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The eye’s structure is vital to comprehend because it is one of the most significant sensory organs in the human body. It is primarily responsible for vision, colour discrimination (the human eye can distinguish around 10 – 12 million colours), and the human body’s biological clock. The human eye and a camera are similar in that they both gather, focus, and transmit light through a lens to create an image of a body.
The human eye is one of the most complex sensory organs in the body.
Q1. When a person wearing a concave lens to correct eyesight does not wear glasses, where would the picture of a distant item be formed?
a) Behind the retina
b) On blind-spot
c) In front of retina
d) On the yellow spot
Answer. In front of the retina is the right answer.
Short-sighted people can’t see properly far away objects. Light rays are bent slightly outwards with concave prescription lenses (also known as negative lenses). When going through cornea and lens, light rays have a higher angle to bend back to focus. The light rays focus back on retina as a result of this.
Q2. Eye lens is a
a) Concave Lens
b) Biconcave Lens
c) Convex Lens
d) Biconvex Lens
Answer. Biconvex lens is the correct answer.
A biconvex lens is a basic lens that comprises 2 convex surfaces in a spherical form, with the same radius of curvature. Eye lens is a biconvex lens.
Q3. Which of the following is the incorrect statement?
a) Rhodopsin is a purplish-red protein found only in rods.
b) The derivative of Vitamin C is Retinal.
c) The Retina is light – an absorbing component of visual photopigments.
d) Rhodopsin, a photopigment, is found in the rods of the retina, whereas cones have 3 separate photopigments.
Answer. The derivative of Vitamin C is Retinal is the correct answer. Retinal is the derivative of Vitamin A.
Q4. In the human eye, the photosensitive compound is made up of the following component?
a) Guanosine & Retinol
b) Opsin & Retinol
c) Transducin & Retinene
d) Opsin & Retinal
Answer. Opsin & Retinal is the right answer.
Rhodopsin is a photosensitive molecule that helps us see. It’s a pigment found in retina’s rods. Opsin and retinal are the components.
Q5. Persistence of the vision for human eye is
a) 1/4th of Second
b) 1/8th of Second
c) 1/12th of Second
d) 1/16th of Second
Answer. 1/16th Second is the right answer.
The normal human eye has a visual persistence of 1/16th of Second. Persistence of vision is an optical phenomenon in which the brain perceives numerous motionless images as one, creating the appearance of motion. The human eye and the brain only process roughly 12 images per second, and each image is only retained for 1/16th of Second.
Q6. In humans, a cornea transplant has never been rejected since
a) It is made up of enucleated cells.
b) It is a non – living layer.
c) It has no supply of blood.
d) Its cells are the least permeable to bacteria.
Answer. It has no supply of blood is the correct answer.
Rejection of the transplanted organs is induced by immune system’s recognition of the transplant as a foreign body, which prompts a response against organ or tissue, resulting in rejection in the majority of cases.
Cornea transplants in humans are never rejected because the cornea collects oxygen directly from the air and is not engaged in the immune system due to a lack of blood supply.
Q7. The primary function of cornea which is present in human eye is
a) It provides structural support to the eye.
b) It bends the light before it reaches the lens.
c) It contains a concentrated amount of cone cells in the correct orientation.
d) It changes the shape of the lens which enables the image to be focused on the retina.
Answer. It bends the light before it reaches the lens is the correct answer.
The region in front of the eye termed as the cornea is located there. By bending or refracting light towards the lens, it concentrates light entering the eye.
Q8. The fovea is the centre of visual field of the mammalian eye where
a) Optic nerve exits the eye.
b) Rods are found only.
c) More rods as compared to cones are found.
d) No rods are found but a high density of the cones occurs.
Answer. No rods are found but a high density of the cones occurs is the correct answer.
The fovea centralis is the small central pit in the eye made up of closely packed cones. It’s in charge of acute central vision, which is necessary for driving and reading. Although there are a lot of cones in this area, there aren’t any rods. The central fovea is made up of relatively compact cones that are thinner and more rod – like than those seen elsewhere. The fovea is not responsive to weak light because it lacks rods.
Q9. The type of cells which are found in the retina are
a) Purkinje Cells.
b) Neuroglial Cells.
c) Schwann Cells.
d) Amacrine Cells.
Answer. Amacrine Cells is the right answer.
The vertebrate retina’s amacrine cells are interneurons which interact at the 2nd synaptic level in the photoreceptor – bipolar – ganglion cell chain’s vertically direct routes.
Q10. What is the function of the tapetum lucidum?
a) It is the coloured portion of eye
b) It gives night vision to the animals.
c) It is transparent jelly – like fluid.
d) It is the area in which the optic nerve attaches.
Answer. Giving night vision to the animals is the right answer.
In some animal species, the tapetum lucidum is the layer of eye. This membrane is found at the back of eye, behind the retina. It reflects light and gives the appearance of glowing eyes in the dark. This membrane is found in many nocturnal animals, such cats, cattle, horses, dogs, and fish.
