Blood

1. Composition and functions
of blood
Dr. Sai Sailesh Kumar G
Associate Professor
Department of Physiology
RDGMC

2. Learning objectives
 Describe the formed elements of the blood
 Explain the difference between serum and
plasma
 Broadly describe the functions of the blood

3. Introduction
 Blood is the specialized connective tissue in
which there is liquid intercellular substance
plasma and formed elements are present.
 Formed elements-
1. Erythrocytes/ Red blood cells
2. Leucocytes/White blood cells
3. Platelets
Formed elements are suspended in the plasma

4. Properties of blood
 Color- Arterial blood is scarlet red in color,
venous blood is purple red in color
 Total blood volume- 5-6 liters (7-8% of body
weight)
 Viscosity- four to five times that of water
 Specific gravity- 1.050-1.061 (total blood)
 pH of the blood- 7.4+/-0.05

5. Composition of the blood
 Highly complex fluid
 Composed of two parts- a liquid called plasma
and different types of cells suspended in
plasma.
 The cells are called blood corpuscles
 Plasma constitutes about 55%
 Cells constitutes about 45%

6. Composition of the blood

7. Composition of the blood
 Plasma- 91-92%, water and 8-9%, solids
 Inorganic constituents- sodium, potassium,
calcium, magnesium, phosphorus, iron, copper etc.
 Organic constituents
1. Proteins – serum albumin, serum globulin,
fibrinogen, prothrombin etc.
2. Non protein nitrogenous substances- urea, uric
acid, creatinine etc
3. Carbohydrates- glucose, etc

8. Composition of the blood
4. Fats – Phospholipids, cholesterol etc
5.Other substances- Internal secretions,
antibodies, enzymes etc
6.Coloring matter- The yellow color of plasma is
due to small amounts of bilirubin, carotene and
xanthophyllin

9. FORMED ELEMENTS
NAME AND
APPEARANCE
NUMBER CHARACTERSTICS* FUNCTIONS
Red Blood
Cells(RBCs) or
Erythrocytes
Hemoglobin within RBCs
transports most of the
oxygen and part of
carbon dioxide in the
blood.
4.8 million/µL in
females
4.5 million/µL in without nuclei; live for
7-8 µm diameter,
biconcave discs,
males about 120 days.
Most live for a few
hours to a few days.
Some called T and B
memory cells can live
for many years.
White Blood
Cells(WBCs) or
Leukocytes
Combat pathogen and
other foreign substances
that enter the body.
5000-10,000/µL
Phagocytosis.
Destruction of bacteria
with lysozymes,
defensins and strong
oxidants, such as
superoxide anion,
hydrogen peroxide, and
hypochlorite anion.
10-12µm diameter;
nucleus has 2-5 lobes
connected by thin
strands of chromatin;
cytoplasm has very
fine, pale, lilac
Granular
Leukocytes
60%-70% of all
WBCs
Neutrophiles
granules.
*Colors are those seen using Wright’s stain

10. 10-12µm diameter; Eliminates parasites, such as
nucleus usually has 2 lobes worms which are too big to be
2-4% of all
WBCs
connected by s thick strand
of chromatin; large, red-
orange granules fill the
cytoplasm.
phagocytosed; phagocytes
antigen-antibody complexes &
combat the effects of
Eosinophils
Basophils
histamine in allergic reactions
8-10µm diameter; nucleus
has 2 lobes; large
Liberate heparin, histamine
and serotonin in allergic
reactions that intensify the
0.5-1% of all
WBCs cytoplasmic granules
appear deep blue-purple. overall inflammatory response.
Medium immune response,
Small lymphocytes are 6-
9µm in diameter; large
lymphocytes are 10-14µm
in diameter; nucleus is
including antigen-antibody
reactions. B cells develop into
plasma cells, which secrete
antibodies, T cells attack
invading viruses, cancer cells,
and transplanted tissue cells.
Natural killer calls attach a
wide variety of infectious
microbes and certain
Agranular
Leukocytes
Lymphocytes
(T cells, B
cells &
natural killer
cells)
20-25% of all round or slightly indented;
WBCs cytoplasm forms a rim
around the nucleus that
looks sky blue; the larger
the cell, the more
cytoplasm is visible. spontaneously arising tumor
cells.

11. Acts on the
hypothalamus, causing
the rise in body
12-20µm
diameter; nucleus
is kidney shaped
or horseshoe
shaped.
temperature with
microbial infections;
stimulates the production
3-8% of all
WBCs
Monocytes
Cytoplasm is blue- of some globulins by the
grey and has
foamy
appearance.
liver; enhances the
production of activated T-
lymphocytes;
Phagocytosis
2-3µm diameter
cell fragments
that live for 5-
9days; contains
many vesicles but
no nucleus.
Form platelet plug in
homeostasis; release
chemicals that promote
vascular spasm and blood
clotting.
150,000-
400,000/µL
Platelets(Thrombocytes)

12. Functions of blood
Transport of respiratory gases
 It carries oxygen from the lungs to the tissues
 It carries carbon dioxide from tissues to lungs
Transport of nutrition
 It carries digested food material absorbed from
intestine to the tissues for utilization
 It also carries stored nutrients from storage areas to
the tissues

13. Functions of blood
Acts as a vehicle
 It carries hormones, vitamins and other essential
chemicals to their site of action
Drainage of waste products
 It carries waste products of cellular activity and
brings them to the organ of excretion- kidney,
lungs, intestine, etc.
Regulation of blood pressure
 By changing the volume and viscosity

14. Functions of blood
Maintenance of water balance
 Water balance
Maintenance of acid-base balance
 Plasma proteins and hemoglobin – Buffer
Maintenance of ion balance
 Ion balance between the cells and surrounding fluid
Regulation of body temperature
Defensive action
Blood coagulation
Functions of plasma proteins

15. Hematocrit
 The ratio of RBC to plasma is expressed as hematocrit
value.
 Plasma volume varies from 52-55%
 Packed cell volume varies from 45-48%
 It can be estimated by an instrument called haematocrit
 It consists of a specially prepared graduated capillary
tube- Wintrobe’s tube
 Blood treated with anticoagulant is taken and
centrifuged at a speed of 3000 revolutions per minute
 Separates plasma and formed elements

16. Packed cell volume

17. Erythrocyte sedimentation rate
 The rate at which RBC’s sediment at the end of
one hour
 Anticoagulant is added to the blood specimen
 Let stand in a glass tube
 Blood cells are heavier than plasma
 Blood cells sediment gradually at the bottom of
the tube (gravitational force)
 Plasma remains as clear supernatant fluid
 The rate of sedimentation- ESR

18. Erythrocyte sedimentation rate

19. Erythrocyte sedimentation rate
 ESR depends on
1. Difference in the densities between plasma
and RBC
2. Rouleaux formation (degree of adherence of
RBC to one another)
3. Resistance that plasma exerts on red cell
surface

20. Erythrocyte sedimentation rate
 ESR increased in
1. Inflammation
2. Auto immune disorders
3. Pregnancy
4. Infections (any infection)
 ESR is decreased in Leukemia, congestive
heart failure

21. Erythrocyte sedimentation rate
 ESR stages
1. Rouleaux formation- occurs in first 10 minutes
2. Sedimentation stage- occurs in next 40
minutes
3. Packing stage – occurs in next 10 minutes
after completion of stage 2
 Normal ESR by Wintrobe’s method is 0-6.5 mm
per hour for males and 0-15 mm per hour in
females

22. Erythrocyte sedimentation rate
 ESR significance
1. Not useful for diagnosis
2. Have prognostic value
 ESR and C-reactive protein together correlate
with degree of inflammation

23. Rouleaux formation
 Rouleaux formation is a term describing groups of red
blood cells that form stacks, such as stacks of coins.

24. Rouleaux formation
 Why Rouleaux formation does not occurs inside the
body.

25. Erythrocytes
 A major function of RBC is to transport
hemoglobin, which in turn carries oxygen from
the lungs
 Normal RBC are in biconcave disc shaped
 7.8 micrometer in diameter
 2.5 micro meters thickness at the thickest point
 1 micrometer or less thickness in the center
 Average volume of RBC is 90-95 cubic micro
meters

26. Erythrocytes
 Average number of RBC in males 5,20,000+/-
300,000
 In women, 4,700,000 +/- 300,000
 Why male and female difference???
 Persons living at high altitudes have greater
number of RBC’s
 Why ???

27. Erythrocytes
 Life span of RBC is 120 days
 Mature RBC does not have a nucleus,
mitochondria, endoplasmic reticulum
 How they survive 120 days???

28. Erythrocytes
 RBC equipped with cytoplasmic enzymes that
are capable of metabolizing glucose and
forming small amounts of ATP
 These enzymes also
1. Maintain pliability of cell membrane
2. Maintain membrane transport of ions
3. Keep the iron of the cells in the ferrous form
rather ferric form
4. Prevents oxidation of proteins in RBC

29. THANK YOU