Biopsych Exam 1 Flashcards
Parts of a neuron
- Presynaptic neuron
- myelin sheath
- nodes of ranvier
- axon
- axon hillock
- cell nucleus
- soma
- dendrites
basic components of a synapse
- composed of the axon terminal of one neuron, the synaptic cleft and dendrite of another neuron
- axon terminal sends the message (releases the neurotransmitter), relays it across the synapse, and the dendrite receives it and sends through the neuron
- synaptic cleft provides space for the chemical transmission of messages
what is the function of myelin sheath?
- fatty white matter
- coating along the axon
- keeps signal intact inside neuron (protective layer)
- increases speed of conduction by permitting flow of ionic current across the membrane
what cells produce myelin sheath?
CNS: oligodendrocyte
PNS: Schwann cell
What happens during resting (membrane) potential? What charge is inside of a neuron?
- Resting potential: an electrical charge along the membrane during inactive state (-65mV)
- Negative charge inside of a neuron during resting potential
At resting potential: - Higher concentration of potassium ions INSIDE the cell
- higher concentration of sodium ions OUTSIDE the cell
What is an ion distribution during resting potential?
- sodium, chloride, and calcium are concentrated outside the cell
- potassium and other anions are concentrated inside the cell
- this leads to a negative resting membrane potential
what is action potential?
the change in membrane potential when a neuron sends the signal down the axon
explain action potential step by step
depolarization:
1. action potential begins when the neuron receives a stimulus (from sensory input or other neurons)
2. if stimulus is strong enough to reach the threshold of excitation, it triggers a change in the membrane potential (enough sodium floods the cell and it becomes positively charged)
3. voltage-gated sodium channels open, sodium rushes into the neuron from the extracellular fluid
- influx of positively charged sodium ions rapidly depolarize the membrane; potassium leaves the cell which leads to repolarization
repolarization:
1. after reaching peak voltage, the voltage gated-sodium channels and voltage-gated potassium channels open
2. potassium ions (K+) exit the neuron moving from inside to outside
- the efflux of positively charged potassium ions restores the negative charge inside the neuron
- brings the membrane potential back towards its resting state
hyperpolarization:
1. sometimes the efflux of potassium ions overshoots the resting membrane potential causing the inside of the neuron to become more negative than the resting state
2. this occurs because the potassium channels remain open for a brief period even after the resting membrane potential is reached
types of synapses
- axo-dendritic
- axo-somatic
- axo-axonic
- dendro-dendritic
What do glial cells do
help support, connect, and protect the neurons of the central and peripheral nervous systems
what are the glial cells of the central nervous system
astrocyte, oligodendrocyte, microglia, and ependymal cells
what are the glial cells of the peripheral nervous system
satellite and schwann cell
what do the astrocyte and satellite cells do, where are they located?
- glial cells
- astrocyte: CNS
- satellite: PNS
- they provide structure to the cell, remove excess neurotransmitters, direct neural growth
- only astrocyte induced blood-brain barrier in the brain
what do oligodendrocyte and schwann cells do, where are they located?
- glial cells
- oligodendrocyte: CNS
- Schwann: PNS
- create myelin sheath
what does the microglia cell do and where is it located?
- glial cell
- CNS
- immune surveillance and phagocytosis
what does the ependymal cell do and where is it located?
- glial cell
- CNS
- create and circulate cerebrospinal fluid (CSF)
Types of nervous systems
- Peripheral nervous system (PNS)
- Central nervous system (CNS): spinal cord and brain
Which neurotransmitter is involved in schizophrenia?
- too much dopamine
Which neurotransmitters are involved in addiction?
- too much dopamine
- norepinephrine
- glutamate
- serotonin
- GABA
Which neurotransmitters are involved in Parkinson’s?
- not enough dopamine
- acetylcholine
- serotonin
Which neurotransmitters are classified as monoamines?
- Dopamine (DA)
- Norepinephrine (NE)
- Serotonin (5-HT)
Which neurotransmitters are classified as catecholamines?
- Dopamine (DA)
- Norepinephrine (NE)
What is a common precursor of all catecholamines?
- Tyrosine (amino acid)
- Serves as the starting point in the biosynthesis of catecholamines such as dopamine, norepinephrine, epinephrine
- All catecholamines are synthesized from tyrosine
How is dopamine synthesized
tyrosine, L-DOPA, dopamine
How is norepinephrine synthesized?
tyrosine, L-DOPA, dopamine, norepinephrine, (epinephrine)
How is serotonin synthesized?
tryptophan, 5-HTP, serotonin (5-HT)
How is GABA synthesized?
glutamine, glutamate, GABA
How is glutamate synthesized?
glutamine, glutamate
How is acetylcholine synthesized?
choline, acetyl-CoA, acetylcholine
vMAT
- vesicular monoamine transporter
- packages monoamines and puts them into the synaptic vesicle for release during neuronal signaling
- NT involved: DA, NE, 5-HT (monoamines)
vGLUT
- vesicular glutamate transporter
- packages glutamate and puts them into synaptic vesicles for release during
- NT involved: glutamate
vChAT or vAChT
- vesicular acetylcholine transporter
- packages glutamate and puts it into synaptic vesicles for release during neuronal signaling
- NT involved: acetylcholine
vGAT
- vesicular GABA transporter
- packages GABA and puts it into synaptic vesicles for release during neuronal signaling
- NT involved: GABA
DAT
- dopamine transporter
- located on presynaptic neuron
- regulates levels of dopamine in the synapse
- transports excess dopamine back into the presynaptic neuron (reuptake)
NT involved: dopamine
SERT
- serotonin transporter
- located on the presynaptic neuron
- regulates levels of serotonin in the synapse
- transports excess serotonin back into the presynaptic neuron (reuptake)
NT involved: serotonin
NET
- norepinephrine transporter
- located on the presynaptic neuron
- regulates the levels of norepinephrine in the synapse
- transports excess norepinephrine back into the presynaptic neuron (reuptake)
NT involved: norepinephrine
CHT
- choline transporter
- located on the presynaptic neuron
- regulates the levels of choline in the synapse
- transports excess choline back into the presynaptic neuron (reuptake)
- NT involved: norepinephrine
EAAT
- excitatory amino acid transporter
- located on the presynaptic neuron
- regulates the levels of excitatory neurotransmitters (glutamate) in the synaptic cleft
- transports excess glutamate back into the presynaptic neuron (reuptake)
NT involved: glutamate
GAT
- GABA transporter
- located on the presynaptic neuron
- regulates the levels of GABA in the synapse
- transports excess GABA back into the presynaptic neuron (reuptake)
NT involved: GABA
ionotropic receptors
- receptor protein that includes and ion channel that is opened when the receptor is bound by a neurotransmitter molecule
- typically ligand-gated ion channels though which ions pass in response to a neurotransmitter
- 4 or 5 subunits that assemble in the cell membrane
- contain an intrinsic ion channel that opens in response to NT or drug binding
- not coupled to second messengers
- fast
metabotropic receptors
- receptor protein that DOES NOT contain an ion channel, but when activated uses a second-messenger system to alter the functioning of the postsynaptic cell
- requires G proteins and second messengers to indirectly modulate ionic activity in neuron
- 1 subunit
- activate G proteins in response to NT or drug binding
- coupled to second-messengers
- slower
Where is cerebrospinal fluid made?
Lateral ventricles
DA receptors
D1-D5 (metabotopic)
5-HT receptors
5-HT1-7 (metabotropic except 5-HT3)
GABA receptors
GABA a (ionotropic), GABA b (metabotropic)
Anandamide receptors
CB1 and CB2 (metabotropic)
NE receptors
NE alpha (-), beta (+) (metabotropic)
Ach receptors
nACh (ionotropic), mACh (metabotropic)
Glutamate receptors
AMPA, NMDA, kainate (ionotropic), mGLU
Mechanism of action for alcohol
- activates GABAa receptors
- inhibits glutamate neurotransmission