Blood-1Lesson # 3 (Chapter 19)

Objectives:1- To describe the general characteristics of blood and its major functions.2- To describe the types of blood cells.3- To describe the functions of red blood cells.4- To list the blood types and explain the importance and basis of blood typing. 5- To discuss the reaction sequences responsible of blood clotting.

The Cardiovascular

System

Blood

Blood vessels

It transports substances from place to place in the body.

It is the liquid medium in which these substance travel.

The plumbing that ensure the proper routing of blood to its destination.

The muscular pump that makes blood to circulate through the blood vessels.

Heart

Introduction to the Cardiovascular System

BloodBlood is specialized fluid of connective tissue, which contains cells suspended in a fluid matrix.

1- Transport of dissolved substances

2- Regulation of pH and ions

3- Restriction of fluid losses at injury sites

4- Defense against toxins and pathogens

6- Stabilization of body temperature

Functions of Blood

Oxygen and carbon dioxide, nutrients, hormones, immune system components , waste products.

Blood eliminates deficiencies or excesses of ions. It also absorbs and neutralizes acids generated by active tissues.

Blood contains enzymes and other substances that initiate the process of clotting.

Blood transports white blood cells that migrate into other tissues to fight infections and to remove debris. Blood also contains and delivers the antibodies.

Blood absorbs the heat generated by active skeletal muscles and distributes it to other tissues. If body temperature increases, the heat is lost through the skin blood vessels. If body temperature is too low, the warm blood is directed to the brain and other temperature-sensitive organs.

Composition of Whole Blood

Plasma (46-63%)

Formed elements (37-54%)

Plasma is 92% water in which are dissolved proteins and a mixture of other materials (hormones, nutrients, wastes and electrolytes).

Albumins (60%)

Fibrinogen (4%)

Globulins (35%)

They are made in the liver.

Functions: Major contributors to osmotic pressure of plasma. Transport lipids and steroids hormones.

It is also made in the liver.Functions: Essential component of clotting system.

They are produce by white blood cells (lymphocytes) and by the liver.

Functions: Antibodies. Transport ions, hormones and lipids.

Regulatory proteins (< 1%)Enzymes, proenzymes and hormones.

The Composition of Plasma

PLASMA PROTEINS

(7%)

Electrolytes

Organic waste

Organic Nutrients

A normal ion composition is essential for vital cellular activities. Ions contribute to osmotic pressure of body fluids.

They are carried to sites of breakdown or excretion.Ex: Urea, uric acid, creatinine, bilirubin, ammonium ions.

Lipids (fatty acids, cholesterol, glycerides), carbohy-drates (glucose), and aminoacids.

OTHER SOLUTES

(1%)

Functions:

They are ions produce by the dissociation of salts in water: Na+, K+, Ca2+, Mg2+, Cl-, HCO3

-, HPO4-, SO4

2-

They are used for ATP production, growth and cell maintenance.

Functions:

Tissue

Arteriole Venule

Capillary

Lung

CO2

Wastes

O2

Nutrients

Venule Arteriole

O2 rich,CO2 poor blood

O2 poor,CO2 rich blood

Gas Exchange

Capillary

CO2 O2

Venae cavae

Aorta

Pulmonary arteries

Pulmonary veins

The Cardiovascular System

PulmonaryCircuit

SystemicCircuit

Tissue

CO2

Wastes

O2

Nutrients

1- Blood Hydrostatic Pressure (BHP) pushes water outside the blood vessels

BOP > BHP

2- Blood Osmotic Pressure (BOP) pulls water back to the blood vessels

BHP > BOP

Blood Osmotic Pressure of the blood depends on:

3- Erythrocytes

1- Electrolytes ( mainly sodium ions)

2- Proteins (mainly albumin)

Venule Arteriole

BHP

BOP

If the osmolarity of the blood is too high, the blood stream absorbs too much water, the blood volume raises, and blood pressure increases.

Ex: Patients with high blood pressure must reduce the intake of salt in the diet.

If the osmolarity of blood drops too low, too much water remains in the tissues and they become swollen (edematous).

KwashiorkorChildren with severe protein deficiency.

Neutrophil

Erythrocyte

Eosinophil

Monocyte

Neutrophil

Basophil

Neutrophil

Platelets

Monocyte

Smalllymphocyte

Smalllymphocyte

Largelymphocyte

Formed Elements of Blood

Red Blood Cells or Erythrocytes

Red blood cells constitute 99.9% of all the formed cell in blood.

Number of RBCs in 1 microliter of whole blood: Male: 4.5–6.3 millionFemale: 4.2–5.5 million

Packed cell volume (PCV) or Hematocrit). It is the percentage of RBCs in centrifuged whole blood:Male: 40–54%Female: 37–47%

Erythrocytes lack of nucleus and other organelles and live only an average of 120 days.

They contain the hemoglobin, which transport O2 and CO2.

They are biconcave discs, thick in the outer edges and thin in the center.

Hemoglobin is a protein that gives the RBCs their color and name. Each RBC contains about 280 million molecules of hemoglobin (33% of the cytoplasm).

Normal hemoglobin (adult male): 14–18 g/dL whole bloodNormal hemoglobin (adult female): 12–16 g/dL, whole blood

Hemoglobin

Hemoglobin has a complex quaternary structure consisting of four globular protein subunits.

Each chain contains one molecule or group heme.

Each heme contains one iron ion, which associates easily with oxygen (oxyhemoglobin) OR dissociate easily from oxygen (deoxyhemoglobin).

Fe2+

Hb + O2Deoxyhemoglobin

HbO2Oxyhemoglobin

Each RBC contains about 280 million molecules of hemoglobin.Each RBC potentially can carry more than a billion molecules of O2 (280 x 4)

4

Hemoglobin Conservation and Recycling

BONE MARROW

LIVER

KIDNEYS

LARGE INTESTINESMALL INTESTINE

Macrophage in spleen, liver, bone marrow

BLOOD PLASMA

Hb

10% Hemolysis

Amino- acids

Heme

Biliverdin

Bilirubin

Bilirubin-derived products

Urobilins, Stercobilins

Bilirubin

Eliminated in feces

Eliminated in urine Bilirubin

Excreted in bile Absorbed into

the circulation

Bilirubin-derived products

120 days average life span (90%)

RBC formation

Fe2+ Fe2+ is transported in circulation by transferrin

If is called hemoglobinuria

Bilirubin

+ Albumin

Indirect or unconjugated bilirubin. It increases in accelerated erythrocyte hemolysis (erythroblastosis fetalis, hemolytic anemia), and hepatocellular disease

Direct or conjugated bilirubin.It increases in obstruction of the biliary ducts (cancer of pancreas’ head), gallstones or hepatocellular diseases such as cirrhosis or hepatitis.

Transferrin

When iron is released into the blood stream, it binds to transferrin, a plasma protein

Excess transferrins, are removed in the liver and spleen and the iron is stored in two special proteins-iron complex: ferritin and hemosiderin.

Iron

Ferritin

Hemosiderin

Plasma protein that transports iron

Protein-iron complex that stores iron

Protein-iron complex that stores iron

Iron Metabolism

Erythrocyte production is called erythropoiesis, which normally takes 3 to 5 days.

Myeloid stem cell

Erythrocytes have no repair mechanisms because they lack of nucleus and other organelles. They live only an average of 120 days.

RBC Production

About 1% of circulating RBCs are replaced everyday.

In this process, about 3 million new RBCs enter the blood stream each second.

White blood cells (leucopoiesis)

Erythropoiesis takes place in the red bone marrow.

Synthesis of hemoglobin (80%).

Nucleus

Pro- erythroblast

Day 1

Erythroblast

Day 3

Normoblast

Day 4

Reticulocyte

Day 5-7

Mature Red Blood Cell

Circulation

Erythropoiesis requires: - Aminoacids- Iron- Vitamins B12, B6, and folic acid

Erythropoiesis is stimulated by: - Erythropoietin- Thyroxine - Androgens- Growth hormone

Blood TypesBlood types and transfusion compatibility are a matter of interaction between antigens and antibodies.

Antigens

They are foreign substances that are able to trigger an immune response. Most of antigens are proteins.

Antibodies

They are proteins produced by cells of the immune system, which are able to recognize an interact with the corresponding antigens.

Plasma cellAntigens

Y

Y YY Y

Y

Y Y

Y YY

Antigen-antibody reaction is specific, meaning that the antibodies can recognize only the corresponding antigens.

Plasma cellAntigens

Y

Y YY Y Y

Y Y

YY Y

Plasma cell

Antigens

Plasma cell

C

CC C

C

Antigens

CC

C C

C

The plasma membrane of the cells contains glycoproteins (surface markers) on the outer surface that can act as antigens. That means that they can trigger an immune response and can interact with the corresponding antibodies.

Surface markers are genetically determined and are different in every person. They are responsible for transplant rejection.

CC

C

C

CTransplant rejection is a process in which a transplant recipient's immune system attacks the transplanted organ or tissue.

Blood types and transfusion compatibility are a matter of interaction between plasma antibodies and surface antigens in the erythrocytes.

The plasma membrane of the erythrocytes contains glycoproteins on the outer surface that can act as antigens. That means that they can interact with the corresponding antibodies.

ABO Blood Group

Type A Type B Type A B Type O

Genotype

A A

B B

A B

A i

Blood Type (Phenotype) Genotype Blood Type (Phenotype)

B i

i i

Blood Types are Genetically Determined

A

B

A B

A

B

O

Plasma contains antibodies against surface antigens that are not present on self cells. That is why foreign tissues are rejected by the immune system.

Plasma contains antibodies against surface antigens that are not present on self red blood cells.

Anti-B antibodies Anti-A antibodies Neither anti-A nor anti-B antibodies

Anti-A and anti-B antibodies

When antibodies attack, the foreign cells agglutinate (clump together). This process is called agglutination.

The antigens that determine the blood types are called agglutinogens, and the corresponding antibodies are called agglutinins

+ Ab

ControlBlood Type

A

B

AB

O

ABO Blood Typing

DD

D

D

DD

D

D

Rh + Rh -

No anti-D antibodies

No anti-D antibodies

Genotypes DD or Dd Genotype dd

The Rh blood group is named for the rhesus monkey, the animal in which the Rh antigens were discovered in 1940.

This group include numerous antigens (C, D, E). Antigen D is by far the most reactive and it is used for Rh typing.

Rh Blood Group

Anti-A Anti-B Anti-DControl Anti-A Anti-B Anti-DControl

A-

A+

B-

B+

AB-

AB+

O-

O+

ABO and Rh Blood Typing

Type B(anti-A)recipient

Blood fromtype A donor

Donor RBCsagglutinated byrecipient plasma

Agglutinated RBCsblock small vessels

Transfusion Reaction

Free hemoglobin can block the kidney tubules and produce death from acute renal failure within a week or so.

The agglutinated RBCs lodge in smaller blood vessels and cut of the blood flow to vital organs.

Hemolytic Disease of Newborn

Rh antibodies attack fetal blood causing severe anemia and toxic brain syndrome (Hemolytic Disease of the New Born).

leaves

Uterus

Placenta

Rh- mother

(a) First pregnancy (b) Between pregnancies (c) Second pregnancy

Rhantigen

Rh+ fetus

Amniotic sacand chorion

Anti-Dantibody

SecondRh+ fetus