Sense Organ Srijan Publications Solutions ICSE Class-10 Biology Ch-11

Sense Organ Srijan Publications Solutions ICSE Class-10 Ch-11. We Provide Solutions of Very Short Answer Type, Short Answer Type, Long Answer Type Questions and MCQs of Exercise-11 Sense Organ Srijan Publications ICSE Class-10 Ch-11. Visit official Website CISCE for detail information about ICSE Board Class-10.

Sense Organ Srijan Publications Solutions ICSE Class-10 Biology Ch-11

Board	ICSE
Publications	Srijan Publications
Subject	Biology
Class	10th
Writer	Veer Bala Rastogi
Chapter-11	Sense Organ
Topics	Solutions of MCQs, Very short and Short Long Answers Questions
Edition	for 2022-2023 Academic Session

A. VERY SHORT ANSWER TYPE QUESTIONS

Ch-11 Sense Organ Srijan Publications ICSE Class-10 Biology Solutions

(Page-164)

Questions 1. Answer the following questions.

(a) Which part of our body helps us in maintaining the body balance?

(b) What type of image is formed on the retina of human eye?

Answer :

(a) The ear

(b) real but inverted image

Questions 2. Give one word for the following.

(a) The tube which connects the cavity of the middle ear to the throat.–

(b) The part of eye responsible for its shape. ‘Sclera

(d) The eye defect caused due to shortening of the eyeball from front to back.–hyperopia.

(e) The structure responsible for protecting the eye from sweat. eyelid

(f) fluid that occupies the larger cavity of the eyeball behind the lens.- vitreous humour

(g) The photosensitive pigment present in the rod cells of retina.- Rhodopsin

(h) The internal layer of the eye which prevents reflection of light. Choroid

(i) An eye defect in which the cornea becomes uneven. Astigmatism

(j) The photosensitive pigment present in the cone cells of the retina.- Iodopsin.

(k) The fluid present in the anterior part of the eye in front of the eye lens. Aqueous Humour.

(l) The kind of lens required to correct myopia. concave lens

Questions 3. State whether the following statements are true or false. If false, rewrite the correct from of statements.

(a) Deafness is caused due to the rupturing of the pinna. False

(b) The part of ear associated with balance is cochlea. False

Correct : The part of ear associated with balance is semi circular canal

(d) Cones are photoreceptor cells that are sensitive to dim light. False

Correct: Rod are photoreceptor cells that are sensitive to dim light

(e) Rods are responsible for vision in the dark. False

Correct: Cone are responsible for vision in the dark

Questions 4. Complete the following statements by choosing the correct alternative out of those given in brackets.

(a) A …concave….. lens is used to correct myopia (concave/convex)

(b) ……..retina…… is the region in eye where the rods and cones are located. (retina/cornea)

(d) Calcium carbonate particles present in endolymph are called …otolith….. (otolith/ampullae/cochlea)

Questions 5. Given here is an example of a certain structure and its special functional activity, e.g, olfactory nerve and smell. On the similar pattern, fill in the blanks below.

(a) Organ of Corti and …transduction of auditory signals.

(b) Cones and …..color vision.

(d) Eustachian tube and ….equalize the air pressure

(e) Suspensory ligaments and…...Hold the lens

(f) Semicircular canals and….keep balance.

Questions 6. Given below are sets of terms. Arrange each set in a logical sequence.

(a) Ear ossicles, oval window, tympanum, auditory canal, cochlea

Auditory canal, Tympanum, Ear ossicles, Oval window, Cochlea.

(b) Pupil, eye lens, vitreous humour, fovea, optic nerve

Pupil → Eye lens → Vitreous humour → Fovea → Auditory nerve

Pinna → auditory canal → tympanum → ear ossicles → cochlea

(d) Pupil, yellow spot, conjunctiva, cornea, lens, aqueous humour

conjunctiva, cornea, pupil ,lens, vitreous humour, yellow spot

(e) Cochlea, malleus, pinna, stapes, incus

Pinna→Malleus→Incus→Stapes→Cochlea

Questions 7. Explain the following terms.

(a) Stereoscopic vision: stereoscopic vision describes the ability of the visual brain to register a sense of three-dimensional shape and form from visual inputs. In current usage, stereoscopic vision often refers uniquely to the sense of depth derived from the two eyes

(b) Power of accommodation of the eye: is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length. Power of accommodation of the eye is limited. It implies the focal length of the eye lens cannot be reduced beyond certain minimum limit.

(c) Cataract : A cataract is a cloudy lens. The lens is positioned behind the colored part of your eye (iris). The lens focuses light that passes into your eye, producing clear, sharp images on the retina — the light-sensitive membrane in the eye that functions like the film in a camera

Questions 8. Given below are certain functional activities of specific structure in the body of living organisms. Name the structure responsible for:

(a) The change in the focal length of eye lens.—Ciliary muscles

(b) Transfer of impulses from inner ear to brain —The cochlear nerve,

B. Short Answer Type Questions

Ch-11 Sense Organ Srijan Publications ICSE Class-10 Biology Solutions

(Page-165)

Questions 1. Answer the following questions briefly.

(a) How do you perceive the colour of an object?

Ans: The human eye and brain together translate light into color. Light receptors within the eye transmit messages to the brain, which produces the familiar sensations of color. Newton observed that color is not inherent in objects. Rather, the surface of an object reflects some colors and absorbs all the others

(b) Describe the functions of rods, cones and lens of the human eye.

Ans: Rods are responsible for vision at low light Cones are active at higher light lens, function of which is to focus light rays onto the retina

Ans: The size of the pupil regulates the amount of light entering the eye

(d) What is eustachian tube? State its role in the body.

Ans: a thin tube that connects the middle ear with the upper pharynx and equalizes air pressure on either side of the eardrum

(e) Write the mechanism through which sound produces a nerve impulse in the inner ear.

Ans: Sound waves strike pinna. Then waves are conducted through auditory canal to the which begins to vibrate. Vibrations from the tympanum are conducted upto the membrane of fenestra ovalis

(f) What is dark adaptation with reference to seeing in dark?

Ans: the adjustment of the eye to low light intensities, involving reflex dilation of the pupil and activation of the rod cells in preference to the cone cells.

(g) How does the thickness of lens change for viewing objects at different distances?

Ans: To see a distant object clearly, the focal length of the lens should be larger. For this, the ciliary muscles relax to decrease the curvature and thereby increase the focal length of the lens. Hence, the lens becomes thin. This enables you to see the distant object clearly

(h) What is lacrimal gland? Where is it located?

Ans : The lacrimal gland is located within the orbit above the lateral end of the eye. It continually releases fluid which cleanses and protects the eye’s surface as it lubricates and moistens it. These lacrimal secretions are commonly known as tears

(i) What is power of accommodation of the human eye? Name the muscles of the eye responsible for the same.

Ans: The power of accommodation of the eye is the process of adjusting the focal length of the lens according to the near or distant objects. The ciliary muscles attached to the lens controls its curvature and alters its focal length

Questions 2. Give difference between the following

(a) Yellow spot and blind spot

Yellow Spot	Blind Spot
It is located lateral to the blind spot at the posterior pole of the eye.	Blood vessels enter and the optic nerve leaves the eye at this spot.
Cone cells are densely packed in this region.	Photoreceptor cells, i.e. rods and cones, are absent.
It is the region of sharpest vision.	No vision is formed at the blind spot.

(b) Rod and cone cells (pigment)

Rods are responsible for vision at low light levels (scotopic vision). They do not mediate color vision, and have a low spatial acuity. Cones are active at higher light levels (photopic vision), are capable of color vision and are responsible for high spatial acuity. The central fovea is populated exclusively by cones

The function of Sclerotic layer is to protect the eye from the mechanical injuries. It is the outermost layer of human eye. Choroid layer, which the second layer of eye, is present between sclera and retina. It provides oxygen and nourishment to the outer retina

(d) Myopia and hypermetropia (cause of defect)

Parameter	MYOPIA	HYPEROPIA
Causes	Due to elongated eyeball or due to the curved cornea.	Due to the flattened eyeball or short eyeball.

Questions 3. Write the location and function of each of the following

(a) Ear ossicles : The malleus connects to the tympanic membrane transferring auditory oscillations to the incus and then the stapes. The stapes connects to the oval window allowing for mechanical energy to be transferred to the fluid-filled inner ear

(b) Lacrimal glands : The lacrimal gland is located within the orbit above the lateral end of the eye. It continually releases fluid which cleanses and protects the eye’s surface as it lubricates and moistens it. These lacrimal secretions are commonly known as tears

(c) Pinna : The auricle comprises a thin plate of elastic cartilage covered by a layer of skin. It consists of funnel-like curves that collect sound waves and transmits them to the middle ear

(d) Eustachian tube : This air-containing space is maintained by the Eustachian tube, which opens intermittently to equalize the intratympanic air pressure with the pressure in the

Questions 4. Give reasons for the following:

(a) We feel almost blind on entering a darkroom at daytime

When we move into a dark room from bright light the eyes need time to adjust and the iris muscles need time to dilate the pupils so that more light can enter the eye. So, in that duration when the eye muscles are trying to adjust the eyes to the amount of light we feel blinded.

(b) We are not able to open our eyes for a moment on coming out in bright daylight from a darkroom.

When the eyes are in bright light the pupil of the eyes shrinks in order to allow less light to enter the eyes

The symptoms of dizziness and vomiting, faced by a person travelling at higher altitude is because of the following reasons The function of Eustachian tube is to equalise the pressure on either sides of the ear drum; sudden elevation in height causes disturbance in maintaining pressure by this area of ear.

(d) Some persons have blue eyes while some have brown or black eyes

Eye color is directly related to the amount and quality of melanin in the front layers of the iris. People with brown eyes have a large amount of melanin in the iris, while people with blue eyes have much less of this pigment. A particular region on chromosome 15 plays a major role in eye color

(e) Deficiency of vitamin A in diet causes night blindness in a person

Vitamin A deficiency may be caused by prolonged inadequate intake of vitamin A. This is especially so when rice is the main food in your diet (rice doesn’t contain any carotene). Vitamin A deficiency may also occur when your body is unable to make use of the vitamin A in your diet

(f) We feel dizzy as if going in circles, after we have stopped spinning round and round.

When you stop spinning, your head stops moving but the fluid in the tube of the balance organ keeps spinning. So now your brain thinks you are spinning in the opposite direction. This is what makes you feel dizzy again.

(g) Throat infections lead to ear infections

Strep throat is a contagious infection caused by a group of bacteria. Strep throat can cause a very painful sore throat that comes on very quickly. Sometimes, the bacteria from a throat infection can travel into the eustachian tubes and middle ear, causing an ear infection

(h) One feels blinded for a short time while coming out of a dark room.

When we are standing in bright light the muscles of the iris contract and the pupils constrict, so that less light can pass into the eye.

(i) Colour blindness is more common in men than in women

Males have 1 X chromosome and 1 Y chromosome, and females have 2 X chromosomes. The genes that can give you red-green color blindness are passed down on the X chromosome. Since it’s passed down on the X chromosome, red-green color blindness is more common in men..

Questions 5. Match the columns.

Column A	Column B
(a) Ear bones	(i) Detects sound vibrations
(b) Cochlea	(ii) Detects change in the position during movement
(c) Eustachian tube	(iii) Amplify sound vibrations
(d) Semicircular canals	(iv) Protects eardrum from damage due to pressure differences on the two sides of eardrum

Answer :

Column A	Column B
(a) Ear bones	(iii) Amplify sound vibrations
(b) Cochlea	(i) Detects sound vibrations
(c) Eustachian tube	(iv) Protects eardrum from damage due to pressure differences on the two sides of eardrum
(d) Semicircular canals	(ii) Detects change in the position during movement