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Flashcards in Eyes Deck (50)
1

The eye is compose of how many tunics

Fibrous,vascular ,and nervous tunics

2

Fibrous tunic

The outer most layer of the eyes consisting of sclera and cornea

3

Vascular tunic

Underneath the fibrous tunic, rich in supply of blood very vasculrized and some pigment (choroid)

4

Nervous tunic

The inner layer of the eyes underneath the vascular tunic, the retina lies here with it photoreceptors cells rods and cones

5

The cavities of the eye

There are two eye cavities, posterior cavity and anterior cavity

6

The anterior cavity has two chamber.

Anterior chamber and posterior chamber

7

Anterior chamber

Located in front of the iris and its filled with aqueous humor

8

Posterior chamber

This is behind the iris

9

Accommodation

The process of focusing light to the retina

10

Explain the process of accommodation

Suspensory ligament is attached to the ciliary muscle, the ciliary muscle

11

Presbyopia

The thicken of the eye lens, causing the weaken of the suspensory ligament attached to the lens

12

Relaxation of the muscle make the lens ....... and contracting makes the lens .......

Thicker and thinner

13

The ciliary muscle is controlled by the

Cranial nerve 3 ocular motor nerve

14

The three layer of the retina are

Photoreceptors cells(rods and cones), bipolar cells, ganglion cells

15

Describe the direction of the signal sent when light hits the eyes

Light hits the photoreceptor cells and send the signal in one direction to the brain and the signal reacting to the stimulus travels in the opposite direction

16

The image of the outside world is perceived as upside down but the brain

Flips the image receive form the outside world

17

What is the function of the iris

The iris controls the amount of light that goes through by relaxing and contracting

18

Posterior cavity

Filled with vitreous liquid which is very gel like located located behind the lens

19

Suspensory ligament

Attaches lens to ciliary muscle. It has a thing layer around it can make the eye lens thinner or thicker

20

Ciliary muscle

Pulls on the suspension ligament to focus light into the retina by changing the thickness of the lens

21

Crystalline lens

The lens, it is a transparent structure along with the cornea helps with refracting light to be be focused in the retina

22

Cranial nerve 3 ( ocular motor nerve) controls the

Ciliary muscles

23

The retina is part of what tunic

Nervous tunic

24

Photo transduction occurs in what tunic

In the nervous tunic in the retina

25

Horizontal cells and amacrince cells

Are specialized interneurons that ends up in the ganglion cells

26

Photo transduction converting light waves to nerve signals occurs at the

Ganglion cells

27

The transmition of the nerve signal away from the retina is after the ganglion cell by the

Optic nerve ( cranial nerve 2)

28

Rhodopsin

Found in the outer most part of the rods and there are two parts scotopsin and retinal

29

Photoisomerization

When light changes the configuration of cis-retinal to trans-retinal

30

Rhodopsin form is

Csi retinal and scotopsin

31

Retinal isomerase

Converts trans retinal into cis retinal when there is no light

32

Describe what happens at the outer segment of the rod cell

At the surface of the rod cells there are Na channels opened by cyclic GMP, Na goes into the cell making it more positive. After light hits then cyclic GMP is converted to GMP thus closing the Na channels making it more negative leading to hyper polarization

33

Describe the closing of Na channels

After light hits rhodopsin activates the G protein transducin, producing GTP, GTP activates phosphodiesterase. It then convert cyclic GMP to GMP thus closing the sodium channel

34

Cones uses what opsin

Photopsin

35

Tri color vision

It is based on the fact we see color base on the absorption of three color receptors blue red and green. And the color we see is due to the percentage of the different color cones

36

We see white light because

All the color cones are activated

37

Color blindness is caused by

The absence of different color cone, it is a x linked recessive gene that is generally found males

38

The neurotransmitter released by the photoreceptors at the base of the retinal is

Glutamate

39

Horizontal cells

Transmit signal horizontally and participates in lateral inhibition. The end result is usually inhibitory.. Have graded potential or electronic potential

40

Bipolar cells

There two types the on cells and off cells, the on cells hyper polarize glutamate is inhibitory and the off cells depolarize where glutamate is excitort...it has very short graded potentials

41

Ganglion cells

Carries signal to the optic nerv, has action potential not graded potential, they are self propagating, and there are three types x, y,and w

42

Amacrine cells

Found between bipolar cell, can transmit vertically and horizontally, can interact with bipolar and ganglion cells.

43

The neurotransmitter released by amacrine are cells are

GABA, glycine, dopamine, acetylcholine, and endolamine

44

In the ganglion cells, the frequency of action potential increase significantly

When there is light stimulus

45

W ganglion cells

Linked to rods activates in dim light. It is the least population of the gang lions..diameter is smaller thus does not conduct rapidly

46

X ganglion

Most of ganglion are x, larger diameter, and it is involved with refine structure of light ,associated with cones

47

Y ganglion

Second large rest , involves determination of rapid change in the visual field

48

Retinal ganglion cells has two functions

Participating in the visual function of the eye
Deploys SCN in the hypothalamus

49

SNC

Biological clock controlled in the hypothalamus region of the brain. Which controls the light dark period involving the pigment melonopsin

50

Optic chiasma

The cross over effect to the ociptal lobe