• Blood: A type of connective tissue that is made up of blood plasma, blood cells and platelets.
• Blood acts as a medium of transportation.
• Heart: Functions as a muscular pump that circulates blood to the whole body. 
• Blood vessels: Consist of arteries, capillaries and veins that are connected to the heart, and transport blood to all the body tissues.

• The heart is located between the lungs in the thorax cavity and contains four chambers, namely the left atrium, right atrium, left ventricle and right ventricle.
• The left chamber is separated from the right chamber by a muscular wall called septum.
• Atrium receives blood that returns to the heart while the ventricle pumps blood out of the heart.
• The ventricle has thicker walls and contract stronger than the atrium.
• The muscular wall of the left ventricle is much thicker than the muscular wall of the right ventricle.
• This is because the left ventricle has to generate greater pressure to pump blood out of the aorta to the whole body while the right ventricle only has to pump blood to the lungs.

At the base of the pulmonary artery and the base of the aorta

Ensures that blood which flows out of the heart does not flow back into the ventricle when the ventricle relaxes

(Located between the right atrium and the right ventricle) ensures that blood which flows into the right ventricle does not flow back into the right atrium

This valve consists of three leaflets

(Located between the left atrium and the left ventricle) ensures that blood which flows into the left ventricle does not flow back into the left atrium

This valve consists of two leaflets

• The human blood consists of 55% plasma and 45% cell components.
• Plasma is the medium of transportation in the body.
• The components of blood cells consist of red blood cells or erythrocytes, platelets and white blood cells or leucocytes.

Blood plasma consists of 90% water.

Water is a medium of transportation and a solvent for respiratory gas, ions, digestive products and excretory substances.

Fibrinogen plays a role in blood clotting.

Albumin controls blood osmotic pressure.

Globulin is a type of antibody that is involved in the body’s defence.

Nutrients are important for energy, growth and maintenance of health.

Excretory substances are toxic substances that need to be disposed off from the body.

Oxygen is required in the respiration of cells.

Hormones control physiological activities in the body.

Enzymes are involved in the metabolic processes of cells

• Has an elastic plasma membrane.
• The biconcave disc shape enables a large TSA/V for efficient gaseous exchange.
• It does not have a nucleus at the mature stage so that more haemoglobin can be loaded into it.
• It is produced in the bone marrow of bones such as the sternum and ribs.
• Can live up to 120 days and is destroyed in the liver or lymph through the phagocytosis process.

• Each erythrocyte has a haemoglobin which is the red pigment that gives blood its red colour.
• Haemoglobin contains a heme group.
• The heme group consists of an iron atom which is the binding site for oxygen.
• Haemoglobin combines with oxygen to form oxyhaemoglobin in high oxygen partial pressure conditions.
• Oxyhaemoglobin releases oxygen in tissues or cells when the partial pressure of oxygen is low.

• Platelets are produced from fragments or scraps of cell cytoplasm that originate from the bone marrows.
• The life span is less than one week.

• Involved in the blood clotting process.

• The shape is irregular and is not fixed.
• Contains nucleus.
• Does not contain haemoglobin.
• Produced in the bone marrow.
• Life span is less than five days.
• It is divided into two types: granulocytes (contain granules) and agranulocytes (no granules).
• Granulocytes include neutrophils, eosinophils and basophils.
• Agranulocytes include lymphocytes and monocytes.

• Leucocyte can diffuse out of the capillary pore and fight pathogens in tissue fluids.

• The nucleus is made up of two to five lobes.
• Ingests bacterial cells and dead cells or tissues from wounds by phagocytosis.

• The nucleus is made up of two lobes.
• Releases enzymes that fight inflammation and allergy reaction.

• The number of basophils is lowest in the blood.
• It contains heparin that prevents blood clotting.

• Contains a large nucleus with very little cytoplasm.
• Produces antibodies to destroy bacteria and viruses that enter the body.
• Can also produce antitoxins against toxins that are produced by bacteria or viruses.

• The biggest leucocytes.
• Spherical-shaped nucleus.
• Ingests bacteria and dead cells or tissues by phagocytosis.

• Arteries are blood vessels that transport blood out of the heart.
• The direction of blood flow in the artery is from the heart to the entire body.
• The function of the artery is to quickly transport blood at a high pressure to the tissues.
• The blood in the artery is under high pressure because of the pumping action of the heart.
• This is why the wall of the artery is thick, muscular and has a small lumen.
• The aorta is the main artery that leaves the heart.
• The artery expands when blood is received from the heart.
• Therefore, the artery wall is elastic to stop it from breaking due to the high-pressured blood that flows through it.
• The branches of an artery become small vessels known as arterioles when they reach the body tissues.
• The arteriole continues to branch out and ends at the capillaries.
• The group of capillaries is called capillary network.
• Artery has no valve except for semilunar valve at the base of the aorta and at the base of the pulmonary artery.

• Capillaries are blood vessels with thin walls, as thick as one cell, not muscular and not elastic.
• The lumen of capillaries is very tiny.
• Capillaries has no valve and the blood pressure here is low.
• Blood capillaries transport blood from the artery to the vein.
• Blood capillaries allow the exchange of gases to occur between blood and cells through diffusion.
• Nutrients, excretory substances and hormones diffuse through blood capillaries.

• Capillaries rejoin to form larger blood vessels called venules.
• The wall of the veins is thin, less muscular and less elastic.
• The lumen of veins is large and the blood pressure here is low.
• Veins contain valves to maintain one-way flow of blood.
• Veins transport blood from the whole body to the heart.
• The venules combine to form veins that transport blood back to the heart.
• Vena cava is the main vein that carries deoxygenated blood back to the heart.

• Blood: A type of connective tissue that is made up of blood plasma, blood cells and platelets.
• Blood acts as a medium of transportation.
• Heart: Functions as a muscular pump that circulates blood to the whole body. 
• Blood vessels: Consist of arteries, capillaries and veins that are connected to the heart, and transport blood to all the body tissues.

• The heart is located between the lungs in the thorax cavity and contains four chambers, namely the left atrium, right atrium, left ventricle and right ventricle.
• The left chamber is separated from the right chamber by a muscular wall called septum.
• Atrium receives blood that returns to the heart while the ventricle pumps blood out of the heart.
• The ventricle has thicker walls and contract stronger than the atrium.
• The muscular wall of the left ventricle is much thicker than the muscular wall of the right ventricle.
• This is because the left ventricle has to generate greater pressure to pump blood out of the aorta to the whole body while the right ventricle only has to pump blood to the lungs.

At the base of the pulmonary artery and the base of the aorta

Ensures that blood which flows out of the heart does not flow back into the ventricle when the ventricle relaxes

(Located between the right atrium and the right ventricle) ensures that blood which flows into the right ventricle does not flow back into the right atrium

This valve consists of three leaflets

(Located between the left atrium and the left ventricle) ensures that blood which flows into the left ventricle does not flow back into the left atrium

This valve consists of two leaflets

• The human blood consists of 55% plasma and 45% cell components.
• Plasma is the medium of transportation in the body.
• The components of blood cells consist of red blood cells or erythrocytes, platelets and white blood cells or leucocytes.

Blood plasma consists of 90% water.

Water is a medium of transportation and a solvent for respiratory gas, ions, digestive products and excretory substances.

Fibrinogen plays a role in blood clotting.

Albumin controls blood osmotic pressure.

Globulin is a type of antibody that is involved in the body’s defence.

Nutrients are important for energy, growth and maintenance of health.

Excretory substances are toxic substances that need to be disposed off from the body.

Oxygen is required in the respiration of cells.

Hormones control physiological activities in the body.

Enzymes are involved in the metabolic processes of cells

• Has an elastic plasma membrane.
• The biconcave disc shape enables a large TSA/V for efficient gaseous exchange.
• It does not have a nucleus at the mature stage so that more haemoglobin can be loaded into it.
• It is produced in the bone marrow of bones such as the sternum and ribs.
• Can live up to 120 days and is destroyed in the liver or lymph through the phagocytosis process.

• Each erythrocyte has a haemoglobin which is the red pigment that gives blood its red colour.
• Haemoglobin contains a heme group.
• The heme group consists of an iron atom which is the binding site for oxygen.
• Haemoglobin combines with oxygen to form oxyhaemoglobin in high oxygen partial pressure conditions.
• Oxyhaemoglobin releases oxygen in tissues or cells when the partial pressure of oxygen is low.

• Platelets are produced from fragments or scraps of cell cytoplasm that originate from the bone marrows.
• The life span is less than one week.

• Involved in the blood clotting process.

• The shape is irregular and is not fixed.
• Contains nucleus.
• Does not contain haemoglobin.
• Produced in the bone marrow.
• Life span is less than five days.
• It is divided into two types: granulocytes (contain granules) and agranulocytes (no granules).
• Granulocytes include neutrophils, eosinophils and basophils.
• Agranulocytes include lymphocytes and monocytes.

• Leucocyte can diffuse out of the capillary pore and fight pathogens in tissue fluids.

• The nucleus is made up of two to five lobes.
• Ingests bacterial cells and dead cells or tissues from wounds by phagocytosis.

• The nucleus is made up of two lobes.
• Releases enzymes that fight inflammation and allergy reaction.

• The number of basophils is lowest in the blood.
• It contains heparin that prevents blood clotting.

• Contains a large nucleus with very little cytoplasm.
• Produces antibodies to destroy bacteria and viruses that enter the body.
• Can also produce antitoxins against toxins that are produced by bacteria or viruses.

• The biggest leucocytes.
• Spherical-shaped nucleus.
• Ingests bacteria and dead cells or tissues by phagocytosis.

• Arteries are blood vessels that transport blood out of the heart.
• The direction of blood flow in the artery is from the heart to the entire body.
• The function of the artery is to quickly transport blood at a high pressure to the tissues.
• The blood in the artery is under high pressure because of the pumping action of the heart.
• This is why the wall of the artery is thick, muscular and has a small lumen.
• The aorta is the main artery that leaves the heart.
• The artery expands when blood is received from the heart.
• Therefore, the artery wall is elastic to stop it from breaking due to the high-pressured blood that flows through it.
• The branches of an artery become small vessels known as arterioles when they reach the body tissues.
• The arteriole continues to branch out and ends at the capillaries.
• The group of capillaries is called capillary network.
• Artery has no valve except for semilunar valve at the base of the aorta and at the base of the pulmonary artery.

• Capillaries are blood vessels with thin walls, as thick as one cell, not muscular and not elastic.
• The lumen of capillaries is very tiny.
• Capillaries has no valve and the blood pressure here is low.
• Blood capillaries transport blood from the artery to the vein.
• Blood capillaries allow the exchange of gases to occur between blood and cells through diffusion.
• Nutrients, excretory substances and hormones diffuse through blood capillaries.

• Capillaries rejoin to form larger blood vessels called venules.
• The wall of the veins is thin, less muscular and less elastic.
• The lumen of veins is large and the blood pressure here is low.
• Veins contain valves to maintain one-way flow of blood.
• Veins transport blood from the whole body to the heart.
• The venules combine to form veins that transport blood back to the heart.
• Vena cava is the main vein that carries deoxygenated blood back to the heart.