Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
47 Cards in this Set
- Front
- Back
|
Schwann cells |
PNS, myelination |
|
|
Satellite cells |
PNS, support cell bodies (protective coat) |
|
|
Oligodendrocytes |
CNS, myelination |
|
|
Microglia |
CNS, phagocytes |
|
|
Astrocytes |
CNS, most abundant ; regulate nutrition and ion concentration ; form the blood brain barrier |
|
|
Ependymal cells |
CNS, lines ventricles ; creates CSF |
|
|
What is the blood brain barrier? |
protects toxins in blood from reaching brain cells |
|
|
What can pass through BBB? |
Oxygen, CO2, organic molecules, ions / polar molecules |
|
|
What CANNOT pass through BBB? |
metabolic wastes ; most drugs (challenge for brain diseases) ; proteins ; non-essential amino acids |
|
|
How is movement facilitated through BBB? What movement is restricted? |
Transcellular movement allowed ; paracellular movement restricted |
|
|
What do astrocytes do? |
secrete regulatory molecules to produce: tight junctions ; carrier proteins ; ion channels ; enzymes to destroy toxins |
|
|
Charges associated with resting membrane potential |
Inside cell is more negative, outside cell is more positive |
|
|
Excitability |
ability to change membrane potential |
|
|
Irritability |
ability to receive and respond to a stimulus |
|
|
Resting membrane potential charge |
-70 mV |
|
|
Action potential threshold (mV) |
-55mV |
|
|
List steps occuring if threshold is reached |
depolarization ; repolarization ; hyperpolarization ; recovery |
|
|
Ligand gated channels |
opens in response to tiny molecules binding |
|
|
Voltage gated channels |
open in response to voltage changes (during depolarization) |
|
|
Thresholds for Na+ and K+ voltage gated channels to open |
Na+: -55mV ; K+: +30mV |
|
|
Events during Depolarization |
voltage gated channels open; influx of Na+ ; -55 mV - +30mV ; positive feedback |
|
|
Events during repolarization |
Voltage gated Na+ channels inactivated ; decrease in Na+ permeability ; voltage gated K+ channels open ; efflux of K+ |
|
|
Why does hyperpolarization occur? |
K+ voltage gated channels are slow to close ; overall charge overshoots from -70mV to -85mV |
|
|
What does increasing stimulus intensity do? |
Increases frequency of action potentials |
|
|
Absolute refractory period |
neuron cannot respond to stimuli (due to inactivation of Na+ channels) ; makes AP unidirectional |
|
|
relative refractory period |
second AP can be generated if a stronger stimulus is applied to overcome efflux of K+ |
|
|
Saltatory conduction |
impulses leaps from node to node (Nodes of Ranvier) ; channels only present at nodes |
|
|
If presynaptic neuron signals...it's called.... (dendrite ; cell body ; axon) |
axodendritic ; axosomatic ; axoaxonic |
|
|
Type of Synapse for cardiac / smooth muscles vs synapse for skeletal muscles |
Electrical synapse (connexion proteins) ; chemical synapse |
|
|
In a chemical synapse, transmission occurs through ... and neurotransmitters are released from ... |
synaptic cleft ; terminal boutons |
|
|
Events occuring when AP reaches synaptic terminal |
1. AP reaches terminal bouton 2. Voltage gated Ca2+ channels open (influx of Ca2+) 3. Ca2+ binds to synaptotagmin 4. Vesicles with NT arrive at plasma membrane via 3 SNARE proteins 5. Ca2+ synaptotagmin displaces parts of SNARE ; vesicles fuse 6. vesicles release NTs through pores |
|
|
EPSP |
Opening of Na+ or Ca2+ channels on postsynaptic neuron ; depolarization ; moving membrane closer to threshold |
|
|
IPSP |
opening K+ or Cl- channels ; hyperpolarization of postsynaptic neuron ; brings membrane farther from threshold |
|
|
Relationship between EPSP and action potential amplitude |
action potential cannot change its amplitude; EPSP can ; creates graded potentials |
|
|
G-protein coupled channels |
receptor is separate from protein that serves as ion channel |
|
|
G-protein subunits |
alpha, beta, gamma |
|
|
process of g-protein coupled channels opening / closing |
1. ACh binds to dissociate alpha subunit 2. Alpha or beta-gamma diffuses through membrane to ion channels 3. Channel opens or closes temporarily 4. subunits dissociate from channel and closes or opens again (return to resting state) |
|
|
Acetylcholine's role |
Ligand channels: directly opens when it binds to receptor G-protein channels: indirectly opens when it binds to receptor - excitatory or inhibitory |
|
|
Cholinergic receptors |
nictonic and muscarinic |
|
|
Nicotinic ACh receptors |
ligand gated; opens directly upon binding of ACh; found at motor end plate of skel. muscle cells |
|
|
Muscarinic ACh receptors |
G-protein coupled reaction; found in smooth and cardiac muscles |
|
|
EPSPs and IPSPs in PNS vs CNS |
PNS EPSPs: nicotinic receptors PNS IPSPs: muscarinic OR nicotinic CNS EPSPs: muscarinic and nicotinic CNS IPSPs: muscarinic |
|
|
Monoamines: catecholamines (what are they / what do they do) |
1. Dopamine: dopaminergic neurons found in midbrain ; motor control, emotional reward 2. Norepinephrine: arousal in CNS ; used in sympathetic neurons in PNS |
|
|
Serotonin |
neurons located in raphe nuclei (mid brainstem) ; mood, behavior, appetite, cerebral circulation |
|
|
Amino Acids: Excitatory vs Inhibitory |
Excitatory: Glutamic acid, Aspartic acid Inhibitory: GABA, Glycine |
|
|
What does Glutamate do? |
Glutamic acid: produces majority of EPSPs in brain ; binds to ligand-gated receptors |
|
|
What do inhibitory amino acids do? |
GABA: most common NT in brain; opens Cl- channels; involved in motor control ; degeneration leads to Huntington's Glycine: produces IPSPs ; opens Cl- channels |
