Activity 6 Blood Physiology

Activity 6 RED CELL FRAGILITY, BLOOD TYPING, BLEEDING TIME AND CLOTTING TIME AND HYPEREMIA

Introduction In clinical practice, hematological information accumulated from a series of blood tests conducted on a small volume of blood - even a single drop - can be of great diagnostic and prognostic value. There are certain molecules on the surfaces of all cells in the body that can be recognized as foreign by the immune system of another individual. These molecules are known as antigens. antigens. As part of  the immune response, particular lymphocytes secrete a class of proteins called antibodies that antibodies that bind in a specific fashion with antigens. The specificity of antibodies for antigens is analogous to the specificity of  enzymes for their substrates, and of receptor proteins for neurotransmitters and hormones. Matria!" and Mt#od"  A. R! "## "## $RA%I#IT& $RA%I#IT& Ten '()* test tubes were prepared in serial dilution of +a"l solution in different concentrations with distilled water. A representative was asked to sterile his pointer finger with alcohol in gauze pad. sin sing g a lanc lancet et pen, pen, the the fing finger er was was pric pricke ked. d. Two drops drops of bloo blood d was was adde added d to each each test test tube tube concentration. ach test tube was covered with parafilm stretching up to the mouth. The blood with salt concentration was mied in a slow inverting manner of the tube using the middle and thumb finger. $inally $inally the () test tubes were all subected for centrifugation at (/))g for 0 minutes. 1. 1#22! T&3I+% 2btain a clean microscope slide. sing a glass-marking pencil, mark one end A and the other end 1. #ance your finger to obtain blood. "lean the palmar surface of the third or fourth finger with a sterile gauze pad soaked with 4)5 ethanol. 6ith a sterile lancet or needle, make a puncture on a fingertip. 6ipe off the first drop. 3lace one drop of blood on each of the marked slide. Add one drop of anti-A serum to the A side. Add Add one drop of anti-1 anti-1 serum to the 1 side. 6ith a toothpick, toothpick, using a differen differentt toothpick toothpick for  each side. 7pread each miture over an area of about ).4/ in diameter. 2bserve the slide for any agglutination of red cells. ". 1#!I+% TI8 A+! "#2TTI+% TI8 7terilize the fingertip using rectified spirit and allow to dry. 8ake a sufficiently deep prick using a sterile lancet, so that blood comes out freely without s9ueezing. 8op the blood by touching the fingertip with a filter paper. This is repeated every (/ seconds, each time using a fresh portion of the filter paper, till bleeding stops. +ote the time. It is seen that the blood stains on the filter paper get smaller to disappear  finally when bleeding stops. nder sterile precautions make a sufficiently deep prick in the fingertip. f ingertip. Touch Touch the blood drop at the fingertip using one end of the capillary tube kept tilted downwards. The tube gets easily easily filled filled by capillary capillary action. After After about two minutes start snapping off small lengths of the tube, at intervals of (/ seconds, each time noting whether the fibrin thread is formed between the snapped ends. +ote the time when the fibrin thread is first seen. !. :&3R8IA 6ind a rubber band in the chosen finger. 6ait for several minutes to note for difference in size and color of the finger. 3repare 3repare a /))-ml tap water in a beaker then put it in water bath set at ;/ degrees ". Immerse the finger in the beaker for a few minutes to note for sensations other than warmth that the finger was eposed to.

R"u!t" A$ Rd C!! Fra%i!ity Tu& Nu'&r  ( 0 = ; / > 4 ? @ ()

Co!or o( )u*rnatant "lear "lear "lear "lear "lear Reddish Reddish Reddish Reddish Reddish

O&"rvation" Pr"nc o( RBC" at t# &otto' o( tu& < < < < < -

0. If a cell that is normally in osmotic e9uilibrium is transferred to a more dilute solution, water will enter the cell, the cell volume will increase, and the solute concentration of the cytoplasm will be reduced. =. If the cell is transferred to a more concentrated solution, water will leave the cell, the cell volume will decrease, and the solute concentration of the cytoplasm will increase. B$ B!ood ty*in%, &!din% ti' and c!ottin% ti' &our 7ample

Anti-A 7erum  Agglutinate

1leeding time "lotting time

Anti-1 7erum Agglutinate

1lood Type A1

( minute ;/ sec

;. A12 typing If your blood cells stick together when mied with • • • •

 Anti-A serum, you have type A blood  Anti-1 serum, you have type 1 blood 1oth anti-A and anti-1 serums, you have type A1 blood If your blood cells do not stick together when anti-A and anti-1 are added, you have type 2 blood.

/. Assessing blood clotting and bleeding factor is very important if you are about to have a surgical procedure. 7urgery or an inury of any kind increases the risk of a blood clot. ThatBs because the clotting process is stimulated as your body attempts to stop the bleeding and close the surgical wound. A clot is normally formed by the blood cells and clotting factors working together to create a protective scab over a healing wound. The surgical procedure may stimulate clots to form in error in blood vessels, which then may block the normal flow of blood.

B$+ Cro""Matc#in% )ru' )a'*!

Rd C!! )u"*n"ion  Agglutination !onor Type A1 Recipient Type A

>. "ross matching is a must before blood transfusion to determine if the donorBs blood is compatible with the blood of an intended recipient. Transfusion errors that result in such agglutination can lead to blockage of small blood vessels and cause hemolysis 'rupture of red blood cells*, which may damage the kidneys and other organs. C$ Hy*r'ia 2bservations 4.(

7ize swell "olor dark-purple color 

1y winding the rubber band on the finger the oygen level decreases and swells due to blood vessel dilation.

4.0

7ize '-()*

If as little as )./5 of the red blood cells are hemolyzed, the released hemoglobin will cause the serum or plasma to appear pale red or cherry red in color. +ote that the hemolyzed sample is transparent, because there are no cells to scatter light. 2n the other hand, the crenated sample after centrifugation formed a cell fractionation where the resulting supernatant is clear and the pellet visible at the bottom looks very pale.

The blood groups refer to the presence on human red blood cells of certain antigens, the blood group factors. 2ne very important group of factors present on the red blood cells is the A12 system. The  A12 group of a person depends on whether hisCher red blood cells contain one, both, or neither of the 0 blood group antigens A and 1. There are, therefore, ; main A12 groups A, 1, A1 and 2. The presence or  absence of agglutinations will determine the blood type found. This agglutination reaction, which is very important in determining the safety of transfusions is due to a mismatch of genetically determined blood types.

 Antibodies 'agglutinins* for the antigens A and 1 eist in the plasma and these are termed anti-A and anti-1. The corresponding antigen and antibody are never found in the same individual since, when mied, they form antigen-antibody complees, effectively agglutinating the blood.  Agglutination 'clumping* of red blood cells occurs when cells with A-type antigens are mied with anti-A antibodies and when cells with 1-type antigens are mied with anti-1 antibodies. +o agglutination would occur with type 2 blood. 3eople with type A blood have type A antigens on their red blood cells and antibodies in their  plasma against the type 1 antigen. 3eople with type 1 blood have type 1 antigens on their red blood cells and antibodies in their plasma against the type A antigen. Therefore, if red blood cells from one blood type are mied with antibodies from the plasma of the other blood type, an agglutination reaction occurs. In this reaction, red blood cells stick together be cause of antigen-antibody binding. Hemostasis 'literally - blood halting* depends on three interrelated and overlapping sets of events •

• •

"onstriction of the blood formation of a platelet DplugD 1lood clotting "lot retraction

vessels

and

Bleeding time is the interval between the moment when bleeding starts and the moment when bleeding stops. +ormal bleeding time is to ; minutes. 8easures the time taken for blood vessel constriction and platelet plug formation to occur. +o clot is allowed to form, so that the arrest of bleeding depends eclusively on blood vessel constriction and platelet action. It is used to evaluate platelet function and is typically performed, along with a platelet count, in people with a personal or family history of bleeding disorders, or as a preoperative safety measure before a scheduled surgery.

Clotting time is the interval between the moment when bleeding starts and the moment when the fibrin thread is first seen. 1leeding time and clotting time are not the same. 1leeding time depends on the integrity of platelets and vessel walls, whereas clotting time depends on the availability of coagulation factors. In coagulation disorders like haemophilia, clotting time is prolonged but bleeding time remains normal. The normal range for clotting time is =-() mins. In order for blood to clot, the enzyme thrombin must be generated from the plasma precursor  prothrombin. Thrombin then converts soluble fibrinogen into insoluble fibrin. %eneration of thrombin involves the se9uential activation of a number of other plasma clotting factor, this process is also being assisted by "a