Peripheral Nervous System(PNS)

BSCI 201 final exam review

Sympathetic Nervous system

Flight, fight, freeze

Norepinephrine and Epinephrine

Increase

• pupil dilation

• blood flow

• heart rate

• breathing rate

decrease

• digestion

• urine production

Parasympathetic Nervous system

Rest and Digest

Acetylcholine

Increase

• digestion

decrease

• blood pressure

• heart rate

• breathing rate

• pupil dilation

Vasoconstriction

narrow blood vessel

occur in other vascular beds

Vasodilation

occur in blood vessel to increase blood delivery to skeletal muscle

Bronchodilation

increase oxygen increase blood delivery

increase 02 to skeletal muscle for aerobic catabolism to prevent muscle fatique

glucogenolysis and gluonegenisis stimulation

provide immediate glucose for energy production by skeletal muscle

Increase cardiac output

occur by increase in contractile force

increase blood flow to skeletal muscle

lipolysis stimulation

make substrate available for energy production

activation of sympathetic nervous system equid body for flight or flight

vasoconstriction

vasodilitation

brochondilation

stimulate glycogenolysis and gluconeogenisis

increase cardiac output

stimulate lipoysis

dilation of pupil

sweating

what are the four special senses?

• somatosensory receptor

• photoreceptor

• mechanoreceptor

• chemoreceptor

  • olfactory cell for olfaction

  • gustatory cell for gustation

somatosensory receptor

tactile receptor in skin, joints, and spatial discrimination

inputs are interpreted in contralateral postcentral gyri in parietal lobe

• fiber carry somatosensory input decussate before reaching post central

• somatosensory information in left side of body processed in right

• somatosensory information in right side of body processed in left

chemoreceptor

sensory receptor that respond to changes in chemical in solution

mechanoreceptor

sensory receptor that respond to mechanical force( touch pressure, stretch, vibration)

photoreceptor

sensory receptor that respond to light energy

Damage to the left cerebral hemisphere can cause:

• Right side paralysis if left precentral gyrus damaged

• braca aphiasia

• wernicke aphasia

• loss of sensation to right side of body if left postcentral gyrus in left partial lobe damaged

Damage to the right cerebral hemisphere can cause:

left side paralysis if right precentral gyrus in right frontal lobe damaged

what are the three layers of the eye wall and there components

• fibrous layer

  • sclera

  • corona

• vascular layer

  • ciliary body

  • iris

  • choroid

• sensory layer

  • pigmented layer

  • neural layer

fibrous layer of eye wall

outer layer composed of dense fibrous CT

• sclera(posterior 5/6)- maintain eye shape, protect eye, attachment site for extrinsic eye muscle

• corona- allow light to enter eye because avascular and transparent

vascular layer of the eye wall

middle layer thats highly vascularized

• choroid- provide nutrient to sclera and sensory layer

• ciliary body

  • ciliary process- contain blood capillaries that secrete aqueous humor

  • ciliary zolule- hold lens in upright postion in the eye

    • suspensory ligament

• iris- seen anteriorly as the colored part of eye

  • pupil- central opening of iris allow light to enter the lens

what are the two layers of smooth muscle in the lens

circular and radial smooth muscle - control size of pupil

radial smooth muscle

activation of sympantetic nervous system cause contraction and result in pupillary dilation

sensory layer of eye wall

innermost layer of the eyewall

confined to posterior wall of eye

• pigmented layer- single layer of cell provide nutreint to neural layer

  • contain melanin which absorb light and prevent scattering

  • contain vitamin a for syntesis of light absorbing retinal- vitamin A

• neural layer(retina)

  • photoreceptor

    • rod

    • cone

  • bipolar neuron

  • ganglion cell

what are the three neural layer of the eye wall

photoreceptor- respond to light and generate electrical signal

• rod- sensitive to light- use dim light puerperal vision

• cone- bright light- acuity color vision

  • 3 types: blue, red, and red cone

bipolar neuron- receive electrical signal from photoreceptor and send signal to ganglion cell

ganglion cell- neuron receive elecrical signal

• axon of ganglion cell form optic nerve and generate and transmit action potential

trichromatic theory of vision

sevreal color are seen depending on which/how many of the three types of cones are activated

ganglion cell

only neuron in retina that can generate and transmit action potentail

bundle of gangion cell form optic nerve

optic nerve

formed from a bundle of ganglion cell

exists through posterior wall of eye through optic disc=blind spot because optic disc last photoreceptor

optic disc

blind spot due to lack of photoreceptor

lateral to optic disc= macula lutea- contain mostly cone

center of optic disc- fovea centralis- only cone and used for hard focus

macular degernation

diagnosed every 3 minutes in the united states

occur in 10% of people over 50 and 33% of people over 75

annually, 1.2 million people with macular degeneration lose part of central vision

what are the two humors in the eye

fluid in the body

aqueous humor

vitreous humor

aqueous humor

filtered from blood capillaries in ciliary process in anterior chamber

supplies nutrient and oxygen to lens and corena

carries metabolic waste

maintain intraocular pressure to support eyeball

drained by canal of schlemm

formed and drained constantly

glaucooma- when intraocular pressure rises causing damage to retina and optic nerve

vitreous humor

gel like fluid in posterior segment behind the lens

formed in embryo and last lifetime

support posterior surface of lens

pushes neural layer against pigmented layer

maintain intaocular pressure

retinal detachment

retina detach from pigmented layer and vitreous humor seep into space

without nutrient source photoreceptor in retina die leading to blindness

the lens of eye

avascular, transparent, bioconvex, and flexible

held in upright postion behin pupil and iris by cilary zonule

function: len refract light and focus light on photoreceptor in retina- accomodation

len of eye focusing on distant vision

normal eye adapted for distant vision so no accommodation needed

far point distance is beyond which accommodation is not needed

the lens focus for close vision

less then 20 ft

involve accommodation of lens where lends blunges to focus close object on retina

near point of vision- distance which lens can bulge maximally to focus

myopia

nearsightedness- near object seen clearly while distant object appear blurry

when distant object focus infront of retina

eyeball to long

correction- concave lenes to diverge light before it enter eye

hyperopia

farsightedness- distant object seen clear while close object appear blurry

occur when light from close object focused behind retina

eyeball to short

correction- convex lenes to converge light into retina

path taken by light through the eye

cornea, aqueous humor, pupil, lens, vitreous humor, ganglion cell, bipolar neuron, photoreceptor

path taken by light through retina

ganglion cell, bipolar neuron, photoreceptor

transmission of electrical signal

when light hit photoreceptor and they generate electrical signal

phototransduction

1)light abosrbing pigment. retinal captures photon light energy

• light causes photoreceptor potential (hyperpolarization)

2) release bipolar cell from inhibition

• bipolar cell generate graded potential which transferred to ganglion cell

3) activated ganglion cell and axon form optic nerve generate and transmit action potential

phototransduction in the absence of light(dark)

photoreceptor are depolarized and release the neurotransmitter glutamate that inhibit bipolar neuron from generating electrica signal

phototransduction in presence of light

photoreceptor become hyper polarized and stop releasing glutamate thus inhibition on bipolar neuron is halted

bipoalr cell generation electrical singal that transfered to ganglion cell

axon of ganglion cell form optic nerve which depolarize and generate action potential that eventually transmit to primary visual cortex in each occiptical love

what happens when the LEFT optic nerve is damaged? RIGHT?

blindness in the LEFT eye

Blindness in the RIGHT eye

what happens as optic nerve exit from the back of the eye?

1) medial axon fiber of each optic nerve decussate to opposite side at OPTIC CHIASMA

2) continue to enter brain as OPTIC TRACT

• each optic tract contains axons from both eye to give wider range of vision for each eye

what happens if the left and right optic tract are damaged

left optic tract causes partial blindness in both eye

right optic tract causes partial blindness in both eyes

what happens when the left and right occipital lobe is damaged?

LEFT occipital lobe damage causes partial blindness in both eyes

RIGHT occiptial lobe damage causes partial blindness in both eyes

impulses are transmitted to visual reflex center in midbrain called

superior colliculi if visual reflex such as tracking is involved in what you are viewing

all visual impulses are transmitted to visual relay center in thalamus called..

lateral geniculate nucleus(LGN)- primary visual cortex- association area in each OCCIPITAL LOBE

what are the three major regions of the ear?

• external outer ear

• middle ear

• internal inner ear= labyrinth

external outer ear

pinna + external auditory canal( external acoustic meatus)

middle ear

three ossicles

• malleus

• incus

• stapes

tympanic membrane- cone shaped membrane that separate external ear from middle ear

interanl ear

bony labyrinth- vestibule, semicircular canal, cochlea

membranous labyrinth- interconnecting sacs and ducts located inside bony labyrinth

utricle and saccule- membranous sac located inside vestibule

semicircular ducts- membranous duct located inside semicircular canal

cochlear duct- membranous duct located in cochlea

bony labyrinth

vestibule, semicircular canal, cochlea

contain perilymph- csf fluid type

membranous labyrinth

interconnecting sacs and ducts located inside bony labyrinth

fluid called endolymph

utricle and saccule

membranous sac located inside vestibule

contain eqilbirium receptor called MACULAE that respond to pull of gravity and head position

semicircular ducts

membranous duct located inside semicircular canal

expand ends called ampullae house equilibrium receptor called cristate ampullares that respond to rotational movement of head

cochlear duct

membranous duct located inside cochlea

what are the expanded ends of semicircular duct called

ampullae which house equilbirum receptor called cristae ampullares that respond to rotational movement of head

cristae ampullares

respond to rotational movement of head

endolymph

fluid in membranous labyrinth

perilymph

csf type fluid in bony labyrinth

maculae

equilibrium receptor that respond to pull of gravity and head postion

the organ of corti

• located in cochlear duct which contain endolymph

• rests on an inferior flexible membrane called basilar membrane

• composed of supporting cell and hair cell

• apical surface of hair cell have sterocilia which are microvilli stiffened by actin filament

tectorial membrane

• inside organ of corti

• superior gel like membrane

route of sound waves through ear/impulse transmission

pinna, external auditory canal, tympanic membrane vibrate, vibration transferred to malleus, incus, status, perilymph + endolymph move, basilar membrane oscillate, hair cell move, sterocilia of hair cell trapped in tectorial membrane bend

• cause electrical signal to develop, impulse transfered to cochlear nerve, cochlear nerve generate and transmit action potential via vestibulocochlear nerve, auditory reflex center in mid brain called interior colliculi, to auditory relay center in thalamus called medial geniculate nucleus, primary auditory cortex/ association area in each temporal lobe

conductive hearing loss

• sound is not conducted efficiently through outer or middle ear

• reduction in sound level

• often be corrected medicine or surgery

• causes: ear wax, fluid in middle ear, ear infection

sensorineural hearing loss

• damage to inner ear

• reduction of sound level, affect speech understanding or ability to hear clearly

• permanent loss, no correction

• causes: birth defect, genetics, virus, head trauma, aging, noise exposure

olfactory epithelium and three components

yellowish patch in roof of nasal cavity

• olfactory cell- bipolar neuron that are chemoreceptor

• basal cell- differentiate to form new olfactory cell to replace damaged

• supporting cell- produce thin layer of mucus covering cilia in which odorants dissolve

why are olfactory cells unique neurons

they do not exhibit longevity

why are olfactory cells called bipolar neuron

axon bundle up to form olfactory nerve

olfactory hair

dendrites of olfactory cells are ciliated cells and cilia called olfactory hair

what are the two components the chemical/odorants meet in olfaction sense of smell?

• chemical must be volatile(gaseous) so it can be inhaled

• inhaled gas must be soluble in thin coat of mucus covering olfactory hair

olfaction sense of smell process

• dissolved chemical attach ti cilia of olfactory cell resulting in depolarization

• transfred to axon of olfactory nerve which generate and transmit action potential

• impulse transmitted to mitral cell in olfactory bulb

• bundle of axon of mitral cell form olfactory tract

• transmitted to medial dorsal nucleus( mediodorsal thalamic nucleus(MDT)

• impulse relayed to primary olfactory cortex/association mostly in temporal lobe

impulses also transmitted to mammillary bodies- limbic system which consist of servral areas of brain

taste(gustation)

• is chemical sense

• fungiform papillae have pores that allow chemical to pass through to taste buds

• receptor cells found in taste buds are located on tongue and inside mouth

• when taste bud activated, receptor cell in taste buds send neural message to thalamus which send to different areas of brain to process

what are the two types of epithelial cell in each taste bude

basal cell

gustatory cell= chemoreceptor

gustatory cell=

chemoreceptor