CH10

Question 1

Circulatory system of unicellular organism

Answer 1

Does not require transport system
Body cell is in direct contact with environment
Has high total surface area over volume ratio
Substance exchange occur through diffusion

Question 2

Structure of Circulatory system of Insects

Answer 2

Open circulatory system

Haemolymphs:
transport nutrients & hormones
exchange substances directly with body tissues
moves back into heart by muscle contractions

Ostium and hearts:
When heart contract, ostium close, haemolymph flows into haemocoel
When heart relax, ostium open, haemolymph flows back into the heart through ostium

Question 3

Structure of circulatory system of fish

Answer 3

Closed single complete circulatory system

Gills:
Site for gaseous exchange between blood and environment
Carbon dioxide diffuse into environment through simple diffusion
oxygen diffuse into the blood through simple diffusion

Systemic capillary
Site for gaseous exchange between blood and body cells
Oxygen diffuses into body cells by simple diffusion
carbon dioxide diffuses into blood by simple diffusion

Heart
One atrium
One ventricle

Question 4

Structure of circulatory system of amphibians

Answer 4

Closed double incomplete circulatory system

Heart
2 Atria 1 Ventricles
Both atria contract simultaneously, bloods enter the same ventricle
Oxygenated and deoxygenated bloods are mixed
Incomplete seperation of oxygenated and deoxygenated blood

Question 5

Components of bloods

Answer 5

Plasma
Yellowish Fluid
Medium for blood
90%-92% water

RBC/Erythrocytes
Biconcave; increase TSA/V ratio
No Nucleus; more space to transport haemoglobin
Haemoglobin + oxygen = Oxyhaemoglobin
Carbon dioxide + oxygen = Carbaminohaemoglobin

Platelets
Irregularly shaped
blood clotting mechanism component

White Blood Cells

Question 6

Types of Leucocytes

Answer 6

Basophils
2 Lobes
Produce heparin; anti-coagulant

Eusinophils
2 Lobes
Reduces inflammation

Neutrophils
Multi lobes
Phagocytosis

Monocytes
Bean shaped nuclei
Largest leucocytes
Phagocytosis

Lymphocytes
Spherical nuclei
Little cytoplasm
Produce antibody

Question 7

Mechanism of heartbeat

Answer 7

Sinoatrial nodes is a natural pacemaker
Sinoatrial node generates electrical impulse to trigger heartbeat.
Electrical impulse produced causes both atria to contract simultaneously.
Blood is forced into the ventricles.
Electrical impulse produced by SA stimulate atrioventricular nodes to generate its own electrical impulse
The electrical impulse is conducted by bundle of His and purkinje fibre to the whole ventricle walls
Both ventricle contracts simultaneously
Blood is pumped out of the heart

Question 8

Mechanism of Blood Clotting

Answer 8

Platelets group together to seal off the wound temporarily
Platelets that grouped together releases thrombokinase
Thrombokinase groups together with calcium ion and vitamin K to convert prothrombin to thrombin
Thrombin convert fibrinogen to fibrin
Fibrin form a network that trap blood cells, causing them to coagulate and block the wound site.
Coagulated blood harden forming a scab.
New cells are formed under the scabs

Question 9

Formation of Lymph and Tissue fluid

Answer 9

When bloods move from artery to smaller capillary, high hydrostatic pressure is produced
High hydrostatic pressure cause blood plasma to diffuse into intracellular spaces from blood capillary
Blood plasma in intracellular space is called tissue fluid
Tissue fluid does not contain platelet, erythrocytes and plasma protein as they are too big to diffuse out of blood capillary
At venule end of blood capillary, blood plasma is hypertonic to tissue fluids surrounding it
Blood pressure is also lower.
Tissue fluid diffuse back into venule end
The remaining fluid forms lymph