synapses and neurotransmitters Flashcards
what is the basic functional unit of the nervous system
neuron
How do incoming signals enter a neuron
through synapses located mostly on neuronal dendrites
How do neurons send signals
through the synapses on the end of axons
sensory receptors
aka affecter neurons
info comes in from skin/eyes/ears/nose/tongue (5 senses) as well as pain! and is sent to the CNS
what happens when afferent neurons (sensory receptors) receive input?
it causes depolarization and causes the Na channels to open
What happens when a motor receptor receives input
it sends impulses to an effector organ and causes contraction of smooth or skeletal muscles. also causes secretion of certain chemicals from glands (such as acetyl coa)
what is controlled by the ANS
smooth muscle, cardiac muscle and glands
Integration
Stimuli that are received by sensory structures are communicated to the nervous system where that information is processed
what causes neurotransmitters to be secreted
chemical synapses
what causes the generation of an electrical signal
excitatory post synaptic potentials
(an action potential that excites)
What causes the prevents generation of an electrical signal
inhibitory post synaptic potentials
(an action potential that inhibits)
when is the neuron excited enough to open sodium channels
when the axon hellic is depolarized to at least -55 or higher.
what keeps you from feeling your jewelry around your neck all day and other sense such as this one
inhibitory post synaptic potentials
What is the purpose of inhibitory neurons
to decrease sensory input for allowed increase of focus.
how are signals transported from one neuron to another
draw this out or explain it
how do inhibitory synapses work
neurotransmitters are released from presynaptic membrane and bind to receptor proteins on postsynaptic cleft and triggers potassium ion channels to open (causing the inside of the cell to become more negative)
how do excitatory synapses work
neurotransmitters are released from presynaptic membrane and bind to receptor proteins on postsynaptic cleft and triggers sodium ion channels to open (causing the inside of the cell to become more positive)
job of motor neurons
get info from brain and send it to muscles, organs and glands
job of interneurons
to transport information from neuron to neuron (such as sensory neurons to motor neurons)
job of acetyl coa
motor movement
para and sympathetic nervous system
job of norepinephrine
postganglionic sympathetic NS
job of dopamine
usually inhibition
job of glycine
always inhibitory
job of glutamate
excitation
job of seratonin
inhibition of pain
control mood and sleep
job of nitric oxide
long-term behavior/memory
not pre-formed
synthesized instantly as needed
What are G-Proteins
a protein with three subgroups (alpha, beta and gamma) that has the ability to convert GDP to GTP by using a G protein coupled receptor
Describe the presynaptic membrane
increased calcium channels
transmitter vesicles with DPB found
What causes tansmitters to be released into the synaptic cleft
large influx of calcium into the presynaptic membrane
What is the bindng component
found in post synaptic membrane, grabs neurotransmitters and pulls them into the post synaptic membrane
what are ionophore components
sodium or potassium channels that open in response to neurotransmitters being let into the post synaptic membrane
What part of a G protein is seperated and what does this seperated part do
the alpha part and it opens specific channels and activates CAMP system and gene trrasnciption
What are neuropeptides
proteins that are synthesized by ribosomes in the neuron and sent to the golgi apparatus to be released in the cytoplasm and travel down the axon. (lots to do with pain signals!)
Explain decremental conduction
the tips of dendrites are less negative because tey have more potassium channels that are consnantly leaking. this makes the tips of dendrites susceptible to excitatory signals, however the charge drops lower as you go towards the axon helic which assuresthat the excitatory signal is strong enough to create a response.
Where are inhibitory channels found in the neuron
the soma
What has to reach -55mV for a neuron to be excited
the axon helic
White muscle fibers
fast twitch, type 2 muscle fiber
red muscle fiber
slow twitch type 1
Why does hyperventilation increase the chance of epileptic seizures
alkalosis (too much basidity) increases excitability by a great amount
What causes comas in diabetics
acidosis (too much acidity) decreases excitability and inhibits it. which causes no neural activity = coma
how does caffiene affect synaptic transmission
decreases excitatory threshold and makes it easier to excite
how do anesthetics affect synaptic transmission
increases excitatory threshold and makes it more difficult to excite
