nota sains tingkatan 3 (bab 2)

7/28/2019 Nota Sains Tingkatan 3 (Bab 2)

1/8

1

BAB 2: Circulatory and Transport System


2/8

2

1. There are three types of valve in the heart, i.e. tricuspid valve, bicuspid valve and

semilunar valve.

Types of valve in the heart and their functions

2. There are four blood vessels connected to the heart.

Types of blood vessel and their functions


3/8

3

Blood circulation through the heart

Blood circulation through the heart

1. The flow chart below shows the blood circulation starts from the vena cava throughthe heart to the whole body.

Blood circulation starts from the vena cava through the heart to the whole body


4/8

4

Blood vessels in humans

1. Blood vessels are tubes in the body that channel blood.2. There are three types of blood vessel in the human body, i.e.:

(a) Artery(b) vein(c) blood capillary

.

Comparison between artery, vein and blood capillary


5/8

5

Oxygenated blood differs from deoxygenated blood in characteristics and content.

Comparison between oxygenated and deoxygenated blood

Blood circulation

1. Humans have a double blood circulatory system.2. There are two types of blood circulation in humans, i.e.:

(a) Pulmonary circulation(b) Systemic circulation

Types of human blood circulation


6/8

6

Functions of Blood Constituents

Plasma

1. Plasma is the liquid part of blood. It is light yellow in colour.

Blood constituents

2. Plasma consists of 90% water and 10% dissolved substances.3. Dissolved substances in plasma include amino acids, glucose, mineral salts, vitamins,

excretory products, oxygen and carbon dioxide.4. Plasma functions as a medium for transport. It transports nutrients from the digestive

tract and oxygen from the lungs to body cells. 5. Plasma also transports excretory products such as urea and carbon dioxide to be

removed from the body cells.6. Plasma transports other substances too. These include enzymes, hormones and

antibodies.7. Fibrinogen is the plasma protein responsible for the clotting of blood.8. Plasma also helps to maintain the body temperature at 37C.

Red blood cells (erythrocytes)

(a) (b)

A red blood cell

1. Red blood cells are biconcave discs. They have no nucleus.2. The cytoplasm of red blood cells contains red pigments called haemoglobin which give

blood its red colour.3. Red blood cells transport oxygen from the lungs to body cells.4. Red blood cells are produced in the bone marrow.5. These cells have a lifespan of about four months.6. Old red blood cells cannot function normally. These are destroyed in the liver and spleen.


7/8

7

White blood cells (leucocytes)

1. A white blood cell is larger than a red blood cell.2. There are about 600 to 700 red blood cells to one white blood cell.

White blood cells3. It has no definite shape.4. It has a nucleus, but is colourless and does not contain haemoglobin.5. White blood cells protect the body against diseases.

6. Functions of white blood cells(a) They digest bacteria.(b) They produce antibodies.(c) They also produce antitoxins to neutralise poisonous substances (toxins) produced

by the bacteria.7. White blood cells are produced in the bone marrow, lymph nodes and spleen.

8. Some white blood cells (neutrophils) die within a few days.

9. Old white blood cells are destroyed in the liver and spleen.

Platelets

1. Platelets are fragments of cell produced in the bone marrow.2. A platelet does not have any nucleus. It also does not have a definite shape.3. There are about 150 000 to 400 000 platelets in one cubic millimetre of blood.

Blood platelets4. (a) Platelets play an important role in the clotting of blood.

(b) They prevent excessive bleeding and initiate healing or repairing of the injury.

Blood Group and Compatibility1. A person with blood type O is known as a universal donor. This blood group is

compatible with all other blood groups.2. A person with AB blood group is known as a universal recipient.

(A) He can receive blood from all the blood groups.(B) However, he can only donate blood to individuals belonging to the same blood

Group. That is group AB.


8/8

8

Transport in plants through the xylem and phloem

1. The xylem is a vessel which transports water and mineral salts from the roots to the

leaves.

2. The phloem is a vessel which transports food (glucose) from the leaves to the stems

and roots. Food is synthesised in the green leaves during photosynthesis.

3. On the stem of a dicotyledon plant like the balsam plant and the rambutan tree, the

xylem is located in the middle section while the phloem is located in the bark of the

plant.

nota sains tingkatan 3 (bab 2)

Documents