नमस्कार मित्रांनो इयत्ता बारावी Biology या Subject च्या Practical मध्ये PART - B: Demonstration Experiments (Spotting) हा भाग Practical Exam च्या दृष्टीने फार महत्त्वाचा आहे. या Blog Post मध्ये आपण Spotting Practical Number 14: Observe the prepared slide of blood smear to identify different types of blood cells. ह्या Practical Experiment चे Answer पाहणार आहोत. खाली दिलेल्या उत्तरांमध्ये काही अडचण असल्यास आम्हाला comment करा किंवा तुमच्या संबंधीत विषय शिक्षकांशी चर्चा करा.
B. DEMONSTRATION EXPERIMENTS (Spotting)
14. Observe the prepared slide of blood smear to identify different types of blood cells.
Aim :- To identify and observe the types of blood cells in freshly prepared blood smear.
Requirements :- Blood sample, two slides, Leishman's stain, compound microscope, etc.
Procedure :- A blood smear is used to study not only the types of blood cells but also the parasites, if any, in the blood e.g. Plasmodium. To be able to see the different types of cells in the blood, the blood must be spread in a thin uniform layer on the slide. This spread of blood on a slide is called Smear.
To observe all the cells present in the blood sample under the microscope, they must be stained appropriately. This process is called Staining. Various stains like Leishman's stain or Wright's stain can be used for staining the blood cells:
Preparation of the Smear :-
1. Take two clean and dry slides.
2. Place a drop of blood towards one end of a slide (base slide).
3. Hold this slide having the drop of blood by one hand.
4. Take the other slide (viz. the spreader slide) and keep it inclined on the first slide such that it is just touching the edge of the drop of blood.
5. Hold the second slide in this position till the drop has spread evenly along its edge.
6. Gently move the spreader slide once over the base slide to form a thin layer of blood, called Blood Smear. The smear should cover approximately half the slide.
7. Leave the smear for air drying.
Figure :
Staining of the Blood smear :-
1. With the help of a dropper, put a few drops of Leishman's stain on the slide to cover the smear completely.
2. Keep the stain on the slide for about 5 minutes for its action. Do not allow the stain to dry. Add a few drops of distilled water, if the stain dries.
3. Drain off the excess stain and wash the slide under gentle running tap water till excess stain is removed.
4. Allow the slide to dry at room temperature. Observe it first under low power and then under high power of compound microscope.
5. Observe and identify the different types of blood cells.
Observation :-
1. The main cellular components of mammalian blood are the erythrocytes or RBCs. They are circular biconcave cells without a nucleus. The cells contain a large amount of haemoglobin.
2. A number of leucocytes or WBCs are also found. They are generally irregular in shape and show prominent nuclei. The leucocytes are divided into two main types i.e.Granulocytes having a granular cytoplasm and Agranulocytes (W.BCs with a clear non-granular cytoplasm). Depending upon the shape of the nucleus and the nature of granules, the granulocytes are further divided into acidophils, basophils and neutrophils. The Agranulocytes are divided into two sub-types as lymphocytes and monocytes.
3. Thrombocytes (platelets) are also present in the blood. They are spindle shaped cells. However normally these are not visible in the casual preparations.
Complete the following table after observing your slide.
Questions
1. Give the function of haemoglobin.
Ans :- Haemoglobin binds to oxygen in the lungs and transports it to tissues, while also carrying carbon dioxide from tissues to the lungs for exhalation.
2. What is haemopoiesis?
Ans :- Haemopoiesis is the process of formation and development of blood cells, occurring primarily in the bone marrow.
3. What is the haemoglobin count for a normal healthy male and female in humans?
Ans :- Male: 13.8–17.2 g/dL
Female: 12.1–15.1 g/dL
4. Which blood cell is known as a scavenger?
Ans :- Macrophages are known as scavengers as they engulf and digest pathogens and cellular debris through phagocytosis.
5. Why is RBC enucleated?
Ans :- RBCs are enucleated to maximize space for haemoglobin and improve their oxygen-carrying efficiency.
6. What is stain?
Ans :- A stain is a dye used in microscopy to color biological specimens, enhancing contrast and enabling the observation of cellular structures.
7. What is the purpose of using Leishman’s stain?
Ans :- Leishman’s stain is used to differentiate and study blood cells and detect abnormalities, such as parasites or disorders, under a microscope.
Multiple Choice Questions
1. The life span of RBC is.....
a. 120 days
b. 612 days
c. 90 days
d. 100 days
Ans :- a. 120 days
2. The % of neutrophils among WBCs is.....
a. 3%
b. 0.5%
c. 25 to 30%
d. 62%
Ans :- d. 62%
3. Platelets are produced from special cells in the bone marrow called as.....
a. red blood cells
b. thrombocytes
c. megakaryocytes
d. microkaryocytes
Ans :- c. megakaryocytes
4. The two main types of lymphocytes are.....
a. monocytes and B-lymphocytes
b. neutrophils and T-lymphocytes
c. lymph cells and WBCs
d. B-lymphocytes and T-lymphocytes
Ans :- d. B-lymphocytes and T-lymphocytes
5. The WBCs with twisted nuclei are.....
a. basophils
b. lymphocytes
c. eosinophils
d. neutrophils
Ans :- a. basophils
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