Experiment-4 (Clotting Time)

Experiment No. 4

Human Anatomy and Physiology

Experiment No. 4 1.0

TITLE : To determine clotting time of blood sample by capillary glass method. (Use of own blood sample is suggested)

2.0

PRIOR CONCEPTS: Coagulation of blood When the blood vessel ruptures , in a few minutes blood loses its fluidity and sets into a semisolid mass called clot. This process is called blood coagulation. 1. In vitro - blood clots outside the body on cuts and injuries. 2. In Vivo - Blood clots inside the blood vessels. Haemophilia : A genetic disorder where longer clotting time due to absence of some clotting factors.

3.0

NEW CONCEPTS: Proposition 1 : Clotting time : It is the time interval in between onset of bleeding and appearance of jelly like semisolid mass i.e. blood clot. Proposition 2 : Clotting Time (Capillary glass method) Blood Clotting (extrinsic)-

Proposition 3 Method used : 1. Lee and white method - The accurate method where blood is collected by venupuncture, placed in test tube at 37°C. Other methods 1. Variation in clotting time - Physiological - during Menstruation cycle before and during parturition it is reduced 2. Pathological - Clotting time is prolonged in haemophillia. Liver diseases, Afibrinogenemia, Christmas disease, Vitamin K deficiency. 3. Clot retraction --- Clot formed shrink gradually, resulting in oozing out of fluid called serum. Total clot retraction takes 24 hours. 4. Bleeding time is lesser than clotting time, since bleeding is stopped by vascular spasm and platelet plug formation. While clotting involves a series of enzymetic reaction taking more time. 5. Normal clotting time 4 to 9 minutes.

4.0

LEARNING OBJECTIVES : 1 Intellectual skills : 1. To understand formation of blood clot. 2. To interpret observed clotting time.

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MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

Human Anatomy and Physiology

2.

5.0

6.0

Experiment No. 4

Motor Skills : 1. To correctly prick finger aseptically. 2. To fill the capillary quickly without air entrapment. 3. To identity fibrin clot formation.

APPARATUS : 1

Apparatus : 1. Sterile disposable pricking needle or lancet. 2. Stop watch 3. Dry glass capillary tube (narrow diameter 1 top 2 mm, minimum 10 cm long.) 4. Cotton Swab of absorbent cotton. 5. Spirit wetted, cotton swab.

2

Chemicals : 1. 70 % v/v ethyl alcohol or 70 % v/v denatured spirit.

DIAGRAM :

Clotting time of blood

Breaking of capillary tube Fig. 4.1

7.0

STEPWISE PROCEDURE : 1. 2. 3. 4. 5. 6. 7.

8.0

Apply alcoholic 70 % v/v to the clean finger with cotton swab. Allow it to dry naturally. Prick the finger with usual aseptic precautions. Immediately stop watch is started. Dip one end of the capillary into blood drop gently without pressure. Allow to fill the capillary with blood by lowering the end of fitted capillary. (Do not suck the blood) around ¾th of its length undipped. After every 30 seconds, using stopwatch, break a small piece of capillary. Repeat breaking at regular time intervals, till fibrin thread appears at the broken end of capillary tube. Do not pull away the cut pieces ling apart and bristly. Record time interval between pricking finger and first appearance of fibrin thread at the broken ends of capillary tube. That is clotting time of blood.

OBSERVATION: The fibrin thread is formed at the breaking point after clot is formed. Note the time……

9.0

RESULT : The Clotting time of own blood is ……………….. (normal clotting time is 4 to 9 min)

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

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Experiment No. 4

Human Anatomy and Physiology

10.0 CONCLUSION : The clotting time is …………. (normal/prolonged/reduced)

11.0 QUESTIONS : Note:- Student to answer Q…………, Q……………, Q…………… and the question numbers shall be allotted by the teacher.) 1. Name various methods of determination of clotting time. 2. Give the significance of clotting time. 3. Name the two clotting mechanisms. Which clotting occurs more quickly than other ? 4. State two pathological conditions when clotting time is prolonged. 5. State two physiological conditions when clotting time is reduced. 6. What is haemophilia ? What happens to bleeding and clotting time in this disease ? 7. Why bleeding time is smaller than clotting time ? Give the reason. 8. Write down major steps involved in extrinsic blood clotting. 9. What is thrombocytopenia ? Space for writing answers

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MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

Human Anatomy and Physiology

Experiment No. 4

Space for writing answers

Remarks :

Signature of Teacher

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

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