Bishop Cotton Boys’ School

Bengaluru
Grade X
Biology Practical Manual

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 Experiment Number- 1
Mitosis
Aim: To observe the permanent slides and study the different stages of Mitosis.
Requirements: Permanent slides of Mitosis, Microscope
There are two types of cell divisions: Mitosis and Meiosis
Mitosis is the cell division in which one parent cell divides into two identical cells.
Phases of Mitosis: Mitosis is completed in two steps
A. Karyokinesis
B. Cytokinesis

KARYOKINESIS [DIVISION OF NUCLEUS]

Karyokinesis in Mitosis occurs in four main phases. The four main phases are :
1. PROPHASE :
(i) The cenrioles move towards the opposite poles.
(ii) Chromosomes become more distinct and the chromatids split longitudinally.
(iii) Spindle fibres appear between the two centrioles.
(iv) Nuclear membrane and nucleolus disappear.

2. METAPHASE:
(i). Chromosomes line up in one plane at the equator of the cell.

3. ANAPHASE :
(i) The centromere of the chromosome divides.
(ii). The two sister chromatids move towards the opposite poles by the contraction of the
spindle fibres.
4. TELOPHASE :
(i) Two sets of daughter chromosomes reach the opposite poles.
(ii) Spindle fibres and aster disappear.
(iii) Chromosomes decondense and form chromatin fibres.
(iv) Nuclear membrane and nucleolus reappear.

B. CYTOKINESIS [DIVISION OF CYTOPLASM]

(i) The cleavage furrow deepens and divides the cytoplasm into two daughter cells in animal
cells
(ii) A cell plate divides the cytoplasm into two daughter cells in plant cells.
Conclusion:

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(i) After Mitotic cell division, two new cells are formed.
(ii) Each daughter cell will have the same number of chromosomes.
(iii) Mitosis is responsible for growth, repair, replacement and asexual reproduction.

MITOSIS [ANIMAL CELL] LABELLED

DIAGRAM TO BE COPIED FROM THE TEXT
BOOK

Experiment Number – 2
Diffusion
Aim: To demonstrate the process of diffusion.
Materials required: beaker, water, potassium permanganate and glass rod.
Principle: Diffusion is the movement of molecules of a substance from the region of their
higher concentration to the region of their lower concentration when the two are in a direct
contact.
Procedure: Place a few crystals of potassium permanganate in a beaker containing water in
one corner.
Observation: When the crystals of potassium permanganate dissolve, the water turns light
purple in colour. As it continues to dissolve at the bottom of the beaker, the colour of water at
the bottom of the beaker becomes dark purple. After a period of time, the color becomes
uniform throughout the beaker.
Inference: The molecules of potassium permanganate are more concentrated at the bottom of
the beaker. The molecules move away farther and farther in the region where they are fewer
or absent (less concentrated). This movement continues until the molecules are uniformly
distributed. Stirring with a spoon or glass rod hastens the process of uniform diffusion to get
homogeneous solution much faster.

Experiment Number – 3

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 Osmosis
Aim: To demonstrate the process of osmosis using a thistle funnel.
Materials required: beaker, water, thistle funnel, concentrated sugar solution, cellophane
paper, string and metal stand.
Principle: Osmosis is the diffusion of water molecules across a semi-permeable membrane
from a more dilute solution to a less dilute solution.
Procedure: Take pure water in the beaker and concentrated sugar solution in the thistle
funnel. Cover the mouth of the thistle funnel with the help of cellophane paper and secure it
tightly with rubber band or string. Tie another string on the stem of the funnel to mark the
initial level of the sugar solution. Keep the apparatus undisturbed for few hours.
Observation: The level of the sugar solution in the thistle funnel rises, indicating the
movement of water molecules from the beaker into the thistle funnel. The cellophane paper
acts as a semi-permeable membrane.
Inference: Water molecules move from the beaker where they are in higher concentration
into the thistle funnel where they are in lower concentration through semi-permeable
membrane (cellophane). Endosmosis occurs thus demonstrating the process of osmosis.

Experiment Number – 4
Potato Osmoscope
Aim: To demonstrate the process of osmosis by using potato osmoscope.
Materials required: A medium sized potato, petri dish, water, concentrated sugar solution,
pins and few drops of eosin stain.
Procedure: Peel the potato. Wash it and cut the lower surface so that it can stand flat in the
petri dish. Scoop out a cavity with the help of knife and fill the cavity with concentrated sugar
solution. Mark the level of sugar solution with the help of the pin. Add a drop of eosin to the
water in the petri dish and place the potato osmoscope in the petri dish containing water.
Leave the set up undisturbed for few hours.
Observation: It was observed that the level of sugar solution in the cavity of the potato rises
and its colour changes from colourless to pink indicating the movement of water molecules
from the petri dish to the cavity of the potato containing sugar solution. The membranes of
the potato cell acts as a semi-permeable membrane.

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Inference: Water molecules move from the petri dish where they are in higher concentration
to the cavity in the potato where they are in lower concentration through semi-permeable
membrane of the cells of potato. Endosmosis occurs.
Precautions: The cavity should be made carefully to prevent the sides of the potato from
becoming thin and thus tearing.

Experiment Number- 5
Roots Absorb Water
Aim: To demonstrate that roots absorb water
Materials required: Test tubes, water, young leafy plant and oil.
Procedure: Take a test tube(P) filled with water. Pull out a young leafy plant (balsam) from
the soil with roots intact. Insert the roots into the test tube soon. Put few drops of oil in the
test tube to prevent any loss of water by evaporation. Mark the level of water. Set up a similar
test tube (Q)but without the plant.
Observation: The level of water in the test tube (P) falls but not in the test tube (Q).
Inference: This experiment proves that water lost in test tube (P) was absorbed by roots.

Experiment Number - 6
Transpiration
Aim: To demonstrate the process of transpiration.
Materials Required: Two well - watered plant, two polythene bags, some strings, two strip
of Cobalt Chloride paper, three bell jars

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Definition: Transpiration is the loss of water in the form of water vapour from the aerial parts
of the plants.
Procedure: Take a small well-watered potted plant with broad leaves. Cover the pot with a
polythene bag so that the soil is not exposed. Now cover the entire plant under a bell jar as in
set up A.
Take the second polytene bag, cover the pot and tie the mouth of the bag at the base of the
stem tightly. Place a piece of dry cobalt chloride paper by the side of the plant inside the bell
jar B. The paper may be pinned to a wooden stick.
Take a third bell jar without a plant. Place a piece of cobalt chloride paper.
Keep all the three bell jars together in the sun.
Observation: After a given period of time, droplets of water are seen on the inner side of the
bell jars covering the plant in set up A and B. The strip of dry blue Cobalt Chloride paper
placed inside the bell jar in set up B will be seen to change colour from blue to pink, proving
that the droplets are water droplets. The third bell jar in this experiment is a control.
Inference: Transpiration has taken place. Water vapour which was produced as a result of
transpiration on the inner sides of the polythene bags as droplets of water

Precautions:
1. The plants should be well-watered herbaceous with broad leaves.
2. The polythene bag covering the soil and the plant should be air tight by securing the
sides tightly.

Experiment Number - 7

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 Unequal Transpiration
Aim: To demonstrate unequal transpiration from the two surfaces of a dorsi-ventral leaf.
Materials required: A well- watered plant with dorsiventral leaves, two strips of dry Cobalt
Chloride paper, two glass slides, two rubber bands.
Procedure: Place a strip of blue Cobalt Chloride paper on either surface of one leaf of a
plant. Cover the paper strip with glass slides on either side of the leaf of the plant. Fix them
tightly as shown in the diagram. Leave the apparatus in sunlight for two to three hours.
Observation: After the given period of time, it will be noticed that the strip of Cobalt
Chloride paper on the lower surface has turned completely pink where as there is little or no
colour change in the strip of the paper kept on the upper surface of leaf.
Conclusion: A dorsi-ventral leaf has more number of stomata on the lower surface. Hence,
the colour changes faster on the lower surface of the leaf, thus showing unequal transpiration
from the two surfaces of a leaf.
Precautions:
1. The plant should have fresh and clean and leaves should be free of any oily
substances or dust particles.
2. The Cobalt Chloride paper must be attached closely to the leaves and made air tight
by securing the sides with rubber bands.

Experiment Number - 8

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 Ganong’s Potometer
Aim: To demonstrate the rate of transpiration using Ganong’s Potometer
Materials Required: A fresh balsam twig, a beaker half filled with coloured water,
Ganong’s Potometer and tap water
Procedure: Fix the apparatus as shown in the diagram. Fill the graduated tube and the
reservoir with tap water. Insert the end of the bent capillary tube into the beaker of coloured
water. Introduce an air bubble into the horizontal tube and note its initial position. Keep the
apparatus in sunlight for 5 to 6 hours and note the movement of the air bubble.
Observation: The air bubble keeps moving towards the reservoir at a specific rate. The
difference between the initial and the final readings can be calculated. The movement of the
air bubble towards the plant shows that water is being used up by the plant, as it undergoes
continuous transpiration.
Conclusion: The rate of water uptake can be calculated from the movement of the air bubble.
Precautions: 1. The air bubble should be introduced carefully.
2.The twig may not remain alive for a long time

Experiment Number – 9
Photosynthesis
Definition: Photosynthesis is a process in which living plant cells containing chlorophyll
produce glucose (food), from carbon-dioxide gas and water using light energy.

Equation: 6CO2 + 12H2O ------------> C6H12O6 + 6O2 + 6H2O

Sunlight & chlorophyll

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De-starching: Before conducting any experiment to demonstrate photosynthesis, the plant
should be first de-starched. This is done by placing the plant in the dark for 24 to 48 hours to
remove the stored starch from the leaves of the plant.

Aim: To test a leaf for starch.

Requirements: Burner, beaker, test tube, white tile, forceps, water, methyl alcohol, iodine
solution, dropper
Procedure:

1. Boil the leaf in water for a minute to kill the cells.

2. Now boil the leaf in methylated spirit over a water bath, till the leaf becomes pale
white, due to removal of chlorophyll.
3. Boiling the leaf in methyl alcohol makes the leaf brittle. Therefore, place it in hot
water to soften it.
4. Spread the leaf on a white tile and add a few drops of iodine solution on it.
Observation: On adding iodine, the colourless leaf will change colour to blue-black.

Inference: Blue-black colour is a positive test for the presence of starch. Thus, the presence
of starch in the leaf has been demonstrated.
Precaution: While boiling the leaf in methyl alcohol, use a water bath as methyl alcohol is
inflammable.

Experiment Number – 10
Aim: To show that chlorophyll is necessary for photosynthesis.
Requirements: A plant with variegated leaves, and all the requirements of starch test
Procedure:

1. Take a plant with variegated leaves having some green and non-green areas.
2. De-starch the leaves by keeping the plant in a darkroom for a few days.

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 3. Place the plant in the sun.
4. After a few hours, pluck the leaves.
5. Make its outline on paper and mark the green and non-green areas on the outline.
6. Test the leaf for starch.
Observation: On conducting the starch test, only the green parts of the leaf turn blue-black,
the other parts of the leaf show no colour on adding iodine.
Inference: As only the green parts of the leaf test positive for starch, this proves that
chlorophyll is necessary for photosynthesis.

Experiment Number – 11
Aim: To show that light is necessary for photosynthesis.
Requirements: Potted plant, black paper, clips, and all the requirements of
starch test
Procedure:

1. Take a plant with de-starched leaves.

2. Cover a small part of one of its leaves with black paper. A design cut out from the
black paper can also be used in the experiment.
3. Place this plant in the sun for few hours.
4. After a few hours, test the leaf covered with black paper for starch.
Observation:
It was observed that the parts of the leaves covered with black paper do not turn blue
– black on adding iodine, while the uncovered parts of the leaf test positive for starch.
Inference:
As the black paper did not allow sunlight to reach the covered part, those parts of the
leaf tested negative for starch, whereas the areas of the leaf which received sunlight
tested positive for starch. This demonstrates that sunlight is necessary for
photosynthesis.

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 Experiment Number – 12

Aim: To show that carbon-dioxide is necessary for photosynthesis.

Requirements: Potted plant, split cork, conical flask, stand, Potassium
hydroxide, and all the requirements of starch test
Procedure:
1. Take a plant with de-starched leaves.
2. Insert one of the leaves through a split cork into a conical flask containing Potassium
hydroxide.
3. Leave the plant in sunlight.
4. After a few hours, pluck a leaf and test this leaf for starch.
Observation: It is observed that the art of leaf inside the conical flask tests negative for
starch while the other half of the leaf outside the flask tests positive for starch.
Inference: Potassium hydroxide is a chemical which absorbs carbon-dioxide. Hence the half
of the leaf inside the flask cannot photosynthesize in the absence of carbon-dioxide and
therefore tests negative for starch. the part of the leaf outside the flask has carbon-dioxide and
therefore tests positive for starch.

Experiment Number - 13
Aim: To show that oxygen is evolved during photosynthesis.

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 Requirements: Beaker, short stemmed funnel, conical flask, stand, Potassium
hydroxide, and all the requirements of starch test
Procedure:

1. Take a beaker containing tap water.

2. Place a few twigs of hydrilla and cover the plants with a short stemmed funnel.
3. Invert a test tube full of water over the stem of the funnel.
4. Place the apparatus in the sun or close to a lamp for few hours.
Observation: Bubbles of gas were seen to come out of the cut ends of the twig and collected
at the top of the inverted test tube.
Inference: On testing the gas with a glowing splinter, the splinter rekindles. This proved that
the gas evolved was oxygen. This proves that green plants evolve oxygen during
photosynthesis.
Precautions:

1. The stems of the plant should face towards the stem of funnel.
2. The level of water in the beaker should be above the level of the stem of the inverted
funnel.
3. Do not use distilled or boiled water.

SUNLIGHT

Experiment Number - 14
Blood Cells
Aim : To observe and study the different kind of blood cells
COMPOSTION OF BLOOD
i. i. Plasma: The fluid part which is light yellow coloured and alkaline .
It contains water, inorganic salts like NaCl, NaHCO3, glucose, aminoacids,
hormones ,proteins like Fibrinogen and Prothrombin.

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 ii.Cellular elements: Are of three categories (1) Erythrocytes (2)Leucocytes
(3) Thrombocytes
1. ERYTHROCYTES [RED BLOOD CELLS]
a. STRUCTURE:
i. Biconcave disc like structures
ii. 7 micron in diameter
iii. No nucleus
Significance:
1. The small size and concavities on either of side provide a large surface
area for absorption of Oxygen.
2. The small size enables the red blood cells to travel through very fine
capillaries
iv. Mitochondria and Endoplasmic Reticulum are absent
Significance :
1. Absence of Mitochondria enable them to deliver oxygen to the tissues
without utilizing it.
2. Absence of ER make Red blood cells more flexible.
Contain the respiratory pigment Haemoglobin
2. LEUCOCYTES [WHITE BLOOD CELLS]
A Types: 1. Granulocytes 2. Agranulocytes
b. Origin: Bone marrow and lymph glands like spleen, tonsils etc
c. Life span: Their average life span is two weeks but neutrophils live for few hours

Categories Cell type Structure Function

A. GRANULAR 1.Neutrophils *Nucleus with 3-4 Engulf bacteria
lobed nucleus

Cytoplasm with granules and

nucleus is lobed 2.Eosinophils *Nucleus with 2 Secrete
lobes antitoxins
Engulf bacteria

3.Basophils *Nucleus large Release

and indistinctly Histamine
lobed
B.NON-GRANULAR 4.Lymphocytes *single large Produce
Cytoplasm without granules Nucleus Antibodies
and nucleus is single large *smallest WBCs

5. Monocytes Nucleus large and Ingest germs

kidney shaped

THROMBOCYTES [ BLOOD PLATELETS]

a. Structure: Blood platelets are minute oval or round structures, non- nucleated,
floating in the blood.
b. Origin: The are derived from megakaryocytes in the red bone marrow.

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 c. Life span: 3 to 5 days
d. Function: Initiate clotting of blood

Experiment Number - 15
Human Heart
Aim: To observe and study the internal structure of human heart

1.Location: In the thoracic cavity right in the centre between the two lungs and above the
diaphragm.
2.Protective membrane: Pericardium
3.Pericardial fluid:
i. Location: Between the two membranes of the pericardium.
ii. Function: It reduces friction during heart beat and protects the heart from mechanical
injuries.
4. Chambers: 4
(i) Upper: Auricles or Atria, left and right- have thinner walls
Function: Receive blood from the body and pump it into the ventricles.
iii. Lower: Ventricles, right and left- have thick muscular wall
Function: Pump blood away from the heart.
Right ventricle pumps deoxygenated blood to the lungs for oxygenation.
Left ventricle pumps blood to the farthest points of our body.
5.Blood vessels:
(i) Entering the heart: The right auricle receives
a. Anterior or superior vena cava or pre caval-brings deoxygenated blood from the
upper regions of the body.
b. Posterior or inferior vena cava or post caval- brings deoxygenated blood from the
lower region of the body.
c. Pulmonary veins: The left atrium receives 4 pulmonary veins which bring
oxygenated blood from the lungs.
(ii) Leaving the heart:
a. Pulmonary artery: Arises from the right ventricle and carries deoxygenated
blood to the lungs for oxygenation
b. Aorta: Aries from the left ventricle and carries oxygenated blood to supply to
all parts of the body
(iii). Coronary arteries: Arising from the base of the aorta and supply blood to the heart
muscles.
6.Valves: Regulate the flow of blood in a single direction
I. CUSPID VALVES

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 i. Right atrioventricular valve or Tricuspid
valve
Location: at the aperture between the right auricle and right
ventricle
Function: allows the flow of blood from right auricle to the right
ventricle and prevents the flow of blood from the right ventricle to
the right auricle.
ii. Left auriculo-ventricular valve or Bicuspid valve or Mitral valve:
Located at the aperture between the left auricle and left ventricle. Allows
the flow of blood left auricle to left ventricle and prevents the flow of
blood from the left ventricle to left auricle.
II. SEMI LUNAR VALVES:
i. Pulmonary semilunar valve: Located at the opening of the right
ventricle into the pulmonary artery. Prevent the flow of blood from the
pulmonary artery to the right ventricle
ii. Aortic semilunar valve: Located at the point of origin of aorta from the
left ventricle. Prevent the flow of blood from aorta to the left ventricle.
7. Chordae tendinae - Holds the flaps of the cuspid valves in position preventing
their upturning due to pressure exerted by the contracting ventricles.

Experiment Number – 16
The Excretory System
Aim – To study the human excretory system
 Kidneys are bean shaped. Located on either side of the back bone.
 Ureter- arises from the notch in the median surface of each kidney.

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 Urinary bladder – present in the lower part of the abdomen.
 The front end of the ureter is somewhat expanded into the kidney and is called pelvis.
 The urine is emptied from the urinary bladder to outside of the body through the
urethra.
 A sphincter guards the opening of the bladder into the urethra and relaxes only at the
time of urination.
 A longitudinal section of kidney shows two main regions,
outer dark cortex and inner lighter medulla.
 The medulla is composed of a finely striped substance arranged in several conical
pyramids.
 Nephrons or renal tubules are the structural and functional units of the kidney.
 Both the Bowman’s capsule and the proximal convoluted part lie in the cortex giving
it a dotted appearance.
 Henle’s loops and collecting ducts lie in the medulla giving it a striped appearance.
 The glomerulus is a mass of thin-walled capillaries.
 The Bowman’s capsule is a double-walled, cup-shaped structure.
 The proximal tubule leads from the Bowman’s capsule to the Loop of Henle.
 The loop of Henle is a long loop which extends into the medulla.
 The distal tubule connects the loop of Henle to the collecting duct.
 Each nephron has its own blood supply

The Human Urinary System

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 Longitudinal section of kidney

Experiment Number -17

The Brain

Aim: To observe and study the parts of human brain

The brain is a very delicate organ well protected inside the cranium. The brain is protected by
three membranous coverings called meninges.
PARTS OF THE BRAIN
The brain has three main parts visible externally.
1. CEREBRUM: The cerebrum is the largest portion of the brain. It is divided into two
cerebral hemispheres. Corpus callosum is a sheet of fibres connecting two cerebral
hemispheres. The outer gray matter of the brain contains cytons and inner white matter
contains axons.
The cerebrum enables us to think, reason out, invent, plan and memorise.
It is the seat of intelligence, consciousness and will power. It controls all voluntary
actions.
2. CEREBELLUM: The cerebellum is located just at the base and under the large
cerebrum.

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 The main function of the cerebellum is to maintain balance of the body and coordinate
muscular activity.
3. MEDULLA OBLONGATA:The medulla oblongata is the lowest portion of the brain
located at the base of the skull.
Its function is to control the activities of the internal organs like heartbeat, peristalsis
etc.
THREE PRIMARY REGIONS OF THE BRAIN
1. FOREBRAIN : (1) Cerebrum (2) Diencephalon –(i) Thalamus(ii) Hypothalamus
2. MIDBRAIN
3. HINDBRAIN: (1) Cerebellum (2) Pons (3) Medulla oblongata
1. Cerebrum
2. Cerebellum
3. Medulla oblongata

Experiment Number - 18
The Eye
Aim: To observe and identify the different parts of human eye using a model and a chart.
Location. The two eyes are located in deep sockets or orbits on the front side of the head.
The eye lids, eyebrows and eyelashes are outer protective structures.
Tear glands: Tear glands are located at the upper sideward portion of the orbit
which secrete tears.
Conjunctiva. The conjunctiva is a thin membrane covering the entire front part of the eye.
THE STRUCTURE OF THE EYE BALL

The wall of the eye ball is composed of three concentric layers.

1. The sclerotic layer: is made of tough fibrous tissue and is white. It bulges out and
transparent in the front region where it covers the coloured part of the eye and is
called cornea. The sclerotic layer gives shape to the eye ball.

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 2. The choroid layer: The middle layer is richly supplied with blood vessels for
providing nourishment to the organ. It contains melanin pigment and prevents light
rays from reflecting and scattering inside the eye.
a. Ciliary body: In the front of the eye, the choroid expands to form ciliary body.
The smooth muscles in the ciliary body alter the shape of the lens.
b. Iris: The iris is also an extension of the choroid, partially covering the lens and
leaving pupil in the centre. The iris contains radial muscles to widen and circular
muscles to constrict the pupil and thus regulates the size of the pupil and the
amount of light entering the light.
3. The Retina: The innermost layer which is sensitive to light. It has Rods with
Rhodopsin pigment which are responsible for dim light vision. The rod cells are
distributed almost throughout the retina.
The cones are sensitive to bright light and responsible for colour vision.The cones
contain Iodopsin pigment.
a. Yellow spot: lies at the back of the eye almost at the centre on the horizontal axis of
the eye ball. This spot contains maximum number of cones. As a result, this is the
region of brightest vision and also of colour vision.
b. Blind spot: Lateral to the yellow spot on the nasal side is the blind spot. There are no
sensory cells here and therefore is the point of no vision.
c. Optic nerve: originates from the blind spot and conducts impulses to the brain.

LENS: The lens is a transparent biconvex crystalline body located just behind the pupil.
The lens is held in position by suspensory ligaments.
Aqueous chamber: Is the front chamber between the lens and the cornea. It is filled with a
clear watery liquid called aqueous humour. This fluid keeps the lens moist and protects it
from physical shock. It refracts light
Vitreous chamber: is the larger cavity of the eyeball behind the lens. It is filled with a
transparent jelly like thicker fluid called vitreous humour. This fluid helps in keeping the
shape of the eyeball and protects the retina and nerve endings.

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 Experiment Number - 19
The Ear
AIM: To observe and study the parts of the human ear using a model and a chart.
The human ear is concerned with two functions, hearing and body balance.
1. The outer ear: The outer ear consists of Pinna and auditory canal. The pinna collects the
sound waves and conducts it through the auditory canal.
2. Ear drum: Thin membrane where sound waves changes to vibrations
3. The middle ear: The middle ear contains ear ossicles [ Malleus, Incus, Stapes] and
Eustachian tube which connects the cavity of the middle ear with the throat. The flat part
of the stirrup fits on oval window. A round window connects the middle ear and inner
ear. The ear ossicles magnify and transmit sound vibrations
4. The inner ear: The inner ear has two main parts- the cochlea and the semicircular canal.
The cochlea is concerned with hearing. The organ of corti present in the median canal
are the specialized cells responsible for hearing.
The semi-circular canals are responsible for dynamic balance and the vestibule is for
static balance.

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 Experiment Number - 20
Endocrine Glands
Aim: To study the different endocrine glands in our body.
The ductless glands in our body are called endocrine gland and their secretions are called
hormones.
1.ADRENAL GLANDS: The adrenal glands are like caps above the kidneys. Each adrenal
gland consists of two parts.
a. Adrenal medulla. The central part of the adrenal gland is the medulla. It secretes
Adrenaline hormone which is known as emergency hormone.
Functions of Adrenaline:
1. IT increases heart beat accompanied by an increase in blood pressure.
2. It increases blood supply to the muscles while decreasing it to the skin and visceral
organs.

b. Adrenal cortex: The peripheral part of the adrenal gland is the cortex. It secretes cortical
hormones.
1. Mineralocorticoids: eg. Aldosterone. Regulates mineral metabolism
2. Glucocorticoids: eg. Cortisone, Corticosterone Regulates carbohydrate, protein fat
metabolism
3. Sex corticoids: Eg Adrenal androgens. Stimulates the development of secondary sexual
characteristics.

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2. PANCREAS: Pancreas is an exo-endocrine gland which is present just below the stomach.
The special hormone secreting cells of the pancreas are called Islets of Langerhans.
INSULIN: Hormone insulin is secreted from the beta cells of the Islets of Langerhans
Insulin promotes glucose utilization by the body cells and stimulates the conversion of
glucose to glycogen by the liver.
GLUCAGON: Hormone glucagon is secreted from the alpha cells of Islets of Langerhans.
It stimulates the conversion of glycogen to glucose by the liver.
3. THYROID GLAND: The thyroid is a bilobed gland in front of the neck just below the
larynx. It secretes Thyroxine hormone.
FUNCTIONS OF THYROXINE
1. Regulates the basal metabolism.
2. Influences general growth of the body and mental development
3. Influences ossification of bones.
4. Regulates body temperature.
5. PITUITARY GLAND. The pituitary gland is a small projection which hangs from
the hypothalamus. It is popularly called Master gland.
Hormones from the anterior lobe of the pituitary gland
1.Growth hormone: It is essential for normal growth
2. Tropic hormones: These hormones stimulate other endocrine glands
Examples. TSH, ACTH, GONADOTROPIC HORMONES
Hormones from the posterior lobe of the pituitary gland
1. Vasopressin: Constricts blood vessels with rise in blood pressure. Regulates
the reabsorption of water from the kidney tubules.
2. Oxytocin. Stimulates vigorous contractions of the uterus in a pregnant mother
leading to the birth of the baby

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