Blood

S Naghma Rizvi

March, 2015.

Acknowledgement :Muhammad Nisar

Objectives

Define blood, its general properties and function.

Explain the composition.

Describe the formation of Blood cells

Discuss the structure and functions of blood cells

RBC (Erythrocytes)

WBC (Leukocytes)

Platelets (thrombocytes

Discuss the composition of plasma

Describe the three mechanism that contribute towards

hemostasis

Briefly discuss the ABO blood groups and Rh factor.

Blood

It is a connective tissue which consists of

plasma and formed elements (blood cells)

flowing inside the closed vessels.

Physical characteristics of blood

Color Red (varies with O2 content)

Volume 5-6 (males) & 4-5 (Females)

pH 7.35 - 7.45

Viscosity (relative to water) 4.5 – 5.5

% of total body mass 8%

Temperature 380C

Salinity 0.9% Nacl

Functions of Blood 1.Transportation

oxygen and carbon dioxide

food molecules (glucose, lipids, amino acids)

ions (e.g., Na+, Ca+2, HCO−3)

wastes (e.g., urea)

hormones

2.Regulation

Body temperature

pH

3.Protection

Clotting

Defense

Composition of blood

Centrifuged

blood RBCs & WBCs are whole cells platelets are

cell fragments

Un-

clotted/un-

centrifuged

blood

Plasma Yellowish clear liquid, composed of:

Water = 91%

Proteins = 7% (all synthesized by the liver)

• Albumin = 54%, regulates osmotic pressure of blood

• Globulins = 38%, alpha and beta globulins in transport,

• gamma globulins in defense (antibodies)

• Fibrinogen = 7%, coagulation

Other solutes =2%

• Electrolytes - Na+, K+, Ca++, Mg++

• Nutrients - glucose, amino acids, fatty acids, monoglycerides

• Gases - O2, N2, CO2

• Regulatory substance - hormones, enzymes

• Vitamins and wastes

• Wastes

Hemopoieses The process of development of blood cells

Erythrocytes (RBC)

Physical characteristics of Erythrocyte

Size 7 µm in diameter & 2.2 µm thick

Shape Flattened and biconcave disc

Mean count 4.5-5.5 per mm3 of blood

Morphology Red color, (variable) non-nucleated, each RBC

contains 280 millions Hb molecules, that can carry

over a billion O2 molecule

Site for production Bone marrow

Life span 120 days

Function Carries O2 and nutrients, removes CO2 & wastes

Structure of Erythrocyte

(Hemoglobin molecule)

•

HEME molecule

Globin Molecule

Hemoglobin molecule

contain 4 protein chains

called globins, each of

which is bound to 1 heme

(iron). Iron is able to

combine with oxygen in

the lungs and deliver it to

body tissues.

is able to combine with oxygen in the lung and release

oxygen in the tissue.

Life Cycle of RBC

• http://highered.mheducation.com/sites/007250

7470/student_view0/chapter19/animation__he

moglobin_breakdown.html

Life Cycle of RBC

• Macrophage in spleen & liver, phagocytize RBC & split heme & globin

• Globin broken into amino acids to be reused

• Fe removed from heme & attaches to transferrin

• Fe-transferrin → red marrow → Hb synthesis

• Erythropoiesis in red marrow

• Fe removed from heme → non-Fe portion → biliverdin →bilirubin →bile → GI tract

• Bilirubin →urobilinogen in large intestine →some urobilinogen →blood → urobilin → yellow pigment in urine

• Most urobilinogen → feces → as brown pigment stercobilin

Leukocytes (WBC) They are largest of all blood cells, have nuclei and

do not contain Hb.Forms 1% of blood volume

On the basis of presence of absence of chemical

filled cytoplasmic granules WBCs are classified

into two types:

Granular leukocyte

Agranular leukocyte

Granules

Granulocyte or PMNLS Agranulcytes

Granulocytes Multi-lobed nuclei

Named according to dyes they take up

Basophil Neutrophil Eosinophi

l

Neutrophils (PMNLs) Life span 6-9 hours

%of WBCs 60%-70%

Nucleus lobular

Granules Reddish-violet

Functions Phagocytosis, diapedesis, chemotaxis,

extravasation, release antimicrobial subs

Basophil (PMNLs) Life span

%of

WBCs:

0.5%-1%

Nucleus large and U to S shaped

Granules Blue

Functions Secretes histamine ,serotonin, prostaglandin, leukotrien & heparin

Eosinophil (PMNLs)

Life span

%of WBCs: 2-4%

Nucleus 2 large lobes

Granules Stain red

Functions Release enzyme that destroy parasites

Phagocytosis of antigen antibody complex, and allergens

Agranulocytes Their nucleus are round or slightly indented and

stains dark

Lymphocyte

T- lymphocyte(T cells)

B- lymphocyte(B cells)

Natural killer cells (NK cells)

Monocyte

Lymphocyte %of WBCs: 20-25 %

Nucleus Nucleus round or slightly indented

Types B-lymphocytes, T-lymphocytes & Natural killer

cells.

Functions B-cells bacteria, T-cells attack microorg and

infected cells, Natural killer cell tumor

B lymphocyte T lymphocyte Natural Killer

cells

Monocyte

%of WBCs: 3-8

Nucleus Kidney or horse shoe shape nucleus

Functions

Differentiate into macrophages. Phagocytize pathogens, dead neutrophil and debris of dead cells

Platelets or

Thrombocytes

Size 4 µm in diameter

Shape Disc shape

Mean count 130000-400000 per mm3 of blood

Morphology Non-nucleated fragments of cells

Site for production Bone marrow

Life span 5-9 days

Function Blood clotting

Hemostasis/Haemostasis

Heamostasis or cessation of bleeding takes place through a series of responses, these include.

• Vasospasm

• Platelet plug formation:

• Coagulation

Follow the sequence to events initiated when platelets come into contact with an injured surface

Vasospasm

• Vessel wall constricts for a short period

• Platelets (sticky) adhere to the injured wall

• Platelets change their shape

• Platelets (activated) release serotonin that constrict

the vessel

Platelet Plug formation

• Passing platelets stick to the site and release

chemicals that attract more platelets.

• More platelets move leading to platelets

aggregation (positive feedback.

• Platelets form a plug or a temporary seal

within six minutes.

Coagulation

• Thromboplastin (TP) or tissue factor released by damaged tissue cells.

• TP activates (through series of chemical reactions) the inactive clotting factors already present in the blood.

• Prothrombin activato, first step in final common pathway.

This final common pathway can be initiated by two processes usually occurring together…

The insoluble fibrin threads

increase in number and forms a

meshwork that trap blood cells and

is much stronger than platelet plug

Vasospasm

Platelet Plug Formation

Plasma clotting Factors Factor Name Function

I Fibrinogen Converted to fibrin

II Prothrombin Enzyme

III Tissue Thromboplastin

Co factor

IV Ca++ Co factor

V proaccelerin, Labile factor

Co factor

VII proconvertin Enzyme

VIII AHF A Co factor

IX AHF B Enzyme

X Trombokinase Enzyme

XI AHF C Enzyme

XII Hageman Factor

Enzyme

XIII Fibrin stabilizing factor

Enzyme

ABO Blood System

This system consists of three types of antigens

Antigen A

Antigen B

Antigen Rh

Two types of antibodies

Anti-A antibody

Anti-B antibody

ABO system forms four major types of blood groups.

The table below shows the possible combinations of

antigens and antibodies with the corresponding ABO

type ("yes" indicates the presence of a component and

"no"indicates its absence in the blood of an individual).

ABO

blood type

Antigen

A

Antigen

B

Antibody

A

Antibody

B

A Yes No No Yes

B No Yes Yes No

AB Yes Yes No No

O No No Yes Yes

Anti-A antibody

Anti-B antibody Ant-Rh antyibody

Blood Transfusion

Hemolytic disease in Newborn

http://mumbaihangout.org/rnd.php