Chapter 11 : Sense Organs - Selina Solutions for Class 10 Biology ICSE

Biology is one of the crucial subjects in ICSE Class 10. ICSE Class 10 Biology speaks about the cell as the basic unit of life, genes, and evolution and deals with how living organisms interact with the environment, including the behavior of living beings. TopperLearning is one of the premier online platforms which helps students of ICSE Class 10 to study various concepts in Biology.

Read  more
Page / Exercise

Chapter 11 - Sense Organs Excercise Ex. 1

Question 1
Which part of the eye is grafted in a needy patient from a donated eye?

(a) Conjunctiva

(b) Cornea

(c) Choroid

(d) Ciliary muscles
Solution 1
(b) Cornea
Question 2
Which part of our ear is shaped like a snail shell?

(a) Semi-circular canals

(b) Cochlea

(c) Stapes

(d) Eustachian tube
Solution 2
(b) Cochlea
Question 3
The three parts of human ear contributing in hearing are:-

(a) Cochlea, ear ossicles and tympanum

(b) Semi-circular canals, utriculus and sacculus

(c) Eustachian tube, tympanum and utriculus

(d) Perilymph, ear ossicles and semi-circular canals
Solution 3
(c) Eustachian tube, tympanum and utriculus
Question 4
The region in the eye where the rods and cones are located is the

(a) Retina

(b) Cornea

(c) Choroid

(d) Sclera
Solution 4
(a) Retina
Question 5

Name the following:

(a) The photosensitive pigment present in the rods of the retina.

(b) The part which equalizes the air pressure in the middle and external ear.

(c) The ear ossicle attached to the tympanum.

(d) The tube which connects the cavity of the middle ear with the throat.

(e) The part of the eye responsible for its shape.

(f) The nerves which transmit impulse from ear to the brain.

(g) The photoreceptors found in the retina of the eye.

(h) The eye defect caused due to shortening of the eye ball from front to back.

Solution 5

(a) Rhodopsin

(b) Eustachian tube

(c) Hammer

(d) Dura mater

(e) Eustachian tube

(f) Cornea

(g) Auditory nerves

(h) Rods and cones

(i) Hypermetropia

Question 6
Note the relationship between the first two words and suggest the suitable word/words for the fourth place.

(a) Cones: Iodopsin:: rods: ________.

(b) Sound: ear drum:: dynamic balance: __________.
Solution 6
(a) Cones: Iodopsin:: rods: rhodopsin

(b) Sound: ear drum:: dynamic balance: semi-circular canals
Question 7

Which one or more of the expressions in column II are appropriate for the items listed in column I? Match the correct pairs:

Column I

Column II

i. The blind spot

(a) colour of the eye

ii. The yellow spot

(b) shape of the lens

iii. Ciliary muscle

(c) amount of light entering the eye

iv. Iris

(d) maximum sensory cells

v. Pupil

(e) no sensory cells

 

Solution 7

Column I

Column II

i. The blind spot

(e) no sensory cells

ii. The yellow spot

(d) maximum sensory cells

iii. Ciliary muscle

(b) shape of the lens

iv. Iris

(a) colour of the eye

v. Pupil

(c) amount of light entering the eye

 

Question 8

Differentiate between members of each of the following pairs with reference to what is given in brackets.

(a) Myopia and hyperopia (cause of the defect)

(b) Rods and cones (sensitivity)

(c) Semi-circular canal and cochlea (Function)

(d) Rod and cone cells (pigment contained)

(e) Dynamic balance and static balance (definition)

Solution 8

(a) Myopia results when the eye ball is lengthened from front to back or the lens is too curved.

Hyperopia results from either too shortening of the eyeball from front to back or when the lens is too flat.

(b) Rods are sensitive to dim light but do not respond to colour.

cones are sensitive to bright light and are responsible for colour vision.

(c) cochlea is responsible for hearing; it can perceive the senses of hearing.

Semicircular canals are responsible for perceiving the senses to maintain the body balance.

(d) Rod cells contain rhodopsin whereas the cone cells contain iodopsin.

(e) Dynamic balance is when the body is in motion whereas static balance is positional balance with respect to gravity.

Question 9
State whether the following statements are true (T) or false (F). If false, correct it by changing any one single word.

(a) Deafness is caused due to rupturing of the pinna.(T/F)

(b) Semicircular canals are concerned with static (positional) balance. (T/F)
Solution 9
(a) False

Correct statement: Deafness is caused due to rupturing of the eardrum.

(b) False

Correct statement: Semicircular canals are concerned with dynamic balance.
Question 10
Mention, where in living organisms are the following located and state their main functions:

(a) Fovea centralis

(b) Organ of corti
Solution 10
(a) Fovea centralis is located at the back of the eye almost at the centre of the eyeball. It is the region of the brightest vision and also of the colour vision.

(b) Organ of corti is located in the inner ear. It contains sensory cells which process hearing.
Question 11

Mention if the following statements are true or false. Give reason.

(a) Sometimes medicines dropped into the eyes come into the nose and even throat.

(b) Ciliary muscles regulate the size of the pupil.

(c) Yellow spot of the retina is the region of the colour vision.

(d) The auditory nerve is purely for perceiving sound.

(e) Malleus, incus and stapes are collectively called ear ossicles.

(f) Short-sightedness and hyperopia are one and the same thing.

(g) Blind spot is called so because no image is formed on it.

Solution 11

(a) True

(b) False/ Ciliary muscles regulate the size of the lens.

(c) True

(d) False/The auditory nerve responsible for sound as well as for the body balance.

(e) True

(f) False/ flavour is a combination of taste and smell.

(g) False/ short-sightedness is myopia and hyperopia is long-sightedness.

(h) True

Question 12
Given below are two sets (a) and (b) of five parts in each. Rewrite them in correct sequence.

(a) Cochlea, tympanum, auditory canal, ear ossicles, oval window

(b) Conjunctiva, retina, cornea, optic nerve, lens
Solution 12
(a) Auditory canal, tympanum, ear ossicles, oval window, cochlea

(b) Conjunctiva, cornea, lens, retina, optic nerve
Question 13

Given below are certain structures. Write against them their special functional activity.

(a) Organ of Corti and __________

(b) Olfactory nerve and ___________

(c) Retina and __________

Solution 13

(a) Organ of Corti and hearing

(b) Olfactory nerve and smell

(c) Retina and vision

Question 14

Answer the following:

(a) What is the function of the lacrimal gland and where is it situated in the body?

(b) In what two ways is the yellow spot different from the blind spot?

(c) Name an age-old eye defect. What causes it?

(d) What is meant by the power of accommodation of the eye?

(e) Mention the characteristics of the image that falls on the retina of the eye.

Solution 14

(a) Lacrimal gland is a tear gland located at the upper sideward portion of the eye orbit. Its secreation lubricates the surface of the eye, washes aways the dust particles and kills germs

(b) Yellow spot is the region of brightest vision and contains maximum sensory cells whereas a blind spot contains no sensory cells and this is the point of no vision.

(c) Presbyopia is an age-old eye defect. In this condition, the lens loses flexibility resulting in far-sightedness.

Cataract is also very common in old people, the cornea becomes opaque and the vision is cut down even to blindness.

(d) The process of focusing the eye at different distances is called the power of accommodation.

(e) The image formed on the retina is inverted and real.

Question 15
What is meant by optical illusion? Give one example.
Solution 15
An optical illusion is the life-like continuous movement on the screen. Television is an example of optical illusion, where the scanning beam of a picture frame of the TV camera moves so rapidly on the viewing screen of the TV set that our eyes cannot keep pace with it.
Question 16
Where are the following located? Briefly mention the function of each:

(a) Oval window

(b) Cochlea

(c) Semicircular canals

(d) Utriculus
Solution 16
(a) Oval window is located in the middle ear. It helps in setting the fluid in the cochlear canals into vibration.

(b) Cochlea is located in the inner ear. It helps in transmitting impulses to the brain via the auditory nerve.

(c) Semicircular canals are located in the inner ear. These help in maintaining the dynamic equilibrium of the body.

(d) Utriculus is located in the inner ear. It joins the semi-circular canals to cochlea. It also helps in maintaining static balance of the body.
Question 17

Complete the following table by filling in the blank spaces.

Structure

Function

1. Yellow Spot

(i) …………………….

2. …………………….

(ii) Transfers impulse from inner ear to brain

3. …………………….

(iii) Helps to change the focal length of the eye lens

4. Oval window

(iv) …………………….

5. …………………….

Dynamic equilibrium

 

Solution 17

Structure

Function

1. Yellow Spot

(i) Region of brightest vision

2. Auditory nerve

(ii) Transfers impulse from inner ear to the brain

3. Ciliary muscle

(iii) Helps to change the focal length of the eye lens

4. Oval window

(iv) Sets fluid in the cochlear canal into vibration

5. Semicircular canals

Dynamic equilibrium

 

Question 18
Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.
Solution 18
While reading a book, the lens is more convex or rounded due to contraction of ciliary muscles because the book is usually read from a short distance. When we raise our head and look at a distant object, the ciliary muscles relax to build the tension on the suspensory ligament so that they can stretch the lens. This change in the curvature of the lens makes us focus on distant object.



Question 19
Sometimes you remember a vivid picture of a dream you saw. What is the role of your eyes in this experience?
Solution 19
The brain sees the vivid picture of the dream through the eyes. Our eyes have actually never seen the vivid picture. This is an example of optical illusion. The area of dream is controlled by the cerebrum of the central nervous system. So sometime we can remember the vivid picture seen in the dream.
Question 20
By closing the eyes and gently pressing them with your palms, you may see some specs of brilliant light. How do you get this sensation while there is no light entering your eyes?
Solution 20
If we look at a bright object and then close our eyes, the sensation of light persists for a short period. This is known as persistence image or the after image. It lasts for one-tenth of a second. Therefore by closing the eyes and gently pressing them with your palms, you see some specs of brilliant light.
Question 21
Explain the terms 'adaptation' and 'accommodation' with reference to the eye.
Solution 21

Adaptation is the ability to adjust vision in bright and dark areas. When we enter a dark room from bright light, the rhodopsin pigment broken down in bright light is regenerated. It dilates the pupil and allows more light to enter the eyes. This is called dark adaptation. On the other hand, if we enter bright area from a dark room, the rhodopsin pigment is bleached. This constricts the pupil and reduces the light entering the eyes. This is called 'light adaptation'

 

Accommodation is the process of focusing the eye at different distances. This is mainly brought about by a change in the curvature of the lens. When the ciliary muscles contract, the lens becomes thicker and we are able to focus a nearby object. On the other hand when the ciliary muscles relax, the lens remains stretched i.e. the normal condition and we are able to focus on distant object.
Question 22
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
Solution 22
Our eyes are designed to focus at a great variety of distances. To focus constantly at a short distance can make the lens focusing muscles fatigued. Therefore, we do not enjoy watching a movie from a very short distance from the screen in cinema hall.
Question 23
Enumerate the common defects of vision, their causes and the possible methods of correcting them.
Solution 23

Defect of vision

Cause

Corrective measure

Myopia

Lengthening of eye ball from front to back or the lens is too curved.

Using suitable concave lens

Hyperopia

Shortening of eye ball from front to back or the lens is too flat.

Using suitable convex lens

Astigmatism

Uneven curvature of the cornea

Using suitable cylindrical lenses

Presbyopia

Loss of flexibility of lens

Using suitable convex lens

Cataract

Lens turning opaque

Surgery or use of convex lens or implantation of plastic lens.

Colour blindness

Genetic defect

No control measure

Squint

Formation of cross-eye

Surgery and suitable exercise

Question 24
Name the three ear ossicles. How do they contribute in the mechanism of hearing?
Solution 24
The three ear ossicles are: Malleus (hammer), Incus (anvil) and Stapes (stirr up).

The last ear ossicle, stapes, vibrates and transmits the vibration to the oval window.

The role of other two ear ossicles is to magnify the vibration of stapes as a result of their lever like action.
Question 25
What is meant by power of accommodation of the eye? Name the muscles of the eye responsible for the same.
Solution 25
The process of focusing the eye at different distances is called the power of accommodation. The ciliary muscles are responsible for the power of accommodation.
Question 26

With reference to the functioning of the eye, answer the questions that follow:

a. What is meant by power of accommodation of the eye?

b. What is the shape of the lens during (1) near vision (2) distant?

c. Name the two structures in the eye responsible for bringing about the change in the shape of the lens.

d. Name the cells of the retina and their respective pigments which get activated (1) in the dark and (2) in the light.

Solution 26

a. The ability of the eye to focus sharply on things which are near to the eye as well as far off is known as the power of accommodation.

 

b. Shape of the eye:

 Near vision - flattened

 Distant - rounded or more convex

 

c. Ciliary muscles and suspensory ligament

 

d. In the dark: Cells - rod cells, Pigment - rhodopsin

In the light: Cells - cone cells, Pigment - iodopsin

Question 27

With reference to the human ear, answer the questions that follow:

a. Given the technical term for the structure found in the inner ear.

b. Name the three small bones present in the middle ear. What is the biological term for them collectively?

c. Name the part of the ear associated with (1) static balance (2) hearing (3) dynamic balance.

d. Name the nerve, which transmits messages from the ear to the brain.

Solution 27

a. The middle ear or membranous labyrinth has two structures inside it, the cochlea and the semi-circular canals.

 

b. Malleus, incus and stapes

 

c. Static balance - Utriculus and sacculus (inner ear)

Hearing - Internal ear

Dynamic balance - Semi-circular canals (inner ear)


d. Collectively they are termed as ossicles.

Question 28

The figure below compares a part of our eye with a part of a photographic camera.



(a) Name the corresponding parts of the eye and the camera shown here that are comparable in function.

(b) Explain the mode of working and the functions of the parts of the eye mentioned above.

Solution 28

(a) Cornea is comparable to the lens cover of the camera.

The iris and pupil act like the aperture of a camera.

(b) The cornea is the eye's main focusing element. It takes widely diverging rays of light and bends them through the pupil; the rays are further converged by the lens.

Question 29

Given below is a diagram depicting a defect of the human eye? Study the same and answer the questions that follow:



(a) Name the defect shown in the diagram.

(b) Give two possible reasons for this defect.

(c) Name the parts labeled 1 to 4.

(d) Name the type of lens used to correct this eye defect.

(e) Draw a labeled diagram to show how the above mentioned defect is rectified using the lens named above.

Solution 29

(a) Myopia

(b) The two possible reasons for myopia are either the eye ball is lengthened from front to back or the lens is too curved.

(c) 1 - vitreous humour, 2 - blind spot, 3-lens, 4-pupil

(d) Concave lens

(e)

Question 30

The figure below is the sectional view of a part of the skull showing a sense organ:

(i) Name the sense organ.

(ii) What are the parts labeled 'm', 'i' and 's'? What do these parts constitute collectively?

(iii) What do you call the part shown in the form of a spiral? What is its function?

(iv) Name the part labeled 'tm'. What is its function?

Solution 30

(i) Ear

(ii) m - malleus, i - incus and s - stapes respectively. These are collectively called as ear ossicles.

(iii) Cochlea. The vibrating movements in the hair of the sense cells of cochlea transmit the impulse for hearing to the brain via auditory nerve.

(iv) Tympanic membrane. It vibrates and then sets the ear ossicles into vibration in the process of hearing.

Question 31

Given below is a diagram of a part of the human ear. Study the same and answer the questions that follow:



(i) Give the collective biological term for Malleus, Incus and Stapes.

(ii) Name the parts labeled A, B and C in the diagram.

(iii) State the functions of the parts labeled 'A' and 'B'.

(iv) Name the audio receptor region present in the part labeled 'A'.

Solution 31

(i) Ear ossicles

(ii) A - Cochlea, B - Semicircular canals, C - Ear ossicles

(iii) Cochlea helps in transmitting impulses to the brain via the auditory nerve. Semicircular canals help in maintaining dynamic equilibrium of the body.

(iv) Organ of Corti

Question 32

Draw a labeled diagram of the inner ear. Name the part of the inner ear that is responsible for static balance in human beings.

Solution 32

 

 

Utriculus and Sacculus are responsible for maintaining static balance in human beings.

Question 33

Have a look at the posture of this woman who is reading a book and answer the questions which follow:



(a) What problem is she facing? Name the problem.

(b) What are the two conditions shown in sections A and B of the eye as applicable to her?

(c) What kind of looking glasses she needs?

Solution 33

(a) Myopia

(b) A-Normal eye, B-Myopia

(c) Looking glasses with the concave lens are required here.

Key Features of Study Materials for ICSE Class 10 Biology:

  • Easy to understand  
  • Prepared by subject experts
  • Designed according to the latest ICSE syllabus
  • Helpful when doing homework
  • ‘Ask the Expert’ facility
  • Helpful for quick revision
  • Significantly improve your scores