General Neurophysiology

Question 1

Blood Pressure=?

Answer 1

(HR x Stroke volume) x Total peripheral resistance (TPR)

Question 2

Where do the afferents from the baroreceptors synapse?

Answer 2

Nucleus Tractus Solitarius (NTS)

Question 3

The secondary afferents from the NTS do what to the depressor region (parasympathetics) and what to the pressor region (sympathetics)?

Answer 3

Stimulate depressor and inhibit presser

Question 4

Blood flow to the brain is under ______ control

Answer 4

Local

Question 5

Why is baroreceptor/central control unable to override local control mechanisms in the brain?

Answer 5

Largely due to reduced/absent sympathetic innervation of the vasculature

Question 6

Can CO2 and hydrogen cross the blood brain barrier?

Answer 6

CO2 CAN

H+ CANNOT

Question 7

What is ventriculomegaly and what can cause it?

Answer 7

An enlargement of the ventricles as a result of hydrocephalus but there is also a congenital form which is not related to increased intracranial pressure

Question 8

What things have about the same concentration in CSF and plasma?

Answer 8

• Na
• Cl
• HCO3

Question 9

What things are greater in concentration in the CSF than in plasma?

Answer 9

• Mg
• PCO2
• creatine

Question 10

What things are lowing in concentration in the CSF than in plasma?

Answer 10

• K+
• Glucose
• Ca
• Protein
• Inorganic phosphate
• Urea
• Uric acid
• Cholesterol

Question 11

pH of CSF?

Answer 11

7.33 (7.4 in plasma)

Question 12

What foreman does CSF travel through after it leaves the ventricle?

Answer 12

• Magendie

- Luschka

Question 13

What is the mechanism by which the mesothelial cells of the arachnoid villi take up CSF?

Answer 13

Bulk pressure driven flow and also Pinocytosis

Question 14

Below what pressure does absorption of CSF stop?

Answer 14

68 mm CSF

Question 15

What is hydrocephalus?

Answer 15

accumulation of excess CSF and results from a mismatch of production and reabsorption

Question 16

What are the general causes of hydrocephalus?

Answer 16

• Decreased absorptive capacity of the arachnoid villi (external or communicating)
• Blockage of either foreman or somewhere else in the ventricular system (Internal or non communicating)

Question 17

What is the transporter that allows glucose to enter the CSF from the blood?

Answer 17

GLUT1 (not insulin dependent)

Question 18

What is the Na/K/2Cl transporter stimulated by?

Answer 18

ET-1 and 3

Question 19

Areas of the brain that do NOT have a tight blood brain barrier?

Answer 19

• Posterior pituitary (hormone release into blood
• Area Postrema (chemotactic trigger zone that initiated vomiting from blood-borne chemicals
• OVLT (osmoreceptor for ADH) thirst
• Subfornical organ (Angiotensin acts here to initiate thirst)

Question 20

Sympathetic innervation of cerebral vasculature

Answer 20

• Post ganglionics from superior cervical ganglion
• Norepinephrine and NPY
• ALPHA- adrenergic receptors for vasoconstriction
• Large arteries

Question 21

Why does a lumbar puncture or decreased CSF cause a headache?

Answer 21

Distal arteries are innervated by nociceptors activated by torsion and reduced intracranial pressure reduced buoyancy which makes the brain heavier and normal motion can cause torsion

Question 22

At any given moment how much CSF is in the central nervous system?

Answer 22

150 ml

Question 23

Which form of GLUT1 is on capillaries?

Answer 23

55K

Question 24

which form of GLUT1 is on astroglia?

Answer 24

45k

Question 25

Do the GLUT1 transporters need insulin?

Answer 25

NOOOOOOOO!

Question 26

When a drug crosses the blood brain barrier, what pumps it back to the blood?

Answer 26

P-glycoprotein

Question 27

Parasympathetics to cerebral vasculature?

Answer 27

• Large vessels
• Ach
• VIP and PHM-27
• vasodilation

Question 28

What are the substances that cause dilation of smaller vessels in response to torsion and nociception?

Answer 28

• Substance P
• Neurokinin A
• CGRP