up
53
what is in the CSF?
clear liquid, very few cells, similar to plasma but much lower protein ; different electrolyte levels
54
what is the blood brain barrier?
several features that prevent harmful substances getting into brain & spinal cord from blood
55
what is the structure of the blood brain barrier in capillaries in nervous tissue?
-tight junctions between endothelial cells restrict movement
-thick continuous basement membrane
-astrocytes' processes cover vessels
56
what is the structure of the ependymoctes cells that line the ventricles and spinal canal?
-tight junctions restrict movement
-very small areas of BBB have higher permeability
-sensory functions e.g. area postrema -toxin detection
-secretory functions eg pituitary gland
57
what does the BBB do?
keeps toxins out, stops fluctuation of ions, nutrients and metabolic concentrations in CNS., many drugs cannot cross the BBB
58
what Is the BBB permeable to?
substances that can diffuse across eg water, small lipophilic molecules, gases)
active transport for specific substances too
59
what is the function of the frontal lobe?
social interaction and behaviour
60
how many spinal nerves do we have?
31 pairs
61
how many cranial nerves do we have?
12 pairs
62
what does afferent mean?
arrives in to spinal cord and brain inwards
63
what does efferent mean?
exits the brain and spinal cord outwards
64
somatic meaning?
cell of the body, not a germ line cell
65
visceral meaning?
internal organs in main cavities of the body
66
where do somatic efferents go to?
to skeletal muscle, specifically
67
where do visceral efferents go to?
to the smooth muscle glands or cardiac muscle
68
what is the autonomic nervous system?
the part that we cannot control
69
what is the function of the frontal lobe?
executive function, long term memory, speech personality
70
what is the function of the parietal lobe?
sensory integration, language interpretation, spatial/visual perception
71
what is the function of the occipital lobe?
visual processing (colour, light)
72
what is the function of the temporal lobe?
primary auditory cortex, memory, understanding language
73
what is the telencephalon?
the cerebrum
74
what is the diencephalon?
the thalamus and the hypothalamus
75
what makes up the forebrain?
telencephalon and diencephalon (cerebrum thalamus and hypothalamus)
76
what is the midbrain?
mesencephalon (vision, hearing, motor function, arousal state
77
what is the hindbrain?
rhombencephalon (developmental organisation)
78
where are edindymal cells found?
lining the inside of the central canal
79
what is the function of the thalamus?
relay station of sensory and motor systems and regulates sleep, consciousness and our level of awakeness
80
what is the function of the hypothalamus?
regulates the endocrine system via the pituitary gland and thermoregulation
81
what is the corpus callousum?
connects and links the cerebral hemispheres and has been linked to cognitive function
82
what are the areas that supply the sensory neurons called?
dermatomes
83
what blocks of muscle do motor axons supply?
myotomes
84
how many nerves are there extending from each section of the vertebrae?
C - 8
T - 12
L - 5
S - 5
C - 1
85
what is a pseudo unipolar neutron?
has 1 extension from its cell body and splits into 2 branches - one goes peripherally and the other centrally
86
what is a multipolar neutron?
single axon and many dendrites typically motor neurons
87
what is an autonomic multi polar neuron?
synapse between 2 neurons
88
what do the cranial nerves do?
provide sensory and motor supply to the head and neck structures.
89
what is different about the cranial vagus nerve?
goes down to innervate the heart, lungs and gut. slows HR and breathing, increases gut motility
90
how many neurons are in the visceral efferent pathway?
2
91
how many neurons are in the somatic efferent pathway?
1
92
what is the groove called that separates the brain hemispheres?
longitudinal fissure
93
what is coning?
when an area of the brain swells or when cranial cavity presses on the brain stem. it can impact respiratory and cardiac systems.
94
function of the frontal lobe?
executive functions, long term memory, speech, movement, personality
95
function of the parietal lobe?
sensory integration, language interoperation, spatial and visual perception
96
function of occipital lobe?
visual processing
97
function of the temporal lobe?
primary auditory cortex, memory, understanding and language.
98
what is the homunculus?
the distorted representation of our body in the brain, based on a neurological map of the areas and proprtions of the human brain.
99
what are dermatomes?
sensory neurons
100
what are myotomes?
blocks of muscle supplied by motor axons
101
what are rami?
branches the spinal nerves divide into
102
what do posterior ramus supply?
deep muscles and skin of the posterior surface of the trunk
103
what do the anterior ramus supply?
muscles and structures of the upper and lower limbs and the skin of the lateral and anterior surfaces of the trunk.
104
what are plexuses?
Axons from the anterior rami of spinal nerves, except for thoracic nerves T2-T12, do not go directly to the body structures they supply. Instead, they form networks on both the left and right sides of the body by joining with various numbers of axons from anterior rami of adjacent nerves
105
what is considered the main excitatory neurotransmitter in the CNS?
glutamate
106
what is considered the main inhibitory transmitter in the CNS?
GABA
107
what is GABA?
gamma amino butyric acid, most common inhibitory neurotransmitter in CNS. lessens ability of a nerve to receive, create or send chemical messages to other nerve cells. known for its calming effects.
108
What do nociceptive fibres transmit information about?
Pain
109
what does the arachnoid mater act as a barrier between?
separates CSF in the subarachnoid space and extracellular fluid in the dura
110
what anatomical structure demarcates the frontal from parietal lobes?
the central sulcus
111
what is the white matter mainly composed of?
myelinated axons
112
what is the grey matter mainly composed of?
neurons (cell body, axons, dendrites) and supporting cells (glia)
113
what does the dorsal root ganglia contain?
composed of cell bodies of afferent neurons
114
how many spinal nerves are there?
31 pairs
115
what 2 major vessels provide the brain blood supply?
internal carotid arteries and vertebral arteries
116
where does venous blood from the brain drain to?
dural venous sinuses and ultimately to the internal jugular veins
the internal jugular veins are highlighted in blue in the above diagram
117
from what vertebral levels does the sympathetic nervous system arise?
T1-L2
118
what are the origins of the parasympathetic nervous system?
cranial nerves 3,7,9,10
S4-4
119
where does the spinal cord terminate in an adult?
S2
120
where in the spinal cord does somatic afferent information pass to first?
dorsal grey horn
121
what is the function of the cerebrum?
conscious thought and reasoning
122
what is the function of the temporal lobe?
receiving auditory info
123
what is the function of the medulla?
cardiac and resp regulation
124
where is the auditory cortex located?
temporal lobe
125
where are unipolar neurons found?
cochlear nucleus of brain
126
where are pseudo unipolar neurons found?
sensory neurons
127
where are bipolar neurons found?
retina
128
where are multipolar neurons found?
motor neurons
