Tag: biology

Quizzes (1160) Questions (12174)

Questions Related to biology

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

Retina is most sensitive at

  1. Optic disc

  2. Periphery

  3. Macula lutea

  4. Fovea centralis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A minute yellowish area containing the fovea centralis located near the center of the retina of the eye at which visual perception is most acute is called as yellow spot or macula lutea. When an eye is looking directly at an object, light rays from that object are focused on the macula lutea, a yellow oval spot at the center of the retina. It is the part of the retina, that is responsible for sharp, detailed central vision also called as visual acuity.
So, the correct answer is 'Fovea centralis'
Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

If the circular ciliary muscles of the eye are unable to contract, the 

  1. Lens will become more convex

  2. Lens will be thin and stretched

  3. Vision will be lost completely

  4. Bright light will have no adverse effect on retina
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ciliary body and the attached suspensory ligament change the shape (flattened or round) of the lens through relaxation and contraction of ciliary muscles and thereby the focal length to focus on the distant and near object. Contraction of ciliary muscles releases the suspensory ligaments and allow the lens to become round (convex) while relaxation of these muscles makes the lens taut. Since ciliary muscles are involved in accommodation required for close vision, loss of their contraction would not cause loss of vision but would affect the close vision only. The amount of light entering retina is controlled by the iris. 

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

Choroid is

  1. Middle layer of ear

  2. Innermost layer of eye

  3. Innermost layer of ear

  4. Middle layer of eye
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The choroid is a layer of eyeball. The eyeball has three coats namely sclera, choroid, and retina. The choroid is middle dark pigmented thin vascular layer of the eyeball and is characterized by the presence of many blood vessels. Retina forms the innermost layer of the eye. 

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 have "ommatidia" as unit of eye?

  1. Pheretima

  2. Housefly

  3. Pila

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

Compound eyes are the characteristic feature of insects. The compound eye of insects consists of many ommatidia, each of which is a separate visual unit that portrays each object into several broken pieces. This type of vision is called as mosaic vision. Among the given options, housefly is an insect and has ommatidia as a unit of an eye. Pheretima (annelid) and pila and sepia (molluscs) do not have compound eyes. 

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 black pigment in the eye, which reduces the internal reflection is located in

  1. Retina

  2. Iris

  3. Choroid

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

The choroid is the part of the vascular coat in eyes. It also contains blood vessels that provide nourishment to the eye. It is pigmented towards a rear of the eye and absorbs light. It is a dark brown in colour. It darkens the cavity of the eyeballs to prevent internal reflection of light that might blur the image.

Thus, the correct answer is C.  

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

Caring, diagnosis and cure of eye diseases

  1. Orthopaedics

  2. Ophthalmology

  3. Pathology

  4. Andrology
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The word ''Opthalmology'' comes from the Greek roots ''Ophthalmol'' means ''Eye'' and ''Logos'' means ''Study''. Hence Ophthalmology literally means the ''The science of eyes''. 
  • An Ophthalmologist is a specialist in medical and surgical eye problems.
  • Hence Ophthalmology is the study of Caring, diagnosis and cure of eye diseases.
  • So, the correct answer is 'Ophthalmology'.
Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

In a similarity with photographic camera, retina acts as

  1. Shutter

  2. Lens

  3. Diaphragm

  4. Film
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
In a photographic camera, image is formed on the film. Similarly, in eye, image is formed on the retina which is the light sensitive surface in the eye. The light rays enter the eye through an aperture called pupil. The eye lens which is biconvex, focus the light rays on the retina and an image is formed. Both the camera and eye have the ability to regulate the amount of light for image formation.
So, the correct answer is 'Film'.
Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

A student has problem in reading as he is unable to contract his ______.

  1. Suspensory ligament

  2. Ciliary muscles

  3. Pupil

  4. Iris
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A. Suspensory ligaments attach the eye lens with the ciliary body.
B. Ciliary muscles change the shape of eye lens to focus on nearby and distant objects.
C. Pupil is an aperture in eye through which light enters the eye.
D. Iris is pigmented and opaque structure of eye which controls the amount of light entering the eye by changing the size of pupil.
If a student has problem in reading, this means his eye lens is not able to focus on the alphabets and this is due to inability of the ciliary muscles to contract.
So, the correct answer is 'Ciliary muscles'.