ch.8 Flashcards
neurons transmits and processes info from through ?? define
action potentials: localized area of depolarization of the plasma membrane that travels along the axon.
synaptic transmission
the signal reaches the synapse (end of axon) and its transformed into a chemical signal with the release of NT into the synaptic cleft
what is the structure of a neuron from top to bottom
dendrites to soma to axon to synaptic knots
the axon is surrounded by ?? what are the areas that dont have this called
myelin and the areas without it are called nodes of ranvier
neurons only have ONE ?? but can have multiple ?? what are the two called
one AXON but they can have one dendrite called bipolar or many dendrites called multipolar
a nerve is what
a group of different axons from different neurons
what is the resting membrane potential of a cell? the inside of cell is what charge? outside?
resting membrane is -70mv and the inside of the cell is (-) and outside is (+)
what are the ways you can maintain resting membrane potential
- NA/K ATPase that pumps 3 NA out of cell and 2 K+ into cell.
- leak channels that are always open and allow K+ ions to leak out
what is depolarization? repolarization?
depolarization is the change in membrane potential to less (-) or even (+) . repolarization is when it goes back to negative
what causes these polarizations
VG sodium and potassium channels that are located in the membrane of cell
how does an AP occur
sodium channels are slightly opened to allow depolarization of cell to reach the threshold potential of -50mv, and the sodium channels fully open to allow Na ions in
does Ap ever stop once it has started? what is all or nothing?
they cant stop until it reaches the synapse. neurons have a all or nothing response where unless the threshold is passes, nothing will occur
how does repolarization occur
VG sodium channels inactivate very quickly and VG K+ take a bit to open but stay open longer to allow cell to go back to RMP at -90mv (hyperpolarization) and jumps back to -70mv
what is myelin made up of? can AP occur here?
myelin is made up of schwann cells in the PNS a type of glial cell & oligodendrocytes in the CNS. Ap cannot occur because ions cannot travel freely in myelin
if Ap cant travel in myelinated parts of axons, how does it travel?
it jumps on the nodes of ranvier through saltatory conduction
what is a glial cell
a specialized cell (nonneuronal) that usually provides structural and metabolic support to neurons
schwann cell does?
forms myelin in PNS and increases speed of AP
oligodendrocytes does?
forms myelin in CNS and increases speed of AP
astrocytes does?
in CNS guide neuronal development and regulate synaptic communication
microglia does?
In CNS removed dead cells and debris
during an AP, Na and K+ movement (what type of transport) is
passive and driven by gradients
ependymal cells
In CNS produce and circulate CSF
equilibrium potential
the membrane potential at which this driving force (gradient) doesnt exist therefore no ions would move across them. equal ions on both sides
refractory period, what are the two phases?
when the neuron cannot be depolarized and its unable to transmit another AP after one just passed. absolute refractory period and relative
absolute refractory period
a neuron will not fire an AP no matter what. Na channels are inactive NOT CLOSED
relative refractory period
a neuron can be induced to make an AP but depol needs to be way stronger than normal because cell has been hyperpolarized
whats a synapse? what are the two types
a synapse is a junction between the axon terminus of one cell and dendrites of another cell. theres chemical and electrical
how does chemical synapse work
depol causes Calcium channels to open which causes exocytosis of NT to other cell and it binds to LG channels which causes AP in posy synaptic cell
how electrical synapse work? example?
occurs when cytoplasm of 2 cells are joined by a gap junction. examples are smooth muscle and cardiac muscle
what are some NT’s? what do you call an NT that induced depol? repol?
Ach, dopa, GABA, serotonin. depol: excitatory repol: inhibitory
what is the adding effect of a bunch of synapses on one cell? can they be excitatory or inhibitory?
summation and they can be both
excitatory NT’s cause what? inhibitory NT’s cause what?
excitatory NT’s cause excitatory post synaptic potential or EPSP and inhibitory causes inhibitory post synaptic potential or IPSP
receiving info is whos job? integrating info is whos job?
receiving info is sensory/motor and done by PNS and integrating is CNS
effectors
motor neurons that carry info from NS to organs that can act upon sensory info
motor neurons that carry info towards are called? away?
efferent neurons go from NS to organ and afferent neurons go from organ to NS
reflexes are
direct motor reponse to sensory input that occurs without conscious thought, doesnt use brain at all and mediated by spinal cord
muscle stretch reflex
a sensory nueron detects stretching of muscle and has a long axon
monosynaptic reflex arc
reflex involving only 2 neurons and 1 synapse
relaxation of one muscle and contraction of another muscle is an example of
reciprocal inhibitions
PNS is divided into
somatic (voluntary movement) and autonomic (involuntary like digestion, metabolism, circulation
autonomic is divided further into
sympathetic (fight or flight) and parasympathetic (rest and digest)
many sympathetic effects come from where
epinephrine from adrenal medulla
myelinated axons in both CNS and PNS are considered to be what matter
white matter
unmyelinated CNS cells are
grey matter
the entire CNS floats in ? what does it do?
CSF, CSF acts as a waste disposal, nutrient exchange, and shock absorber
what does spinal cord do
connected to brain and its the site for info integration and processing and simple reflexes
what does hindbrain include?
hindbrain includes medulla, pons, and cerebellum
medulla does
connects brain with cord and relies info between other brain areas and regulates AUTONOMIC FUNCTIONS (VITALS)
pons does
connection between brain stem and cerebellum, controls autonomic and coordinates movement and BALANCE
cerebellum does
where COMPLEX MOVEMENTS are coordinated, damage causes pour hand eye coordination and balance
midbrain does
relay for VISUAL and AUDITORY INFO, WAKEFULNESS TOO
forebrain has what two parts
includes diencephalon and telencephalon.
diencephalon contains what? what does each one do?
thalamus: relay and processing of sensory information
and hypothalamus: controls emotion, pituitary gland controls hormones
telencephalon has what two functions
left brain : controls right half of body and speech and right brain: controls left half od body and deals with visual spatial and music
how is left and right brain connected
by the corpus callosum which is a bunch of axons
what is the biggest region of the brain and what does the surface of the brain is called?
biggest region is the cerebrum and the surface consists of cerebral cortex
frontal lobe function
voluntary movement and executive function
parietal lobe function
sensation and taste
temporal lobe function
auditory and smell, and short term mem
occipital lobe
visual
what is brocas area? wenicke’s?
brocas is speech production and wernickes is language composition
basal nuclei (basal ganglia) function
voluntary motor control
limbic system includes? function?
amygdala, dienolate gyrus, and hippocampus, deals with emotion and memory
all neurons entering and exiting the CNS are carried by?
12 pairs of cranial nerves and 31 spinal nerves
cranial nerve
convey sensory and motor function to and from brain stem
spinal nerve
convey sensory and motor function to and from spinal cord