IC1

Question 1

number of cranial nerves and spinal nerves

Answer 1

12 vs 31 nerves

Question 2

midbrain make what

Answer 2

neuromodulators eg dopamine, serotonin
regulate physiology

Question 3

white matter vs grey matter in the cerebral cortex

Answer 3

grey matter: receive info, regulate outgoing info. usually cell bodies of the neurons
white matter: transmit signals to other regions. usually axons.

Question 4

gyri and sulcus

Answer 4

grooves (folds and bumps) used to separate brain regions

Question 5

nuclei of the midbrain associated with

Answer 5

visual and auditory pathways

Question 6

medulla oblongata nuclei associated with

Answer 6

CV and respiratory function

Question 7

which region of brain consists the most number of neurons

Answer 7

cerebellum (80%)

Question 8

foramen magnum, conus medullaris

Answer 8

foramen magnum: opening in the occipital bone of the skull

conus medullaris: tapered, lower end of the spinal cord.

Question 9

types of cells in the brain and their qty and function

Answer 9

neurons vs glial cells

neurons = structural and functional unit of the nervous system; conduct and generate impulses

glial cells = are non-conducting, support (transport o2, nutrients, waste products) and protect the neurons. IT HAS 10X THE NUMBER VS NEURONS

Question 10

cell body of neuron and the associated organelles and structures

Answer 10

cell body of neuron is called the soma

contains nucleus, various cytoplasmic organelles, cytoskeletal elements (eg actin) and inclusions

golgi complex

Question 11

organelles and structures in an axon

Answer 11

axon arise from the axon hillock in the cell body

cytoplasm (axoplasm) lacks ribosomes, RER, and golgi apparatus
= unable to synthesise new proteins or degrade old ones
= materials must be transported back and forth

Question 12

fast and slow components of the axon

Answer 12

fast (50-400mm/day) = transports cytoplasmic proteins and macromolecules required for metabolic and synaptic activity

slow (1-4mm/day) = transports cytoskeletal components

Question 13

anterograde and retrograde transport in axon

Answer 13

forward (cell body to axon terminal)

vs

backwards (from axon terminal to cell body) = for movement of waste materials, carried to cell body for degradation.

Question 13

what does the dendrite contain

Answer 13

all cytoplasmic components found in the cell body except the golgi apparatus

Question 14

what does the plasmalemma contain?

Answer 14

voltage gated ca2+ channels

Question 15

length of the synaptic cleft?

Answer 15

20-40nm wide space between the pre and post synaptic membrane.

Question 16

difference between excitatory vs inhibitory synapse in movement of ions

Answer 16

EXCITATORY: binding of neurotransmitter leads to opening of Na+ channels = depolarisation
eg binding of glutamate to AMPAR and NMDAR receptors

INHIBITORY:
binding of neurotransmitter leads to opening of K+ and Cl- channels = hyperpolarisation
eg binding of GABA to GABA-A receptors

Question 17

types of glial cells

Answer 17

astrocytes
oligodendrocytes
microglia

Question 18

percentage, shape, function of astrocytes (and type)

Answer 18

25%

largest of neuroglial cells

have numerous processes with expanded end feet (pedicles) terminating on capillaries or on the pia mater. *(blood brain barrier)

fibrous: found in white matter. long, spindly processes with few branches

protoplasmic: found in grey matter. thick, lightly branched process. closely apposed to neuron cell bodies

FUNCTION:
- regulate the composition of the intercellular environment and the entry of substances into it (water transport, excess transport = cerebral edema)
- secretion of nerve growth factors.
- structural support to neurons and synapses
- metabolism of neurotransmitters (glutamate-glutamine shuttle) (tripartite system) (takes up excess neurotransmitter from NMJ, metabolism and recycles it for pre-synaptic transmitter > transported back)
- mediate the exchange of nutrients and metabolites between blood and neurons. pedicles can expand or narrow blood vessels.
- scar formation caused by astrocytes

Question 19

percentage, shape, function of oligodendrocytes

Answer 19

60-80%

in white matter: predominant neuroglial cell type
- produce myelinated fibres (ONLY IN THE CNS)

gray matter: function as satellite cells for neuron cell bodies.

OTHERS:
express Nogo-A (myelin associated neurite-outgrowth inhibitor)

Question 20

percentage, shape, function of microglia

Answer 20

5-10%
enlarge and become mobile after injury to the CNS.

• antigen presentation
• immunocompetent cells
• brain macrophages, phagocytosis
• secrete proinflammatory cytokines, chemokines,

Question 21

what cell marker used to identify oligdendrocytes

Answer 21

CNPase

Question 22

role of Nogo-A

Answer 22

inhibition of axonal regeneration following injury and ischemia in the CNS. = antibodies to nogo-A may help with neurodegenerative recovery

Question 23

implication of microglia in disease

Answer 23

may be implicated in Alzeimers, parkinsons, cerebral ischemia

Question 24

composition of PNS?

Answer 24

neuron processes neuroglia cells (Schwann cells, satellite cells)

Question 25

structure of PNS?

Answer 25

bundles (fascicles) of nerve fibres (axons) surrounded by myelin sheaths or schwann cells around the nerve: endoneurium (thin reticular layer, consist of Schwann cells) around the fascicle: perineurium (dense connective tissue) around the entire merve: epineurium (connective tissue)

Question 26

difference between oligodendrocytes and schwann cells in formation of myelin sheath

Answer 26

oligodendrocyte form myelin sheath around portions of several axons schwann cells form myelin sheath on ONLY ONE axon. it also spins around the nerve axon

Question 27

what is peripheral ganglion?

Answer 27

ganglia are encapsulated collection of neuron cell bodies located outside CNS contain satellite cells (forms a capsule of cells around the neuron cell bodies) and connective tissue elements along with neurons

Question 27

basilar artery (originate, supply)

Answer 27

two verterbal artery = join to form the basilar artery branch and supply to pons, cerebellum, and inner ear.

Question 28

vertebral artery (originate, supply)

Answer 28

from the subclavian artery in neck enter skull through the foramen magnum supply blood to spinal cord, medulla, and cerebellum.

Question 29

posterior cerebral arteries

Answer 29

basilar artery divides into posterior cerebral arteries supply to the midbrain, medial aspect of the occipital lobe, base of the temporal and occipital lobe.

Question 30

internal carotid arteries (originate, supply, divides into...)

Answer 30

from the common carotid artery enters skull through carotid canals situated within the cavernous sinus divides into anterior cerebral and middle cerebral anterior cerebral passes through medial longitudinal fissue and sweeps back to the parieto-occipital sulcus - supplies medial surface of hemisphere except medial aspect of the occipital lobe. middle cerebral passes through the lateral fissue and supplies most of the lateral surface of the hemisphere (frontal, parietal, temporal, occipital)

Question 31

circle of willis

Answer 31

May help to supply blood to the opposite side, in cases of slow occlusion of an artery on one side [the communicating arteries have time to enlarge, to accommodate the increased blood flow]. joined together by posterior and anterior communicating

Question 32

brain cardiac output

Answer 32

uses 15-20% of the TOTAL cardiac output despite only being 2% of total body weight

Question 33

subdural haemorrhage

Answer 33

rupture of cerebral vein as it drains into the superior sagittal sinus = slow seepage (venous pressure is low) = expanding hematoma presses on the brain = dizzy, headache, apathy, confusion, falling, drwosiness. subdural hemorrhage

Question 34

where does blood from the brain drain out of?

Answer 34

SUPERFICIAL ASPECT: superior sagittal sinus > transverse sinus > sigmoid sinus INFERIOR part of brain: transverse sinus AND superficial middle cerebral vein - superficial middle cerebral vein > cavernous sinus CENTRE: deep cerebral veins > venous sinus > transverse sinus > sigmoid sinus OVERALL: internal jugular vein

Question 35

CSF properties

Answer 35

Cerebrospinal fluid (CSF) is a clear fluid that acts as a protective "liquid cushion" around the brain and spinal cord by absorbing shock waves from blows and falls. - also helps to remove metabolites from the brain since there are no lymphatic channels.

Question 36

CSF production and movement

Answer 36

- produced by choroid plexus in the cerebral ventricles > 3rd ventricle (via cerebral aqueduct) > 4th ventricle > bathe the entire brain and spinal cord. absorbed into superior sagittal sinus by arachnoid granulations