Physiology

Question 1

main component of CSF

Answer 1

water

Question 2

what produces CSF?

Answer 2

secretory epithelium of the choroid plexus

Question 3

how much ml of CSF is made per day?

Answer 3

500ml

Question 4

how much CSF is present in the CNS?

Answer 4

150ml

Question 5

how many choroid plexuses are there and where are they located?

Answer 5

4

the ventricles of the brain

Question 6

explain the direction CSF travels in starting from its production

Answer 6

lateral ventricles
via interventricular foramina to 3rd ventricle
via aqueduct to 4th ventricle
subarachnoid space
venous circulation

Question 7

3 main functions of CSF

Answer 7

protect brain tissue
maintains homeostasis
create a medium between BBB

Question 8

how is CSF tested clinically?

Answer 8

lumbar puncture

Question 9

what should normal CSF look like?

Answer 9

clear

colourless

Question 10

CSF has lots of proteins and antibodies T or F

Answer 10

F, has very little

Question 11

cause of hydrocephalus?

Answer 11

accumulation of CSF in the brain due to overproduction or obstruction

Question 12

what does the choroid plexus derive from embryologically?

Answer 12

cells in the walls of the ventricles

Question 13

what ventricles is choroid plexus found in?

Answer 13

3rd
4th
lateral (2)

Question 14

what is the choroid plexus?

Answer 14

networks of capillaries in walls of the brain ventricles

Question 15

what causes the secretion of cerebrospinal fluid?

Answer 15

ions eg Na needing to be transported from the blood

Question 16

why is the CSF mainly composed of water?

Answer 16

water crosses the membrane from the blood because ions have crossed (osmosis)

Question 17

what separates the lateral and third ventricles?

Answer 17

foramina of monroe

Question 18

what separates the 3rd and 4th ventricles?

Answer 18

cerebral aqueduct

Question 19

what makes up the final portion of CSF?

Answer 19

brain interstitial fluid

Question 20

what cells are the site of the blood brain barrier?

Answer 20

endothelial cells in brain capillaries

Question 21

3 layers of the blood brain barrier?

Answer 21

capillary endothelium
basal membrane
perivascular astrocytes

Question 22

main obstacle for drug delivery to the CNS?

Answer 22

BBB

Question 23

common location for a colloid cyst?

Answer 23

often at the interventricular foramen

Question 24

patient with headache and poor vision; no sign of hydrocephalus on CT but dos have increased CSF pressure?

Answer 24

idiopathic intracranial HT

Question 25

what is papilloedema?

Answer 25

optic disc swelling due to increased intracranial pressure

Question 26

what causes the visual loss in papilloedema?

Answer 26

subarachnoid space surrounds the optic nerve and when there is increased pressure there it will compress the nerve

Question 27

visual symptoms of papilloedema?

Answer 27

enlarged blind spot blurred vision visual obscurations loss of vision

Question 28

is Cl more concentrated in the blood or CSF?

Answer 28

CSF

Question 29

causes of papilloedema?

Answer 29

increased cranial pressure | inadequate CSF drainage

Question 30

what makes aqueous humour?

Answer 30

ciliary body

Question 31

where is the ciliary body?

Answer 31

lateral to the lens

Question 32

name the 2 layers covering the ciliary body?

Answer 32

pigment epithelium of the retina | non pigmented epithelium of the retina

Question 33

how to ions get to and from the pigmented and non pigmented epithelial cells

Answer 33

gap junctions

Question 34

what molecule is essential for aqueous humour present?

Answer 34

HCO3

Question 35

cause of the raised intraocular pressure in glaucoma?

Answer 35

imbalance between the rates of secretion and removal of aqueous humour

Question 36

what kind of signal does light have to be in order to be processed by the brain?

Answer 36

electrical

Question 37

where do the ganglion cell axons project to in the retina?

Answer 37

the forebrain

Question 38

what structures of the eye focus light on the retina?

Answer 38

cornea | lens

Question 39

list the 4 main regions of a photoreceptor

Answer 39

outer segment eg rod/cone inner segment cell body synaptic terminal

Question 40

is the resting Vm of photoreceptors more positive or negative than other neurons?

Answer 40

positive

Question 41

what effect does light have on the Vm of photoreceptors?

Answer 41

hyperpolarises it (makes it more negative)

Question 42

why is the Vm of a photoreceptor so positive?

Answer 42

cGMP gated Na channel is OPEN in the dark and closes when there is light

Question 43

main visual pigment in rods?

Answer 43

rhodopsin

Question 44

average current of a photoreceptor?

Answer 44

-29 to -40mV

Question 45

what does rhodopsin consist of?

Answer 45

retinal + opsin

Question 46

what does the retinal part of rhodopsin do?

Answer 46

activates transducin (GPCR) which activates cGMP to close Na channels

Question 47

what kind of vision do rods allow?

Answer 47

seeing in dim light

Question 48

what kind of vision do cones allow?

Answer 48

seeing in normal daylight

Question 49

do rodes or cones have higher convergence and why?

Answer 49

rods | want to have more sensitive (eg to light) than acute vision

Question 50

what does high convergence mean?

Answer 50

large spacing and number of cells to one ganglion

Question 51

where in the retina are rods located?

Answer 51

peripheral retina

Question 52

where in the retina are cones located?

Answer 52

centrally

Question 53

do cones or rods provide visual acuity?

Answer 53

cones

Question 54

what is retinotopy?

Answer 54

separation of the retina