PSY 360 exam 2 Flashcards
what are Ion channels ?
are proteins that span the membrane and allow ions to pass.
what are the two different types of Ion channels ?
sodium potassium pump
potassium leak channels
what are gated channels? what two types are there? (neurotransmitter receptors)
they open and close in response to signal; voltage gated and ligand-gated channels
what do voltage gated channels do?
the change in voltage, open in responses to changes in the membrane potential
what are ligand gated channels
open when a specific signaling molecule (ligand) binds to them
also neurotransmitter binding
what are the two types of ligand receptors?
Ionotropic receptors and metabotropic receptors
ionotropic receptors
fast, quickly change shape and open or close an ion channel when the transmitter molecule binds
what are the two types of Metabotropic receptors? (GPCR)
longlasting and amplification
- Slow, when activated they alter chemical reactions in the cell, using a system of second messengers to open an ion channel
- activate enzymes that lead to biochemical cascade (change in membrane potential; gene expression)
what are the 4 different types of neurotransmitters?
amino acid neurotransmitters
amime neurotransmitters
neuropeptides
gas neurotransmitters
what types are the amino acids
glutamate= 5 carbons
GABA = 4 carbons
Glycine= 2 carbons
what are the types of amime neurotransmitters?
Acetylcholine
Dopamine
Serotonin
what are the types of neuropeptides?
oxytocin and vasopressin
what are the types of gas neurotransmitters?
nitric oxide and carbon monoxide
frog heart experiment
stimulate the vagus nerve to slow the heart, collect fluid from around the slowed heart and apply the fluid to a second heart
the second heart slowed
conclusion: the vagus nerve uses a chemical neurotransmitter to communicate to cells of the heart and cause it to slow down
what are the steps of synaptic transmission ?
1.) The AP is propagated over the presynaptic membrane
2.) depolarization of the presynaptic terminals lead to influx of CA2+
3.) CA2+ causes vesicles to fuse with the presynaptic membrane and release transmitter into the synaptic cleft
4.) the binding of the transmitter to the neurotransmitter receptors in the postsynaptic membrane opens channels, permitting ion flow and initiating an excitatory or inhibitory postsynaptic potential
5.) excitatory and inhibitory postsynaptic potentials spread passively over dendrites and the cell body to the axon hillock
Otto Loewi stimulated which nerve to slow down the frog heart?
Vagus (CN X)
Which of the following receptors acts quickly?
Ionotropic
Neurotransmitters are designed to either be excitatory or inhibitory
false
what does the PNS consist of?
sensory (afferent)
motor (efferent)
what does the motor (efferent consist of?
somatic (voluntary) (skin, joints, muscles)
autonomic (involuntary)
what does the autonomic nervous system consist of?
sympathetic (fight/flight)
parasympathetic (rest/digest)
soma (cell body) consists of
CNS - nucleus
PNS -Ganglion
axon (myelin)
CNS tract + Oligodendrocytes
PNS nerves + schwann cells
Acetylcholine
all PNS motor neurons release ACh except postganglionic sympathetic neurons (sweat glands)
Acetylcholine: storage and release
1k-50k Ach molecules/vesicles
300k vesicles cholinergic neuron
Lambert Eaton Myasthenic syndrome (LEMS)
Rare autoimmune disorder
● Antibodies block/destroy v-gated calcium
channels
● Ca2+ dependent triggering of synaptic
vesicle does not occur
● ACh vesicles do not fuse with membrane
● No ACh release
What are the 2 acetylcholine receptors?
Nicotinic and Muscarinic
Nicotinic acetylcholine receptors
Agonist: nicotine (tobacco)
Antagonist: Curare (arrowtip) - paralysis
location: skeletal muscle
function: muscle contraction
Ligand gated Ion channel
Muscarinic acetylcholine receptor
agonist: Muscarine (mushrooms) poison
antagonist: atropine
location: heart muscle
function: decrease blood pressure
GPCR’s
substance A attacks SNARE
location Neuromuscular junction
result?
stop vesicle binding
Acetylcholine
PNS
No action potential
Nicotinic acetylcholine receptor
BOTOX
how can GABA be excitatory ?
Ionictropic
Cl- transporter
immature neuron (less than 1 year old)
immature Ecl= -30mv
mature Ecl= -65
Metabotropic
GPCR’s
not voltage gated
can change DNA/Gene expression
retina
layer of neurons in the back of the eye
detects differences in frequency and intensity of light
photoreceptors
converts light energy into neural activity (transduction)
are sensory neurons that detect light
rods and cones
cones
4 million
day vision
near fovea
rapid
rods
100 million
night vision
outside fovea
slow
fovea
center region of the retina has high density of smaller, tightly packed cones with high acuity
this region receives direct light input that does not pass through other cells or blood vessels
rods
are more numerous in the periphery and are absent in the fovea
lateral inhibition
a process in which sensory receptor cells inhibit information from neighboring receptor cells, producing an effect of contrast at the edges of regions
pure tone (amiplitude)
loudness, dB
frequency
pitch/tone Hz
how sound travels from our surroundings, into the ear, and converted into electrical signals to the brain
1.) Entry: sound waves are channeled into Ear canal
2.) Amplification: sound waves hit eardrum setting 3 small bones in motion
3.) Vibration: Bones push against cochlea causing fluid to move
4.) signaling: fluid moves hair cells, whose motion get translated into nerve impulses which travel to the brain
Base of Basilar membrane
Narrow, stiff fibers
high frequency and travel short distance
Apex of Basilar Membrane
wide, floppy fibers
low frequency
travels entire distance
