CNS

Question 1

3 main division.

Answer 1

forebrain = cerebrum and diencephalon

midbrain.

hindbrain = pons and medulla oblongata and cerebellum

Question 2

cerebrum

Answer 2

largest area of brain
divided into two cerebral hemispheres
separated by longitudinal fissure
connected by corpus callosum

conscious though processes and intellectual function
memory storage, processing and retrieval
conscious and subconscious regulation of skeletal muscle contraction

Question 3

cortex

Answer 3

surface layer called cortex 
gray matter
thrown into folds:
1. gyri = ridges, 
2. separated by fissures = sulci

both increase surface area

-subdivide surface into lobes in cortex

Question 4

lobes of cerebral hemisphere

Answer 4

frontal lobe
parietal lobe
occipital lobe

Question 5

which sulci seperate which lobe

Answer 5

central sulcus = frontal from parietal

lateral sulcus = frontal from temporal

parietoocipital sulcus = parietal from occipital lobe

Question 6

functional areas of the brain I

Answer 6

pre central gyrus = primary motor area, controls voluntary movement

post central gyrus = primary sensory area, receives and interprets sensations

Question 7

functional areas of brain II

Answer 7

superior temporal gyrus = primary auditory area, on lateral sulcus, reception and interpretation of sound

brocas area = motor speech, above lateral sulcus, left side of brain, controls movement involved in speech

Question 8

functional areas of brain III

Answer 8

wernickers area = located in posterior section of superior temporal gyrus on left side of brain, comprehension of speech

calcimine sulcus = primary visual area, located on posterior pole of occipital lobe around calcirine sulcus, receives visual impressions

Question 9

cerebellum

Answer 9

coordinates complex somatic motor patterns

postural muscles = maintain balance

Question 10

brainstem I

Answer 10

medulla oblongata, pons, midbrain

processing and relay centre for information passing to and from cerebrum and cerebellum

contains reflex centres associated with respiratory and cardiovascular functions

Question 11

brainstem II

Answer 11

midbrain = most superior of 3 parts of brainstem

pons = largest part, above medulla oblongata, nerves to connect cerebellum to cerebrum

medulla oblongata = raised bumps to carry nerve signals between brain and spinal cord

Question 12

diencephalon I

Answer 12

region of brain almost completely hidden from surface

consist of dorsal thalamus and ventral hypothalamus

Question 13

diencephalon II

Answer 13

thalamus = relay and processing centre

hypothalamus = involved in hormone production and emotional control

Question 14

arterial supply of brain

Answer 14

brain supplied by:

• two internal carotid arteries
• two vertebral arteries
• four arteries on anastomose on inferior surface of brain and form Circle of willis

Question 15

internal carotid arteries

Answer 15

leaves neck by passing into cranial cavity through carotid canal

passes upwards and forwards in cavernous venous sinus

leaves sinus, passes lateral to optic chiasma

terminates by dividing into anterior and middle cerebral arteries

Question 16

vertebral arteries

Answer 16

ascend in neck through foramina in transverse processes of upper six cervical vertebrae

enters cranial cavity through foramen magnum

join together from either side to form basilar artery

Question 17

circle of willis

Answer 17

unity of carotid and vertebral arteries

allows for collateral circulation of blood if one or part of circle becomes blocked or narrowed

avoids ischemia

Question 18

auroregulation of cerebral blood flow

Answer 18

ability of brain to maintain relatively constant blood flow

auto regulation is present in many vascular beds, but is particularly well developed in brain
- need constant blood supply and homeostasis

reductions in cerebral blood flow stimulate release of vasoactive substances from brain that cause arterial dialation

cerebral smooth muscle in arterioles constrict in response to elevated pressure

Question 19

stroke

Answer 19

interuption of blood supply to parts of brain

2 main causes of stroke:
- ischaemic = blood supply blocked due to blood clot

• haemorrhagic = weakened blood vessel supplying brain bursts

Question 20

anterior cerebral

Answer 20

loss of blood supply effect primary motor cortex for lower limb and perineum of contralateral side

can lead to incontince due to lack of control of pelvic floor muscles

Question 21

middle cerebral

Answer 21

blockage will lead to loss of sensation and motor function of body except for lower limb and perineum

supplies Broca’s motor speech area and wernickes sensory speech area

loss of function can effect how someone speaks and ability to understand speech

Question 22

posterior cerebral

Answer 22

supplies primary visual cortex = blockage can lead to visual defects

supplies hippocampus = blockage can lead to memory loss

Question 23

the meninges

Answer 23

three protective membranes:

dura mater = tough, fibrous outermost covering

arachnoid mater = consist of arachnoid membrane and arachnoid trabecular which extends to surface of…

pia mater = blood vessels run along surface of pia mater within subarachnoid space

Question 24

cranial dura mater

Answer 24

double layer

endosteal layer = periosteum covering the skull

meningeal layer = dura mater proper, covers brain, continuous through foramen magnum with dura mater of spinal cord

Question 25

cranial dura mater - meningeal layer

Answer 25

sends inward four septa divide cranial cavity into freely communicating spaces contain subdivisions of brain restrict rotatory displacement of brain

Question 26

reflections of dura mater

Answer 26

falx cerebri = lies in midline between two cerebral hemispheres tentorium cerebelli = roofs over posterior cranial fossa covers upper surface of cerebellum supports occipital lobes of cerebral hemispheres tentorial notch = passage of midbrain falx cerebelli = projects forward between cerebellular hemispheres \ diaphragma sellae = small circular fold of dura, allows passage of infundibulum

Question 27

venous sinuses

Answer 27

situated between periosteal and meningeal layers of dura mater receive tributaries from brain, skull bones, orbit and internal ear

Question 28

intracranial haemorrhages I

Answer 28

may result from trauma or cerebral vascular lesions | extradural = raises intracranial pressure

Question 29

intracranial haemorrhages II

Answer 29

subdural = tearing of veins as they enter superior saggital sinus caused by blow to front or back of head, displacing skull blood accumulates in potential space between dura and archanoid mater

Question 30

intracranial haemorrhages III

Answer 30

subarachnoid leakage or rupture of circle of willis severe headache, loss of consciousness diagnosed by withdrawing heavily blood-stained cerebrospinal fluid through a lumbar puncture

Question 31

ventricular system and central canal

Answer 31

fluid filled central passageway extends along spinal cord and brain filled with cerebrospinal fluid - continuously circulated fluid which also surrounds brain and spinal cord -provides protective cushion - transports nutrients and waste - passageway forms enlarged chambers in brain called ventricles

Question 32

cerebrospinal fluid I

Answer 32

clear, colourless fluid formed by choroid plexus (coloured red) circulates through ventricular system enters subarachnoid space through three foramina in roof of the fourth ventricle circulates both upwards over surface of cerebral hemispheres and downwards over spinal cord

Question 33

cerebrospinal fluid II

Answer 33

eventually enters bloodstream by passing through arachnoid villi into dural venous sinuses, in particular superior sagittal sinus removes waste products of neuronal activity fluid cushion for protection

Question 34

hydrocephalus

Answer 34

overproduction of CSF or blockage of ventricular system leads to accumulation of CSF in neonatal skull, increase in pressure will force unfused cranial bone apart leading to cranial abnormalities as well as neurological complications fused adult skull leads to dangerous rise in intracranial pressure can be treated with a shunt that drains CSF from ventricular system into body cavity where it can be reabsorbed

Question 35

cranial nerves

Answer 35

1. olfactory = smell 2. optic = vision 3. oculomotor = eye movement, pupil size and lens 4. trochlear = eye movement 5. trigeminal = sensory to face, operates muscles of mastication 6. abducens = eye movement 7. facial = taste, facial expression, secretion 8. vestibulocochlear = balance, hearing 9. glossopharyngeal = taste, blood pressure, gases, swallowing and secretion 10. vagus = taste, sensory to thoracic, abdominal viscera, movement and secretion 11. accessory = movement (pharynx, larynx and neck) 12. movement (tongue)