2.2 : Human Blood Constituents of Blood in Human Beings

•  Normal adult has about 5 – 6 litres of blood •  Blood : A type of fluid that is made up of liquid

and solid •  Liquid component : –  Is called plasma –  55%

•  Solid component : – Red blood cells – White blood cells – Platelets – 45%

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood in Human Beings

•  Both components can be separated from a blood sample by using centrifuge

•  When blood is rotated in a spinning centrifuge, it is separated into –  blood cells (lower

section) –  Plasma fluid

(upper section) Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – PLASMA

•  Light yellow •  Contains 92%

water and 8% dissolved substances such as –  Digested food

(glucose, amino acid, fatty acid)

–  Excretory products (CO2, urea)

–  Proteins (albumin, antibody)

–  Vitamins & minerals Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – PLASMA

•  Functions – Transport

digested food to tissues

– Transport excretory products from tissues

– Distribute heat throughout the body to maintain body temperature at 37°C

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – RED BLOOD CELLS

•  Are called as erythrocytes – found most in blood

•  Haemoglobin – red pigment which contains iron & protein

•  Biconcave disc-shaped

•  Thick on the edge & thin in the centre – able to squeeze in the small capillary

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – RED BLOOD CELLS

•  No nucleus – increases the surface area to transport MORE 02

•  Produced in bone marrow with lifespan up to 120 days

•  Old RBC is destroyed in the liver and lymph

•  Anaemia : lack of RBC

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – WHITE BLOOD CELLS

•  Is called as leucocytes

•  Made up of membrane, cytoplasm & nucleus

•  Bigger size than RBC •  Colourless with

indefinite shape to penetrate the blood capillary/body cells

•  Defends the body against microbes

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – WHITE BLOOD CELLS

TYPES OF WBC •  Lymphocytes –  To produce

antibodies that are able to destroy pathogens

•  Phagocytes - To ingest the

pathogens before destroying them.

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – WHITE BLOOD CELLS

•  Produced in the bone marrow & lymph nodes

•  Lifespan : A few days to many months

•  Old WBC is destroyed in blood circulation – excrete together with urine & faeces

•  Lack WBC – weak immune system

•  Leukaemia : A type of cancer with excess WBC – patients get infected easily & can be fatal Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – PLATELETS

•  Known as thrombocytes

•  Not complete cells – fragments of cytoplasm from bone marrow

•  No nucleus, colourless & spherical

•  Lifespan : 10 days •  Old platelets are

destroyed in blood circulation

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – PLATELETS

•  Helps in blood clotting to prevent –  blood loss –  Microbes entering

the body through injured skin

•  Haemophilia : genetic disorder caused by insufiicient platelets –  continuous

bleeding –  Prevent clotting –  Fatal Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Constituents of Blood – PLATELETS

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Blood Group

•  Four groups :- •  A, B, O, AB

•  Knowledge of blood groups is important in the blood transfusion

•  Transfusion : Process of blood transferring

•  When blood of two incompatible groups is mixed, RBC of the donor & recipient will clump together – AGGLUTINATION : reduces surface area for gas diffusion & leads to fatal

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Blood Group

•  Blood group O : •  Aka universal

donor – can donate to any blood group

•  Can only receive from group O

•  Blood group AB : •  Aka universal

recipient – can receive blood from any blood group

•  Can only donate to group AB

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Compatibility of Blood Groups

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.2 : Human Blood Blood Donation

•  There are many reasons why blood transfusion is needed

•  Who can donate blood? •  Donated blood is

screened to ensure free of microbes : parasites, hepatitis virus or HIV

•  Screened blood is divided into its components

•  RBC : stored in fridge & last about 40 days

•  Plasma : frozen & last for about 1 year

Prepared  by  Ms  Sue  Soh  Ya  Lee