Tag: eyes and their function

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Questions Related to eyes and their function

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

In man, the nictitating membrane is 

  1. Absent

  2. Vestigial

  3. Non-functional

  4. Functional
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The plica semilunaris in humans is a small fold of tissue on the inside corner of the eye. It is the vestigial remnant of the nictitating membrane, an organ that is fully functional in some other species of mammals.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

Eye is most sensitive to 

  1. 20 $\mathring { A }$ light
  2. 1000 $\mathring { A }$ light
  3. 5000 $\mathring { A }$ light
  4. 7000 $\mathring { A }$ light
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At extremely low intensities of stimuli, when only rods are stimulated, the retina shows a variable sensitivity to light according to its wavelength, being most sensitive at about 5000 angstroms, the absorption maximum of the rod visual pigment, rhodopsin. There is a characteristic shift in the maximum sensitivity from 5000 angstroms for scotopic (night) vision to 5550 angstroms for photopic (day) vision, called Purkinje shift.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

For the synthesis of rhodopsin, which of the following food is needed?

  1. Mango

  2. Rice

  3. Carrot

  4. Tomatoes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Opsins are the light sensitive proteins of rods. Binding of opsin to retinal (a chromophore) makes rhodopsin which serves as the visual purple pigment of rod cells. Retinol is a form of vitamin A and carrots are a rich sources of vitamin A. So, the correct answer is option C.
Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

How many oblique and rectus muscles are found to move the eye ball in various direction inside the eye orbit? 

  1. Two

  2. Four

  3. Six

  4. Eight
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Six extraocular muscles facilitate eye movement. These muscles arise from the common tendinous ring in the orbit, the eye cavity and attach to the eyeball. The six muscles are the lateral, medial, inferior and superior rectus muscles and the inferior and superior oblique muscles. The muscles, when contracting, cause movement of the eyeball, by pulling the eyeball towards the muscle.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

Lens and retina of vertebrate eye develop from 

  1. Mesoderm

  2. Ectoderm

  3. Endoderm

  4. Partly from ectoderm and partly from endoderm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Neuroectoderm gives rise to the following compartments of the eye: retina, epithelial lining of ciliary body and iris, optic nerves. Surface ectoderm produces the following parts: lens, corneal epithelium, skin of eyelid.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

Harderian gland occurs in 

  1. Lizard

  2. Frog

  3. Birds

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The harderian gland is a gland found within the eye's orbit, which occurs in tetrapods (reptiles, amphibians, birds and mammals) that possess a nictitating membrane. The gland can be compound tubular or compound tubuloalveolar, and the fluid it secretes (mucous, serous or lipid) varies between different groups of animals. In some animals it acts as an accessory to the lacrimal gland, secreting fluid that eases movement of the nictitating membrane. 

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

Pigmented connective tissue in rabbit occurs in 

  1. The eyelids

  2. The choroid of eye

  3. The adipose tissue of skin

  4. The choroid and iris of eye
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Vascular tunic is the middle coat of the eyeball consisting of highly vascular and heavily pigmented connective tissue consisting of a posterior choroid layer and an anterior ciliary body and the iris. Choroid is the posterior portion of the vascular middle tunic of the eyeball, lined on the inside by a layer of darkly pigmented cells; it provides the main blood supply to the back of the eye and gives rise to the ciliary body and the iris anteriorly.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

The nictitating membrane of rabbit is 

  1. Also called as third eye lid

  2. Situated in the inner corner of the eye

  3. Movable across the eye ball to clean it

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nictitating membrane is also called as the third eye of rabbit and is found in medial canthus (inner corner) of an eye. This is swept closed across the eye in the direction from beak to ear to protect the eye as well as to clean and lubricate it with the moisture of lachrymal gland. 

So, the correct answer is option C.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

Pecten is a comb like structure found in the eyes of 

  1. Amphibians

  2. Reptiles

  3. Birds

  4. Mammals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pecten or pecten oculi is a comb-like structure of blood vessels, belonging to the choroid in the eye of a bird. It is a non-sensory, pigmented structure that projects into the vitreous body from the point, where the optic nerve enters the eyeball. The pecten nourishes the retina and controls the pH of the vitreous body.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

The part of rabbit's eye which acts like diaphragm of camera is 

  1. Pupil

  2. Iris

  3. Lens

  4. Cornea
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Iris is the part of the eye, which is responsible for one's eye color. It acts like the diaphragm of a camera, dilating and constricting the pupil to allow more or less light into the eye.

So, the correct answer is option B.