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55 Cards in this Set
- Front
- Back
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neuron structure
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-cell body (soma) contain nucleus, ER, ribosomes
-dendrites receive info-->soma and integrated at axon hillock - axon carries signal -myelin insulates/prevents signal loss/speed up conduction -nerve terminal |
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myelin made by ___in CNS
and by___in PNS |
-oligodendrocytes
-schwann |
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action potential
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-all or none mechanism
-release NT into synaptic cleft(synapse) |
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many different type of neurons but all similar in that
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-chemically signal after electrical excitation
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resting potential
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-voltage difference=-70mV ie inside more negative
-maintained by selective permeability to ions and the Na/K ATPase -inside Na low/K high (also have - proteins), outside Na high/K low -membrane more permeable to K -Na/K ATPase help restore resting after AP (3Na out, 2K in for each ATP used) |
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action potential initiation
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-have inhibitory and excitatory inputs
-inhibitory cause hyper-polarization (cell more negative) -excitatory cause depolarization (cell less negative) -axon hillock depolarize to threshold=AP triggered |
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how AP executed
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-depolarization=voltage gated ion channels open
-first Na voltage gated open (electric/chemical gradient cause Na influx-->membrane potential around 35+ now) -K voltage gate open, K efflux-->repolarization (gets more -) and overshoots ie hyperpolarization |
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neurons refractory periods
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-absolute: no matter stimulation no AP will fire
-relative: need greater than normal stimulation to get another AP |
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impulse propagation
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-movement of AP down axon
-Na influx=depolarization wave, K efflux= re-polarization wave resetting axon for next AP -info flows one way due to refractory period behind area where AP just generated -speed depends on: length and cross sectional area (more important) |
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longer axon
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higher resistance and slower conduction
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larger cross sectional area (like increased diameter)
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-faster conduction since less resistance
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saltatory conduction
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-myelin causes it
-membrane permeable to ions only at nodes of ranvier -signal hops fro one node to next making faster conduction |
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NT release ___dependent
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calcium
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afferent neurons=
efferent neurons= |
-sensory
-motor |
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nerves=
and 3 types |
-bundle of axons
-sensory, motor, mixed (refer to type of info carried) |
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ganglia vs nuclei
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-ganglia= collection somas in PNS
-nuclei= collection somas in CNS |
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CNS made of (2)
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brain and spine
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brain:
-for(3) -white matter -grey matter -3 parts |
-cognition, motor movement, integrate sensory info
-unmyelinated axons -unmyelinated somas/dendrites -forebrain, hind brain, midbrain |
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gyri (folds in brain) allow
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higher level cognitive functions
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forebrain
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-most evolutionarily developed
-telencephalon and diencephalon |
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telencephalon
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left/right hemispheres
* independent from each other but communicate via corpus callosum |
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cerebral cortex
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-part of telencephalon
-grey matter -high level functioning here |
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diencephalon
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-thalamus and hypothalamus
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thalamus
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-all ascending sensory pass thru here then into cortex
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midbrain
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-relay point
-pass sensory/visual to forebrain -get motor from forebrain to hindbrain |
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hindbrain
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-for involuntary functions
-cerebellum, pons, medulla= brainstem |
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brainstem
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most primitive part, for basic functions like breathing/HR
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cerebellum
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- like quality control
-make sure sensory info and motor match up |
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medulla
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-most primitive (conserved) part of brainstem
-modulate HR,ventilation rate, GI tone |
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spine
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-cervical, thoracic, lumbar, sacral divisions
-vertebral column protect -white matter axons=motor (exit ventral side) and sensory (enter dorsal, cell bodies in dorsal root ganglia) |
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somatic nervous system
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-part of PNS
-voluntary movement-->neuromuscular junction Ach release=contraction -reflexes -1 neuron system--> motor neuron directly onto muscle no synapsing |
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reflex
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-no input/integration from brain needed
-monosynaptic and polysynaptic |
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monosynaptic reflex
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-one synapse between sensory neuron and motor neuron ex)knee jerk reflex
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polysynaptic reflex
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-least 1 interneuron between sensory and motor neuron
ex) withdrawal reflex--> hit tack foot withdraws via mono, need to balance other foot ie interneuron connect sensory of withdrawn to motor of balancing foot |
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ANS
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-involuntary
-2 neuron system-->preganglionic and postganglionic neurons -regulate organ individually or coordinated via sympathetic and parasympathetic |
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preganglionic neuron
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-1st neuron of ANS
-soma in CNS, axon go to ganglion in PNS -synapse on cell body of postganglionic |
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postglangionic neuron
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-2nd neuron of ANS
-affects tissue target |
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sympathetic NS
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-ANS
-fight or flight -preganglionic use Ach (also cause epinephrine release from medulla) -postganglionic use norepinephrine |
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parasympathetic NS
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-ANS
-rest/digest -preganglionic/postganglionic use Ach -use vagus nerve for effects on adb/thoracic cavities |
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3 sensory neurons
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-interoceptors=monitor internal ex)BV, pH etc
-proprioceptors= position sense -exteroceptors= monitor external ex) light, sound etc *nociceptors=sense pain |
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eye:
sclera choroid retina cornea iris lens ciliary muscles |
-white part
-nutrients/oxygen -photoreceptors turn light-->electrical info -bends/focus light -pigmented/muscular part adjusting amount of light by changing pupil diameter -final focusing -adjust lens thickness |
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order light pass thru structures of eye
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-cornea,pupil, lens, vitreous humor, retina
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2 photoreceptors
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rods cones
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rods
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-black white
-low intensity light ie good for night vision -one pigment: rhodopsin |
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cones
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-color
-3 types (each pigment absorb different wavelength) red, blue, green |
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photoreceptor hit with light then
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-signal to bipolar cells-->retinal ganglion cells (axons bundle=optic nerve)
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blindspot
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-optic nerve exiting eye cause area of no photoreceptors but since 2 eyes blindspots minimized
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fluid in eye
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help transmission of light
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ear converts
ear nerves coordinate |
-mechanical disturbance of pressure ie sound waves--> electrical signals (HAPPENS IN COCHLEA organ of corti part of it)
-balance |
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movement of sound
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-outer ear-->tympanic membrane (middle ear ossicles malleus, incus,stapes) vibrates--> ossicles move -->oval window-->inner ear (cochlea/semicircular canals)
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ossicles moving oval window=
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-fluid waves of inner ear=depolarize hair cells of cochlea= electrical signal
-AP thru auditory nerve into brain |
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semicircular canals
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-balance
-3/ear -endolymph=fluid, put pressure on hair cells |
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chemical senses
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-taste(gustation) smell(olfaction)
-chemical signal--> electrical |
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taste receptors on___
between taste buds is 4 taste sensations taste buds respond___to sensation |
-taste hairs
-nerves -sour,sweet,bitter,salty -preferentially (repsond to all 4 but may repsond lower threshold to 1 or 2 of them) |
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olfaction
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-odours bind receptors on cilia=depolarize receptor
-axons join olfactory nerves-->olfactory bulb in brain |
