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Biology Project

The document outlines various biology experiments focused on plant and animal life, including the observation of mitosis stages, osmosis, diffusion, transpiration, and the structure of the urinary system. Each experiment includes objectives, requirements, procedures, observations, and conclusions, demonstrating key biological processes. The document serves as a lab manual for ICSE Biology, providing practical insights into cellular processes and plant functions.

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10 views24 pages

Biology Project

The document outlines various biology experiments focused on plant and animal life, including the observation of mitosis stages, osmosis, diffusion, transpiration, and the structure of the urinary system. Each experiment includes objectives, requirements, procedures, observations, and conclusions, demonstrating key biological processes. The document serves as a lab manual for ICSE Biology, providing practical insights into cellular processes and plant functions.

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kazizunaid884
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PLANT LIFE EXPERIMENT NO, - 4 Objective Observation of permanent slides of stages of mitosis. Requirements 1. Prepared permanent slides of different stages of mitosis. 2. Microscope. | Procedure : Different stages of mitosis are focussed under the low and high power of microscope. Make labelled diagrams of different stages of the cell division—Mitosis. Observation Raita A. Interphase (phase between the two successive, division) itosi asm 1. The slide shows the interphase of mitosis. ws ee 2. The nucleus is large and prominent. Chromatin, 3, Nuclear membrane, nucleolus present. Threads 4. Chromatin network is distinct. \_ Nuclear ‘Membrane 4B. Prophase : (First phase of Karyokinesis) Nudeotus 1. The slide shows prophase of mitosii Nucteoplesm 2. The nucleus is slightly bigger in size. ver 3, The nuclear membrane starts disappearing. 4. The nucleolus starts disappearing. Prominent, dense, long, cylindrical chromosomes are seen. They later split into two chromatids, Nuclear membrane Microtubule forming disappearing part of spindle Centromere Nucleolus ‘disappearing Chromosomes Spindle fibres B Early prophase ICSE Biology Lab Manual-X C. Metaphase ‘The slide shows metaphase of mitosis 2. The nuclear membrane and nucleolus disappest 3. The chromosomes arrange themselves at the equator. 44. The chromosomes appear to be short thick and ‘X’ shaped. : 5. The spindle is formed by the fibres given off from the opposite poles. G. The chromosomes get attached to the spindle fibres at the centromere. chromosomes lie along the equatorial plane ofthe call | D. Early metaphase E. Late metaphase D. Anaphase 1. The slide shows the anaphase of Mitosis. 2. The spindle fibres shorten and pull apart the chromatids. 5. The centromere splits into two. ‘The chromosomes are pulled towards the opposite poles as the spindle fibres shorten. ‘The chromatids are towards the poles with their arms towards the centre of the cell. | Chromatids reach their respective poles F Early anaphase G Late anaphase E, Telophase + ik 2 Ba 4. 5. The slide shows the Telophase of mitosis, ‘The spindle fibres disappear. ‘The nucleolus and nuclear membrane reappear. ‘The chromosomes lose their dense appearance and form the ch ' omatin jetwork, ho | Us Cell-plate formation starts and division of cell takes place ie ch ar ah les) ny yok Which ae is ¢ ie a ICSE Biology Lab Manual 1. Late telophase VIVA-VOCE _ — Define the ‘Mitosis’. ne oo division in which two identical daughter cells are produced by the SP... Name the different stages of mitosis. (i) Prophase, (ii) Metaphase, (ii) Anaphase, (iv) Telophase. 1. Why do the cells divide? The cells divide to maintain surface to volume ratio. Where does the mitotic division take place? ‘The mitotic division takes place in somatic cells of animals and vegetative cells of plants. 0 5 What is interphase? Ano._It is the phase in between the two successive phases of the division, It is the resting stage. EXPERIMENT NO. > 2 (osmosis) PS Objective To demonstrate using ‘potato osmoscope’. the phenomenon of osmosis through live membrane Requirements : 1. A large sized, uniformly textured potato tuber 2, 10% sugar solution 3, Stain to colour water 4. Beaker 5. Water 6, Scalpel 7. Pin “aa n er and peel off its skin with the help of scalpel. Make it flat at the base by © tul "Ty nt ee cS the he re the base. Pour some coloured sugar solution till half of the hollow cavity is up. ACSE Biology Lab Manual-X it SS “gs snital level of water by inserting a common pin in the wall of the Ps ie beaker containing water. The level of water in the beaker shou! in the potato tuber. Let the apparatus stand undisturbed for sometime. Observation The level of the sugar solution in the potato tuber rises after sometime. Inference and Conclusion ‘The rise in the level of the sugar is due to the movement of water molecules into the beaker (Endosmosis). This demonstrates the pher of osmosis: “Osmosis is the phenomenon from their~higher concentration to their | through a semipermeable membrane.” Here in this experiment the living cells of potato tuber collec- tively act as semi permeable Jor differentially permeable mem- solution in the potato tuber from the pure water nomenon ‘of movement of water molecules Jower concentration otato as shown in the figure. Put the potat id be less than the level of sugar solution EXPERIMENT NO. - 3 (osmosis) Objective To demonstrate the phenomenon of osmosis by “Thistle Funnel method”. Requirements 1. Thistle funnel 2. Cellophane paper or goat's bladder 3. Water 4. Thread or rubber band 5. Sugar solution (10%) 6. Beaker ‘Thistle funnel 7. Stand. Procedure rocedurt ae Take a thistle funnel. Close its wide mouth with goat's bladder or cellophane paper and tie it securely pyre wator. with the thread or rubber band as shown in the figure, Pour 10% sugar solution in the inverted funnel till it reaches upto the middle of the vertical tube. Dip the inverted funnel in a beaker containing water, Fix the funnel on a stand holding the vertical tube in position. Mark the initial level of solution in the tube. Leave the apparatus as such for a while and then observe, Denson of sano Thistle Funnel method i‘ Stand 8 ICSE Biology Lab Manual-x Inference and Conclusion : After sometime the level of s fare ; | Fe eos ee ee f solution in the vertical tube of the thistle funnel starts rising, This explains that asa ae water of the beaker move into the solution in the thistle funnel due to the rough a semi permeable membrane)(goat's bladder or cellophane paper). EXPERIMENT NO. - 4 (DIFFUSION) Objective : To demonstrate the phenomenon of “difusion’. «",)) “\ Requirements : yr * UN 1. Beaker yed # Water NG a, ’ Wrenn yy Si. Peaster penne aOR tema phate (hydrated){), 0) alee Procedure : Take a beaker and fill the beaker more than half with distilled water. Place a small crystal of potassium permanganate of Copper sulphate at the bottom of the beaker and observe. Observation : ‘The crystal starts dissolving immediately and colour the water slowly. After the whole of the crystal is dissolved, the water gets uniformly coloured. 74%] > Demensraton of tusion Inference and Conclusion : The above experiment demonstrates that when there is no intervening partition, most molecules mix (diffuse) into each other till they thoroughly make homogenous mixture. Here it shows the diffusion of solid into the liquid medium. In living processes, this phenomenon of diffusion holds great importance for the movement of solutes. It is a passive process without involvement of metabolic energy. VIVA-VOCE What is the difference between ‘osmosis’ and ‘diffusion’? “Diffusion’ is a process of movement of any Substance from its higher concentration to its lower concentration. Whereas, ‘Osmosis'\s a kind of process which allows only solvent molecules to move from their higher concentration to their lower concentration through a semipermeable ‘membrane which separates solution of different \con¢entrations, Q. 2. How is phenomenon of osmosis important fa relation to plant processes? ‘Ans, Following are few examples where a js plays a significant role in plants (a) Absorption of water by the ro (b) Opening and closing of sto (c) Transportatoin of water. Q1 Ans. ta. ICSE Biology Lab Manual-X _/ZEXPERIMENT.N (TRANSPIRATION) Objective To demonstrate the phenomenon of Transpiration by bell jar method. Requirements : 1. A bell jar A glass plate Oil cloth Grease Thread and A small potted plant. a2 Pep Procedure Take a well watered potted plant. Cover the area of the soil which is open paper to prevent evaporation ‘of water, Place the pot on the glass plate and cov apparatus as such for sometime and then observe. with an oil cloth or cellophone ‘er it with a bell jar. Leave the ICSE Biology Lab Manual-X m1 Observation va roplta Small drops of watei and conclusion + start appearing on the inner side of :he bell jar. Bal ar condensed water vapours which wa the nave been Fanspired tough the stomaal openings from the ventral side of the leaf of the potted plant. ; nal Transpiration is a phenomenon of loss of water from the aerial parts of the plant in the form of water vapour. ool Precautions case il 1. The apparatus should be air tight. 2. The potted plant should be thoroughly watered. 3. The open soil surface should be well covered. Demonstration of transpiration EXPERIMENT, NO. 37, (TRANSPIRATION CONTD.) Objective To compare the rate of Transpiration from the two surfaces of dorsiventral leaf of a plant by cobalt chlorée method. Requirements 1. A potted plant with dorsiventral leaves 2. Filter paper 3. Cobalt chloride solution (5%) 4. Glass slides 5. Thread, Procedure Dip a filter paper in slightly acidic 5% cobalt chloride solution. Dry it thoroughly. Now, take a plant and select a healthy dorsiventral leaf. Clean its both dorsal and ventral surfaces with dry cotton, Carefully place the dry cobalt chloride strips on both upper and lower surfaces of the leaf and immediately cover them with dry clean glass slides, Press them together and tie the slides with thread or rubber band, Leave the set up as such for some time and observe, Observation : It is observed after sometime that the dry blue coloured cobalt chloride strip which was put on the lower side turns pink faster as compared with one on the upper surface which takes a longer time to do so, Inference and Conclusion : ‘The observation infers that the loss of water from the lowe: surface is comparatively much higher than from the upper sur- ha aay olereteaa) face. It is due to the presence of higher number of stomata per ‘6% Menention from two om method. holding CoC!, papers 2 ICSE Biology Lab Manual-X unit area on the lower surface than those on th ») are released from uv ee ee hose on the upper surface)More water vapours are rele@i" ite the hich hydrates the dry cobalt chloride strip and it turns from blue t0 ppink (CoC, *2H,0 or CoC, » 4H eu | 41130), On the upper surface only cuticular transpiration takes place Precautions 1. The cobalt chloride paper should be securely placed under the glass slides s0 th contact with air. at it is not in direct 2 Thee sxperimental setups should not be placed in too windy or humid surroundings which will hinder the rate of transpiration. ESSERE No. - 8 (TRANSPIRATION CONTD.) monet To demonstrate the rate of transpiration by Ganong’s potometer, Requirements 1. Ganong’s potometer 2, A leafy shoot cut under water 3. Vaseline or melted wax 4. Beaker 5. Water coloured with a drop of saffranine. Apparatus = ) “Ganong’s potometer consists of a horizontal glass tube which is graduated. It is connected to a Bide vertical tube and a reservoir on one side, wi nereas it is bent downwards on the other end hav ____ ing a small hole on the Jateral side. There is a glass -nstopper below the reservoir. The whole apparatus is n fixed on a wooden stand as shown 1 the figure.” Ganong's potometer Procedure : Fill the Ganong’s potometer completely 1 coloured water. Choose a healthy leafy twig of 2 plant and cut it under wa tube through a hole in the cork. Dip the ie er end of horizontal tube in a small beaker containing water. The | hole apparatus is to be made air Hight by applying vaseline or melted woe To start the experiment, bring | the bent tube end above water level in ‘ne beaker and introduce a single air bubble In the tube with the help of the finger. Place back the tube in the beaker. Keep the whole set up in bright sunlight and observe, ith er. Fix the twig in the wide vertical \ tne cut end of the twig, Repeat tis Je starts moving towards ¢ Observation : oduced air bubbl rate of transpiration. In a short while, the intr ind take out the average procedure two to three Ames 2 13 ICSE Biology Lab Manual ow «i the rate of transpiration can be calculated, The readings can be put in a tabulated form an‘ ‘Rate of Transpiration “gq Time Taken ‘t S.No. Pies Talal a re 13/5 : ae a 5 sec. 3. 16 em : ——— The rate of transpiration will be about 14.33 cm in 5 sec: ta, This ‘ As the plant twig is in direct sunlight, it starts transpiring water fone i ted oe is a iy ent ofa sto eco date nsecteain tee ate elven rizontal is taking the bubble along with it. This gives us the readings in the Ganong's po! 1. The twig should always be cut obliquely under water. This increases the surface area of the cul surface and also no air bubble enters the twig, 2. The apparatus should be absolutely air tight. Define the term “Transpiration’, | transPitation isthe phenomenon of removal of excess of water from the aerial arts of the plant in the form of water vapour, What are the morphological diferences between the upper and lower surface ofa dorsiventral leaf and thy? In UPPer surface ofthe leaf is more shiny, thicker, smooth and darker as compared with the lower Surface due to the presence of thicker waxy Transpiration is reparded asa ‘Necessary evil forthe plants, why? C Hranspiration is regarded as a ‘necessary evi’ since the Plant requires water for its various functior but due to the anatomical built up ofthe structure of leat it looses lots of water during transpiratior which is not favourable for the plants, ©) © Name various factors which afect Transpiration, 1. Humidity 2. Wind 3. Temperature 4. Amount of soil water available, 5. Any other factor which affects the opening and closing of stomata, © © Suggest « control experiment forthe experineyg on Transpiration nm The leaves can be covered by antitranspirants, thus, the "anspiration will be hindered, Serer eee i | u ICSE Biology Lab Manualx Unit 2 ANIMAL LIFE Z es SRIMEN TNO. 43 oe “ (STRUCTURE OF INTERNAL ORGANS) Obj To study the structure of the urinary system of human. Requirements Model or chart showing external and internal structure of human urinary system. Procedure and Observation Study the given chart or model carefully. Observe each part, draw, label and write comments on the structure. us Structure Urinary system consists of the following organs : 1. A pair of kidneys be 2. Ureters 3, Urinary bladder 4. Urethra J. Kidney Kidneys are a pair of reddish brown pean-shaped structures found in our abdomen 2, Ureter ‘A tube arises from the notch (hilum) in the median surface of each kidney. Ureters carry the urine from kidneys to the urinary bladder. 3, Urinary bladder ‘The ureters, in turn, are connected t0 Jarge sac called the urinary bladder. ICSE Biology Lab Manual-X 19 4. Urethra Leading from the bladder is another muscular tube called the urethra, which works as the outlet passage ‘Adrenal gland Renal artery renal vein Kidiey Inferior vona cava Dorsal aorta ‘Urinary bladder Urethra Urinary System VIVA-VOCE ( @ 1. What is the main function of urinary system? Ans. To remove liquid waste from the blood in the from of urine. @ 2 Kidneys contain an endocrine gland on each of its top. Name that gland. ‘Ans. Adrenal gland, © 4. Name the organs constituing the excretory system. Ans: Kidney, ureter, urinary bladder constitute the excretory system. @ 4 Name the artery that enters to a kidney in human, ‘Ans. Renal artery @ 5 Where does the urine get collecied after filtering from kidneys? Ans. In the urinary bladder. 2 6 Name the connectors found between kidney and urinary bladder Ans. Ureters connect the kidneys to urinary bladder. __/ EXPERIMENT NO, = 14" (STRUCTURE OF INTERNAL ORGANS CONTINUED) Objective : To study the structure of human heart Requirements : Model or chart showing external and internal structure of human heart 20 ICSE Biology Lab Manual-x and Observation Procedure given model or chart. Observe each part, carefully. Then draw, Study the Jabel and write comments on the structure. External Structure (i) Heart is hollow, muscular, cone-shaped organ {i It is about the size of a fist and weighs approximately 200 gms (ii) It is enclosed in a membranous sac called pericardium, (iv) Pericardial fluid flows between the membranes protecting the hi also keeping the latter warm (@) Coronary artery supplying the blood to the heart muscles heart muscles are found on the heart eart from shocks, injury and friction, and coronary veins bring blood from the Internal Structure = () Heart has four cham! # (i) Auricles are two upper chambers (left and right), thin walled a septum. we a Left auricle bers — two auricles and two ventricles. mnd! separated by inter auricular ~ Aorta ‘Lot pulmonary artery ‘Superior vena. ‘cava Rit pulmonary ‘Pulmonary veins. Left atium Pulmonary ortery Biscuspid pare ce cea ve exc Levees Teena ene rant vetie Fre Patil ‘ ine Right ventricle, gryepiticutar septum : ran heart Vertical section through the human art External svucture of a hum (iii) The walls of auricles are thin (iv) Right auricle receives deoxygena! 10 lower chambers thick walled an yy two large veins. ted blood from the body b: - interventricular septum. d separated by thic (v) Ventricles are tw' Right ventricle however has thinner walls. (vi) The right ventricle pumps blood to Jungs through pulmo! blood to the body through aorta. permit the flow o nary avery and left ventricle supplies £ blood in one direction only. So they prevent back ‘The heart has four valves. They (vii) flow of blood. {CSE Biology Lab Manual-X a EXPERIMENT NO, -.15 (STRUCTURE OF INTERNAL ORGANS CONTINUED) To study the structure of human kidney. Requirements A model or chart showing external and internal structure of human kidneys. Procedure and Observation : Observe carefully each part of the structure in the given model or chart. Study and then draw the labelled diagram and write comments on the same. External Structure (i) Kidneys are bean-shaped reddish brown structures, G (ii) Each kidney is about 10 cm long 6.5 cm broad and 3.5 cm thick, slightly flattened organ. The left kidney is located slightly above the right (ili) The outer margin of the kidney is convex while the inner margin is concave, The concave margin is called Hilum. Blood vessels and ureters have the kidney through Hilum. (iv) On the top of each kidney, an endocrine gland called adrenal gland is found, Internal Structure : LS, of a kidney shows three main regions — © Outer cortex @ Medulla in the middle © Internal renal pelvis (i) Outer Cortex ; The cortex is dark red in colour who granular due to the presence of nephrons, Nephrons kidney } is covered by a fibrous capsule, It looks are structural and functional unit of the 22 ICSE Biology Lab Manual-X 7 lt” ‘The apex of each (i) Medulla : Its lighted in colour, subdivided into many conieal renal pyramids, smids are aligned renal pyramid forms the renal wveduilla deep to the renal cortex. These renal py ‘with their bases towards the cortex (ii) Renal Pelvis : Renal pelvis is the ‘anne! like dilated proximal part of the ures’ © the kidney. The major function of renal pelvis is to act 25 5 ‘anne for urine flowing to the ureter, \S urine flows ral the Kidney to the urinary bladder through it J L Ay) oe i . \ || Enos \ secney ral peo fetta seralarery rnalven ral K STE. et HN me me A pair of kidneys Injernal structure of Kiéney VIVA-VOCE 0. 1. Give the size and ghape of a normal Kidney of human. ns, Generally each Kidney is about 10 cm long 65 em bro# flat and bear-shaped. 0,2. Give the shapes of ont and inner mare’ of the kidney. vce, The outer margin is convex while the innee ‘margin is concave. ad and 3.5 cm thick. The kidneys are slightly . 3. List three distinct parts of a kidney. ‘Ans. Three distinct parts of @ kidney are — (@) Outer cortex (ji) Medulla in the middle XX (ii) Renal pelvis (in the internal sid®), (0. 4. Name the outermost region of @ kidney ‘ans. Cortex is the outermost part of a Kidiiey that is covered by @ fibrous capsule. @Q. 5. Why does the cortex look granular? < ‘Ans, Due to the presence of nephrons in cortexnit looks granular. Q. 6, In which region of kidney, the conical renal pyramids are found? vans, In the middle region of a Kidney called medulla, Q. 7. What is the function of renal pelvis? ‘ans, Renal pelvis functions Iike a funnel through which urine flows to the urinary bladder. ICSE Biology Lab Manual-X a mumebr of conical renal pyramids are found. - EXPERIMENT NO. - 16 (STRUCTURE OF INTERNAL ORGANS CONTD.) Objective To study the structure of human brain = Requirements conor iepheres Model or a chart showing external and internal aan structure of human brain. Procedure and Observation Study the given chart or model carefully. Ob- serve each part, draw, label and write comments on the structure, Structure Sensory sre ‘Human brain is most developed as compared to Corebetum = ae shined all other animals in the animal kingdom. It is GY Inoremation isles located in the head protected by bony cranium and eiemech its coverings. The meninges, which are continuous Medulia with the spinal cord are oblongata (2) Outermost duramater ieee eal ne Human brain showing various parts, (©) Innermost piamater. {The spaces between the membranes are filled with Cae fi 10st parts of th , phere cerebro-spinal fluid. In most parts of the brain, the grey hemisphere re ‘matter containing the nerve cells is outside the white matter made up of fibres of nerve cells, The brain can be studied in 3 Parts Corpus callosum 1. Fore brain : Consists of (a) Cerebrum (6) Olfactory lobes and (©) Diencephalon, (=) Gerebrum : It is the largest part of the brain pee Hypothalamus aa Pituitary Spinal cord Medulia oblongata intelligence, thinking, memor Bence, q ‘Ys reasoning, Section thro, Perception and stimulus interpretation 5 mae (6) Olfactory lobes : These are a Par Of small club shaped solid stru © Thalamus and hypothalamus, lamus rela 'S SO} ¥8 some of the sensory impulses, whereas hypothalamus Coordinates autonomi mic ac- tivities, ICSE Biology Lab Manual-x Shia Brain «1 connects the fore brain to hind brain and controls muscle toning, some motor activities | Mind Brain : It consists of (a) Cerebellum (b) Medulla oblongata. Cerebellum ; It lies below cerebrum and above medulla oblongata, The white matter appears like branching tree. It has numerous furrows but no convolutions, It maintains posture, ‘equillibrium and muscular toning. {p) Medulla oblongata : It is the lowest part of the brain. Oblongata continuing into spinal cord. It has white matter on the outer side and grey matter on the inner side. The roof of medulla contains fa choroid plexus where cerebrospinal fluid is formed. Medulla oblongata has cardiac centre, res- piratory and vasomotor centre. ~<— VIVA-VOCE —— 0. 1. What are the parts of nervous system which comprise central nervous system? Ans. Brain and spinal cord. ©. 2 What is the adoantage of folds in the cerebrum? Is cerebellum also having such folds? Bn. The folds in cerebrum of human brain incréase its surface area, Cerebellum does not have such folds ©. How are brain and spinal cord protected? Sm ‘Ane. Brain is covered by cranium and the spinal cord by the vertebral column, The cerebrospinal fluid also protects the organs from shock and infection. _ EXPERIMENT NO. 47 (IDENTIFICATION OF DIFFERENT TYPES OF BLOOD CELLS) Objective Identification of different types of blood cells under the microscope. Requirements Permanent slide of the cells of blood, microscope Observation and Comments : The permanent slide of blood shows the following features 1. Erythrocytes (Red blood corpuscles or RBCs) : They are (a) Red in colour. (b) Larger in number (6) Biconcave disc-like structures (d) Anucleated 2 Leucocytes (White blood corpuscles or WBCs) : (a) Fewer in number as compared with RBCs (b) Bigger in size than RBC (c) Colourless, irregular or oval in shape. (d) They are of two major kinds (i) Granulocytes — having distinct granules in the cytoplasm (ii) Agranulocytes — do not have granules. ICSE Biology Lab Manual-X co (a) They have bilobed nucleus. os o Cytoplasmic granules stain orange red with acid dye (Eosin) (©) Engulf particles. (@) 60 - 300 per ml of blood. (2) Nucleus has two or more lobes. : (®) Affinity for basic dyes and stain blue black with them. (©) Found in small numbers, 35 - 100 per ml of blood. (a) Nucleus is polymorphic, with three to five lobes, (©) Found in large number, 400 - 500 per ml of blood. (6) Stain with neutral dyes. (4) Phagocytic in nature. (2) Small blood cells with large indented nucleus (&) Number ranging from 1500 - 2000 Per mi of blood. (©) They are irregular in shape. (@) Migrate through the walls ofthe blood capillaries into the tissues by the process of diapedesis, (0) They are bigger cells having larger cytoplasm, (©) Nucleus is kidney shaped. (6) 200 - 700 per ml of blood in number. (d) Phagocytic in nature. — < [ Erythrocytes I Leucocytes Patelets Biconcave Polymorphic Bilobed nucleus rues ED) a Grex D> SS Mp aig at EF a) ae nae ai Res bod copie a ial =f Lymphcetes Monocwte (9) They are colourless on-nucleated and i , ind irregular fr, ® hey have a very shor lifespan Of 3 to 5 ed eames @) It an adult, these number frem 200,000 IA te (4) They help in the clotting of blood Siamese ae 26 ICSE Biology Lab Manualxx i _ExpeR MENT NO. - 18 (SENSE ORGANS) Objective : To study the structure of human ear. Requirements : Model or a chart sowing the structure of human ear. Procedure and Observation : Study the given chart or model, Observe, draw, label and write comments upon the structure. Structure : ar is the organ for hearing and equillibrium. The ears in human beings are present on the two lateral sides of the head. Each ear is divided into three parts ~ the external, middle and the inner ear. External Ear : This is the outer part of the ear consisting of trumpet-shaped ear lobe, pinna which is carlilagenous. and skin covered. It is meant to collect the sound waves and direct them to the middle ear through a canal called the auditory meatus. The canal is lined ‘with ceruminous glands which secrete a Wary material called cerumin which entangles the foreign bodies. Fine hair are also present throughout the inner lining of the auditory canal membrane called Which also trap the unwanted material 0 eniet ‘ito the middle ear, A thin obliquely placed xe lies between the external and middle ear. Sound waves striking against it the tympanic drum or membré cause it to vibrate. Middle Ear : It is represented by a “tympanic cavity’ which lodges three malleus (hammer shaped), incus (anvil shaped) and stapes (stirrup drum while stapes lies against small membrane covered oval window — tiny bones called the ear ossicles called the shaped). The malleus is placed close to ear fenestra ovalis opening into the inner ICSE Biology Lab Manual-X 27 ear and the inner ear. A tube called Eustachian window connects the middle ar at ha prewure on both sides ofthe car. Another opening, the round Soke Cotas the muddle ear to the pharynx of the mouth to ear drum nes i ybranous labyrinth consists oyrin .d within a bony labyrinth. Mem yyrin ‘co fama hr Ya ef fd a cea to each other in three different planes, so that one is horizontal and SWE Et = ‘One end of each canal enlarges into a swelling called the ampulla containing sensory balance. Nerve fibres from them join the auditory nerve ; mi Vestibule consists of utriculus and succulus. It joins the semi circular canals to the cochlea on cerned with static balance. Pinna ‘Semicreular canals Exernal auditory meatus Eustachian Ear drum mach {neal structure of human ear The cochlea arises from the lower side of the sacculus. It is spiral shaped tube with two and a half turns. Its inner cavity is divided into three parallel tubes, separated by membranes. The outer and inner canals are filled with perilymph, whereas the middle one is filled with endolymph. The middle canal has the sound sensitive system called the ‘organ of Corti’ containing receptor cells which transform sound vibrations into nerve impulses which are sent to the brain via the auditory nerve. VIVA-VOCE Q. 1. What are the dual functions of ear in human beings ? Ans. The two functions of the ear are (a) Hearing (b) Balancing 2 Name the smallest bones in human body, Ans The smallest bones in human body are the ear ossicles named malleus, incus and stapes 0.3. What is Cochlea? An». It's the coiled tubular part of the internal ear meant for hearing, . 4 What is the rote of eustachian tube? ‘ns, To keep the balance of the air pressure on either side of the ear drum, 5. What is the function of ear ossicles? ‘ne. They transmit the sound vibration from the external ear to the internal ear. cs ICSE Biology Lab ManualX — What is the wee of ear pinna in human beings? it helps to collect the sound vibrations and also protects the inner part lke auditory meatus and tympanic membrane RIVENT No. 19 (SENSE ORGANS CONTD.) Jo study the structure of human eye. Requirements Model or a chart showing the structure of the human eye. Procedure and Observation Study the given chart or model carefully. Observe, draw, label and write comments upon the structure Eyelashes Structure ved a cote Human beings are provided with two eyes which are mean ceauet Nain ds situated in the deep bony cavities called the orbits in front of front of eve) the skull. Each eye consists of the eye ball and accessory Front view of human eye structures like the eyelids, eyebrows, eyelashes, Jacrymal glands, etc. Accessory Parts vw Upper and lower eyelids are Eye muscle protective movable parts which Eye lid scare protect the eye from excessive light, Suspensory choroid foreign particles and their blinking Loc Rotina spreads lubricating secretion over Aqueous mo the eyeball. Pupil Yellow spot conjunctiva —{ Eyelashes Cornea __ They are a row of short thick tai Bind spot hair on the margin of the upper and ower eyelids. They protect the eye Optic none ei i i from foreign particles from falling a ees into the eye. \VS. through the human eye Lacrymal Glands Each eye has a set of lacrymal glands at the upper, outer end of the eye: ‘They produce a secretion-the lacrymal fluid which spread evenly En the eye ball, thus, lubricating it. Excessive Tacrymal fluid- the tears wash away dust particles. They also have antiseptic property as they contain enzyme-lysozyme. Eyebrows 'h row of hair is present above the eyes t0 protect sweat, etc, from falling, into the eye. Structure of Eye Ball (i) Conjunctiva ‘A thin membrane which covers the entire part of the eye, It is continuous with the inner lining of the 29. = ICSE Biology Lab Manual-X cornea epithelial layer over the ee ener aaa ea ded to the bones by six muscles. Only the front, one Eye ball is embedcled in a bony socket and is suspen eee a sep coverd By te 9 = a ae ia oes fibrous sclera which is thick, white, non elastic covering, of the eye ball leaving Thc chtesor most portion, the irs where Sclera bulges as non-vascular transparent, fiberous, coat, covering the coloured part of the eye. The middle layer of the eyeball is soft, ‘This is called the comea. vascular and thin which nurishes the eye, called is ing in front called the e is layer com roses the eye ball leaving a circular opening in = seas Pasa ras velour of the pupil. The contraction and relaxation of cireulay uupil. Colour of the eye colour of the 5 roe ial muscles ofthe iris constrict or widen the diameter of the pupil regulating the amount of the light entering into the eye Ciliary Body is the part of chloroid arising from comea. It consists of ciliary processes and ciliary muscles. Ibis the innermost thin layer which is sensitive in nature having senory cells = the rods and cae receives the images of the objects focused by the lens. The retina thins off and terminates tehind the ciliary muscles, Rods are sensitive to dim light are meant for night or dark vision. They contain a pigment called Rhodopsin, Cones are sensitive to bright light and colour vision. They contain pigment Iodopsin. It is transparent, biconvex, crystalline structure situated behind the pupil. The suspensory ligaments ofthe cillary body hold this in position. The contraction and relaxation of ciliary muscles change the shape of the lens of viewing objects at different distances, The presence of lens divides the cavity of the eyeball into two chambers \oueous Chamber + Situated between cornea and lens, filled with aqueous humour which supplies oxygen and nutrients in addition to removal of wastes. Keeps the lens moist and gives protection to the eye (6) Vitreous Chamber ; Lies behind the lens and is filled with jelly - like vitreous humour. Tt maintains the shape and protects the retina. \llow Spot» This is a small area on the retina which has maximum number of cone cells. This is also called as Macula or Fovea centralis. This is the region of best vision. (i) Blind Spot Itis the region on retina which is devoid of sensory cells, therefore, no image is formed here. This is the point, where the nerve fibres from all the sensitive cells of retina converge and together leave the eyeball as optic nerve to reach the brain. VIVA-VOCE 2 Name some accessory structures associated with eye to protect it (a) Eyebrows (b) Eyelashes What is the third eyelid in human eye? A rudimentary structure present on the inner a was functional in groups like Amphibia. What is lacrymal fluid? the point just behind the junction of sclera and (©) Lacrymal glands. ingle of the eye near the nose is the third eyelid which Lacrymal fluid is protective fluid secreted by the | “ ball to lubricate it and helps to remov. ron ia Blands above the eye. This covers the eye e or destroy any foreign bod i The bats and owls cannot see in the day time, wohy?

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