1
Q
what is the CNS composed of?
A
Brain and spinal cord
2
Q
what percent of the cns are neurons?
A
10%, the rest are neuroglia
3
Q
what fluid is the CNS supported by?
A
cerebral spinal fluid (CSF)
4
Q
what are the specific areas of neuronal cell bodies called?
A
nuclei
5
Q
what do axons form?
A
multiple nuclei running in parallel called fibres (aka nerve tracts or white matter)
6
Q
what is the basic functional unit of the nervous system and what is it responsible for?
A
the neuron, responsible for sending and receiving nerve impulses or signals
7
Q
what are glial cells?
A
non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin and facilitate signal transmission in the NS
8
Q
what cells is the CNS made of?
A
astrocytes, oligodendrocytes, microglia, ependymal cells
9
Q
what cells is the PNS made of?
A
satellite cells, Schwann cells
10
Q
how much percent of the body weight does the brain make up?
A
2%
11
Q
how much percent of the body oxygen and glucose consumption does the brain make up?
A
20%
12
Q
what are the major regions of the brain?
A
forebrain- prosencephalon
midbrain- mesencephalon
hindbrain- rhombencephalon
13
Q
what is the forebrain subdivided into?
A
the telencephalon (cerebral hemispheres) and diencephalon (thalamus and hypothalamus)
14
Q
what is the midbrain region?
A
narrow and short region connects forebrain and hindbrain
15
Q
what is the hindbrain composed of?
A
pons, cerebellum, medulla, oblongata
16
Q
what is the brain stem?
A
midbrain, pons and medulla oblongata
17
Q
what protects the brain?
A
cranium- skull
meninges
cerebrospinous fluid
blood brain barrier
rich blood supply
18
Q
what are meninges?
A
shock absorbers- prevent brain from contacting the skull
layers: dura mater, arachnoid., pia mater
19
Q
what is cerebrospinous fluid (CSF)?
A
cushions the brain and spinal cord
circulates through channels
produced in ventricles- choroid plexus
constantly absorbed and replenished
20
Q
what is blood brain barrier?
A
membrane between the blood and interstitium of the brain
tight junctions- prevent diffusion of materials between cells
only lipid soluble compounds diffuse into the interstitial fluid
21
Q
what is the dura matter layer?
A
has 2 fibrous layers
periosteal (fibrous outermost)- fused with periosteum lining of cranial bones
meningeal (innermost)
22
Q
what is the arachnoid layer?
A
delicate membrane located between meningeal dura and Pia matter, riding both sulci and gyri
23
Q
what is the pia matter layer?
A
tightly attached to the surface contour of the brain and lines the sulci
24
Q
what do the meningeal dura folds do?
A
extend deep in some locations of the cranial cavity and subdivide the cranial cavity, support the brain and limit its movement
25
what is epidural space?
located between the skull and outermost dura
middle meningeal artery runs in this space
26
what is subdural space?
located between the inner dura layer and arachnoid
bridging veins traverse it
27
what is subarachnoid space?
located between the arachnoid and pia matter
CSF fills this space
28
what is the longitudinal fissure?
separates the 2 hemispheres
each hemisphere is divided into lobes named after the overlying bones of the skull
29
what is the central sulcus?
deep groove extends laterally from longitudinal fissure
frontal lobe anterior to central sulcus
30
what is the lateral sulcus?
marks the inferior border of frontal lobe
region inferior to later sulcus is the temporal lobe
31
what is the Parieto-occipital sulcus?
infer border of parietal lobe
parietal lobe- extends posteriorly from the central sucus to the p-o sulcus
region posterior to this sulcus is the occipital lobe
32
what is the frontal lobe?
primary motor cortex- conscious control of skeletal muscles
33
what is the parietal lobe?
primary somatosensory cortex- conscious perception of touch, pressure, vibration, pain, temperature, and taste
34
what is the temporal lobe?
auditory and olfactory cortex- conscious perception of auditory and olfactory stimuli (hearing and smell)
35
what is the occipital lobe?
visual cortex- conscious perception of visual stimuli
36
what do fibres do?
carry information within and between hemispheres
37
what are association fibres?
connect areas of cerebral cortex within one hemisphere
38
what are commissural fibres?
connect one cerebral hemisphere to another
39
what are projection fibres?
connect the cerebrum to other parts of the CNS and spinal cord
40
the central sulcus separates what?
motor and sensory portions of the motor cortex
41
what is the primary motor cortex?
represented by pre central gyrus of the frontal lobe which forms the anterior margin of central sulcus
42
what is the primary somatosensory cortex?
represented by the post central gyrus of the parietal lobe which forms the posterior margin of central sulcus
43
how many ventricles are in the brain?
4
two lateral
third and fourth
44
what are the 2 lateral ventricles?
one in each central hemisphere
separated by septum pellucidum
no direct connection
45
what is the third ventricle?
in diencephalon
communicates with lateral ventricles by interventricular foramen
46
what is the fourth ventricle?
in medulla oblongata
mesencephalon has a slender canal cerebral aqueduct connects 3rd to 4th ventricle
fourth ventricle narrows and is continuous with central canal of SC
communicating network of chambers filled with CSF
47
what are the overall functions of limbic system?
processing of memories; creation of emotional states, drives, and associated behaviours
48
what are the cerebral components of the limbic system?
cortical areas- limbic lobe (cingulate gyrus, senate gyrus, and parahippocampal gyrus)
nuclei- hippocampus, amygdaloid body
tracts- fornix
49
what are the diencephalic components of the limbic system?
thalamus- anterior nuclei
hypothalamus- centers concerned with emotions, appetites (thirst, hunger) and related behaviours
50
what is the reticular formation?
other component in the limbic system
network of interconnected neclei throughout brainstem
51
what is central white matter?
covered by the grey matter of the cerebral cortex
contains myelinated fibres forming bundles connect cortical area to another
52
what are the central white matter bundles divided into?
association fibres
commissural fibres
projection fibres
53
what are association fibres?
interconnect areas of cortex within a single hemisphere
54
what are commissural fibres?
connect the 2 hemispheres, this involves corpus callosum and anterior commissure
55
what are projection fibres?
connect cerebrum with other regions of the brain and spinal cord
56
what is a gyrus?
an elevated ridge or hill
57
what is basal nuclei?
paired masses of grey matter within each cerebral hemisphere- deep to the floor of lateral ventricle
embedded with central white matter
58
where do the projection and commissural fibres travel in basal nuclei?
travel around or between these nuclei
59
what inlcudes caudate and lentiform nuclei?
basal nuclei
60
what does lentiform nucleus consist of?
of lateral putamen and medial globes pallid us
61
basal nuclei do not function to initiate the movement but...
once underway they coordinate the movement by providing rhythm and pattern
62
what are caudate nucleus?
stimulates muscles in limbs to produce normal pattern and rhythm in walking
63
what is putamen?
controls muscles patters at a subconscious level
64
what are globus pallidus?
interacts with the thalamus to regulate muscle tone
65
what are the three structures that are collectively referred to as the basal ganglia?
caudate nucleus, putamen, globus pallidus
66
what is the diencephalon?
connects brainstem to the cerebral hemispheres
thalamus, subthalamus, epithalamus, hypothalamus
67
what is the thalamus in the diencephalon?
largest part, receives input from most sensory neurons in the body
68
what does the sub thalamus do in the diencephalon?
motor functions
69
what is the epithalamus in the diencephalon?
emotional and visceral responses to odours; biological clock
contains the pineal gland- secretes melatonin
70
what is the hypothalamus in the diencephalon?
major endocrine tissue; homeostatically regulates many important physiological processes
infundibulum connects hypothalamus to pitituary gland
71
what is the medulla oblongata?
relay station between spinal cord and brain
72
what is the pons?
relay station from medulla to higher cortical structures of the brain
sensory and motor nuclei of 4 cranial nerves
neclei regulating invloentary control of respiration
nuclei that process and relay cerebellar commands
relay station as per above
73
what is the midbrain?
process visual and auditory stimuli
connect primary motor cortex with motor neurons in brain and sc and carry ascending sensory info to thalamus
74
what is the cerebellum?
anterior and posterior lobe assist in planning, execution and coordination of limb and truck movements
stores memories of learned movement patterns
functions also to adjust postural muscles of the body- coordinates rapid autonomic adjustments that maintain balance and equibilbirum
75
how many pairs of cranial nerves are found on the ventrolateral surface of the brain?
12 pairs
76
what is the olfactory nerve (I)?
olfactory epithelium (smell)
77
what is the optic (II) nerve?
retina of eye
78
what is the oculomotor (III) nerve?
inferior, medial and superior rectus, inferior oblique, levator palpebrae (intricstic muscles of the eye)
79
what is the trochlear (IV) nerve?
superior oblique mm (eye)
80
what is the trigeminal (V)?
(many branches)- motor and sensory to jaw, sensory to orbits, nasal cavity, eyebrows, forehead, lower eyelid, upper lip and motor to muscles of mastication
81
what is the abducens (VI)?
lateral rectus (of eye)
82
what is the facial (VII) nerve?
sensory for taste receptors anterior 2/3 of tongue, motor to muscles of facial expression and glands
83
what is the vestibulochlear/acoustic (VIII)?
cochlea (receptor for hearing) and vestibule (receptors for motion and balance)
84
what is the glossopharyngeal (IX)?
posterior 1/3 sensory of tongue, carotid body, motor to pharyngeal muscles, parotid gland
85
what is the vagus (X) nerve?
sensory- pharynx, diaphragm visceral organs, motor palatal and pharyngeal muscles and visceral organs in thoracic and abdominopelvic cavities
86
what is the accessory (XI) nerve?
skeletal muscles of palate, pharynx and larynx, SCM and trapezius
87
what is the hypoglossal (XII) nerve?
tongue musculature
88
what is the spinal cord?
made of about 100 million neurons
it is the pathway for sensory input to brain and motor output from the brain
it provides quick reflexes to stimuli- for example, touching a hot object will make you involuntarily pull your arm away without being aware
89
what shape is the spinal cord?
oval in shape
90
where does the spinal cord start and end?
starts from medulla oblongata, ends at conus medlars as film terminale- spinal cord ends in different levels according to age
91
where does a newborns spinal cord end?
3rd or 4th vertebra
92
where does an adults spinal cord end?
L1/L2
93
where does elongation of spinal cord stop at?
stops at age of 4 or 5 while vertebral column continues to grow
94
where does the conus medullairs (terminal part of spinal cord) end?
at the level of intervertebral disc of between L1-L2
95
what does the film terminale (slender filament of the pia matter) do?
extension of conus medullaris (slender tapering of the SC)
extends from L1 to the dorsum of coccyx and connects sc to first coccygeal vertebrae
96
what are extensions of lumbar nerve roots?
cauda equina
97
what is the cauda equina?
filum terminate + long ventral and dorsal roots
branching out of the spinal nerves once sc tapers
98
how many pairs of spinal nerves are there?
31
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
99
do nerves from lumbar, sacral and coccygeal regions leave the vertebral column at the same level they exit the spinal cord?
no
100
what is a spinal tap (lumbar puncture)?
a local anaesthetic is given and a Lon hollow needle is inserted into the subarachnoid spaces to withdraw (CSF) for diagnostic purposes; to introduce antibiotics, contrast media for pyelography or anaesthetics to administer chemotherapy; to measure CSF pressure; and or to evaluate the effects of treatment for diseases such as meningitis
101
where is lumbar puncture performed?
in adults between the L3 and L4 or L4 and L5 lunar vertebrae because this region provides safe access to the subarachnoid space without the risk of damaging the spinal cord
102
what is the central nervous system protected by?
vertebral column
meniges
CSF
denticulate ligament
103
what are meninges?
3 layers that lay between the nervous tissues and the bones
104
what is CSF?
between meningeal layers, shock absorbent
105
what are plexuses?
network of nerve roots formed before supplying the body
106
all roots make plexus except the?
thoracic 2-12
107
what are all the plexuses in the body?
cervical
brachial
lumbar
sacral
coccygeal
108
what is the cervical plexus?
C1-C4 with contribution from C5
supplies the head, neck, and superior border of shoulder and chest
deep to SCM and anterior to middle scalene and elevator scapulae
109
what are the sensory branches of the cervical plexus?
C2-C4
110
what are the muscular branches of cerviacal plexus?
C1-C5
phrenic nerve C3-5
branches to muscles- levitator scapula innervated by dorsal scapular nerve (C5) and cervical nerves (C3-C4)
111
where does the brachial plexus arise from?
C5 -C8 and T1
112
what is the brachial plexus?
supplies the whole upper limb, lateral chest wall and supefcical muscles of the back
roots unite to form trunks (superior, middle and inferior)
trunks diverge into divisions (anteior and posterior)
113
what are the roots of the brachial plexus?
C5- dorsal scapular
C6, 7, 8 T1- long thoracic nerve, 1st intercostal nerve off of T1
114
what are the trunks of the brachial plexus?
C5 and C6- superior trunk(super scapular nerve, nerve to subclavius)
C7- middle trunk
C8-T1- inferior trunk
115
what are the divisions of the brachial plexus?
superior- divides into anteior and posteior
middle- divides into anteior and posteior
inferior- divides into anteior and posteior
116
what are the cords of the brachial plexus?
anterior form middle and super trunks combine to form lateral cord, posteior cord is combined form all of the posteior form all trunks, anteior continues on to become your medial cord
117
what is the lateral cord of the brachial plexus?
let me lift
lateral pectoral continuing as muscluocuatneous lateral contribution to median nerve
118
what is the poertrior cord of the brachial plexus?
ultra
upper sub scapular nerve
lower sub scapular nerve
throacodorsal nerve
radial nerve
axillary nerve
119
what is the medial cord of the brachial plexus?
medial pectoral
medial antibrachial
cutaneous brachial
medial brachial cutaneous
medial contribution to median nerve
ulnar nerve
120
what is the lumbar plexus?
roots of spinal nerves L1-L4
psoas muscle is a landmark- embedded in this
121
what does the lumbar plexus supply?
supplies the anterolateral abdominal wall, external genitalia and part of lower limb
122
what is the largest part of the lumbar plexus?
femoral nerve which innervated the anteior compartment of lower limb
123
what do 5 trunks combine to form in the lumbar plexus?
lateral femoral cutaneous nerve
femoral nerve
obturator nerve( passes through obturator foramen)
124
what is the sacral plexus?
the roots of spinal nerves L4-L5 and S1-S4
125
what does the sacral plexus supply?
supplies buttocks, perineum and lower limbs
126
what nerve arises from the sacral plexus?
sciatic nerve- largest nerve in body
127
sciatic nerve though greater sciatic notch branches to:
tibial nerve on medial side that branches to sural that depends to lateral side of ankle
common fibular( peroneal) nerve on lateral side
128
what does the sciatic nerve branch into?
beaches into the tibial and common fibular nerve as it approaches the popliteal fossa
129
what is the tibial nerve?
innervates the flexors of the knee and plantar flexors of the ankle and flexors of the toes
it runs along with posteior tibial artery and vein
130
what is the common fibular nerve?
innervates the short head of the biceps femoris
131
what does the common fibular nerve divide into?
superficial fibular nerve; innervates fibularis longus and fibularis brevis
deep fibular nerve; innervates anteior tibial muscles run along with anteior tibial artery and vein
132
what does tom, dick, and nervous harry stand for?
flexor Digitorum longus
tibial Artery
tibial Nerve
flexor Hallucis longus
133
what is the coccygeal plexus?
small plexus by S4-S5 and coccygeal nerves
134
what does the coccygeal plexus supply?
small area of the skin in the coccygeal region
135
Winter Term 2026
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