1_Biology Lab Manual - 2nd Sem 2011-2012

8/3/2019 1_Biology Lab Manual - 2nd Sem 2011-2012

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BatterjeeMedical College for Sciences & Technology

FoundationAcademy for Sciences & Technology

FAST

BIOLOGY LAB MANUAL


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Batterjee Medical College

FOUNDATION YEAR

Biology Practical Second semester

Syllabus 2011-2012

WeekDate

Experiments.Date Initials

Start End

Week 1Sat

28-01-12

Thu

02-02-12

Blood Pressure measurement using

mercury sphygmomanometer.

Week 2Sat

04-02-12

Thu

09-02-12

Slide preparation of human blood. Bloodcell count.

Week 3Sat

11-02-12

Thu

16-02-12Blood Types

Week 4Sat

18-02-12

Thu

23-02-12

Haematocrit, packed red blood cells volume

Week 5Sat

25-02-12

Thu

01-03-12

To determine your own bleeding time.

Week 6Sat

03-03-12

Thu

08-03-12

To compare the amount of urea in threebody fluid (urine, renal artery plasma, renal

vein plasma.

Week 7Sat

10-03-12

Thu

15-03-12

Histology of cerebellum and spinal cord.

Week 8Sat

17-03-12

Thu

22-03-12

Anatomy of cerebrum, model and specimen(sheep brain)

Week 9Sat

24-03-12

Thu

29-03-12Structure of eye ball & Layers of ratina

Week10

Sat

31-03-12

Thu

05-04-12Histology of Thyroid Gland

,

Week11

Sat

07-04-12

Thu

12-04-12

Stages of the mitosis in the root tip slide

Week12

Sat

14-04-12

Thu

19-04-12Physiology of endocrine gland (slides)

Week

13

Sat

21-04-12

Thu

26-04-12

Stages of the mitosis in the root tip slide


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Week14

Sat

28-04-12

Thu

03-05-12

Gematogenesis

a. Slide of mammalian ovary.b. Slide of study of mammalian

testis.

Week15

Sat

05-05-12

Thu

10-05-12Basic techniques of microbiology.

Week

16

Sat

12-05-12

Thu

17-05-12

Lab Quiz

Revision

Week17

Sat

19-05-12

Thu

24-05-12ASSESSMENT QUIZ


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Table of content

Serial

No.

Content Page

1 Respiratory system 9-12

2 Blood pressure measurement 11-12

3 Preparation of blood smear 13-15

4 To determine your blood group 16-18

5 To determine the packed cell volume orhematocrit ratio

19-20

6 To determine your own bleeding time 21-22

7 To determine the difference in composition ofurea in renal artery, plasma, renal vein andurine.

23-24

8 Microscopic structure of cerebellum and spinalcord

25-26

9 Lobes of cerebellum and there function. 27

10 To study the structure of eye ball and layers ofretina.

28-29

11 Microscopic structure of thyroid gland 30-31

12 Stages of mitosis in root tip 32-33

13 Gematogenesis- microscopic slide of ovary andtestes

33-34

Distribution of grades for Biology Practical

Semester % ofmarks

First Semester1. Lab Activities (experiments)2. Quiz & worksheet

10%5%5%

Second semester1. Lab Activities (experiments)2. Quiz & worksheet

10%5%5%

Total Mark for One Academic Year 20%


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Date:___________ Score:______

Experiment No. 1Respiratory System

Respiratory System

Lungs provide the breath of life. Our lungs are about the size of a pair of footballs. Theyfill our chest from the neck to the ribs. The lungs are protected by our ribs. The lungsare the pickup place foroxygenand the drop off place forcarbon dioxide. The lungs arealways working, breathing in oxygen and breathing out carbon dioxide.

Blood is pumped into the lungs from the heart through the pulmonary arteries. Bloodwith oxygen leaves the lungs through the pulmonary veins and travels to the heart.Oxygen is the fuel that makes all the body processes run.

Objectives:To understand the microscopic and gross anatomy of the respiratory tract.

Material:

Microscope

Prepared Slides

Procedure:A. Examine a lung section at high power; identify the alveoli

B. Label the diagram model below.

bronchial tree - the system of airways within the lungs, which bring air from thetrachea to the lung's tiny air sacs (alveoli).cardiac notch - the indentation in the left lung that provides room for the heart.diaphragm - a muscular membrane under the lungs.larynx - a muscular structure at the top of the trachea, containing the vocal cords.left inferior lobe - the bottom lobe of the lung on the left side of the body.left superior lobe - the top lobe of the lung on the left side of the body.right inferior lobe - the bottom lobe of the lung on the right side of the body.right middle lobe - the middle lobe of the lung on the right side of the body.right superior lobe - the top lobe of the lung on the right side of the body.trachea (windpipe) - the tube through which air travels from the larynx to the lungs.
http://library.thinkquest.org/5777/glossary.htm#ribshttp://library.thinkquest.org/5777/glossary.htm#ribshttp://library.thinkquest.org/5777/glossary.htm#oxygenhttp://library.thinkquest.org/5777/glossary.htm#oxygenhttp://library.thinkquest.org/5777/glossary.htm#oxygenhttp://library.thinkquest.org/5777/glossary.htm#carbon%20dioxidehttp://library.thinkquest.org/5777/glossary.htm#carbon%20dioxidehttp://library.thinkquest.org/5777/glossary.htm#carbon%20dioxidehttp://library.thinkquest.org/5777/glossary.htm#carbon%20dioxidehttp://library.thinkquest.org/5777/glossary.htm#oxygenhttp://library.thinkquest.org/5777/glossary.htm#ribs


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http://www.enchantedlearning.com/label/anatomy.shtml


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Histological Slide Of Trachea

1. Trachea

It is the only tube that extends between larynx and bronchi through which air can reach lungswormed, and humidified. Trachea is lined with respiratory mucosa membrane (ciliated

pseudostratified columnar epithelium. If it is closed, we will choke, thats why it is made of C

shaped rings of cartilages placed one above the other with only little soft tissue in-between to

secure constant opening of its lumen and prevent its collapse.

The tracheal wall consists of the following four components:

1. Mucosa(ciliated, pseudostratified epithelium and elastic fibre-rich laminapropria);

2. Submucosa(denser connective tissue);3. Cartilaginous layer (C-shaped cartilages);4. Adventitia(binds trachea to other structures).
http://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#mucosa_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#mucosa_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#submucosa_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#submucosa_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#adventitia_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#adventitia_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#adventitia_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#submucosa_of_tracheal_wallhttp://download.videohelp.com/vitualis/med/his_respiratory_sys.htm#mucosa_of_tracheal_wall


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Date_________ Score:______

Experiment (2)Blood Pressure Measurement

Introduction:Blood pressure or arterial blood pressure is the pressure (force

per unit area) exerted by the blood on the walls of the blood vessels. Thedoctor measures the maximum pressure (systolic) and the lowest pressure(diastolic) made by the beating of the heart.

The systolic pressure is the maximum pressure in an artery at the movementwhen the heart is beating and pumping blood through the body (ventricularcontraction)

The diastolic pressure is the minimum pressure in an artery in the momentbetween beats when the hearts is resting.Both the systolic and diastolic pressure measurements are important is eitherone is raised; it means you have high blood pressure (high hypertension).Arterial blood pressure is usually measured in millimeters of mercury (mmHg)using a sphygmomanometer.The average blood pressure for an adult is

120/80 mm Hg

Objectives:To measure blood pressure by using mercury sphygmomanometer.To define blood pressure, and explain why blood exerts a pressureon the walls of blood vessels.

To define systolic and diastolic pressure.Indicate the precautions that must be taken before and during reco-rding the blood pressure.


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Observations: Fill in table with your results.

Blood pressure in different activities

Activity Blood pressure/mmHg

1.Sitting and relaxing

2. Jogging in place

Procedure:1. A soft arm cuff is warped around the arm. A hand bulb pumps air into the cuff,

gently squeezing the arm and temporarily interrupting the flow of blood inbrachial artery. The pressure gauge reaches a peak (200mmHg).

2. Then the cuff is slowly deflated, letting blood flow again. As the cuff deflatesand the pressure gauge gradually decreases, the return of the blood flowthrough the main artery in your arm can be heard using a stethoscope.

3. The first time you hear the sound, note what the reading was on the pressuregauge when the heart beat is first heard is your systolic pressure (the peak

pressure as the heart contracts)

4. The reading when the pulse can first no longer be heard is your diastolic

pressure (the lowest pressure as the heart relaxes between beats).

Post-Lab Question:1. What is blood pressure?

Ans:__________________________________________________________

______________________________________________________________

2. What is high blood pressure (hypertension)?


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Ans:__________________________________________________________

______________________________________________________________

3. How to measure blood pressure?

Ans:__________________________________________________________

______________________________________________________________

____________________________________________________________.

4.What causes high blood pressure?

Ans:__________________________________________________________

______________________________________________________________


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Date________ Score:______

Experiment No: (3)

Preparation of Blood SmearIntroduction.

Much valuable information about the health of a patient can beobtained by a thorough and competent study of a smear of their peripheralblood. To prepare a blood smear, a drop of blood is spread on a glass slideand then stained. Wright's stain is widely used for staining blood smears. Itcontains eosin and methylene blue, both of which stain independently as wellas in combination.

Following are the different categories of blood cells.

ERYTHROCYTES (Red cells): The erythrocytes are the mostnumerous blood cells, have biconcave shape devoid of a nucleus.The red blood cells are rich in hemoglobin, a protein able to bindoxygen for providing oxygen to tissues

PLATELETS (thrombolytic): Platelets are fragments ofmegakaryocytic. Megakaryocytic are found in red bone marrow.The main function of platelets is to stop the loss of blood fromwounds.

LEUKOCYTES (White cells): Leukocytes or white cells are responsible forthe defense of the organism. In the blood, they are much less numerous thanred cells. Leukocytes are divided in two categories: granulocytes and agranulocytes (lymphoid cells).Each type of leukocytes is present in the bloodin different proportions:

Neutrophils 50-70%: Neutrophils are very active in phagocytingbacteria and are present in large amount in the pus of wounds.Unfortunately, these cells are not able to renew the lysosomes used

in digesting microbes and dead after having phagocyted a few ofthem.

Eosinophils 2-4%: Eosinophils attack parasites and phagocytesantigen-antibody complexes.

Basophils 0-1%: Secrete anti-coagulant .Even if they have aphagocytory capability, their main function is secreting substanceswhich mediate the hypersensitivity reaction.


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Lymphocyte 20-40%: Lymphocytes may vary somewhat in size,but the majority of them will measure 7-8 m (slightly larger than anerythrocyte). They have a relatively large, spherical nucleus.Lymphocytes yield antibodies and arrange them on their membrane.

Monocytes 3-8%: The three most useful diagnostic features ofthese cells include their dull grey-blue cytoplasm, their larger size(12-15 m), and their distinctive horseshge or kidney shapednucleus.

Objective:

1. To determine red blood cells, white blood cells, and platelets arenormal in appearance and number.

2. To distinguish between different types of white blood cells.3. To determine their relative percentage in blood.4. To help diagnose a range of deficiencies, diseases, and disorders

involving blood cell production.

Materials:

1. Sterilized lancet2. Clean microscope slide3. Ethyle alcohol4. Eosin

5. Methylene blue

Procedure:

1. Taking the Blood:Cleansa finger. With a sterile lancet, make apuncture on a fingertip. In the meantime, keep all the materials neededready and protected from dust. The edge of another slide in contactwith the drop and allow the drop to bank evenly behind the spreader.

2. Fixing: A fixing technique consists of dipping the smear in 95% ethylalcoholfor 3-5minutes

3. Staining:To stain a smear, take a slide with a fixed and dry smear.

Put on the slide a drop of stain until it is fully covered.4. Observation:A magnification of 40 times is enough to observe and

identifythedifferent types of cells.

Type of cells Size (diameter) No. in bloodErythrocytes 67.5 m 4-6million/mm3

platelets 2---3 m 200000-300000/mm3Leukocytes 12---15m 50007000mm3


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Question:

1. What is Blood smear?

Ans:__________________________________________________________

______________________________________________________________

1. Draw different types of blood cells as you see underthe microscope,and name them.


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Date___________ Score__________Experiment: (4)

Blood Types

IntroductionHuman Blood is about 45% cell by volume, although it is only slightly thicker than

water. Blood cells are suspended in a straw-colored fluid calledplasma(about 55% of totalblood volume). Plasma is mostly water but contains many dissolved substance, includinggases, nutrients, wastes, ions, hormones, enzymes, antibodies and other proteins.On the surfaces of your red blood cells are one or more antigensthat will cause theiragglutination if exposed to the complementary antibodies. Agglutination is the clumpingof erythrocytes. This could theoretically occur during blood transfusion. The transfusion ofincompatible blood causes the destruction of donor erythrocytes and perhaps the death ofthe patient when clumping cells block blood vessels. For these reasons, blood used fortransfusion is very carefully matched for compatibly with the patients blood.

The Blood type you belong to depends on what you inherited from your parents.

ABO Blood Typing SystemAccording to the ABO blood typing system there are four kinds of blood types:A, B, AB or OBlood Group AIf you belong to the blood group A, you have A antigens on the surfaceof your red blood cells and B antibodies in your blood plasma.

Blood group B

If you belong to blood group B, you have B antigens on the surface areaof your red blood cells and A antibodies in your blood plasma.

Blood Group ABIf you belong to blood group AB, you have A and B antigens on thesurface of your red blood cells and no AB antibodies at all in your bloodplasma.

Blood Group OIf you belong to blood group O, you have either A nor B antigens on thesurface area of your red blood cells but you have both A and B

antibodies in your blood plasma.

Rh factor blood grouping systemMany people have so called Rh factoron the red blood cells surface.This is also known as antigens and those who have it are called Rh+.Those who havent are called Rh-. A person with Rh- blood not have Rhantibodies naturally in the blood plasma. But a person with Rh- bloodcan develop Rh antibodies in the blood plasma if he or she receivesblood from a person with Rh+ blood without any problems.


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ll. Objectives:1. To find out your own blood group.

2. To observe Rh factor

lll. Materials:Sterlized lancet, clean glass slide, alcohol swab, antiserum A and B, antiserum D.

lV. Procedure:1. Clean a finger.

2. With a sterile lancet, make a puncture on a finger tip.

3. Place three small drops of blood on the slide.

4. Mix the blood with three different antiserum including either of three different

antibodies, A, B or Rh antibody.

5. Then you take a look at what has happened. In which mixture has agglutination

occurred?

Observation:

Anti Sera A Anti Sera B Anti Sera D

Observation tableNote:Agglutination= +veAgglutination= -ve

Antisera AntiseraA&1drop 0f

blood

AntisearB&1 drop of

blood

Antisera D&1 drop of

blood

My bloodgroup is :

Agglutination


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Post-lab Questions

Q1. What is blood agglutination?Ans.____________________________________________________________________

Q3. How do you know which blood you belong to?Ans._____________________________________________________________

________________________________________________________________

Blood transfusion

Who can receive blood from whom?

Of course you can give A blood to a person with blood group A, B blood to a personwith blood group B and so on. But in some cases you can receive blood from a person withanother type of blood group or donate blood to a person with another kind of blood group.

The transfusion will work if a person who is going to receive has a blood group thatdoes not have any antibodies against the donor bloods antigens. But if the person who isgoing to receive blood has antibodies matching the donor bloods antigens, the red bloodcells in the donated blood will clump.


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Date_______________ Score__________

Experiment: (5)

To determine the packed-red cell volume or hematocrit ratio

Introduction:The hematocrit, the volume of percentage of red cells in the whole blood, is

determined by spinning a blood sample in a high-speed centrifuge for 2 to 5 minutes toseparate the cellular elements from plasma. The hematocrit is expressed as the volume ofpacked red cells per unit volume of the whole blood for example hematocrit 38% in labreport means that the patient has 38 ml of red blood cells per 100 ml of blood, red bloodcells comprise 38% of the total volume. For men 42% to 54%, for women 36% to 46%. Tomeasure hemoglobin level, hemoglobin is released from red blood cells, and the color ofblood is compared with known color scale.

Objective:

1. Describe how to perform a hematocrit.

2. The student should be able to describe the conditions in which the ratio is altered

(decrease or increase).

Material:Hematocrit tube, centrifuge machine, sterilized lancet,alcohol swab.

Procedure:

1. Work in groups for four. Fill a plain capillary tube to the mark with aseptic or

simulated blood and seal it with clay. Fresh blood requires a capillary tube with the

inside surface coated with a anticoagulant heparin to prevent clotting.

2. Place the sealed capillary tube in a microhematocrit centrifuge along with those from

other groups.

3. After your instructor has secured and spun the tubes and open the centrifuge,recover your tube. Determine the percent red cell packed cell volume using a ruler.

4. Dispose of your capillary tube in the blood waste disposal jar.

Observation:

Note: The percent packed volume of the red blood cells is calculated by dividing

the height of the column of packed blood cells by the length of the total column and

multiplying by hundred.


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Result:

The volume percentage of red blood cells in my blood is: _____________=_______%.

Draw the capillary tube length and measurethe packed-red blood cell volume using theruler. Calculate the percentage volume.


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Date____________ Score__________

Experiment: (6)To determine your own bleeding time.

Introduction:Whenever there is a trauma, wound, cut or injury bleeding takes place. To

prevent the excessive loss of blood, nature has provided the mechanism of Hemostasis thatoccurs in different steps. The first step is vasoconstriction which takes place on both sidesof ruptured vessel up to several centimeters.

The second step is the formation of platelet plug. As the vessels aretraumatized, the nearby passing platelets come and adhere to the rough surface (collagenfiber) and secrete ADPs and thromboxan A2 which make these platelets sticky for eachother passing platelets i.e platelet plug is formed which plugs the rent in the vessels.Sharply cut vessels bleed, more then the crushed vessels. The more a vessel istraumatized more is the degree of spasm. Platelet plug is unstable and temporary. Properhaemostasis occurs due to addition of clotting factor leading to formation of fibrin.

Material: sterilized lancet, alcohol swab, filter paper, stop watch.

Procedure:1. After all usual precautionary measures, prick the finger with sterilized blood lancetabout 3mm deep and start the stop watch.

2. Wipe off the blood from site.3. Apply a gentle pressure and touch the site of prick with filter paper so that the spot

of the blood appears on the filter paper.4. Repeat the procedure after every 30 second by touching the site of prick with the

filter paper and wiping it off every time till there is no spot of blood appears. Stop thestop watch.

5. Circle the spot of blood with pencil and note the time of each spot.6. Note the bleeding time and paste the filter paper in your practical manual.

7. Bleeding time is also calculated by dividing the total number of drops on the filterpaper by 2.

Bleeding time = No. of drops on filter paper2


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Observation:

Results: My bleeding time is ________ minute.


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Date____________

EXPERIMENT NO. (7)

Difference In Composition 0f Urea In Renal Artery Plasma,Renal Vein Plasma and Urine.

INTRODUCTION:

To compare the amount of urea in three different samples of artificial body fluid,

the three artificial body fluids are plasma from the renal artery, plasma from the renal vein

and urine. They are in test tubes labelled F1, F2 and F3 but not necessarily in that order.Urease is an enzyme that breaks down urea to produce ammonia.

Urea + Urease Ammonia (NH3)

Material:

1. Test tubes.

2. Urea solution.3. Urease enzyme.4. Red litmus paper.

5. Bung (rubber stopper).6. Pipette

PROCEDURE:

1. You are provided with a solution of urease enzyme.

2. Use the Pipette provided to add 3cm3 of urease to each test-tube.3. Ammonia turns red litmus paper blue.4. Moisten three pieces of litmus paper with water and place a piece of litmus paper in

each test-tube, such that it is trapped by the bung, as shown:

Detection of urea

Bung

Damp Litmus Paper

Solution (mixture of sample &Urease)


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5. Start timing and record how long it takes for the litmus paper to being to change colour.If a colour change has not occurred within 10 minutes, record the time as infinity.

OBSERVATIONSRecord your results in the table below:

Test-tube

Time taken to being tochange colour /min

F1

F2

F3

Q (1) State what colour the litmus paper turned in F1...

..

Q (2) For each solution, F1, F2 and F3, suggest which is urine, which is renal artery plasmaand which is renal vein plasma.

Explain your answer.

F1 is.

..

F2 is

F3 is


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Date______________ Score___________

Experiment No: (8)

Microscopic structure of spinal cord & cerebellumIntroduction:

The spinal cord and brain makes the central nervous system (CNS). Put simply, theirjobs is to coordinate nervous information so that the right impulses are sent to the rightplace at the right time.Observation:

The purpose of this investigation is to examine section of the spinal cord and brainand related their microscopic structure of their overall function of coordination.

Procedure:Before you at the spinal cord under the microscope it is useful to have the picture of

generalized reflex arc in your mind (you figure). You will then know what to expect to findinside different region of the cord.

1. Examine a prepared transverse section of spinal cord under low or medium power.

Identify the structure shown on the figure. Distinguish between the central grey

matter and the peripheral white matter. The gray matter contains of cell bodies of

numerous neurons, the white matter contain slender axon which transmit impulses

in and out of spinal cord and axon which transmit impulses up and down the spinal

cord to and from the brain.

2. Note the meninges surrounding and protecting the spinal cord; the outer and inner

layer are separated by a delicate vascular middle layer.3. Locate the cell body of an effector neuron in the ventral part of the grey matter in

figure. Examine it under high microscope. Note in particular its slender branches

(dendrites). These connect the other neuron. Look at a particular branch which may

be axon. Extend your study of motor neuron by examining neuron in a prepared

smear of spinal cord.

4. Label the layers of spinal cord.


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Microscopic Structure of cerebellum and spinal cord

Introduction:

Cerebellum is a distinct part of the brain and its characterized by complex folding ofcerebellum cortex, generating a pattern of pleats (cerebellar folia).the folia contains nucleiof nerve cels.

Under high power, cerebellum showing following layers:

1. The molecular layer: this layer is composed of nerve cells processes with scanty glial

cells.

2. The granular layer: the bulk of small nerve cells with dark staining around nuclei.

3. White matter: below the granular layer is the white matter which contains myelinatedfibers.

4. Purkinge cells: charaterised by vast branching pattern of the dendrite in the

molecular layer, but this is only visible by the specific staining method.

Function of cerebellum:

The cerebellum controls fine movements by sending impulses down the axon ofthe purkinge cells.

Q. Label the microscopic structure of cerebellum


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Date__________ Score___________

Experiment (9)

Lobes Of Cerebrum And Their Functions

Q.Match the function of the cerebrum with their lobes

Lobes FunctionsA Parietal lobe ____ 1 Responsible for hearing and smelling

B Frontal lobe ____ 2 Responsible for vision

C Temporal lobe ____ 3 Responsible for sensation oftemperature, touch, pressure and painfrom skin.

D Occipital lobe ____ 4 Responsible for movement ofvoluntary skeletal muscles andelaboration of conscious thoughts.


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Date:____________ Score_______

Experiment: (10)

To Study The Structure Of Eye Ball And Layers Of Retina

Introduction:Of all our senses, vision is the most developed. The retina contains photo

receptors. You will discover that the eye is similar to a camera in structure in that our eyesuse a lens to focus, and the retina is the camera flim our brain uses to make images.

Objectives:

1. Differentiate various structure of the eye ball.

2. See the retina and its important land marks3. Know function of the lens.

Material:

1. Light microscope section of eye with retina and optic nerve.

2. Preserved sheep eye.

3. Dissecting scissors

4. Dissecting needle.

5. Forceps

6. Scalpel.

Procedure:

1. Obtain a preserved eye sheep eye and place it on a stalk of several paper towels.

Identify the external features.

2. Use dissecting scissors to dissect outer eye muscles and expose the tough, white,

fibrous connective tissues of the sclera. In life these muscles move the eye ball.

3. With a scalpel, make a incision about inch in black of and parallel to the edge of

the cornea into the interior cavity. Use scissors to extend the incision completely

around the eye ball and gently pull the tow pieces apart. Identify the interal featuresof the eye ball.

4. Allow the lens and vitreous body of the posterior cavity to flow out of the posterior

portion of the eye ball. Fill the posterior portion of the eye ball with water so as to

flatten the retina for examination. Identify the blind spot.

5. Examine the lens and vitreous body.


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Q1. On the basis of the above knowledge about the external and internal eyestructure, label the following diagram.


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Date:__________ Score_______

EXPERIMENT NO. (11)

Microscopic structure of the thyroid gland.

INTRODUCTION:

The thyroid gland is situated in the neck close to the larynx. Its main function is to

secrete the hormone thyroxine into the bloodstream.

OBJECTIVE:

The purpose of this investigation is to look at the thyroid under the microscope and

relate its structure to its function.

PROCEDURE:

1. Examine a section of thyroid gland under medium power and use it to help you interpret

its structure. Notice in particular numerous follicles, each surrounded by a single layer

of cuboidal epithelial cells. The cavity (lumen) of each follicle contains a substance,

thyroglobulin, which takes up stains and is usually visible in sections.

2. Consider the following information on how the gland works. The follicle cells absorb

iodide and other metabolites from the bloodstream. They synthesis thyroglobulin from

these raw materials and secrete it into the lumen of the follicle for temporary storage.When required, they absorb thyroglobulin from the lumen and convert it into thyroxine,

which is then secreted into the blood.

An Epithelial cell in the wall of a thyroidPart of thyroid gland under microscope.Follicle with an adjoining capillary


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On the basis of the above knowledge about thyroid gland fill the following blanks:1. The thyroid gland in composed of numerous _______________.

2. Each follicle consists of a single layer of _____________ cells.

3. Single layer of epithelial cells surrounding the cavity of follicle called________________.

4. The lumen of follicle is filled by ___________..5. The colloid which is the store of large glycoprotein known as__________.

6. Lysosomes degrade thyroglobulin to produce small hormone molecule that arereleased into the ________________.

Questions:

Q1. Write two precursors (raw material) of thryoglubulin that enter a thyroid epithelialcells.

Ans.___________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Q2. Name two hormone molecule that thyroid gland releases into the blood.

Ans.___________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Q3. What is collide?

Ans.___________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Q5. State two advantages of storing the hormone molecules as thyroglobulin.

Ans.___________________________________________________________________

______________________________________________________________________

_____________________________________________________________________


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29

Date:__________ Score______

Experiment No. (12)

Stages of Mitosis in Root Tip

Introduction:

Mitosis, also calledkaryokinesis, is division of the nucleus and itschromosomes. It is followed by division of the cytoplasm known as cytokinesis.Both mitosis and cytokinesis are parts of the life of a cell called the Cell Cycle.Most of the life of a cell is spent in a non-dividing phase called Interphase.Interphase includes G1stage in which the newly divided cells grow in size, Sstage in which the number of chromosomes is doubled and appear as chromatin,and G2 stage where the cell makes the enzymes & other cellular materials

needed for mitosis.Mitosis has 4 major stages --- Prophase, Metaphase, Anaphase, and

Telophase. When a living organism needs new cells to repair damage, grow, orjust maintainits condition, cells undergo mitosis.

During Prophase, the DNA and proteins start to condense. The twocentrioles move toward the opposite end of the cell in animals or microtubulesare assembled in plants to form a spindle. The nuclear envelope and nucleolusalso start to break up.

Prophase

During Metaphase, the spindle apparatus attaches to sister chromatids of eachchromosome. All the chromosomes are line up at the equator of the spindle.They are now in their most tightly condensed form.

..Metaphase


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During Anaphase, the spindle fibers attached to the two sister chromatids ofeach chromosome contract and separate chromosomes which move to oppositepoles of the cell.

Anaphase

In Telophase, as the 2 new cells pinch in half (animal cells) or a cell plate forms(plant cells), the chromosomes become less condensed again and reappear aschromatin. New membrane forms nuclear envelopes and the nucleolus is

reformed.

Telophase

Objective:

1. .To recognize changes in chromosomes and other nuclear materialsduring mitosis.

2. You may use your textbook and class notes to help you identify the stagesof mitosis as seen under the microscope.

Materials:

Microscope, prepared slide onion root tip,lab worksheet, pencil

Procedure:

1. Set up a compound light microscope and turn on the light.2. Place a slide containing a stained preparation of theonion root tip3. Locate the meristematic or growth zone, which is just above the root cap

at the very end of the tip or


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4. Focus in on low power, and then switch to medium or high power. Belowfind micrographs of the four stages of mitosis. Use them to help youidentify the stages on the microscope slide.

Q1. The photomicrograph shows cells dividing by mitosis in a longitudinal section

of a root tip.

Look at the cells labelled 1, 2, 3, 4, and 5.Q1. Name the stage of mitosis for each numbered cell.

1 __________________________

2 __________________________

3__________________________

4__________________________

5__________________________

Q2. List the cell numbers in the correct sequence for the stages of mitosis.______

______

__________________


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Date:__________ Score______

Experiment No: (12)

Gametogenesis

Introduction

Gamete formation (gametogenesis) is called oogenesis in the female

and spermatogenesis in the male. Here we examine the gamete formation in

the gonads of mammals. The gonads are paired organs and are called testes in

male and ovaries in female.

Materials:

1. Microscope

2. Prepared slides of a section of

a. Adult mammalian testis

b. Adult mammalian ovary with follicles

c. Adult mammalian ovary with a corpus luteum

Procedure and Observations:

(A) Mammalian spermatogenesis:

1. With your microscope, look at the prepared slide of the testis. Most of the

interior of a testis is filled with coiled seminiferous tubules, which coil.

Transverse and oblique section are present in your slide. Look for

glandular interstitial cells between the seminiferous tubules. Interstitial

cells secrete the male sex hormone testerone.

2. Center a cross section seminiferous tubules in the field of view and

increase the magnification until you see only a portion of the tubules wall.

In the wall of seminiferous tubule, identify as many stages of

spermatogenesis as possible, as well as Sertoli cells, which function to

nurture the development of sperm.

Spermatogenesis in most animal species is seasonal, its completion

coinciding with mating. In humans, however, sperm production is continuous

from puberty throughout the males lifetime.


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On the basis of above knowledge label the diagram of testes below:

Label the name for

A:______________

B: _______________

C:_____________

(B) Mammalian oogenesis:

1. With the microscope, examine a prepared slide of a section of

mammalian ovary. Look for primordial follicles.

Both the follicles and their primary oocytes. Groups of primordial

follicles tend to occur between maturing follicles or between maturingfollicles and the ovarian wall. Note the wall of the primordial follicle is

composed of single layer of smaller cells.

2. Now look for the maturing follicles.

In maturing follicles, the size of the cells and in the follicle wall and of

the primary oocyte its self increases. Also, the follicle cells divide,

causing the wall to become first two cells thick and then multilayered.

Then a space appears between the follicles cells. This fluid-filled space

increases in size until the primary oocyte and the follicle cells

immediately around the primary oocyte are suspended in it. The mass

of the cells in connected to the rest of the wall by a narrow stalk offollicles cells. Just prior to ovulation, the follicle reaches its maximum

size and bulges from the surface of the ovary.

3. Replace the slide on the microscope with one of the mammalian ovary

with a corpus luteum. Locate a corpus luteum.

A

B

C


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In fertilization and implantation of the embryo in the uterus do not occur,

luteum degenerates and its replaced by scar tissue. This scar is now called the

corpus albicans.

On the basis of above knowledge label the diagram of ovary below:

Label the following:

A: ________________

B: _______________

C: _______________

D: ______________

E: ______________

A

B

C

E

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1_Biology Lab Manual - 2nd Sem 2011-2012

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