Physiology Flashcards
refractory power sum of the eye and the main cotributor is:
59 diopters and the cornea
lenns refractive power is:
20 and changes to 34 when accommidation
the light rays of close objects fall behind the retina in ____ meanwhile in front for far objects in the _______
hypermetropic
myotropic (too srtong eye lens or long eye. ball)
the type of lenses that are used for myopic and hyperopia and astigmatism and keratooconus
concave and convex
cylindrical lens
lenses
uneven irrigular curvature of the cornea. is seen ______
buldgin of the cornea is. ____
astigmatism
keratoconus
when there is no accommodation :
ciliary muscles are relaxed and zonula fibers are stretched and an open iris
accommodation is linked to
convergence of the eyes and constriction of the pupil
intraocular pressure is ____ and abnormal elevation of it causes ____ and the rate of humor production is:
15 mmHg
glucoma
2-3microliter \ minuets
location of the optic disc and fovea
nasal part of the retina and has no photoreceptor
temporal to optic disc and has highest visual activity. containing many cones and less rods.
layers of retina are pushed aside resulting in less light scattering , absence of of blood vessels, connection between foveal cones and. ganglion, lower ratio of cones:ganglions and yellow pigmented
fovea centralis
pupil diameter ranger from ___ to ____ and the square of this diameter tells us the amount of light, of can go from ____ to _____
1.5 - 8
2.25 - 64
blood supply of the retina
inner two thirds by the central retina
outer third by the inner vascular choroid
horizontal and amarcine cells functions
inhibition to enhance contrast
light turn on and off and light movement respond
in rods, what are the type of photopigment and protein of pigment , how is it distributed and excitation duration and sensitivity to light and adaptation to dark
same for the cones
rhodopsin, scotopsin ,periphery , needs more time and high sensitivity slow
color pigment , photopsin , fovea, less time and less sensitivity fast
induction of signals of the light
rhodopsin (11 cis retinal + protein) > metarhodopsin 2 > phosphodiesterase > less cGMP > closure of Na channels and hyperpolarization > no inhibitory NT
metarhodopsin 2 pathway for vit A formation
break down into all trans retinal + protein > 11 cis retinal > used again
break down into all trans retinal + protein > all trans retinol (vit A) > 11 cis retinol > 11 cis retinal
adaptation of eyes to dark and light
- more photochemicals ands Vit A converted to retinal form and increase in pupil size
- less photochemical , retinal converted to vit A, more vit A concentration
ganglion cell that is small, velocity = 8, crude rod vision and directional movements
w ganglion cells
ganglion cells that are medium with 14 velocity and transmit colors
X ganglion cells
ganglion cells that are large , 50 is its velocity
- detect lights density
- detects rapid movements
- black and white vision
Y ganglion cells
Lateral geniculate body branches are:
receives info from:
suprechiasmic ( biological clock) , pretectal (light reflex and focus on objects) , superior colliculus
visual cortex , mesencephalon, optic erve
layers of the geniculate body and their innervation of the visual cortex
- magnocellular (1+2) : receive from Y and blind vision»_space; innervate to C alpha
- parvocellular (3 > 6) : receive from x and colored »_space; innervates to A, C beta , blob
secondary visual cortex divisions and functions
- dorsal stream
WHERE , 3D image and motion, uses black and white - ventral stream
WHAT, lateral occipital complex for objects and inferior temporal for faces , colored vision
The softest audible sound is _ db (absolute threshold)
Normal conversation is _ db
Discomfort & damage to hearing receptors occurs at _ db
Pain occurs at _ db
0
60
140
160
the total amplification of sound is — and the tympanic membrane contributes _ meanwhile ossicles amplify.
times
22 times
17 times
1.3 times
reducing sound waves (attenuation) of loud sounds, 100ms latent period
• protection fromloud sounds
• reducing background voices
• decreasing senation of speech.
the functions of middle ear muscles
_ covers the hair cells
tectorial membrane
- ——— is similar in composition to the ECF (high sodium & low potassium)
- ———composed of fluid with 1 potassium and I sodium
- Endolymph is——— mV compared to perilymph
- Inside hair cells is ——- mV compared to perilymph
- Inside hair cells is —— mV compared to endolymph
Perilymph
Endolymph
+80 -70 -150
3500 cells
Main cells of hearing
90-95% of afferent sensory fibers come from inner cells to brain
Damage causes complete hearing loss
• A single row of inner hair cells
12,500 cells
95% of them are supplied by efferent fibers from auditory nerve
Modulate the response of the inner hair cells
Stimulation of efferent fibers of auditory nerve causes
Shortening of outer hair cells
Change in the inner hair cells sensitivity
Damage causes large amount of hearing loss
Three rows of outer hair cells
Difference in arrival time to each ear: to localize_
- Difference in intensity of sound reaching each ear:
low frequency sounds < 3000 Hz to localize high frequency sounds
utricle senses:
linear horizontal acceleration
head position upright status
saccule sense :
linear vertical acceleration
laying down
the sensory part of saccule and utricle is called_____and has a gelatinous membrane filled with________
kinocilia is :
maccule
CaCO3
the longest stereocilia
If bending of cilia is — the kinocilium = hair cell excitation
If bending of cilia is ___from the kinocilium = hair cell inhibition
toward
away from
the sensory part in semicircular canals is called____
crista ampullaris is ______
capula in the ampulla
baase of the hair cells in the capula
Left and right horizontal
Left anterior and right posterior
Left posterior and right anterior
nod no
head tilt
nod yes
caloric stimulation of vistibular apparatus, irrigation with cold water causes nystagmus to the _______, meanwhile hot water causes in______ direction
it can also cause
opposite side
same side of the ear
nausea, vertigo too
pathway of vestibular system
SC canals > vestibular nucleus > CN nuclei and then extra-ocular muscles
vestibular nerve 2nd order to:
flocculonodular of cerebullum
CN 3 4 6
spinal cord
- Injury at the level of optic chiasm causes_______
- Injury at the level of optic radiation causes contralateral________
bitemporal hemianopia
homonymous hemianopia
macula
capula
crista ampularis
orthodronic conduction is:
antidromic conduction is: and happens in:
one direction only
opposite direction and seen : when nerve is stimulated in the middle and axon reflex
synaptic delay si
.5 ms
acidosis and hypoxia causes :
alkilosis and caffieine and theophylline cause
depress
excitation
hypoxia effects:
pressure effects:
local anesthesia effects:
B>A>C
A>B>C
C>B>A
are for fast pain
are for slow pain
A delta
C Fibers
compound action potential is
its average ____
peak of cap represents____
sum of all excitations
5-30
largest fibers
hypocalcemia causes _____
its signs are ____
tetanus
chovestek and tousseau
decreased magnisuim levels casue
excitaility
neurotmesis
Neuropraxia
Axonotmesis
Cutting
focal demyelination
Axons are cut, but Schwann cells are in their place
ligand dated ion channels :
g protein ccoupled receptors
2nd messenger c amp stimulation
nicoinic
muscarinic
adrenergic
most of afferent (sensory) nerve fibers in ANS are
PSNS specially the vagus
nocireceptors are carried by
SNS
______ drug inhibits prostaglandins
aspirin
lateral nuclei of hypothalamus
feel hunger
OSMORECEPTORS
leptin is produced when ___ in fat deposition
ghrelin causes____
insulin causes_____
peptide YY CCK cause ____
increased
increases foot intake
less food
less food
