Biol 155 Quiz 3

vision- features

-more neurons than any senses

-inverted image on retina

-Extrinsic eye muscle- Oculomotor CN III, Trochlear IV, Abducens VI

-sensitive to visible light (380-760 nm)

conjunctiva

membrane covering the eye

extrinsic eye muscles

aim eye towards area of interest and anchor on to the sclera

cornea

clear and round window for light entry s

sclera

outer fibroud layer of eye- forms shape of eye i

iris

muscular structure and regulates the amount of light entering through the pupil (color)

lens

behind the iris that focuses light rays on the retina

lens is anchored by what to what

tiny suspensory ligaments onto a ciliary body

accommadation

near: relaxed suspensory ligaments- balls up

far: contracted suspensory ligaments, flat

ciliary body

anchors lens and contracts to change shape of lens and permit focusing on near vs distanct objects; produces aqueous humor

choroid

middle vacualr layer of eye that supplies nutrients to metabolically active areas of eye; absorbs stray light rays

supplies most of blood-pigmented epithelium of choroid

retina

inner sesnory nervous layer of photoreceptors in vitreous chamber

optic nerve (CN II)

carries the light signals to rear portion of brain where it is interpreted

aqueous humor

produced by ciliary body that circulates in the space b/w the lens and cornea and pressurizes the eye

canal of Schelmm

collects aqueous humor from anterior chamber and delivers it to veins

vitreous humor

jelly-like fluid in rear chamber of eye

ganglion layer of retina

final cells in chain and their axon collectively exit eye and form the optic nerve b

bipolar cells

recieve light after photoreceptors and send to ganglion

rods

respond to black and gray images

cones

respond to color images

fovea/macula lutea

contains large concentration of cones

highest visual acuity o

optic disk/blind spot

part of retina forming the optic nerve that contains no photoreceptors-only nerves

myopia

near sighted- eye is too long

concave lens corrects

hyperopia

far sighted- eye too short

astigmatism

different cornea thickness

detached retina

retina pulled from its normal position - risk of eye damage/blindness

presbyopia

age related farsightedness

Presbyopia- features

usually after 40

everyone will develop to some degree

lens collage fibers crosslink

lens becomes less compliant/elastic

near point increases

correction of presbyopia

bifocals in glasses or contacts, or reading glasses

note- laser vision correction (lasik) surgery will not correct

Cataracts

opacities develop in protein structure of lens- blocks or scatter light rays prior to hitting retina

cataracts- features

-everyone develops to at least some degree

-most common serious eye disease (50% >65)

-more common in Women

risk factors of Cataracts

age, female, UV-B light exposure, diabetes, smokingc

correction of cataracts

surgery when severe enough

removes lens and an artifical lens is put in place

most common surgery in US

macular degeneration

degeneration of retina (esp in fovea)

features of macular degeneration

second most common serious eye disease

leading cause of blindness in elderly

cause is uknown

no cure, tx slows progression

wet form of macular degeneration

most severe and progressive

blood vessels leak fluid b/w retina and choroid

hemoglobin has oxidizing effect—> destroys photoreceptors

dry form of macular degeneration

mild form, slowly progressive

accumulation of deposition called “Drusen”

retina dries in these areas

tx of macular degeneration

-laser and photodynamic tx show promise

vit A and E- preventative?

Luteine leveles (antioxidant) important?

REgneration BioTech “Eyelea: new injectable tx- 2014 anti VEGF which blocks blood vessel formation

Glaucoma

excess intraocular pressure (IOP)

features of Glaucoma

if left unchecked, pressure destroys retina and blindness results

more common in African Americans VS whites

open angle glaucoma

80%

causes is unknown

constant elevation of IOP

loss of peripheral vision

treated with drugs (beta blockers, vasodilators) or laser surgery

angle closure or acute glaucoma

rapid onset

painful, burning eyes, h/a, nausea

if left untreated- severe and permanent (vision loss 2-5 days)

diabetic retinopathy

side effect of diabets that leads to deterioration of retina

diabetic retinopathy features

3rd leading cause of blindness in US

high blood glucose values oxidize tissues and weaken blood vessels of retina

—cause hemorrhage throughout retina and results in deterioration and detachment of retina

treatment of diabetic retinopathy

prevantative

laser tx to fuse broken blood vessels

regeneration’s Eyela injection shows promise by limiting new blood vessel growth

ear-features

system of mechanoreceptors (for hearing) and range 50-18,000 cycles/second

dogs- up to 20,000; bats- up to 100,000

proprioreceptors

receptor that responds for positioning and movement (for balance and equlibrium

auditory canal

canal extedning form external auditory canal to tympanic membrane-transmits sound waves to tympanic membranet

tympanic membrane

ear drum that vibrates sound waves to middle ear ossicles

ossicles

amplify sound vibrations and transmit sound waves to the oval window and eustachian tube

-malleus (hammer)

-incus (anvil)

-stapes (stirrup)

eustachian tube

equalizes pressure b/w middle ear chamber and outside world

tensor tympani muscle

prevents injury to ear

oval window

end of ossicles that transmits sound to cochlea

round window

on cochlea that equalizes hydraulic pressure

inner ear includes

osseous labyrinth and membraneous labryinth

osseous labyinth

bony canals, filled wiht perilymph and contain membrane tubes and chambers

cochlea (osseous labybrinth)

half the size of a pea and has a spiral tubular turn- three canals which recieve vibrantions from ossicles

include scala vestibuli and scala tympani

scala vestibuli

first sound goes through the perilymph of

scala tympani

sound comes from scala vestibuli and then goes to scala tympani

semicircular canals

help with balance (osseous labybrinth)

membranous labybrinth

filled with endolymph

cochlear duct

has organ of corti in canals

organ of corti

basilar membrane, hair cells, tecotiral membrane

transmits hearing signals to brian via Cochlear portion of auditory nerve VIII

hair cells are stimulated from the

sound and nerve fibers extend and connect to a larger cochlear nerve bundle

physiology of hearing

sound wave captured by tympanic membrane—>amplified by ear ossicles—> transmitted to fluid of cochlea via stapes on oval window—> organ of corti hair cells vibrate accoridng to tonal quality of sound—> hair cell vibration sends nerve signals to temporal lobe of brain

ciristi ampullaris

hair cells that are pushed when body moves and send signals to the brain

Utricle/Saccule

static equilibrium, perception of up and down, body psotion, relative to pull of gravity m

macula with otholiths

hair cells that fall in response to gravity, pulling cilia with them, resulting in depolarizaiton and sending signals to brain

vestibular portion of auditory nerve (VIII)

motion sickenss

utricle/saccule vs conflicting visual signals

Presbycusis

age related hearing loss

Presbycusis featuers

3rd most common chronic ailment in elderly

more common in men (occupational?)

risk factors of presbycusis

occupation

smoking

middle ear infxns

Conduction presbycusis

problems with conducting sound vibrations

caused by: fused ossicles, ruptured ear drum, wax

more easily corrected w/ surger/hearing aid (hard compliances)

Nerve deafness presbycusis

damage to hair cells/cochlear nerve

more permanent

cochlear implants can be used

cochlear implants

microphone and electrodes translate sound into electric stimulation of vestibulococohlear nerve (artificially induced but follows normal pathways to brain)

deaf community’s view-being deaf is an identity (sign language and lip reading)

Tinnitis

persistent ringing in the ears

causes of tinnitis

infxn/tumor in CNS

high BP, DM

migranes

meds

(may be cured depending on cause)

if severe tinnitis, can result in:

sleep distrubances

irritability, depression

dizziness/Vertigo

age related declines in signals from msucles, joints, eyes, and ears can lead to loss of balance

most important fxn of auditory system (vestibular portion)

balance and equilibrium

what can affect vestibular portion of auditory system

age and meds

factors that make dizziness/vertigo worse

older individuals more likely to lose balance and fall

declines in body fat- less cushioning

weakening of bones (osteoporosis) - can make fall outcome more destructive (broken hip=bad health outcomes)

where is heart located

pericardial sac in mediastinal cavity

layers of heart wall

epicardium (visceral pericardium): visceral layer of serous pericardium

myocardium: cardiac muscle layer- bulk of heart

endocardium: chamber lining and valves

Cardiac blood supply sources

coronary arteries: branch from aorta

capillaries- gas exchange

coronary veins

coronary sinus: returns blood to RA

CO =

HR x SV

SV=

EDV- ESV

Max HR (decilines with age)- formula

Max HR= 208-(0.7 x age)

Aerobic exercise targets how much of max HR

60-80%

ejection fraction

SV/EDV- normally 60-70% and declines with age

age changes in values of the heart as a pump

resting CO=constant

resting HR=constant

SV=relatively constant

EDV increase and ESV increases (due to hypertrophy of ventricles and less elasticity)

20% drop in coronary blood flow age 20-70

peak heart perfomance declines (max HR, max CO, cardiac reserve

cardiac reserve

max CO-resting CO

3 layers of vessels

tunica intima: mostly membrane

tunica media: mostly muscle

tunica adventitia: outermost, protective

veins have more ? arteries more?

veins= more tunica adventita and less media (more rubbery)

arteries=more tunica media, more muscle

varicose veins

valves improperly functioning, blood pools in vein (in lower extremeties)

capillaries only have one:

tunica intimia- just a layer of endothelial cells (diffisuon)

Atherosclerosis

age related plaque build up on arterial wall

arteriosclerosis

pathology related plaque build up

RF of atherosclerosis/arteriosclerosis

family hx, HTN, overweight, DM, pathology trauma (infxns), gingivitis, high cholesterol, partially hydrogeated fats (trans)

high levels of C-reactive protein (inflammation)

high homocysteine levels (6-10 mg/dl)

—damage to vessels

—makes RBCs sticky

smoking

low birth weight

pathology of Atherosclerosis

Plaques narrow blood vessels + epithelial cell damage—> macrophages or foam cells = inflammation

fatty steak formation (cholesterol accumulation) —> possibly calcification

thrombus/embolis= clot

exploding plaque= spontaneous clot