Tag: introduction to sense organs

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

Which part of the eye is grafted in a needy patient from a donated eye?

  1. Conjunctiva

  2. Cornea

  3. Choroid

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

When eye is donated or transplanted only cornea part of the eye is transplanted to the needy person.

The cornea is a contact lens sized, clear piece of tissue in the front of the eye.
So the correct option is 'Cornea'

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

_________ is a decrease in the response to an ongoing stimulus.

  1. perception

  2. visual accommodation

  3. sensory adaptation

  4. both (b) and (c)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Neural adaptation or sensory adaptation is a change over time in the responsiveness of the sensory system to a constant stimulus. It is usually experienced as a change in the stimulus that is, the responsiveness to constant stimulus is decreased or stop

So, the correct option is 'Sensory adaptation'

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

Which of the following gives the correct path for light rays entering the human eye?

  1. Sclera, retina, choroid, lens, cornea

  2. Fovea centralis, pupil, aqueous humour, lens

  3. Cornea, pupil, lens, vitreous humour, retina

  4. Optic nerve, sclera, choroid, retina, humours
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  1. The first thing light encounters when it enters the eye is the cornea, a protective clear covering over the pupil and iris. The cornea bends the light and begins to form an image.
  2. Light passes from the cornea to the pupil, the dark circle in the centre of the iris, which is the coloured portion of the eye. The pupil regulates the amount of light that will enter the inner eye based on environmental conditions: It dilates, growing bigger to receive more light under dim lighting conditions, and shrinks in response to bright light. This response is quicker in young individuals and tends to slow with increasing age.
  3. From the pupil, light waves travel to the lens of the eye. The lens is a clear, flexible structure that focuses an upside-down image onto the retina. It is flexible so that it can focus on images that are close or far away. Eye injuries, normal variations in the eye and age can distort the lens, making it difficult to focus on nearby or faraway objects -- you see the objects, but details are hazy. Late in life, the lens can also become clouded and form cataracts that make images seem hazy and dim.
  4. The lens focuses light and images on the retina, a layer of light-sensitive cells at the back of the eye. It is made up of two kinds of photoreceptor cells: cones and rods. The cones transmit colour and sharp images. The concentration of cones is low on the sides of the retina and increases as the cones approach the centre of the retina or the macula. The rods are more sensitive to light and are more numerous than cones; They let you see when lighting is dim, although what you see lacks colour and clear details.
  5. Once the retina senses the image, it sends impulses to the optic nerve at the back of the eye. The optic nerve then transmits them to special areas in the brain, which automatically flips the upside-down image so that it becomes upright again. Disease or injury can damage the optic nerve, resulting in varying degrees of blindness.

So, the correct answer is 'Cornea, pupil, lens, vitreous humour retina'.

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

Match column I with column II and select the correct option from the codes given below.

Column I Column II
A. Cornea (i) Provides opening for light to enter
B. Iris (ii) Transducens blue, green and red light
C. Lens (iii) Controls the amount of light that enters
D. Optic nerves (iv) Alters the shape of lens
E. Pupil (v) Transmit information to the CNS
F. Ciliary muscles (vi) Focus light directly on retina
G. Fovea (vii) Bends light and protects inner eye


  1. A - (vii), B - (iii), C - (vi), D - (v), E - (i), F - (iv), G - (ii)

  2. A - (i), B - (ii), C - (iii), D - (iv), E - (v), F - (vi), G - (vii)

  3. A - (vii), B - (vi), C - (v), D - i(v), E - (iii), F - (ii), G - (i)

  4. A - (vii), B - (iv), C - (vi), D - (v), E - (i), F - (iii), G - (ii)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cornea (vii) bends light, Iris (iii) controls light, Lens (vi) focuses light, Optic nerves (v) transmit to CNS, Pupil (i) provides opening, Ciliary muscles (iv) alter shape, Fovea (ii) transducens light. Matching these leads to A.

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

Rhodopsin is found in

  1. Rods only

  2. Whole of retina

  3. Cones only

  4. Ganglion cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rhodopsin is found in specialized light receptor cells called rods. These are light-sensitive tissue present in the retina. They provide vision in low light. Other light receptor cells in the retina, called cones, are responsible for vision in bright light.

Thus, the correct answer is 'rods only.'

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

The portion of the eye which is differently coloured in different people and gives characteristically coloured eyes is the

  1. Retina

  2. Cornea

  3. Sclera

  4. Iris
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Retina is the innermost layers of the eyeball. The cornea is the transparent anterior window of the outer layer of the eyeball located within otherwise opaque sclera. Iris is the colored part of the eye that imparts characteristic color of eyes to different people. 

So, the correct answer is option D.

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

A comb-like vascular structure pectin, used for nourishment and focussing in the eyes of

  1. Amphibians

  2. Birds

  3. Mammals

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

In the eye of the bird, a comb-like structure is present. It is called as pectin. It is soft and vascular. It is a rectangular plate. It projects into the vitreous humor from the blind spot. So, the correct answer is option B.

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

The entry of light in a photographic camera is controlled by the shutter and iris diaphragm, comparable structure in human eye are

  1. Cornea and iris

  2. Eyelids and iris

  3. Ciliary muscles and pupil

  4. Ciliary body and iris
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Iris is the part of the eye, which acts like the diaphragm of a camera, dilating and constricting the pupil to allow more or less light into the eye. The iris works like a shutter in a camera. It has the ability to enlarge and shrink, depending on how much light is entering the eye.
The two eyelids act to protect the front of the eye and excessive light by their closure. The inner layer of the cornea is made up of transparent tissue, which allows light to pass. The pupil is the dark opening in the centre of the coloured iris, that controls how much light enters the eye. The ciliary body is a structure located behind the iris which produces aqueous fluid that fills the front part of the eye and thus maintains the eye pressure. It also allows focusing of the lens. 

Thus, the correct answer is the option (B).

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

Which animal have porphyropsin instead of pigment rhodopsin in rods? 

  1. Fish

  2. Birds

  3. Reptiles

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

In the rods of fresh water fishes, rhodopsin is replaced by the purple photolabile pigment porphyropsin. This participates in a retinal cycle identical in form with that of rhodopsin, but in which new carotenoids replace retinene and vitamin A.

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

The retina of the eye acts as a

  1. Lens of the camera

  2. Aperture of the camera

  3. Film of the camera

  4. Shutter of the camera
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The back of the eye is lined by a layer called as the retina, which acts like the film inside a camera. The retina is a thin layer of nerve tissue, that contains photoreceptors. Photoreceptors convert light rays into electrical impulses, which are then sent through the optic nerve to the brain, where an image is perceived. As with a camera, if the film is bad in the eye (i.e., the retina is damaged or diseased), no matter how well the rest of the eye is functioning, a good picture is not possible.