neuronal function Flashcards
internal transmission importance:
- neurons must be intact and have access to glucose, via oxygen
- neurotransmitters must engage
- myelin must be present
- networks must connect
functional importance of synapse
- to influence other neurons or tissues
- using electrical impulses which cause neurotransmitters to be released
- to make it across the synaptic cleft in order to depolarize or hyper polarize the receiving membrane
- to the point that an action potential is fired down the axon
- to “fire together and wire together” in order to form neural networks
structural importance of synapse
- the presynaptic terminal
- the synaptic cleft
- post synaptic terminal - the receiving cell membrane, which might be the dendrite of another neuron, or the muscle cell, or gland cell
STUDY HOW THE SYNAPSE WORKS
IN POWERPOINT
resting potentional
always a state of imbalance
-cell membrane is negatively charged
polarization
- the cell is always negative
- the outside of the cell is always positive, relative to the inside of the cell
reach/breach
-the degree of electrical charge must be strong enough to change the permeability of the cell membrane
when the polarization is disrupted..
- NA rushes in - more negative inside
- K rushes out- more positive on the outside
all or nothing principle
-cell either fires or it doesn’t based on if the threshold has been reached
depolarization
firing of a neuron
hyperpolarization
DO NOT fire the impulse
action potentional occurs
at the moment a neurons sends as impulse down its own axon
sodium potassium pumps
cell returns to its resting potential
absolute refractory period
during that time after an AP, the voltage-gated ion channels are opening to allow Na to rush in and then they become inactive - no other AP can take place
relative refractory period
during the K-rush, and efforts to depolarize the membrane, you could stimulate another AP if the stimulus is strong enough
neurotransmitters
- chemicals released at the synapse of one neuron
- and reabsorb by the next neuron
- one neuron to another
- influencing only one neuron at a time
neuromodulators
- chemicals released at the synapse of many neurons
- NOT reabsorbed
- diffuses out into the CSF, influencing many neurons in a system
- like taking a bath in the neurotransmitter
important neuromodulators
- achetylcholine
- dopamine
- serotonin
- norepinephrine
acetylcholine
-engages arousal
-focus and maintain attention
-supports cognitive awareness
WAKE UP AND GET GOING!
dopamine
-sustains motor function, movement
-sustains motivational focus
-reward the effort
-reinforce the effort
-maintain the effort
low levels= parkinsons
high levels= schizophrenia
serotonin
- balances emotional surges
- modulates affect (emotional state)
- influences concentration
- low levels= depression and anxiety
norepinephrine
- selective attention
- engages when the brain is given new info, interesting stimuli
- ritalin and concerta regulate this
- regulates sleep/wake cycles
- both excitatory and inhibitory
- high levels= increased HR, BP, dry mouth, stops peristalsis
epilepsy
- too many neurons fire
- overruns the system
- neural firing gone awry
- anit-seizure meds attempt to control the excessive firing
myasthenia gravis
- cant sustain effects of Ach
- cant maintain firing of impulses with sustained effort
- need to rest.. try again
