physiology of the eye 1

Question 1

what is cerebrospinal fluid produced by?

Answer 1

secretory epithelium of choroid plexus

Question 2

where is CSF formed?

Answer 2

in ventricles and circulates in subarachnoid space then absorbed into venous circulation

Question 3

what does CSF supply?

Answer 3

water
amino acids
ions

Question 4

what does CSF remove?

Answer 4

metabolites/waste

Question 4

what are the 3 major functions of CSF?

Answer 4

mechanical protection
homeostatic function
circulation

Question 5

what is the mechanical protection?

Answer 5

shock-absorbing that protects brain tissue, brain floats inside cavity

Question 6

what is the homeostatic function?

Answer 6

pH of CSF affects pulmonary ventilation and cerebral spinal blood flow
transports hormones

Question 7

what is the circulatory function?

Answer 7

medium for minor exchange of nutrients and waste products between blood and brain tissue

Question 8

what is clinical CSF obtained by and why?

Answer 8

lumbar puncture
aids in diagnosis of brain, meninges and spinal chord

Question 9

what can conditions that cause accumulation of CSF cause?

Answer 9

serious neurological defects

Question 10

how many ventricles are in the brain?

Answer 10

4

Question 11

where are the ventricles of the brain located?

Answer 11

2 lateral -> in cerebrum, one of each side (at front)
3rd -> in diencephalon in the middle of the brain
4th -> in hindbrain, at the back of pons in the middle of medulla oblongata

Question 12

during embryonic development of the brain what dies the NS consist of at 3 weeks?

Answer 12

tube - neural canal

Question 13

what does the cavity of the neural canal give rise to in adult brain’s and the spinal cord?

Answer 13

brain - ventricles
SC - central canal

Question 14

where does the choroid plexus develop?

Answer 14

cells in walls of ventricles

Question 15

choroid cells are specialized in secreting cells that produce what?

Answer 15

CSF

Question 16

how is the choroid fissure formes?

Answer 16

developing arteries invaginate the roof of the ventricle

Question 17

how is the choroid plexus formed?

Answer 17

involuted ependymal cells along with vessels enlarge into villi

Question 18

what is the choroid plexus of each lateral ventricle responsible for?

Answer 18

CSF production

Question 19

in the adult brain, where is the choroid plexus found?

Answer 19

3rd
4th
lateral ventricles

Question 20

what cells line the ventricles?

Answer 20

ependymal cells

Question 21

CSF secretion involves transport of which ions across what?

Answer 21

Na+Cl- and HCO3-
sodium chloride and bicarb
across epithelium from blood to CSF

Question 22

where is the basolateral membrane closest to?

Answer 22

arteries

Question 23

where is the apical membrane closest to?

Answer 23

veins

Question 24

is production of CSF active or passive?

Answer 24

active

Question 25

what is the intraventricular foramina (of Monroe)?

Answer 25

lateral ventricles to 3r ventricle

Question 26

what is the cerebral aqueduct (of Sylvius)?

Answer 26

3rd ventricle to 4th

Question 27

what is the foramen of megendie?

Answer 27

median aperture - 4th ventricle to subarachnoid space

Question 28

what is the foramina of Luschka?

Answer 28

lateral apertures - 4th ventricle to subarachnoid space

Question 29

explain CSF circulation.

Answer 29

CSF formed in choroid plexuses of each lateral ventricle and flows to 3rd ventricle through 2 openings - IV foramina more CSF added by choroid plexus in roof of 3rd ventricle flows through aqueduct of midbrain into 4th ventricle another choroid plexus in 4th ventricle adds more CSF CSF enters subarachnoid space through openings in roof of 4th ventricle (1 med, 2 lat apertures) circulates in central canal of SC 500ml produced and absorbed every day - constant

Question 30

directional flow through ventricular system into subarachoid space between which mater?

Answer 30

pia and dura mater

Question 31

what does CSF return to venous blood through?

Answer 31

arachnoid granulations into superior sagittal sinus (SSS)

Question 32

what restricts blood supply to majority of the brain?

Answer 32

blood-brain barrier

Question 33

what does the brain interstitial fluid do?

Answer 33

makes up final portion of CSF and drains to CSF through perivascular spaces

Question 34

what cells in brain capillaries are at site of BBB?

Answer 34

endothelial cells

Question 35

what parts of the brain do not have BBB?

Answer 35

circumventricular organs and pineal gland

Question 36

what is the role of BBB?

Answer 36

protects against infection and toxins main obstacle for drug delivery

Question 37

what are some pathologies of ventricles, choroid plexus and CSF?

Answer 37

tumours ventricular haemorrhage hydrocephalus IIH/pseudotumor cerebri

Question 38

what types of tumours can you get?

Answer 38

colloid cyst (found at IV foramen) ependymomas (ependymal cells lining ventricles) choroid plexus tumours

Question 39

what is ventricular haemorrhage and what are the types?

Answer 39

accumulation of blood in ventricles epidural -> arterial bleed between skull and dura subdural -> venous bleed between dura and arachnoid subarachnoid haemorrhage

Question 40

what is hydrocephalus?

Answer 40

accumulation of CSF in ventricular system or around brain (obstruction or overproduction) enlargement of one or more ventricles and increase CSF pressure

Question 41

what is papilloedema?

Answer 41

optic disc swelling due to increased intracranial pressure transmitted to subarachnoic space urrounding optic nerve