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Flashcards in General Neurophysiology Deck (27):
1

most of the CSF is made by ___ the rest is made by whatq

choroid plexus
rest made by tissue that lines the ventricles and blood vessels

2

2 stage process of making CSF

1) passive filtration of serum: plasma loses proteins and fluid filtered into space

2) HCO3, Cl, and K concentrations controlled by channels on epithelial cells
awauporins also exist

3

molecules that end up in equal or near so concentrations in both plasma and CSF

Na+, Cl-, and HCO3

4

concentration in CSF greater than plasma

Mg++
Co2

5

concentration greater in plasma than CSF

K+
Ca++
protein
glucose

6

absorption of CSF is proportional to _____

intracranial pressure
-at pressure below 68 = no absorption
-normal pressure = 112
-increased pressure causes damage to neurons

7

obstructive hydrocephalus

obstruct ability of CSF to get to arachnoid villi

8

non-obstructive hydrocephalus

process of absorption of CSF is impaired not the ability to get there

9

how does CSF get out

enters arachnoid villi then the venous sinuses by bulk flow

10

blood brain barrier passive diffusion molecules

H20, CO2, and O2
-free steroid hormones (most proteins are bound and cannot cross)

11

getting energy to neurons

glucose is main source
-GLUT1 transporter, non insulin dependent
2 forms:
55K on capillaries
45K on astroglia

12

why is the amount of glucose lower in the CSF than plasma

55k and 45k system can be saturated

13

transporter that moves ions from CSF to blood
-expression tied to and signal from
-related to concentration of what

Na+/K+/2Cl-
-expression tied to endothelin 1 and 3
-production tied to signal from astrocytes
-may be related to concentration of K+ in CSF

14

many drugs do cross BBB but are moved back to blood via ____ making them ineffective

P-glycoprotein

15

BBB function

maintain electrolyte composition
-particularly related to K+ and Vm

protection from toxins

prevent escape of NTs

16

where is an area in the brain that we want exposed to the blood and how does this occur

circumventricular organs
capillaries do not have tight junctions between endothelial cells

17

4 regions that fall into circumventricular organ category

1) posterior pituitary: release hormones into blood
2) area postrema: vomiting
3 and 4) OVLT: body water/thirst/blood volume control (angiotensin)

18

sympathetic innervation to cerebral circulation

NPY and norep
a-adrenergic receptors
leads to constriction when systemic CO/BP increases

19

parasympathetic cerebral circulation

Ach
VIP
PHM-27

-cause vasodilation

20

sensory innervation of cerebral circulation is tied to ____ and NTs released are

distension
Substance P
Neurokinin A
CGRP

-all cause dilation
-extremely sensitive to torsion/manipulation-->lead to pain

21

what happens from a lumbar puncture and CSF loss

lose CSF in brain area so it is heavier and simple motion can cause pain and headache due to torsion of blood vessels

-activation of those afferents will also cause vasodilation and increased blood flow

22

cerebral blood flow is under ___ control (_____ ____) dictates where in brain blood will go

local
oxygen consumption

23

as intracranial pressure goes up venous outflow _____ leads to ___

is obstructed
leads to reduced arterial flow

24

cerebral blood flow is strongly ____ which means what

autoregulated
-held constant over wide range of systemic blood pressures

25

increased systemic blood pressure causes blood vessels of brain to ____ from ___

constrict from sympathetic stimulation

26

a decrease in brain perfusion causes what

activate vasomotor centers and increase systemic BP
-consequence: systemic blood pressure can be driven to very high levels in order to perfuse the brain

27

what might increase the intracranial pressure?

hydrocephalus of any variety
edema
bleeding within skull