57 Essential Questions & Answers| human physiology|

                   57 essential questions human physiology|answers|

Part 2,Question & Answer

                      

Table of contents

Sr.No.	Q No from to	Topic
1.	1-18	Blood film and blood cells
2.	19-28	PCV ,Absolute values,Anemia
3.	29-42	White blood cells
4.	39-57	Osmotic fragility, Heam crystal

 

Q 1. What is characteristic of a good blood film?

 

Ø   A. The film should occupy the middle two-third of the slide.

Ø  The blood film should be tongue-shaped, forming a body and tail.

Ø  The blood film should have no striations.

Ø  The blood film should be of uniform thickness.

Ø  In the blood film, the R.B.C should the R.B.C should not clumpingrate characteristics of an excellent stained blood film :

Ø  A perfect stained blood film is bluish pink color.

Ø   An excellent stained blood film will show uniformly distributed cells. The red cells are pink, and

Ø   WBCs are distributed evenly between the red cells. When the stained blood film is satisfactory

Q3.How to recognize the red blood cells :

A.  Red blood corpuscles are recognized as they are 

(A) Nonnucleated.

(B) Most abundant.

(c) Pink colored.

(d) Uniform size of 7.2 microns.

Q4.How you will recognize different types of  WBC /Leucocytes.

A.  Leucocytes are identified by

(a) Their size, nuclei and cytoplasm, and color of granules present in the cytoplasm.

Five types of Leucocytes are seen, which may be divided into two broad groups

depending on the presence or absence of granules in their cytoplasm.

(a)   Granulocytes: the presence of granules in their cytoplasm. They are

   Neutrophils, Eosinophils, and Basophils.

(b)   Agranulocytes:- the absence of granules in their cytoplasm. They are Lymphocytes and Monocytes.

 1. Neutrophils-or polymorphonuclear neutrophils are recognized by

(a) size-10 -14 micron

(b) Nucleus two to six lobed therefore called polymorphonuclear.

(c) Cytoplasm contains pinkish-blue fine granules. Some granules are acidic, and some

are basic, so they take both types of Leishman's stain. And therefore called

neutrophils.

2. Eosinophils :

(a) Size-10 -14 micron.

(b) Nucleus is usually two-lobed.

(c) Cytoplasm contains brick red coarse closely packed acidophilic granules and may

 mask the nucleus.

3. Basophils :

(a) Size-10 -14 micron.

(b) Nucleus is usually two-lobed.

(c) Cytoplasm contains few basophilic coarse granules. They are basophilic.

Lymphocytes are of two types small and large.

Ø  Small Lymphocytes :

(a) Size-7-10micron.

(b) Nucleus is a large round, almost filling the cell.

(c) Cytoplasm is very less and only present as a layer around the Nucleus.

Ø  Large Lymphocytes :

(a) Size-10-14 micron.

(b) Nucleus is large and round.

(c) Cytoplasm is less.

Small Lymphocyte is more mature than large Lymphocytes, and they are concerned with cellular

 immunity. While large Lymphocytes are concerned with humoral immunity.

Monocytes are recognized by :

(a) Size-10-18 micron

(b) Nucleus is kidney-shaped and eccentric.

(c) Cytoplasm is grayish blue and abundant.

Monocytes are the largest leucocytes.

Q5.How you will recognize the platelets.

A. Platelets appear as purple aggregates scattered here and there.

(a) Size-2-3 micron

(b) Nucleus is absent.

(c) Cytoplasm is not clear.

Other cells may be seen in the smear.

Immature cells of W.B.C., R.B.C., or other pathological cells may be seen. Some

parasites, e.g., malaria, and filaria may be visible in the blood smear.

Q6. What is the meaning of philia and penia?

A.The suffix philia or cytosis means an increase in number, and Penia implies a decrease in number.

Neutrophilia means an increase in Neutrophils count above the average count.

Neutropenia means a decrease in Neutrophils count below the average count.

 Eosinophilia means an increase in Eosinophils count above the normal count. 

Eosinopenia means a decrease in Eosinophils count below the normal count.

        Basophilia means an increase in Basophils count above the normal count.  

         Lymphocytosis means an increase in Lymphocyte count above the average count.

Lymphocytopenia means a decrease in Lymphocyte count below the average count.

Monocytosis implies an increase in Monocytes counts above the expected count.

Monocytopenia represents a decrease in Monocytes count below the average count.

Leucocytosis means an increase in Leucocyte count above the average count.

Leucopenia means a reduction in Leucocyte count below the normal count.

      Thrombocytosis means an increase in Thrombocyte count above the average count.

Thrombocytopenia means a decrease in Thrombocyte count below the average count.

       Erythrocytosis, usually known as polycythemia, means an increase in  Erythrocyte count.

       Anemia is a decrease in Erythrocytes count.

Q7. Which slide is known as spreader?

A. Two slides are taken for making the blood film. The slides have round edges. One slide is kept on the table on which a drop of blood is placed. Another slide is held in hand between thumb and index finger so that the edge of the small side of the slide is downward and touches the surface of another slide on which blood is taken. The slide in hand is known as a spreader.

Q8. What is the tally bar method?

A. Tally bar method is used to count white blood cells so that cells are counted, avoiding the uneven distribution of white blood cells. Neutrophils and monocytes accumulate in the periphery, i.e., at the margin, and the tail  and lymphocytes in the center, i.e., middle of the film. Therefore, all the cells should be counted in a single strip running the length of the blood film from base to apex. Again the cells are calculated in a single strip running the length of the blood film from apex to base about 2mm apart. This is repeated.

 The cells are counted once by this method. Usually, 100 WBC are counted, but it is advisable to count 200 cells as a routine procedure and calculate the average count.

Q9. Which part of the blood film should be avoided for counting the cells and why?

A. The head end is avoided for counting the WBCs.

   

 

 

Q 10. How and why the glass slides are made grease-free?

A.The glass slides are made grease-free by cleaning with soap and water and drying them

over the spirit lamp flame. The slides are caught with fingers at their two long sides;

 otherwise, the grease of the fingers will stick to the slides. Blood will not stick to the areas

of the slide which contain grease.

Q 11. Do you know the size of a standard glass slide?

A. Size of a standard glass slide is 7.5 cm x 2.5 cm.

Q 12. Why Leishman's stain is left for 2 minutes on the slide?

A. This is fixation time. The pure absolute methyl alcohol performs two functions :

1. It precipitates the plasma protein, which acts as glue and attaches or fixes the blood cells

 on the glass slides.

2. It preserves the shape and chemistry of cells. The cells are not stained during this time.

 The stain particles are in a unionized state, and in this state, they cannot enter into cells.

When distilled water is added (preferably buffered water), ionization of stain particles

 occurs, and then stain enters into the cells and is left for 10 minutes. This is staining time.

The diluted Leishman's stain cannot be used as it will wash out the blood film.

Alternatively, absolute ethyl or methyl alcohol may fix a blood smear.

Q 13. May tap water be used for diluting the stain after fixation?

A. No, tap water must not be used due to unknown P.H. and salt content of tap water. Tap

water also contain impurities that will produce artifact on the blood film.

Q14. What is buffered water? Why is it preferred over distilled water?

A.Buffered water is a phosphate buffer in which the pH is adjusted at 6.8. The pH is tested with a Ph meter. At this pH, optimal ionization of the stain particles occurs to penetrate the cells more rapidly.

Q15. Name other stains which may be used to stain the blood film?

A. They are Wright's strain and Giemsa's stain.

Q 16. Name other use of Leishman's stain?

A. This strain is excellent for staining all body fluids containing cells.

Q17. What are the methods for studying white blood cells?

A. The methods are :

1. Thin blood film is a drop preparation method in which a drop is spread on a glass slide.

2. Thick blood film a drop of blood on a glass slide is spread by the edge of another glass

slide.

3. Centrifuge method. Not in use.

Q 18. What information can be obtained from a blood film?

A. It is a very informative process. The pieces of information are :

1. Differential count of WBC.

2. Rough idea of total WBC count.

3. Study of the morphology of R.B.C. in many types of anemia.

4. Presence of immature cells of R.B.C., WBC in cases of blood cancers.

5. Sex determination by the presence of female sex chromatin, which appears as a

Drumstick (Bar body) is attached to a lobe of the neutrophil nucleus.

6. Various types of parasitic infections like Filaria, Malaria, etc.

 

Q 19. What is PCV? Mention its average values? Enumerate the factors on which it depends.

 A. The volume of Red blood cells expressed as a percentage of total blood volume is called

Packed cell volume. It depends on

Age –At birth, it is high due to polycythemia, then decreases due to low count of R.B.C., then

increases to the adult level at the age of about  15 years.

Sex –In adult females, it is less than males due to the low R.B.C.

Site from where blood was collected- R.B.C. of venous blood is swollen due to chloride shift

So PCV of venous blood is more than that of arterial blood by approximately 3%. 

 Q 20. What is the clinical importance of PCV?

 A. Measurement of PCV is a very accurate method for detecting the presence of anemia

 and determine the degree of anemia.

 It is used in the determination of MCV (Mean corpuscular volume ), M.C.H.C. (Mean

corpuscular hemoglobin concentration).      

 Q.21 .Mention conditions in which PCV varies.

 A.The conditions are physiological and pathological.

  Q.22. What is average blood volume?

  A.Normal blood volume is 5-6 liters. 8% of body weight or 80 ml /kg body weight.

  Q.23. Name the methods used for estimating PCV.

  A.          1. Wintrobe's tube method

               2. Wintrobe's hematocrit method

               3. By  Microhaematocrit method.

Haematocrit from different segments of the vascular system is determined by using

 Chromium 51 method.

  Q. 24. What is the color index? How you will determine the color index of your blood.

A.Colour Index:  It denotes the ratio of hemoglobin to R.B.C. count.

Procedure:  Hemoglobin is estimated. Suppose it is 12.2gm % of blood. Total R.B.C. is calculated. Suppose it is  4.5million/cumm of blood.

C.I. =          Hb concentration (percentage of normal )     

                  R.B.C. count   ( percentage of normal.)

Normal  range=0.85 --1.15 (1+-0.15.)  

For this  100% RBC count is=5million/cmm of blood.and 100% Hb is= 15 gm%.

 Calculation :

  R.B.C. is 4.5 million, and 12.2 gm Hb is present.  

 5million  is 100%,

Then 4.5 million is =  (100/5)x4.5= 0.9,

15 gm%  is 100%,

Then 12.2gm%  is  =(100/ 15) x12.2=0.81

 Colour index is =8.1/0.9=0.9.

Conclusion  :  It is within normal limit.

Q. 25. What is the importance of the color index?

If the color index is less than 0.85 indicates that Red blood cells are small in size and or

 hemoglobin in red blood cells is reduced.

If the color index is more than 1.15, red blood cells are large, so hemoglobin in red blood

cells is increased. The cell can not contain more hemoglobin.

Colour index determination is not very significant. If both R.B.C. and hemoglobin are

 Less than average, the color index may remain normal. However, anemia is present.

Q26. Classify anemia.

A.According to the size and Hb concentration of R.B.C., anemia is  classified  as :

Normocytic, Microcytic, and Macrocytic.

Ø  Normocytes –R.B.C. with normal range of MCV.

Ø  Microcytes –R.B.C. with a below-average range of  MCV.

.

Ø  Macrocytes –R.B.C. with an above-average range of  MCV.

Ø  Normochromic R.B.C.: M.C.H.C. is within normal range.

Ø  Hypochromic R.B.C.: M.C.H.C. is below the normal range.

 M.C.H.C. never exceeds the maximum limit.

Q. What is the significance of the Color index?

A. Colour index determination is not very significant. I 

Q 27. Why can M.C.H.C. not cross the upper limit of 38%?

A. M.C.H.C. never crosses the upper limit of 38% because R.B.C. cannot hold hemoglobin

 beyond this saturation limit, i.e., the metabolic limit of the cells and hemoglobin forming

 mechanism.

Q 28. What are the norma values of

      PCV, M.C.H., M.C.H.C. and  Colour  Index.

·           MCV - Normal   =86±9 μmm³

· M.C.H.- Normal range is   27 -32 pg

· M.C.H.C. -Normal range   =32%-38%

·         Colour index- Normal  range=0.85-1.15 (1+-0.15.)  

Q 29. What to do if blood is sucked slightly beyond the 0.5 mark in the pipette?

A.  If blood is sucked slightly beyond the 0.5 mark in the pipette, it is brought down to 0.5 by

dibbing the pipette's tip against the palm. It is not removed by a cotton swab because it will

 absorb fluid from the blood and leave the cells into the pipette, increasing cell count.

Q 30. Why are 2-3 drops of fluid discarded from the pipette?

A. Blood is taken up to 0.5 mark, then diluting fluid is sucked in the pipette. Blood with

 diluents enters into the bulb. The stem of the pipette contains only the cell-free diluents.

  Therefore first three drops of  the fluid are discarded from the pipette before the chamber

 is charged.

Q 31. Why is the pipette kept in a horizontal position?

A. Pipette is kept in a horizontal position; otherwise, fluid from the pipette will dribble due

 to gravity.

Q 32. Why is dilution 20 times and not 22 times?

A. Diluting fluid present in the pipette up to the first mark of 1 does not take part in the

dilution of blood. So 0.5 blood is diluted with 9.5 part of the diluent. 0.5 part of blood is

present in 10 parts, so 1 part is present in 20 ml. So dilution is 20 times.

Q 33. Why is there no unit marking on R.B.C. and WBC pipette?

A. Marking on these pipettes only denotes relative volumes to each other.

Q34. Mention some other use of W.B.C. Pipette?

A.      A W.B.C. pipette is used in severe anemia to count R.B.C., as its number is reduced.  

B.      It is also used in sperm count.

Q35. Why is there tenth graduation on the stem of these pipettes?

A. The capillary part of the pipette has ten similar markings of 0.1 each from tip to bottom of the bulb. But only 0.5 and 1 are mentioned as it is widely used. In some cases, severe anemia, blood may be taken up to 0.2 parts only, and calculation is done accordingly.

Q 36. What is Glacial acetic acid?

A. Glacial means pure acetic acid. Only the pure acetic acid provides typical halo or clear reflectivity around the WBC due to swelling of nuclei. Therefore, their identification becomes easy to differentiate them from dust particles of different shapes and sizes and are opaque. During the manufacture of glacial acetic acid, it gives the appearance of a glacier at one stage.

Q 37. How is the absolute count of different white cells calculated?

A. Total count of WBC is estimated, then the differential count is done. It indicates the

absolute count of a particular cell in the blood.

 e.g., the total count of WBC is 6000/per cubic mm of blood.

D/C Neutrophil is 65%. So then its absolute count is 65 x 6000 =3900 / cmm of blood.

Eosinophil 4% Then its absolute count is 4 x 6000 =240 /cmm of blood and so on.

Q.38 What are ghost cells?

A. In the total count of white blood cell count membrane of haemolysed red blood cells are

 faintly visible under the high power of a compound microscope. These are called ghost

cells.

Q39. What is the clinical significance of Arneth –cooks count?

A . Arneth count is not usually used in modern medicine and has become obsolete.  

It is named for J.O.S.E.F. ARNETH-Arneth count or Arneth index.

 Q 40. How will you recognize senile neutrophils?

 A. When neutrophils have six or more lobes in the nucleus, they are known as senile

 neutrophils.

 Q 41 .Do you know stabs or schafs cells?

  A. A newly formed neutrophil in the bone marrow is  Stab or Schaf's cells. This

neutrophil has a single lobed nucleus which is typically U- shaped.

  Q 41. What is a shift to left or regenerative shift?

  A. when neutrophils with one, two, and three-lobed nuclei are more than 80%, it is called

  Shift to left or regenerative shift. This indicates that bone marrow is hyperactive –it is

making cells rapidly. This is seen in acute infections, especially pyogenic infections

hemorrhage. It suggests that the body can respond in need and emergency appropriately.

Q 42. What is a shift to the right or

degenerative shift?

A. when neutrophils with four, five, and six lobed nuclei are more than 20%, it is called

shift to  right or degenerative shift. This indicates that bone marrow is hypoactive. It is

seen in pernicious anemia, vitamin deficiency, aplasia of bone marrow. It shows that

 body can not respond appropriately to need and emergencies. Even in acute

infections, the bone marrow will not form cells to counter the ill effect of

microorganisms.

 

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Q 43. Define osmotic fragility?

A. Osmotic fragility of R.B.C. is defined as the ease with which hemolysis of R.B.C. may occur

in a hypotonic solution.

Q.44. Which anticoagulant is used in this experiment and why?

A. Mixture of Potassium oxalate and Ammonium oxalate is in a ratio of 2:3.is used as

anticoagulant.

 Potassium oxalate shrinks R.B.C. because it makes the plasma hypertonic, so water is drawn from the red blood cells. At the same time, Ammonium oxalate swells the cells (Hamburger phenomenon). And in a ratio of 2:3, the size and shape of the R.B.C. are maintained.  

Q 45. Why the osmotic fragility is almost fixed and starts at 0.5% and ends at 0.3% saline

 solution?

A.Haemolysis starts at 0.5 %  and completes at 0.3% strength of sodium chloride solution.

             Old red cells are more spherocytic than young ones due to their high sodium content.

 Therefore when placed in a hypotonic solution, old red cells rupture easily  at 0.5 %

the solution, young cells haemolyse late, at  0.3 % solution.

 

Q 46. How do you confirm that hemolysis is complete?

 A. Confirmation of complete hemolysis is done by centrifuging the test tube in the

Centrifuge machine at a rate of 1000 RMP for two minutes and then examining the

 sediment under low power of a microscope. If any intact red blood cell is visible, hemolysis

is not complete-it is partial. If no intact red blood cell is seen, it confirms that all red blood cells are haemolysed –hemolysis is complete.

Q47. What is the usual range of osmotic fragility?

A. Hemolysis starts at  0.5 %  and completes at 0.3% strength of sodium chloride solution.

Q48. Why is red blood cells of venous blood more fragile than those of arterial blood?

A. Red blood cells of venous blood are more fragile than arterial blood as they are more spherical than arterial blood. 

Q48. What is a hypotonic solution?

A . When the tonicity of a solution is less than 0.9% NaCl, it is known as a hypotonic solution.

        The isotonic solution, when tonicity is equal to  0.9% NaCl, it is known as an isotonic

Solution.

  Hypertonic solution -when tonicity is more than 0.9% NaCl, it is a  hypertonic solution.

Q 49. Enumerate conditions on which the fragility of red blood cells depends.

A. Increased  fragility  :

Physiological –Venous blood.

Pathological – congenital spherocytosis, inherited membrane abnormalities.

In this case, hemolysis may start from 0.65% of saline and complete at about 0.45 %.

Decreased fragility  :

It is always pathological and seen in Thalassemia, Megaloblastic anemia. Iron deficiency

 anemia.

 Q 50. What are Exosmosis and Endosmosis ?                 

Exosmosis is the passage of water from the cell to the surrounding hypertonic solution.

Endosmosis is the passage of water into the cell from the surrounding hypotonic solution.

Q 51. What is the importance of haemin crystal?

A. The test is of value in medico-legal practice in ascertaining whether a suspected stain is of human

 blood or of any other species.

Q 54. What is the chemical composition of haemin crystals?

A.  Chloride of haem is haemin crystals.

Q 55. Why is sodium chloride not added in fresh blood samples?

A. Fresh blood has an adequate amount of sodium chloride for haemin formation. Sodium

Chlorides should not be added  to fresh blood because crystals of sodium chloride will

obscure the identification of haemin crystals.

Q 56. Why is glacial acetic acid added?

A. Glacial acetic acid is added to haemolyse the R.B.C. hemoglobin is liberated and reacts with chloride.

Q 57. What is the shape of haemin crystals of the human species?

A. Haemin crystal of human species appear like a needle or rhomboid shape.