Nervous system Flashcards
overall functions of the NS
NS
to transmit info rapidly
to gather input and respond accordingly
3 main functions of the 5 main parts of the nervous system
NS
Sensory input - sensory receptor, sensory neurons
integration - CNS including interneurons
motor output - efferent/motor neurons, effector cells (muscle cells)
describe sensory input, integration, motoar output
NS
input - detection of stimulus
integration - processing in brain
output - response in another bodypart
CNS vs PNS
NS
CNS - Brain, spinal cord
PNS - efferent, afferent neurons, all other neurons not in CNS
what are the subdivisions of the PNS
NS
Sensory division - sensing external, sensing internal
Motor division -autonomic (parasympahteic, sympathetic) , somatic
Atonomic vs somatic in PNS
NS
Autonomic - involulntary reactions,signals to smooth msucle, cardiac muscle
somatic - voluntary reactions, signals go to skeletal muscle
sympathetic vs parasympathetic
NS
symp - arousal and eng gen, increase stress response, inhibit digest
parasymp - calming, decrease heart, stimulate digestive
types of senses
external: somatic(skin, muscle, joints), special(vision, hearing, equilibrium)
internal: visceral(fullness of stomach, blood pressure)
NS
Types of sensory receptors by location
NS
Exteroreceptors - detect stimuli from outside
interoreceptors - detect stimuli from inside body (viscerla senses)
Types of sensory receptors by stimulus
5
NS
mechanoreceptor - pressure (in skin, stomach, bladder)
photo - light (eyes)
chemoreceptor - chemcials (nose, mout, brain, arteries)
thermo- temp(skin, organs)
nociceptor - pain (skin, organs, glands, vessels)
NS
what are the 5 components of neuron also funct
dendrites - gets input from other neurons
cell body - does metabolism, protein syth
axon hillock - where action potential starts
axon-sends info
synaptic terminal - contains/releases neurotransl
WHat is neuron
describe
NS
Structural and functional unit of nervous system
are excitable - can make large changes in membrane pot(electrical signals)
do not do cell division when mature
nerve cell = neuron
What are the types of neyrons
NS
sensory
interneuron(CNS)
motor neurons(stereotypical neuron)
What do sensory neurons do
NS
Afferent neurons
carries signals from sense recept to CNS
What do interneurons do
NS
association neurons
get signals from sensory neurons
deliver signals to outgoing neurons
can be excitatory or inhibitory
What do motor neurons do
NS
efferent neurons
carries signals out of CNS to effetor cells
What are supporting cells/ glial cells
3 types
90% of cells in nervous system
structural and metabolic support
astrocytes(CNS)
oligodendrocytes(CNS)
schwann cells (PNS)
What is blood brain barrier
and astrocyte use
NS
blood vessels completly sealed off by astrocytes- no electrical conduction
stop things from contaminating brain
uses active transport proteins instea of hole
Wha do schwann cells and oligodendrocytes do
wrap around axon
provide insulation for electrical impulses
layer cllaed myelin sheath
schwann is PNS
oligodendrocyte is CNS
Purpose of myelin sheath
NS
provide electricla insulation
makes impulse travel faster
like insulation around wires
has nodes of ranvier
Types of nerve ciruits
NS
Divergent
convergent
circular
describe divergent nerve circuit
NS
nerve impulse in one presynaptic neuron
nerve impulses in several prostsynaptic neurons
ex photoreceptors to many parts of brain
Describe convergent nerve circuit
NS
nerve impulse from many presysnaptic neurons
nerve impulse in one postsynaptic neuron
Describe circular nerve circuit
NS
Neurons connections go in loop
ex. processing and storying memroes
What is simplest type of nerve circuit
and describe it
NS
reflex arc - reglates reflex
involuntary response
integration happens in spinal cord
ex. knee jerk reflex, gag reglex
What are steps of reflex arc
NS
receptor
sensroy neuron
integration center
motor neuron
effector
What is voltage and membrane potential
Nerve sig
voltage - diff in elect potential between 2 point
Memb pot- voltage across a membrane , -70mV when resting
outside pos
inside neg
How is resting potential maintianed
3 ways
Nerve sig
Ion distribution
membrane permeabiliy
Na+/K+ pump
how does ion distribution help mainting resting pot
Nerve sig
large negative molec cannot cross memb
ex proteins, sulphate,
maintain neg on inside
How does membrane permeability aid keeping resting pot
Nerve sig
charged ions cannot directly diffuse
uses leak channels
does not determine direciton of flow
more K+ leak channels than Na+
K+ easier to leave
Chem grad vs elect grad
Nerve sig
chem - concentration gradient, move from high to low concentration
(K out, Na In, Cl out )
elect - ion gradient, move from post to neg area
(K in, Na in, Cl out)
What is electrochemical gradient
also what is it for K and Na
Nerve sig
combination of both elect and chem gradient
K+ net move out of cell
Na+ net movement into cell
What is membrane potential if only K+ is used, what does this mean
Nerve sig
Equilibrium potential be -85mV
(potential at which there is no net movt of ion in or out)
this means that another cation is used to make it higher
Na+
What is effect of establishing equilibrium with only Na+ and K+
Nerve sig
influx of Na+ makes cell less neg
drives steady efflux of K+
concentration grad would dissipate
What is the role of Na+ K+ pump
Nerve sig
uses ATP to drive active trans to keep ionic gradient
3 Na out, 2 K in
more pos ions leaving cell than entering keeps it at -70Mv
What are the 3 types of potentials
Nerve sig
Graded (hyperpol, depol)
Threshold potential
action potential
Nerve sig
What is graded pot vs action pot
Nerve sig
graded - all membrane potentials lower than thresh pot
magnituge effected by strength of stim
magnit also from distance of stim
Action - large depol, triggered if depol reaches thresh pot, same mag all time (+35mV), only made in axon
hyperpolarization vs depolarization
Nerve sig
magnitude depend on strength of stim (opens more channels, larger change in pot)
hyperpol - lower than pesting pot (K+ channels open)
Depol - higher than resting pot (Na+ channels open )
What are diff types of ion channels
3
Nerve sig
ungated/leak - all over cell, always open, maintain rest pot
voltage gate - open/close due to memb pot, in action pot, synapses, in nodes of ranvier, and syn term
Chem gate - on/off due to chem, receptors when neurotrans bind, at dendrites
What are 5 phases of action pot
also ion permeabiliyt
Nerve sig
- resting - only Nin open
- threshold - some Nact open
- depol - K open slow, Nact all open, Nin close slow
- repol - K all open, Nact open, nin all closed
- undershoot - K close slow, both Na Closed
Nin = Na inhibition
Nact = Na activation
all are voltage gates
Na inactivation gate vs activation
Nerve sig
inact - on inside end of channel , slow
activ - on outside end of channel, fast
what is process of propegation
Nerve sig
when action pot travels along axon, repeated regen
depol causes neighbor to depol
goes one way
What is refractory period how does it effect propogation
Nerve sig
period where action pot is not possible,
Na inactivation gate too slow, still closed
during repol and undershoot phase
stops propogration from moving backwards
limits freq of act pot
factors affecting speed of conduction
Nerve sig
axon diamter - larger = faster, less res
myelination - no action pot between nodes, like it jumps
What is saltatory conduction
Nerve sig
current gen by act pot jumps to next node of Ranvier(where its exposed to ExCellFluid)
happens in humans
What is frequency coding
what is relevence to stim strength and act pot
stimulus strength correlates to freq of act pot
beacuse act pot mag is indi of stim strength
Elect synapse vs chem synapse
Nerve sig
elect - current from presyn cell directly flow to postsyn, uses gap junctions not common in vert
adv - rapid
dis - difficult to reg
chem - elect-> chem(neurotrans) ->elect
no phys contact
in humans
what are 4 steps in first part of chem synapse
Nerve sig
- presyn memb depol by act pot
- Volt gate Ca+ channel opens on presyn
- Ca+ enters
- stimulates exocyto of syn vesicles
What are neurotransmitters
Nerve sig
used in chem syn
substance released by presyn cell into syn cleft
intercellular messanger
each neuron secretes only 1 types of neurotrans
connect with receptor on postsyn memb
open close quickly
activly transported out
come back if another act pot arrives
What are 8 steps in communication accros a chem synapse
- action pot
- Ca channels open
- Ca enters, NT release by exocytos
- NT diffuse into syn cleft
- NT bind to repeptor in postsyn, response in postsyn
- removal by enzymatic degradation
- removal by going back in presyn
- removal by diffuse away from syn cleft
process and concequences of NT removal
Nerve sig
has 4 removal paths
1. diffuse away
2. degrade in recept
3. degrade in enz on postsyn
4. go back into presyn
if removed completly synapse would not work
excitatory syn vs inhibitory syn
Nerve sig
excit - NT open gate chann (Na in, K out), causes depol
inhibit - opens gate chann(K out, Cl in), causes hyperpol
EPSP vs IPSO
Nerve sig
Excitatory postsynaptic potential - elect change from excite synapse
Inhibitory postsynaptic potential - elect change from inhibit syn
Strenght depends on amt of NT binding to recept
can cancel each other out
What is summation and types
Nerve sig
Temporal - chem transmission happens close in time, before voltage goes back to resting
Spacial - many syn term fire close tgt in time and space, from diff presyn neurons
Describe nerve signalling cycle of events
from NT to next Net
Nerve sig
- receptors on dendrites get NT
- chem gate chann open
- summation of sig at axon hillock
- act pot gen and conduct down axon
- Nt release into syn cleft
Main components of CNS
organ, bone, cavity
CNS
Brain - skull, has ventricles(fluid cavit)
spinal cord - spin, spine column , vert, has central canal (fluis cavity)
what is meninges
(3 layers) strcture, function
CNS
3 layers of elestic tissue
dura mater(outest)
arachnoid mater
pia mater
surround brain, spin cord
encase and protects brain
houses blood brain barrier
Where is the blood brain barrier lcated
CNS
in subarachnoid space
between arachnoid and pia mater
inner and middle layers
what is structure and func of fluid surrounding CNS organs
CNS
fills cavities in CNS
made form filtration of blood
has nutrients, horm, WBC
shock absorber
flows through subarachoid space
what part of neuron is white or gray matter
CNS
gray - dendrite, cell body
WHIte - meylinated axon
What are the 3 section of brain
cera, thala, hypo, cerbell, pons, med loc
CNS
forebrain - cerebrum, thalamus, hypothal, epithal, pituitary gland
midbrain - in brainstem
hindbrain -cerebellum, pons, medulla oblongata
funciton of medulla oblongata
loc
CNS
base of brain stem
involuntary muscles
heart rate, swallowing, blood vessels
instructions it carries are criss crossed. left brain controls right body
Pons function/loc
CNS
hind
bridge info betwen cerebell, med oblong
cereballum function/loc
CNS
hind
unconcious coord, posture, limb movt
voluntary motar skills
ex writing, biking
What does the thalamus do
CNS
relay station, gets sensroy input sends to cerebrum
gets info from cerebrum
what does epithalamust do
where is it
CNS
in fore brain
has pineal gland, secretes hormones
what does hypthalamus do
CNS
hormone plroductions along with pituitary gland
forebrain
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what is most evolved part of human brain
CNS
cerebrum
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What is cerabral cortex
structure, describe
CNS
outer covering for mammals
gray metter
6 sheets of neuron
80% okf brain mass
folds increase surface area
higher cognitive abilities
What is corpus callosum
also funciton
CNS
Connects left and right side of brain,
comm between hemisphere
white mattr
What are 4 lobes of cerebrum and funct
CNS
frontal - volunt muscle movt, reasoning, short term mem, integrate form other lobes, mods emot based on social norms
Temporal llobe - hearing, long term memory, processing of mem and emot
Occipital lobe - visual imfo, coords info from eye
perietal lobe - touch and temp, taste, visiuospacial analysis
Where is visual info processed
CNS
occipital lobe
back of brain
where is smell processed
CNS
frontal lobe
where is touch, temp processed
CNS
perietal lobe
What are the 5 ways the brain integrates diff areas of cerebrum
CNS
- processing of sensory input
- lateralization
- language and speech
- emotions
- memory and learning
steps of processing of sensory input
6
CNS
- sensory inp(by sense recept, afferent neur)
- primary sense area in lobe
- adjacent associ area in lobe
- frontal associ area in frontal lob(compose motar resp)
- primary motor cortex(direct movt of muslce)
- motor output(eff neuron, effe cells)
What is lateralization
CNS
one othe ways the brain integrates
allocation of brain function in left or right hemisphere
happens in child
lateralization of brain funct
left hem vs right hem
CNS
left - language, math, process fine details, fine motor control
right - pattern rec, music multi task, face rec, emotion process
What are the broca and wernicke areas for and loc
CNS
Speach and language processing
Broca - frontla, motor speech, speaking
Wernicke - temporal lobe, speech comprehension(sensory), understanding language
What is limbic system, funct
wha tare 5 parts
CNS
gen emotion, attaches emot to survival programs
has hippocamp, olfactory cortex, amygdala, thal, hypthal
What are the 4 primary emotion
CNS
anger, laugh, cry, fear
What is amygdala role
what system
CNS
in limbic system, in temporal lob
gets info from hippocap
recognizes emote on faces
keeps history of emotional mem
Where is short term vs long term mem processed
CNS
short term - frontal
long term - temporal, hippo camp, influenced by amygdala
What are diff types of long term mem
CNS
declarative - can verbalize (semantic: info abt the world, Episodic: personal info)
non declarative - hard to verbalize (conditoning: socail norms, conseq. Procedural: riding bike, piano)
memory reconsolidation vs consolidation
CNS
consol - sensory exp -> unstable STM -> stable LTM (problem: doesn’t show that mem can be updated)
reconsol- cycle hippo camp-> active mem -> cortex reconsol -> inactive mem(stable)
what are memory concepts used in 12 bio studying
CNS
reconsolidation model used
memories are recalled and made active again
then go bat to stable inactive state
long term potentiation?
long term potention vs long term depression
potent - when postsyn neuron has increase resp to stimuli, caused by fast, repeated act pot, associated wtih mem storage
depress - postsyn neur has dereased resp to stim, through weak repeated stim ex, inability to smell after long exposure to bad odour
What is neural plascticity
ability of mature neurons to adapt to env influences. ex learning or compensation after injury
has 2 types
short term vs long term plascticity
CNS
short - enhancemtn to existing syn connection
long - physical changes or new formation of synapses
after strokes, outerspace, epiliepsy
What are 4 steps fo sensory reception
Spec sense
sensory transduction
amplification
transmission
integraton
What ahppens in sensory transuctions
Spec sens
conversion of stim eng to change in membrane pot
ex- pressure can stretch membr and increase ion flow
done by sensroy receptors
what is receptor potential
Spec sense
graded potential produced in response to stim. causes by sensory transduction
can trigger action pot
What happens in the amplificaiton
Spec sense
second step in sensory reception
strengthens stim eng so that it can travel to brain
can be done by sensory receptor
ex photorecepors
ear drum and bones - sound waves are enhanced before reaching sensory receptors
What happens in third step of sensory reception
Spec sense
Transmission
conduction of impulses to CNS
can be done by sensory receptor
or afferent neuron
depol of recept pot must activate act pot
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What is integration in sensory reception
Spec sense
processing of information
in CNS in particular lobes of brain
What are parts of the eye and funct ICOTSCR
6
Spec sense
iris- regulate amt of light entering eye
Cornea/lens - help focus image on retina
optic nerve - neur send info to brain
3 tissue layers
1. sclera - muscle
2. choroid - blood vessels
3. retina - has rod and cone cell
What does retina do
Spec sense
has rods and cone cells
converts light sig to elect sig
Rods vs cone cells
Spec sense
cone - for colours, best in daytime
rod - for night vision, detect light. more common
what are the parts of photoreceptor
2 compare with plant version
Spec sense
protein: opsin - light sensitive, has 1 rod 3 cone cells (photosystem)
pigment: retinal - light absorbing (chlorophyll)
What is rhodopsin
Spec sense
used in eye
it is photoisomer - changes shape when exposed to light
found in rod cells
Does diff things in light vs dark
what does rhodopsin do in light vs dark
Spec sense
in light - retinal changes from cis to trans, retinal detaches from opsin, free opsin close Na chann, membrane hyperpol
in Dark - opsin attached to retinal(inactive), Na channels open, Depol, increase release of NT glutamate
What are the steps in the process of converting light to electrical sig(act pot)
using 4 steps
Spec sense
sensory transduction: rod, cone
amplification: rod, cone
transmission: optic nerve
integration:occipital lobe
Why are you initually blind to faint light after being in bright light
Spec sense
in bright light opsin leaves from rhodopsin, rod cells are unresponsive
in low light enzyme is used to attach opsin back. enzyme takes a while to work
How does over stimulation of cone cells lead to specific after image
Spec sense
photoreceptors adapt and lose sensitivity in that colour
when eyes go to blank area adapted photoreceptors send out weak sig
cones that were not being excited by that colour send out strong sig
colour seen is opposing secondary colour in light
What are parts of the ear
(6) and loc (mal, inc, st)
Spec sense
ochlea - inner (looks like eye)
malleus/hammer - middle
incus/anvil - middle
stapes/stirrup - middle
tympanic membrane/ear drum
vastibular system
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What are the parts of cochlea
5
Spec sense
upper vestivular cana
lower tympanic canal
seperated by cochlear duct
organ of corti in cochlear duct
attached to tectorial membrane
Process of auditory transuciton in ear
Spec sense
- sound waves translated on pressure movt through cochlea , dissipate at round window, up vesti down tympanix
How is ear involved in stability and balance
Spec sense
uses vastibular system - semicircular canals near cochlea
filled with otoliths - ear stones
gravtiy pulls stones down on hairs in brain, tells position to brain
sensory reception in taste vs smell
Spec sense
Taste
1. Sensory transduction: taste buds
2. Amplification: taste buds
3. Transmission: gustatory (taste) nerve
4. Integration: parietal lobe
Smell
1. Sensory transduction: olfactory receptor cells
2. Amplification: olfactory receptor cells
3. Transmission: olfactory nerve in olfactory bulb
4. Integration: temporal lobe frontal lobe?
what are the recept responsible for sensing each spacial sense
Spec sense
vis - photorecept
hear - hair cells in cochlea
taste - taste buds
smell - olfactory receptors
What sense does each lobe process
vis - occipital lobe
taste - parietal lobe
hear - temporal lobe
smell - frontal lobe
