Visual system & cerebrospinal fluid (CSF)

Question 1

pupillary light reflex

Answer 1

Controls the diameter of the pupil, in response to the intensity of light that falls on the retina

Question 2

Cerebrospinal fluid (CSF)

Answer 2

• Clear, colorless, and transparent fluid that circulates through the ventricles of the brain, subarachnoid space, and central canal of the spinal cord
• Part of the extracellular fluid (ECF)

Question 3

composition of CSF

Answer 3

• Watery solution
• Less protein and different ion concentrations than plasma
• Constant volume

Question 4

function of CSF

Answer 4

Protection: protects the brain from damage by “buffering” the brain

Excretion of waste products: the one-way from from the CSF to the blood takes potentially harmful metabolites, drugs, and other substances away from the brain

Regulation of cranial content volume: it is very important because the brain may be affected if the volume is increased. It is prevented by greater absorption of CSF to give space for the cranial contents

Question 5

what forms the CSF?

Answer 5

choroid plexuses

Question 6

where does the CSF flow?

Answer 6

• flows through the ventricles and into the subarachnoid space via the median and lateral apertures. Some CSF flows through the central canal of the spinal cord
• CSF flows through the subarachnoid space

Question 7

what are 2 applications? explain each.

Answer 7

diagnostic: CSF analysis for detection of pathological conditions

Therapeutic: central neuraxial block such spinal anesthesia ( also called subarachnoid anesthesia), and epidural anesthesia

Question 8

what are the 2 abnormalities with the flow of CSF?

Answer 8

Hydrocephalus: the abnormal accumulation of CSF in the skull associated with the enlargement of head

Hydrocephalus along with increased intracranial pressure causes headache and vomiting: severe conditions leads to atrophy of brain, mental weakness, and convulsions

Question 9

blood brain barrier (BBB)

Answer 9

Selective barrier:
- Allows nutrients to move by facilitated diffusion
- Allows any fat-soluble substances to pass, including alcohol, nicotine, and anesthetics

• Helps maintain a stable environment of the brain
• Separates neurons from some blood borne substances

Question 10

what is the BBB formed by?

Answer 10

• Continuous endothelium of capillary walls
• Basal lamina
• Feet of astrocytes

Question 11

In the myopia images are formed_______.

On the retina
In the front of the retina
Behind the retina

Answer 11

in the front of the retina

Question 12

Activation of photoreceptor by light affects the ______.

Calcium channel
Potassium channel
Sodium channel

Answer 12

sodium channel

Question 13

CSF is formed by which cell and where?

Ependymal cells in cortex
Ependymal cells In hindbrain
Ependymal cells In ventricles

Answer 13

Ependymal cells In ventricles

Question 14

CSF contains less amount of sodium than potassium?

True
False

Answer 14

false

Question 15

To diagnose a neuronal microorganism which site do you prefer to collect CSF:

Directly from brain
Lumbar puncture
From heart

Answer 15

Lumbar puncture