BLOOD CIRCULATION AND TRANSPORT

THE TRANSPORT SYSTEM IN HUMAN

THE HUMAN BLOOD CIRCULATORY SYSTEM CONSISTS OF THE HEART, A NETWORK OF BLOOD VESSELS AND BLOOD.

THE FUNCTIONS OF THE TRANSPORT SYSTEM ARE AS FOLLOWS:

(a) TO TRANSPORT NUTRIENTS, OXYGEN AND WATER TO THE BODY CELLS.

(b) TO TRANSPORT CARBON DIOXIDE AND WESTE PRODUCTS FROM THE CELLS TO THE EXCRETORY ORGANS.

(c) TO BRING HORMONES TO THE TARGET BODY CELLS

THE HEART IS THEORGAN THAT PUMPS BLOODTHROUGH OUT THE BODYBY ITS ALTERNATECONTRACTIONS ANDRELAXATIONS OF THE MUSCLES. THE STRUCTURE OF THEHUMAN HEART.

(a)THE HEART IS MADE UPOF FOUR PARTS THAT IS THEPULMONARY VEIN IN THELEFT ATRIUM, THE VENACAVA IN THE RIGHT ATRIUM, THE AORTA IN THE LEFT VENTRICLE AND THEPULMONARY ARTERY IN

THE RIGHT VENTRICLE.

(b)THE VALVES IN THE HEART PREVENT THE BACKFLOW OF BLOOD AND ENSURE THAT THE DIRECTION OF THE FLOW OF BLOOD IS IN ONE DIRECTION ONLY. THE BICUSPID VALVE SEPARATES THE LEFT ATRIUM FROM THE LEFT VENTRICLES. THE TRICUSPID VALVE SEPARATES THE RIGHT ATRIUM FROM THE RIGHT VENTRICLE.THE SEMILUNAR VALVES ARE LOCATED AT THE BEGINNING OF THE AORTA AND THE PULMONARY ARTERY.

Structure of the human heart

Blood circulatory system

THE HUMAN BLOOD CIRCULATORY SYSTEM IS MADE UP OF A DOUBLE

CIRCULATORYSYSTEM THAT IS:

THE PULMONARY CIRCULATION WHERE BY DEOXYGENATED BLOOD FLOWS THE HEART TO THE LUNGS FOR OXYGENATION. THE OXYGENATED BLOOD OF THE LUNGS IS THEN RETURNED TO THE HEART

THE SYSTEMIC CIRCULATION WHERE BY OXYGENATED BLOOD IS SENT TO ALL PARTS OF THE BODY EXCEPT THE LINGS AND DEOXYGENATEDBLOOD IS RETURNED TO THE

HEART.

• BLOOD THET LEAVES THE LUNGS RICH IN OXYGEN IS CALLED OXYGENATED BLOD. BLOOD IN THE VENA CAVA FROM ALL PARTS OF THE BODY LOW IN OXYGEN CONTENT IS CALLED DEOXYGENATED BLOOD.

• IN THE COURSE OF THE CIRCULATION OF BLOOD,

EXCHANGE OF GASES TAKE PLACE AT:

• THE LUNGS- OXYGEN DIFFUSES INTO THE BLOOD FROM THE LUNG. CARBON DIOXIDE IS REMOVED FROM THE BLOOD AND DIFFUSES INTO THE LUNGS.

• THE BODY TISSUES- OXYGEN FROM THE BLOOD DIFFUSES INTO THE BODY CELLS WHILE THE CAEBON DIOXIDE FROM THE BODY CELL DIFFUSE INTO THE BLOOD.

Artery and Vein

Capillary

HUMAN BLOOD

HUMAN BLOOD IS MADE UP OF 55% PLASMA AND 45% BLOOD CELL.

PLASMA

(a) Has a pale yellow colour, when the blood cells have been removed, the remaining liquid is known as plasma:

blood blood cells plasma

(b) Its function is to transport digested food, mineral salts and vitamins to the body cells. It also transport waste substances like carbon dioxide, water and urea to the excretory organs. It is important as it maintains the PH of blood. Further it distributes hear throughout the body so that the body temperature of 37C in maintained.

Blood cells

• Blood are made up of red blood cells, white blood cells and platelets.

• Old red blood cells and platelets are destroyed in the liver or spleen.

White blood cells Red blood cells

• Human blood can be classified into 4 different groups. The 4 groups are A,B,AB,and O.

• Different blood have different antigens and antibodies.

Blood groups Antigen Antibody

A A Anti-b

B B Anti-a

AB A and B Nil

O Nil Anti-a and

Anti-b

Recipients of blood from suitable donors

Recipient blood group\Donor blood group

A B AB 0

A / X X /

B X / X /

AB / / / /

O X X X /

CELL OF PLANT