Class Seven Flashcards
structural unit of the nervous system
neuron
electrochemical signals of the nervous system
action potentials
where is the nucleus found in a neuron
in the soma
how many axons and dendrites does a neuron have
one axon
can have many dendrites
bipolar vs multipolar neurons
bipolar: only one dendrite
multipolar: many dendrites
resting membrane potential
-70 mV
how does the Na/K ATPase pump work
2 Na out and 2 K in with the hydrolysis of 1 ATP
what type of transport is the Na/K pup
primary active transport → transports against a gradient
how do voltage gated sodium channels open
opened by depolarization of the membrane
3 factors that allow for depolarization
voltage gated sodium channels close
voltage gated potassium channels open
potassium leak channels and Na/K pump continue to function to bring it back to RMP
what is myelin made up of
Schwann cells → type of glial cells
Schwann cells are found in the..
PNS
myelination via oligodendrocytes is found in the..
CNS
what is found in the nodes of Ranvier
concentrations of voltage gated sodium and potassium channels
saltatory conduction
rapid jumping conduction in myelinated axons
function of astrocytes
found in CNS
guide neuronal development
function of microglia
found in CNS
remove dead cells + debris
function of ependymal cells
found in CNS
produce & circulate CSF
Nernst equilibrium potential formula
absolute refractory period
neuron will not fire another AP no matter how strong a membrane depolarization is
voltage gated sodium channels are inactivated (not closed_
relative refractory period
neuron can be induced to transmit an AP but needs a greater depolarization because the membrane is hyperpolarized
2 types of synapses
chemical and electrical
electrical synapses
cytoplasm of 2 cells are joined by gap junctions
action potential spreads from one cell to another
chemical synapses
action potentials are converted into chemical signals
found in the nervous system
what neurotransmitter is released at neuromuscular junctions
ACh
what degrades ACh
acetylcholinesterase
key regulated step in the nervous system
whether or not a neuron will fire an AP
EPSPs
excitatory neurotransmitters cause postsynpaic depolarization
IPSPs
inhibitory neurotransmitters cause IPSPs
temporal summation
presynaptic neurons fire lots of APs that pile on top of eachother
within a short time period
spatial summation
EPSPs and IPSPs from all of the synapses on the postsynaptic membrane are summed at the same time
efferent vs afferent neurons
efferent neurons carry info away from CNS
afferent neurons carry info to the CNS
monosynaptic reflex arc
a reflex involving only 2 neurons and 1 synapse
somatic vs autonomic nervous systems
somatic → voluntary control of skeletal muscle
autonomic → involuntary control of glands + SM
2 branches of ANS
sympathetic and parasympathetic
pupils during parasympathetic activation
constriction
pupils during sympathetic activation
dilation
myelinated vs unmyelinated - white vs grey
myelinated = white matter
unmyelinated = grey matter
role of medulla
regulating vital autonomic functions - BP etc
where is most of the RAS found
in the midbrain
function of frontal lobes
voluntary movements + problem solving
function of parietal lobes
sensations & taste
functions of temporal lobes
auditory + smell
language comp + emotion
function of occipital lobes
visual sensation
how many pairs of cranial nerves
12
how many pairs of cranial nerves
31
cranial nerves convey..
sensory and motor info to & from the brainstem
spinal nerves convey..
convert sensory and motor info to and from the spinal cord
what neurotransmitters do all somatic motor neurons use
ACh
where do somatic motor neurons have their cell bodies
in the brain stem or ventral part of spinal cord
somatic effectors
skeletal muscles
which is the craniosacral system
parasympathetic
which is the thoracolumbar system
sympathetic
usual neurotransmitter for sym. postganglionic axon
norepinephrine
usual neurotransmitter for parasym. postganglionic axon
ACh
what does the adrenal gland secrete (3)
cortisol
aldosterone
hormones (E and NE)
exteroceptors
sensory receptors that detect stimuli from the outside world
interoceptors
receptors that respond to internal stimuli
mechanoreceptors
respond to mechanical disturbances
Pacinian corpuscles
pressure sensors in the skin
nerve ending becomes depolarized when there is pressure from the skin
chemoreceptors
respond to chemicals
e.g. olfactory and gustatory receptors
nociceptors
pain receptors
stimulated by tissue injury
thermoreceptors
stimulated by changes in temperature
electromagnetic receptors
stimulated by electromagnetic waves
e.g. photoreceptors in eyes
tonic receptors
fire electric potentials as long as the stimulus occurs
phasic receptors
only fire APs when the stimulus begins
where are olfactory receptors found
roof of the nasopharynx
where do olfactory nerves project
directly to the olfactory bulbs of the brain
where are olfactory bulbs located
temporal lobe of the brain
what makes up the outer ear
auricle and external auditory canal
what divides the middle and outer ear
tympanic membrane aka eardrum
what makes up the ossicles
the malleus (hammer)
the incus (anvil)
the stapes (stirrup)
what divides the middle and inner ear
oval window
what attaches to the oval window
stapes
what is responsible for releasing excess pressure in the ear
round window
what causes ear popping
the auditory tube
fluids in the cochlea
perilymph and endolymph
what opens the ion channels in the hair cells of the ear
movement of the hair cells
results in neurotransmitter release
how is pitch distinguished
by which regions of the basilar membrane vibrates
where do low frequency sounds stimulate hair cells
at the apex of the cochlear duct, farthest from the oval window
where do high frequency sounds stimulate hair cells
base of cochlea, near oval window
where is the auditory cortex found
temporal lobe
what makes up the vestibular complex (4)
semicircular canals
auricle
saccule
ampullae
where does the vestibular complex send information
to the pons and cerebellum (balance info)
how does light enter the eyes
by passing through the cornea
purpose of the choroid
contains dark pigmented cells to absorb excess light in the eye
what foes the anterior chamber of the eye contains
aqueous humour
what do the muscles in the iris do
regulate the diameter of the pupil
purpose of the eye lens
to fine tune the angle of incoming light so it focuses on the retina
what does the vitreous chamber contain
vitreous humour
what does the retina contain
rods and cones → detects light
what do rods and cones synapse with
bipolar cells
whats special about the optic disk
aka blind spot → no photorecepto4rss
significance of the macula
center of it is the focal point, only contains cones → extreme visual acuity
special pigment proteins in the eyews
opsin, which is bound to one molecule of retinal
rods and cones at rest (in the dark)
retinal has many trans double bonds and one cis bond
this allows for opsin to keep sodium channel open
rods and cones when absorbing light
retinal is converted to its all-trans form
opsin closes the sodium channel → cell hyperpolarizes
what do rods and cones release onto bipolar cells
glutamate (neurotransmitter)
when do rods/cones release glutamate
in the dark → depolarization
on center vs off center bipolar cells
on center: increased glutamate = decreased transmitter release
off center: increased glutamate = increased transmitter release
what accomplishes night vision
rods
emmetropia
normal vision
myopia
nearsightedness → too much curvature of the cornea
hyperopia
farsightedness → dues to the focusing of light behind the retina
how to fix myopia
with a concave lens
how to fix hyperopia
with a convex lens
presbyopia
inability to focus → due to loss of lens flexibility (occurs w aging)
feature detection theory
different parts of the brain are activated when looking at different things (face vs words etc)
parallel processing
many aspects of a stimulus are processed simultaneously
Weber’s law
says that two stimuli must differ by a constant proportion in order for their difference to be perceptible
bottom up processing
begins with the sensory receptors and works up to the brain
top down processing
brain applies knowledge to interpret sensory information
dendrites send nerve impulses towards..
the soma
axons send nerve impulses..
away from the soma
what is hyperpolarization
moving away from rest potential in the negative direction
where are electrical synapses always found
in cardiac muscle cells
what breaks a synapsin bond
calcium
