CNS anatomy Flashcards
1
Q
what are the two parts of the CNS
A
visceral and somatic
2
Q
what is the somatic part
A
recieving and responding to information from the external environment
3
Q
what is the visceral part
A
innervation of organs in the body and other components, more connected with the internal
4
Q
what does the CNS do
A
controls and coordinates most functions of the body and mind
5
Q
what does the CNS include
A
spinal cord and brain
6
Q
role of CSF
A
supports and protects the brain and spinal cord by maintaining uniform pressure
shock absorber between brain and skull
keeps brain and SC moist
exchange of nutrients and waste between CSF and interstitial fluid
acts as a cushion for the brain, making it weightless
keeps the brain in place
regulation of breathing, bathes the medulla where the central respiratory chemoreceptors are found
7
Q
what does CSF contain
A
glucose [gives it a slight yellow colour], lactic acid and proteins
8
Q
where does CSF exit
A
through the meninges into the venous supply
9
Q
what happens to CSF if brain is enlarged
A
fluid levels decrease
10
Q
what happens if the brain volume decreases
A
CSF levels increase
11
Q
what allows for the secretion of CSF into each ventricle
A
choroid plexus [highly vascularised]
12
Q
what cells is the CSF surrounded by
A
ependymal cells
13
Q
how does CSF pass back into the blood
A
by the arachnoid villi, composed of arachnoid matter which project into the venous sinuses
14
Q
what does the movement of CSF depend on
A
the pressure at each side of the villi walls, transferring it from the arachnoid space to the venous sinuses
15
Q
what happens to the CSF movement if CSF pressure is higher than venous pressure
A
CSF pushed into the blood
16
Q
what happens if the venous pressure is greater
A
the arachnoid villi collapse preventing passage of blood constituents into CSF
17
Q
formanen of monro
A
sits behind part of the BS
from 4th to SC
reabsorbed back into circulation via meninges
18
Q
what is the blood supply
A
circulus arteriosus + arteries maintain constant supply of oxygen and glucose to the brain, when the head moves, the contributing artery becomes narrowed
autoregulation of cerebral arteriolar diameter maintains constant blood flow to the brain compensating for fluctuations, protecting the brain
venous blood drains into the dural venous sinuses -> IJ vein
19
Q
what should the systemic BP be
A
65-140mmHg
20
Q
what is the arterial blood supply
A
carotid feeds through the neck
vertebral + internal carotid = connected in the inter cranial space = cerebral arterial circle of willis
two vertebral arteries enter the cranial cavity through the foramen magnum forming the basillar artery
21
Q
what causes a stroke
A
blockage of blood to the brain
22
Q
what causes a haemorrhage
A
over blood supply
23
Q
what causes vascular dementia
A
diameter constriction, less blood to brain causes confusion
24
Q
what are the four ventricles
A
left
right
3rd
4th
25
where are the lateral ventricles
in the central hemisphere on each side of the median plane below the corpus callosum
separated by a narrow septum and lined with ciliated epithelium
26
what do the lateral ventricles communicate with
the 3rd ventricle via the inter-ventricular foramen
27
where is the 3rd ventricle found
below the lateral ventricles, between the 2 parts of the thalamus
28
what does the 3rd ventricle communicate with
the 4th by the canal aqueduct, it recieves CSF fluid via the cerebral aqueduct
29
where is the 4th ventricle
sits below and behind the 3rd between the cerebellum and the pons
slightly alkaline and has a specific gravity of 1.005
consists of water, salts, glucose, plasma proteins, leukocytes, creatinine, urea
30
what is hydrocephallis
blocked ventricle, excess CSF which builds up, failing to reabsorb
causes intracranial pressure and can link to meninge issues
31
how do CSF leaks present
headaches, relief whilst laying down
lack of CSF can cause collapse, as brain becomes heavy
32
CSF leak SE
nausea, headaches, confusion, vomiting, clear fluid from ear and injury site
33
what is the BBB
it is a semipermeable barrier which allows small molecules in via diffusion as well as selective + AT of various nutrients and ions and anions and macromolecules
protects the brain tissue from pathogens + toxic substances
34
what cant pass through the BBB
chemo BUT TEMZ
however a reservoir can be put in so that small doses of chemo can be given
35
what can pass through the BBB
oxygen, carbon dioxide, glucose, lipid soluble
inorganic ions, AA pass slowly or not at all
36
what are the two types of cell of the brain
neurons and glial
37
what is a feature about neurones
THEY DONT DIVIDE
ONCE THEY DIE THEY CANT BE REPLACED
38
what do sensory neurons do
detect stimuli from external
39
what do motor neurones do
carry impulses from brain to muscles
40
what do interneurones do
connect other nerve cells and help relay messages between the brain and other body cells. They allow impulses from sensory neurons -> brain -> motor
41
what structures are grey matter
brain, BS, cerebellum, SC
42
what is GM
six layers of neurons, axon terminals and dendrites
43
what does grey matter do
send nerve signals which govern motor activity to nervous system
44
what does white matter do
myelinated, conductor of nerve signals which process them
conducts, sends and processes signals and responds
there is more white matter so signals can respond after they've been replaced
45
what are the different glial cells
ependymal
astrocytes
oliogodendrocyte
microglia
46
what is the role of the glial cells
support the neurones and protect them
regulate chemical environment
role repair in trauma
47
what is the role of astrocytes
clean up dead neurons
fine branching processes lie in a mucopolyssacharide ground substance
biochemical control which line the BBB
tells the transmitters what to do after the message has been delivered
contributes to homeostasis
structural support of CNS
linked with parkinsons
48
what happens when the astrocytes get damaged
the processes form a mesh as they multiply, which inhibits regrowth of damaged CNS neurones
49
what are ependymal cells
hair like projections which move CSF fluid through fluid filled cavities, which form the lining of the ventricles and the central canal of the SC
50
what would happen if there was no ependymal cells
build up of fluid would occur
51
what do specialised ependymal cells form
choroid plexuses of the ventricles and secrete CSF
52
what are oligodendrocytes
cluster of nerve cells bodies in grey matter which are found adjacent to and along the mylelinated nerve fibres
53
what do the oligodendrocytes form
the myelin sheath around the neurons, faster transmission of information sending, also contains multiple branches which speeds up transmission also.
it protects the neurons, and the gap allows for conduction and impulse of messages, which multiply around degenerating neurones
54
how are oligodendrocytes destroyed
in demyelinating diseases
55
what are microglia
cells derived from monocytes which migrate from the blood to the nervous system. Which remove damaged and infected cells maintaining CSF is a healthy state
static cells are found dispersed throughout the brain
56
what are microglia part of
the mononulear phagocyte system
57
what are the types of meninges
cranial
spinal
58
what do meninges do
they stop the brain/cord from touching bone, contains a blood supply, produces CSF
59
where are meninges
lie in between the skull and the brain, and between the vertebral foramina and spinal cord
brain and SC are completely surrounded by three layers of tissue
60
what are the 3 layers of tissue
[outwards - in]
dura mater
arachnoid mater
pia mater
61
what is found between the dura mater and the arachnoid mater
subdural space - serous fluid
62
what is found between the arachnoid mater and pia mater
subarachnoid space = contains CSF
63
these 3 layers continue in the.....
spinal canal, containing the epidural space
64
what is dura mater composed of
two layers of dense fibrous tissue
outer periosteal layer lines the inner surface of the skull, bones and inner meningeal layer, provides a protective covering.
65
what does the inner layer of dura mater do
sweep inwards following the brain contours, forming membranous extensions that particularly divides the cranial cavity
66
what is the flax cerebri
separates the 2 central hemispheres, penetrates the depth of the corpus callosum
67
what is the falx cerebelli
separates the 2 cerebellar hemispheres
68
what is the tentorium cerebelli
separates the cerebellum and the cerebrum
69
what is the venous blood supply of the dura mater
venous sinuses are found in between the two layers, superior sagittak sinus is formed by the falx cerebri and tentorium.
cerebelli forms straight and transverse sinuses, allows blood to leave and CSF to re-enter the venous supply
70
what is the arachnoid matter made from
fibrous tissue
71
arachnoid mater
passes over the convolutions of the brain and accompanies the inner layer of the dura mater in the formation of the falx cerebri, tentorium cerebelli and falx cerebelli
72
where does the arachnoid mater end
at S2, as it merges with the dura mater
73
what is pia mater made from
connective tissue with tiny blood vessels which adhere to the brain covering the brain convolutions and dipping into each fissure
74
what does the pia continue as at the end of the cord
filium terminale
75
what does the fused pia mater and dura mater become
coccyx periostenium
76
what is the role of the pia mater
act as a physical barrier, separating the neural tissue
77
what is the extradural space
space between the dura mater and the bone which have air spaces to reduce trauma
78
what are the two spaces where CSF flows
arachnoid space and subarachnoid
79
where does the arachnoid space continue to
S2
80
what is the spinal cord protected by
vertebrae, meninges, CSFwh
81
where do the nerves fan out to become causa equina
L1/L2
82
where does the SC extend from
foramen magnum - L1/L2
83
is ventral front or back
front
84
is dorsal front or back
back
85
how many pair of nerves are there
31
86
what holds the spine in place
erectus spinus
87
how many C vertebrae
7
88
how many L spine is there
5
89
how many T spine is there
12
90
how many S spine is there
5
91
what spine is in the upper limbs
C5-T1
92
what spine is in the lower limbs
L1-S3
93
what is the coronal suture
fusion of the frontal bone and the two parietal
94
what is the sagittal suture
fusion of the two parietal
95
what is the lamboid suture
fusion of the occipital bones to the parietal
96
what are sutures
keep the skull sections fused together
97
what does the falx cerebri divide into
left and right cranium
98
what does the falx cerebri determine
the site of the sutures
99
what does the falx cerebri attach to
part of the ethmoid bone (crista gali) which extends to the occipital protuberance
100
what is meningitis
inflammation of the meninges [amputation, seizures, death]
can be cancer induced
101
mengioma is it malignant
no it is benign
102
haematoma
vascular damage due to trauma, extradural space becomes fluid/blood filled
103
what are the spinal nerves attached to
posterior and anterior roots
104
posterior roots
carry information TO CNS (contains sensory neuron processes)
105
anterior roots
carry information FROM CNS (contains motor fibres)
106
what do dorsal problems cause
issues interpreting sensory info
107
what do ventral issues cause
body's ability to receive motor information, paralysis, tingling, muscle weakness
108
what is heavy leg syndrome linked with
ventral root
109
what is spina bifeda
inproper formation of the spine
weakness in legs, bowel/urine incontinence, cant feel hot or cold
birth defect [nerves outside the body]
110
what does motor neurone disease cause
muscle weakness, slurred speech
unpreventable
111
where is the cerebrum located
anterior, middle cranial fossa, divided by a deep cleft, longitudinal cerebral fissure into. right and left hemisphere each containing a lateral ventricle
112
what is the corpus callosum
the connection of two hemispheres by white matter
113
what does the cerebrum do
cross and fine motor skills
hand eye coordination
balance
114
what is bells palsy
one sided face weakness
115
what is the cerebral cortex composed of
nerve cell bodies - superificial
nerve fibres - deep layers
exposed areas = gyri (convolutions) are separated by sulci (fissures) increasing the SA
116
what does the motor areas of the cerebral cortex do
initate and control skeletal muscle movement
117
what does the sensory areas of the CC do
receive and decode sensory impulses, enabling pain perception, temp, touch, light, sight, hearing, taste and smell
118
what do the associated areas of the cerebral cortex do
integration and processing of mental functions [intelligence, memory, reasoning, judgement and emotions]
119
what functions are associated with anterior of the central sulcus
motor
120
what functions are associated with posterior of the central sulcus
sensory
121
what are the different lobes
temporal
occipital
parietal
frontal
122
what marks the lobe boundaries
deep sulci
123
what are the different sulci
central
lateral
parieto-occipital sulci
124
what increases the SA of the brain
gyri and sulci
125
what does the parietal lobe contribute to
object classification
knowledge of numbers
visuo-spacial processing
spelling
perception
126
what does the frontal lobe contribute to
thinking
processing information
planning
behaviour control
problem solving
emotions
decision making
motor speech [brocos area = just above the lateral sulcus, controls the muscle movements for speech]
127
what does the temporal lobe contribute to
memory
speech
vision
hearing sensitivity to sound and how nerves process it
facial recognition
understanding language
128
what does the occipital lobe contribute to
vision
colour identification
visual processing
129
what does the corpus callosum act as
a communicator for the left and right side of the brain
[bundle of nerves along the longitudinal fissure]
130
why is good oxygen supply needed
optimal processing
131
what does the internal capsule connect to
cerebral cortex and other structures ie thalamus and brainstem
132
what do the nerve fibres in the internal capsule form
pyramidal tracts which cross at the medulla oblongata (to the skeletal muscles), ones which dont pass through have connections to parts of the brain: basal ganglia, thalamus and cerebellum
133
what is the role of basal ganglia
initiation and fine motor control of complex movement, learned coordinated activities
134
what happens if motor control is inadequate
jerky movements, clumsy and uncoordinated
135
what is the diencephalon
connection of the cerebrum to the BS
136
what is the thalamus
relay station for sensory impulses, role in memory, sleep wake signals
137
what is the olfactory bulb responsible for
smell
138
what is the amygdala
fight or flight
produces adrenaline
139
what is the pineal gland responsible for
sleep/wake cycle
sensitive to steroids
140
where is the pineal gland located
behind the corpus callosum, secretes melatonin
141
what is the roles of the hypothalamus
heart rate
BP
body temp
glandular secretions of stomach and intestines
sleep cycles
secretions of substances which influence pituitary gland to release hormones
appetite and body weight
fluid and electrolyte balance
142
what is the hippocampus responsible for
recalling info
memory station: converts short term to long term
alzheimers
143
where is hippocampus found
temporal lobe
144
what is the brainstem responsible for
communication between brain + SC
control centre
contains 10/12 nerves [- optic and olfactory]
145
what is the midbrain responsible for
hearing
vision
temp regulation
eye movement
motor control
sleep/wake cycle
alertness
146
what is the pons responsible for
connects L+R hemisphere
sleep
respiration
swallowing
bladder control
body movements
147
what is the medulla responsible for
respiratory
digestive system
cardio system
regulation autonomic involuntary functions: breathing, heart rate, BP
vomiting
148
describe the location of the brain stem etc from top to bottom
thalamus
midbrain
pons
medulla
SC
[midbrain to SC = brain stem]
149
what is the basal ganglia responsible for
fine motor skills [involuntary]
receives impulses from the cerebrum, processed and adjusted which are sent to the thalamus and info is relayed back to the GM of the cerebrum before signals are sent to the spine
150
where is the basal ganglia found
deep within WM
151
where is the taste area of the limbic system
above the lateral sulcus, in the deep layers of the somatosensory area
sensory receptors in taste buds are received and interpreted
152
what is the limbic system
the sensory areas of the cerebral cortex
153
where is the auditory area of the limbic system
below the lateral sulcus within the temporal lobe
154
what does the auditory area do
nerve cells receive and interpret impulses transmitted from the inner ear by the cochlear of the vestibulocochlea nerves
155
where is the somatosensory area
behind the central sulcus
156
what does the somatosensory area do
pain sensation, temp, pressure, touch, awareness of muscular movement and joint position
right hemisphere receives impulses from the left side of the body and vice versa
157
what is the size of the cortical areas proportional to
the extent of the sensory innervation
158
where is the olfactory area in the limbic system found
deep within the temporal lobe
159
what do the olfactory nerves do in the LS
receive and interpret impulses
160
what are the areas of the limbic system
auditory
sensory
taste
somatosensory
olfactory
[vestibular relates to touch, NOT AN AREA THOUGH]
