Karius- Maintenance of CNS Environment

Question 0

Which ions are in greater concentration in the CSF?

Answer 0

Mg (d/t NMDA receptors), CO2 (from neuron metabolism)

Question 1

Which ions are near equal across CSF and plasma?

Answer 1

Na, Cl, HCO3

Question 2

which ions are in less concentration in CSF than plasma?

Answer 2

K (changes excitability), Ca2+ (toxic in hi conc.), proteins (not allowed in), glucose (because the neurons use all of it)

Question 3

Is production or absorption proportional to intracranial pressure?

Answer 3

absorption

Question 4

why is increased pressure in the skull can cause problems because?

Answer 4

myelinated axons don’t like to be compressed; decrease function

Question 5

where and how is CSF absorbed?

Answer 5

arachnoid villi; bulk flow and pinocytosis (just a little bit)

Question 6

what passively diffuses across BBB?

Answer 6

water, CO2, O2, free steroids (rare, most protein bound)

Question 7

Which ion transporter is tied endothelin 1 and 3?

Answer 7

Na/K/2Cl

Question 8

what does endothelin do?

Answer 8

vasoconstriction (opposite NO)

Question 9

what are the 4 circumventricular organs? functions?

Answer 9

1- posterior pituitary: hormones
2- area postrema: vomiting (chemotactic trigger zone)
3- OVLT & 4- subforinical organs: osmoregulation

Question 10

what are the sympathetic neurotransmitters of cerebral blood vessels?

Answer 10

NE and NPY

Question 11

what blood vessels does parasympathetic activation in cerebral blood flow focus on?

Answer 11

large vessels

Question 12

what are the neurotransmitters involved in parasympathetic activation in cerebral blood flow?

Answer 12

Ach, VIP (vasoactive intestinal peptide), & PHM (from pre-pro VIP)

Question 13

what neurotransmitters are involved in sensory innervation of distal blood vessels in brain? function?

Answer 13

Substance P, Neurokinin A, CGRP; dilate

Question 14

what causes HA and migraines?

Answer 14

torsion or manipulation of blood vessels

Question 15

what do blood vessels do if there is decreased CSF volume?

Answer 15

dilate in order to try to compensate for decreased intracranial pressure

Question 16

what will happen to cerebral blood flow in increased intracranial pressure?

Answer 16

increased pressure d/t obstructed venous outflow leads to decreased arterial pressure

Question 17

what is autoregulation?

Answer 17

blood flow to brain is held constant over wide range of BPs (60-140); increases after 140, range is extended with sympathetic activation

Question 18

what does decreased perfusion to the brain cause? what can results lead to?

Answer 18

activation of vasomotor centers, increases BP, increases intracranial pressure; hydrocephalus, edema, bleeding