Physiology

Question 1

What is cerebrospinal fluid?

Answer 1

• clear liquid
• composed of water
• Na+ and Cl-
• very little protein

Question 2

What are the 3 functions of CSF?

Answer 2

• Mechanical protection
• Homeostatic function
• circulation

Question 3

How do you clinically analyse the CSF?

Answer 3

• Lumbar puncture

- L4/5

Question 4

What is the ventricles of the brain embryologically formed from?

Answer 4

• neural tube

Question 5

What is the choroid fissure?

Answer 5

• developing arteries invaginate the roof of the ventricles

Question 6

Where is the choroid plexus found?

Answer 6

• lateral ventricles (2)
• 3rd ventricle
• 4th ventricle

Question 7

What is lower in CSF compared to blood?

Answer 7

• protein
• glucose
• potassium

Question 8

What is in higher concentrations in the CSF compared to blood?

Answer 8

• Na+

- Cl-

Question 9

What produces CSF?

Answer 9

• Ventricles

- ependymal cells - choroid plexus

Question 10

What is the connection between the lateral ventricles and the 3rd ventricle called?

Answer 10

• intraventicular framing of monroe

Question 11

What is the connection between the 3rd and 4th ventricle called?

Answer 11

• cerebral aqueduct of sylvius

Question 12

Where is the final destination of CSF

Answer 12

• Subarachnoid space

- venous sinuses through arachnid granulations

Question 13

What is the function of the blood brain barrier?

Answer 13

• protects the brain from common bacterial infections and toxins

Question 14

Define hydrocephalus?

Answer 14

• accumulation of CSF in the ventricular system
• subsequent enlargement of one or more ventricles
• increase in pressure

Question 15

Define papilloedema?

Answer 15

• optic disk swelling due to increased intracranial pressure transmitted to the subarachnoid space surrounding the optic nerve

Question 16

What are the symptoms of papilloedema?

Answer 16

• enlarged blind spot

- blurring or less of vision

Question 17

What would papilloedema appear like in the fundoscope?

Answer 17

• bulging of the optic disk

Question 18

Where is the aqueous humour found?

Answer 18

• between the cornea and lens

Question 19

Name a powerful antioxidant in the aqueous humour?

Answer 19

• ascorbate

Question 20

Aqueous humour production is energy ___dependant/independant___

Answer 20

• dependant

Question 21

Where does the aqueous humour finally drain into?

Answer 21

• scleral venous sinus

- iridocorneal angle

Question 22

What is responsible for the production of the ions in the aqueous humour?

Answer 22

• carbonic anhydrase

Question 23

What drug class can be used to reduce intraocular pressure as a result of a build up of aqueous humour?

Answer 23

• carbonic anhydrase inhibitors

Question 24

What is the symptoms of open angle glaucoma?

Answer 24

• gradual reduction of the peripheral vision

Question 25

What is the name given to the field of vision which is the overlap between the right and left visual field?

Answer 25

- binocular visual field

Question 26

superior visual field is perceived by the _____

Answer 26

- left cortex

Question 27

Where is the processing dominant neutrons in the cortex found?

Answer 27

- level 4C

Question 28

What is the role of photoreceptors?

Answer 28

- converts electromagnetic radiation to neural signals

Question 29

Where are cones found?

Answer 29

- fovea

Question 30

Where are rods found?

Answer 30

- distributed along the length

Question 31

At rest (dark) what is the membrane potential of the photoreceptors?

Answer 31

- depolarised

Question 32

When activated (light) what is the membrane potential of the photoreceptors?

Answer 32

- hyperpolarised | - more negative

Question 33

Explain why when it is dark the membrane potential is depolarised?

Answer 33

- Na+ channel open - cGMP present - depolarised

Question 34

List the steps that occur when light hits the photoreceptors?

Answer 34

- light converts 11 cis-retinal to all trans-retinal - signals opsin - G protein transduction - PDE hydrolyses cGMP - reduced concentration of cGMP - closes Na+ channels - hyperpolarisation

Question 35

Define visual acuity

Answer 35

- ability to distinguish two nearby points | - determined largely by photoreceptors spacing and refractive power

Question 36

Where are rods less likely to be found?

Answer 36

- fovea

Question 37

Where are cones most likely to be found in greatest numbers?

Answer 37

- fovea

Question 38

Short wavelength cones see what colour?

Answer 38

- blue

Question 39

Medium wavelength cones see what colour

Answer 39

- green

Question 40

Long wavelength cones see what colour

Answer 40

- red

Question 41

What returns CSF to the superior sagittal sinus?

Answer 41

- arachnoid granulations

Question 42

What is the activated form of 11-cis retinal?

Answer 42

- all trans-retinal

Question 43

__Rods / Cones___ have high convergence?

Answer 43

- rods