week 5 spinal cord Flashcards
pre synapitc cell
neuron
Ca+ influx triggers release of
neurotransmitter
What triggers the opening of the Ca+ channels?
Action Potential
How did ACh end up in the vesicles? And where is it released?
manufactured in the cell body and out through axon terminal. Axon cleft by exocytosis
What happens when ACh binds to its receptor?
Sodium inside the post synaptic cell
What is the function of the Na+/K+ pump?
requires ATP because its pushing Na+ through its against concentration gradient.
What is an Action Potential?
Reflecting a change of voltage across the cell membrane. If that voltage is high enough to reach the threshold (-60) will trigger action potential. It will open gates allowing sodium to enter. Action Potential can only go through 1 direction.
What is a neurotransmitter?
molecules
How does this differ from a hormone
Cell makes it, hormones are released across blood. Nervous system much more rapid
What is a synapse
cell communication, between pre synaptic cell and post synaptic
What is a cholingergic synapse?
Acetocolin is the only one being released.
T/F All NMJs are Cholinergic Synapse
True
T/F All neuron to neuron synapses in the CNS and PNS are also Cholinergic
False. Most important in PNS.
Which enzyme breaks down ACh?
ACh E
What happens to the breakdown products of ACh E
Part of it goes back into axon terminal to be recycled
Events at the Cholingeric Synapse
Voltage gated calcium opens, AP arrives at the Axon Terminal, calcium will tell vesicles to release endocytosis. Ca+ enters, ACh released diffused across synaptic cleft. Neurotransmitter binds target, sodium channels open in post synaptic membrane. ACh E enzyme break down
Norepinephrine (NE)
released at Adrenergic Synapse in Brain, ANS
Dopamine
In CNS, excitatory, or inhibitory (hyperpolarize)
Serotonin
In CNS, sleep/wake and mood
Gamma Aminobutyric acid (GABA)
in CNS, inhibitory
Neuromodulators
alter rate of NT release of pre synaptic neuron OR alter response to NT post synaptic (does not have to be neuron)
Opioids
pain relief, euphoria:
- Endorphins
- Enkephalins
- Endomorphins
- Dynorphins
g protein
enzyme complex, binds GTP (highly energy)
Net effect (at Axon Hillock)
integrates and determines response for information processign
Graded potential that develop in a postsynaptic cell
in response to neurotransmitters
Two types of Postsynaptic potentials
excitatory postsynaptic potential and inhibitory postsynaptic potential
Excitatory Postsynaptic potential EPSP
graded depolarization of postsynaptic membrane
Inhibitory Postsynaptic Pontential IPSP
graded hyperpolarization of postsynaptic membrane
Temporal summation
stimuli arrive at a single synapse in rapid succession (multiple times)
Spatial summation
stimuli arrive at multiple synapses simultaneously (multiple locations)
Longer time above threshold =
more APs generated
refractory period
time neuron is resting
epaxial muscles: erector spinae (dorsal) & list muscles included
extension: illiocostalis, longissimus, spinalis
Hypaxial muscles: rectus and obliques. & list muscles included
flex: external and internal oblique muscles, transverses abdominis, rectus abdominis.
Synergist
works to assist another muscle, carrying out same action
Antagonist
works to oppose another muscle, usually located on opposite side of a structure
End of spinal cord
conus medullaris
Last nerve of the spinal cord
cauda equina
portion of menages that are protecting spinal cord
filum Terminale
Ventral root
contains axons and motor neurons
To: somatic and visceral effectors
Dorsal Root
contains axons of sensory neurons
To: the spinal cord
Dorsal root ganglia
contain cell bodies of unipolar sensory neurons
Intervertebral formina
where dorsal and ventral roots exit spinal cord
afferent fibers
towards spinal cord
efferent fibers
going away spinal cord
Spinal Meninges: 3 maters
Dura mater, arachnoid mater, pia mater.