Nervous system Flashcards
what is the data coming into the nervous system called
afferent (accept)
what is the data going of the nervous system called
efferent (exit)
what is the electromagnetic senses
sight
what is the mechanical senses
touch and hearing
what is the chemical senses
taste and smell
what is sensory transduction
energy changes due to the movement of ions across the membrane
what is the “language” that the brain understands
movement of ions across membrane
how are wavelength and frequency related
inversely
how does light enter the eyes
photoreceptors
what type of light do humans see
visible light
where is taste detected
gustatory cortex
what converts chemical to brain signals in taste
chemoreceptors on the tongue
what are chemoreceptors on the tongue called
papillae
what is the movement of ions across the membrane in regards to salt and sour
a channel lets H+ and Na+ ions through membrane
what is called when the inside of the cell becomes more positive
depolarized
what is the movement of ions across the membrane in regards to sweet, bitter, and umami
ion attaches to receptor to activate the G protein
what happens when the G protein is activated
stimulates the release of neurotransmitters
where is smell detected
olfactory cortex
where are taste and smell interpreted
in the brain
what is the order of how scent travels to the brain
epithelium –> nerves –> bulb –> tract –> CNS
what is the unit of what we hear
Hz
where are vibrating air molecules sent
ear canal
where is sound sent from the ear canal
ear drum
where is sound sent from the ear drum
ossicles
where is sound sent from the ossicles
cochlea and vestibulocochlear
what happens to sound once it exits the cochlea and vestibulocochlear
hair cells are stimulated
what happens once the hair cells in the ear are stimulated
nerve fibers send info to auditory cortex
what do mechanically gated ions respond to
pressure, stretch, distortion of the membrane
where is touch processed
somatosensory cortex
where is motor input located
frontal lobe
where is somatosensory input located
parietal lobe
where is visual input located
occipital lobe
where is auditory and olfactory input located
temporal
what is the fundamental unit of the nervous system
the neuron
where in the neuron does ATP synthesis occur
mitochondria
where in the neuron are proteins made
Golgi
what part of the neuron sends info to other neurons
axon terminals
what part of the neuron receives info
dendrites
what kind of channels is input
ligand gated channels
what kind of channels is conduction
voltage gated channels
what kind of channels is output
voltage gated calcium channels
what do ligand channels open in response to
ACH
what do voltage gated channels open in response to
membrane potential
when are voltage gated channels closed
-70 mV
when are voltage gated channels opened
-60 mV
when are voltage gated channels inactivated
+30 mV
what is axonal transport
movement of materials between cell body and axon terminals
how do materials move along the neurotubules
+K and -D motor proteins
what is anterograde fast transport
vesicle transport
what are the vesicles used in anterograde fast transport
transmembrane proteins on membrane bound ribosomes
what is anterograde slow transport
non-vesicle transport
what are the non-vesicles in anterograde slow transport
cytoplasmic on free ribosomes
what are glial cells
cells of the CNS and PNS
what is the purpose of glial cells
support and protect neurons
what are the glial cells found in the CNS
astrocytes, ependymal, oligodendrocytes, microglial (OMEA)
what are the glial cells found in the PNS
satellite cells and Schwann cells
what are the functions of astrocytes
blood brain barrier, control interstitial environment, and recycle neurotransmitters
what are the functions of ependymal cells
line ventricles, protection of brain, and nourishment and waste removal
what is the function of oligodendrocytes
myelinate the axon of CNS neurons
what is the function of satellite cells
surround ganglia and regulate fluid in neurons
what is the function of Schwann cells
myelinate the axon of PNS neurons
what is resting membrane potential
unstimulated resting cell
what is graded potential
temporary change in resting potential
what is action potential
electrical impulse
what is the goal of resting membrane potential
seeks equilibrium for ion that is dominate
what is a characteristic of the membrane in resting membrane potential
selectively permeable
what is voltage in ohms law
force that moves the current
what is current in ohms law
ions moving across the membrane
what is resistance in ohms law
how much membrane restricts movement
how does myelination effect resistance of the membrane
higher resistance with myelination
what is the movement of ions in a chemical gradient
passive
how is the movement of ions driven in a chemical gradient
concentration gradient
what causes potassium to move out of the cell in a chemical gradient
increase in intracellular K+
what causes sodium to move in to the cell in a chemical gradient
increase in extracellular Na+
what is the movement of ions in a electrical gradient
passive
how is the movement of ions driven in a electrical gradient
charge differences
how is potassium effected by the electrical gradient
is is weakened
what does sodium do in the electrical gradient
goes into the cell
what does sodium do in the electrical gradient
goes into the cell
what is equilibrium potential
membrane potential with no net movement
what does the membrane in equilibrium potential have high permeability to
potassium
what does the membrane in equilibrium potential have low permeability to
sodium
how is equilibrium potential calculated
Nernst equation
what is the determinant of the Nernst equation
ionic concentration of the inside and outside of cell
can graded potential create and full action potential
no
why doesn’t local current spread in graded potential
cytosol is resistant to ion flow and Na+ efflux
what is the result of the local current not being able to spread in graded potential
graded potential cannot reach full action potential
what is involved in graded potential
depolarization and hyperpolarization
osteoclasts cause calcium to be reabsorbed into the bones
“tonin” = tone it down
what is temporal summation
2 stimuli on the same spot at a different time (the first stimuli is temporary to move for the second one)
what is spatial summation
2 stimuli received at the same time but different location (the stimuli are physically spaced out)
where does the action potential send a charge down
the axon
what does an action potential affect
the entire membrane
where do action potentials begin
initial segment of axon
how does the graded potential get the action potential to threshold
depolarizes the axolemma (axon membrane)
what has to be reached in order to begin an action potential
threshold
what is the term for when the membrane potential begins to increase
depolarization
what causes depolarization in an action potential
Na+ channels start to open
what is happening during rapid depolarization of an action potential
Na+ rushes into cytosol
what is the membrane potential during the peak of an action potential
+30mV
what is happening in an action potential as the membrane reaches +30mV (peak)
Na+ channels close, K+ channels open
what is happening during depolarization in an action potential
K+ moves out of cell
what happens at the very end of an action potential
K+ channels close, Na+ channels become inactive
what causes temporary hyperpolarization in an action potential
K+ is still moving out cell while the channels are closing
how do action potential across an axon when it is unmyelinated
continuously
what happens in the initial segment of an unmyelinated axon
depolarization
what happens in the 2nd segment of an unmyelinated axon
sodium ions spread –> depolarized to threshold
what happens to segment 1, when segment 2 becomes depolarized
repolarizes
what brings segment 3 to threshold
graded potential brings axolemma to threshold
how does an action potential move down a myelinated axon
it jumps from node to node
do action potentials move faster down unmyelinated or myelinated axons
myelinated
what occurs at the initial segment of a myelinated axon
Na+ ions go in
how does node 2 get to threshold in a myelinated axon
local current causes the graded potential to bring the axolemma to node 2
what is the very first step of an action potential in a cholinergic synapse
action potential depolarizes axon terminal
what does depolarization in an action potential in a cholinergic synapse cause to happen
Ca2+ channels open and Ca2+ enters cytosol
what happens once Ca2+ enters the cytosol in an action potential in a cholinergic synapse
ACh is released from vesicles by exocytosis
what happens once ACh is released from presynaptic cleft in an action potential in a cholinergic synapse
binds to receptors on post synaptic neuron
what happens once ACh binds to post synaptic neuron receptors in an action potential in a cholinergic synapse
Na+ channels open –> depolarization
what is ACh broken down into after it binded to post synaptic neuron in an action potential in a cholinergic synapse
acetate and choline
what happens to choline once ACh is broken down in an action potential in a cholinergic synapse
it’s reabsorbed into axon terminal and is resynthesized to make ACh
what activates the SNARE complex
synaptotagmin
how do astrocytes regulate neurotransmitters
they metabolize them and release precursor back to neurons
what are postsynaptic potentials
graded potentials in response to a neurotransmitter
what is EPSP
graded potential caused by arrival of neurotransmitters
what is IPSP
graded hyperpolarization
what is released during inhibition of axoaxonic synapse
GABA
what does the release of GABA cause during inhibition of axoaxonic synapse
inactivation of Ca2+ channels
what are post synaptic potentials
graded potentials that respond to neurotransmitters
what is EPSP
graded depolarization caused by arrival of neurotransmitter
what is IPSP
graded hyperpolarization
what is released at the axoaxonic synapse during inhibition of presynaptic regulation
GABA
what does GABA being released for the axoaxonic synapse result in during inhibition of presynaptic regulation
inactivation of calcium channels
what is the result of less calcium in the presynaptic axon during inhibition of presynaptic regulation
less neurotransmitters
what is released at the axoaxonic synapse during facilitation of presynaptic regulation
serotonin
what does serotonin being released for the axoaxonic synapse result in during facilitation of presynaptic regulation
activation of calcium channels
what is the result of more calcium in the presynaptic axon during facilitation of presynaptic regulation
more neurotransmitters
what do each pair of spinal nerves monitor
regions of the body surface called dermatomes
what is the purpose of meninges
provide stability and shock absorption
what does the epidural space separate
dura matter from vertebral canal
what does the subarachnoid space contain
cerebrospinal fluid
what kind of tissue can be found in the epidural space
adipose tissue
what part of the spinal cord carries sensory input
posterior root
what part of the spinal cord carries motor output
anterior root
what is the function of grey matter
integrates info and initiates commands
what is the function of white matter
carries info from place to place
do reflexes produce the same motor response every time
yes
what is the reflex arc
sensory info goes through posterior root, and motor info goes out through anterior root
what is the sensory info sent once it enters the spinal cord (in the reflex arc)
CNS part of the brain
what causes the response in the reflex arc
effector
what type of reflex is stretch
monosynaptic
what is monosynaptic reflex
sensory neuron synapses directly with motor neuron
what type of reflex is tension
polysynaptic
what does a polysynaptic reflex use that a monosynaptic doesn’t
interneuron
what sends a signal to the sensory neuron in a stretch reflex
distortion of receptor
where does the motor neuron send the signal to in a stretch reflex
motor unit
what happens when the motor unit receives a signal
muscle contraction
what kind of reflex is a spinal reflex
withdrawal
is a withdrawal reflex mono or polysynaptic
polysynaptic
what do the flexors and extensors do during a withdrawal reflex
flexors contract, extensors relax
what does the response of a withdrawal reflex depend on
intensity and location of stimuli
where is the body of a 1st order neuron located
posterior root ganglion
where is the cell body of the 2nd order neuron located
spinal cord
where does the 2nd order neuron span to
brain stem
what does the 2nd order neuron cross to
one side of the CNS to the opposite side
where does the 2nd order neuron connect to the 3rd order neuron
thalamus
where is the cell body of the 3rd order neuron located
thalamus
what does the 3rd order neuron connect to
primary somatosensory cortex
what is the spinothalamic pathway referred as
crude
what is the posterior column medial lemniscus pathway referred as
fine
what does the 2nd order neuron cross in the crude pathway
spinal cord
what does the 2nd order neuron descend into in the crude pathway
thalamus (hence the name spinothalamic)
what does the crude pathway detect
light pressure and pain
what does the 2nd order neuron cross in the fine pathway
brainstem
what does the 2nd order neuron descend into in the fine pathway
medial lemniscus
what does the fine pathway detect
fine touch, deep pressure (crosses deep in the brain)
what is brown-sequard syndrome (BSS)
lesions in the spinal cord
what does BSS result in
weakness on one side of the body and loss of sensation on the other side
what is the sensory homunculus a map of
primary somatosensory cortex
what is the sensory homunculus proportional to
density of neurons
what does the motor homunculus indicate
fine motor control available for specific regions of the body
what is the size of the hands, face, tongue in the motor homunculus
large
what is the size of the trunk in the motor homunculus
small
what kind of control is the autonomic nervous system
involuntary
what are the 2 divisions of the autonomic nervous system
sympathetic (SNS) and parasympathetic (PSNS)
what is longer, the PSNS or SNS
PSNS
what is the distance between the cell body and tissue in the SNS
far
what hormones are released during SNS activation
epinephrine and norepinephrine
what does epi or norepi bind to in the blood
GPCR (G- protein coupled receptors)
where is the cell body relative to target tissue in PSNS
adjacent
what hormone is released during PSNS activation
ACh
what kind of channels are ACh released onto
ligand-gated
what do autonomic neurons do
maintain background levels/regulatory effect
how is heart rate maintained via autonomic tone
ACh and norepinephrine are released continuously
what is G-alpha-s
subunit
what is G-alpha-i
subunit
what do G-alpha-a and i bind to
adenylyl cyclase
what effect is Ga-s
stimulatory
what effect is Ga-i
inhibitory
what does Ga-s do
excites adenylyl cyclase to form cAMP from ATP
what does Ga-i do
inhibits adenylyl cyclase and reduces cAMP levels
what does G-alpha-Q cause to happen
alpha subunit binds to PLC and causes PIP2 to split into IP3 and DAG
what happens once IP3 is formed from Gaq
binds to calcium and moves it into cytoplasm
what happens once calcium moves into cytoplasm
smooth muscle contracts
