Neurons and Synapses

schwann cells

• contains nodes of ranvier which accelerates action potential

what cells form a myelin sheath on axon

true

true or false: neurons w/o myselin sheaths are slower

schwann cells

statellite cell/ganglion gliocytes

two types of supporting cells in the peripheral nervious system

1. oligodenrocytes

2. microglia

3. astrocytes

4. ependymal cells

4 types of supporting cell in CNS

form myelin sheaths around axons of the CNS

what do oligodenrocytes do

phagocytose forgein and degenerated material

what do mircoglia

accelerates the circulation of CSF inside the ventricles of the brain

what do ependyma do?

replace gliosis

• when neurons die they prolieferate and fill the spaces previously occupied by neurons

• limits the influence of glutamate and GABA

• formation of blood brain barrier

• take glucose from blood → energy

what do astrocytes do?

oligodendrocytes

• around many axons instead of 1 

what forms myelin sheaths of the cns

absence of a continous neurilemma

why is regeneration limited in CNS?

barrier between cerebral capillary blood and the CSF

• lipid-soluble susbtances and freely cross

what is the blood brain barrier?

no

• L-DOPA must be used

can dopamine cross the bbb?

na+

cl- 

hco3

osmolarity 

CSF = Blood

K+

Ca2+ 

Glucose

Cholestrol

protein

CSF < blood

Mg2+

creatinine

CSF > blood

Ach= nuermuscular junctions, autonomic ganlia, parasympatheitc nerve

where are is Ach found?

sympathetic nerve ending  and CNS: hypothalamus

• stress

where is norepinephrine found and what does it do?

spinal cord

where is glcine found?

exitatory amino acid in CNS

• easier for the nueron to fire an action potential

what is glutamate?

gap junctions

• bidrectional 

• 6 parts called connexins

location: tryptophan

affect: mood, appetite, and sleep

sterenonin location and function

high: schizophrenia

low: parkinson’s disease

abnormality high and low dopamine leads to

GABA and glycine

inhibitory nuerotranmitters

• 36 amino acids

• regulation of energy balance, memeory, learning, and epilepsy

• aguments the vasoconstrictor effects of noradrenergic neurons

• release leptin and corticoptropin

what does neuropeptide y do?

satiates you

leptin?

increases appetite

crotisol?

elevated production of nitric oxide

what lets ppl avoid hypoxia?

neurons: transmit electrical signals found in grey matter

neuroglial cells: nonexctiable, surrounded and wrap neurons

difference between two main cell types

• do not divide: fetal neurons lose their ability to undergo mitosis

• high metabolic rate: require abudnant oxygen and glucose

what are the characteristics of neurons