Transport in humans

Question 1

What is the plasma?

Answer 1

• Yellowish liquid in the blood
• Contains mainly water and substances such as glucose, salts, proteins, amino acids, fats, vitamins, hormones and metabolic waste products such as urea.
• It contains red and while blood cells

Question 2

What is the function of the plasma

Answer 2

• transports blood cells around the body
• transports nutrients from the small intestines to other parts of the body
• transports metabolic waste products from organs where they are produced to organs such as kidneys and lungs for removal
• transports hormones from endocrine glands to target organs

Question 3

What are platelets

Answer 3

Fragments of the cytoplasm. They contain an enzyme that catalyses the conversion of fibrinogen to fibrin threads

Question 4

Functions of the platelets

Answer 4

Prevent excessive blood loss and the entry of harmful organisms into the bloodstream

Question 5

Features of the white blood cell

Answer 5

• White blood cells are irregular in shape
• They have a nucleus

Question 6

White blood cell function (phagocytes)

Answer 6

Phagocytosis is the process by which a while blood cell engulfs and destroys foreign particles such as bacteria

Question 7

White blood cell function (Lymphocytes)

Answer 7

Lymphocytes produce antibodies that
- recognise foreign particles
- destroy disease-causing organisms such as bacteria and viruses
- cause bacteria to clump together for easy ingestion by phagocytes
- neutralise the toxins produced by bacteria

Question 8

Why is blood clotting important?

Answer 8

Clot seals the wound and prevent excessive loss of blood, and prevents foreign particles from entering the bloodstream.

Question 9

Blood clot deficiency

Answer 9

haemophilia

Question 10

Process of blood clotting

Answer 10

Platelets are involved in converting soluble protein fibrinogen to insoluble threads of fibin. Fibrin threads entangle blood cells and the whole mass forms a clot. The clot seals the wound, preventing entry of microorganisms and excessive loss of blood

Question 11

Organ rejection

Answer 11

Organ from another person may be treated as a foreign body by the recipient’s immune system. The recipient’s white blood cells may respond by producing antibodies to destroy the transplanted organs.

Question 12

Tissue rejection

Answer 12

A foreign tissue may be recognised by the white blood cells. The white blood cells respond by producing antibodies to destroy the foreign tissues

Question 13

Heart

Answer 13

• The blood is kept circulating throughout the body by means of the muscular pump, the heart.
• When the heart relaxes, it fills up with blood.
• When it contracts, the blood is squeezed our with great force.
• Blood then circulates though the blood vessels, which direct the blood flow around the body

Question 14

Arteries

Answer 14

• Blood vessels that carry blood away from the heart.

Question 15

Arterioles

Answer 15

• Arteries branch to form tiny vessels called arterioles.
• Arterioles divide and ultimately become very tiny blood vessels called capillaries

Question 16

Functions of blood capillaries and it’s adaptation

Answer 16

*They have walls made up of only a single layer of flattened cells - partially permeable allowing certain substances to diffuse quickly through them
*Small arteries branch our to form capillaries - numerous branches provides large s.a.t.v ratio between the blood and the tissue cells.
*Arteriole branches into many capillaries- the total cross sectional area of the blood vessels increases. This lowers the blood pressure in the capillaries + flow of blood is slowed down, giving more time for the exchange if substances

Question 17

Venules

Answer 17

Before the capillaries leave an organ/ tissue. they unite to form small vessels called venules.

Question 18

Veins

Answer 18

Venules in turn join to form bigger veins that carry blood back to the heart

Question 19

Direction os blood blow in artery

Answer 19

Arteries receive blood directly from the heart. They branch to form arterioles.

Question 20

Blood pressure and speed of blood flow in arteries

Answer 20

blood that flows in the arteries is fast-moving so it needs to be able to withstand high pressure of the blood forced out of the heart.

Question 21

Type of blood transported in artery

Answer 21

arteries carry oxygenated blood except for pulmonary artery that carries deoxygenated blood from the heart to the lungs

Question 22

Adaptation of arteries

Answer 22

arteries have thick elastic walls to enable the artery to withstand the high blood pressure inside it as blood is forced out of the heart and the elastic wall enables it’s wall to stretch and recoil or spring back which helps to push the blood in spurts along the artery and give rise to the pulse.

Question 23

Direction of blood flow in veins

Answer 23

veins carry blood back to the heart
they are formed when venules are joined together

Question 24

Blood pressure and speed of blood flow in veins

Answer 24

blood pressure in veins are much lower than blood pressure in the arteries. blood flows more slowly and smoothly in the veins

Question 25

Type of blood transported in the vein

Answer 25

Veins carry deoxygenated blood except pulmonary vein the carries oxygenated blood from the lungs to the heart

Question 26

Adaptations of veins

Answer 26

Veins have internal valves along their length to prevent backflow of blood

Question 27

How does blood circulate around the body

Answer 27

From the heart, the pulmonary arteries carry blood to the lungs
Oxgen enters the blood at the lungs, oxygenated blood is returned to the heart by the pulmonary vein.
oxygenated blood leaves the left side of the heart and is distributed by arteries to all parts of the body except the lungs