vessels + blood

Question 1

What are the three types of blood vessel in the

body?

Answer 1

● Arteries
● Veins
● Capillaries

Question 2

How are arteries adapted for their function?

Answer 2

● Function: carry blood away from the heart.
● Thick muscle layer - adds strength to resist high
pressure.
● Thick elastic layer - allows arteries to stretch
and recoil - in order to withstand high pressure.

Question 3

How are veins adapted for their function?

Answer 3

● Function: carry blood towards the heart
● Wide lumen - enables low pressure
● Valves - prevent backflow of blood

Question 4

How are capillaries adapted for their function?

Answer 4

● Function: enable transfer of substances between
the blood and tissues.
● Walls are one cell thick - short diffusion path.
● Permeable walls - substances can diffuse across.
● Narrow lumen - blood moves slowly - more time
for diffusion.

Question 5

How would you calculate the rate of blood flow?

Answer 5

Volume of blood / number of minutes

Question 6

What substance carries the different components of blood around the body?

Answer 6

Plasma

Question 7

What substances are transported by plasma?

Answer 7

● Red blood cells
● White blood cells
● Platelets
● Carbon dioxide
● Urea
● Products of digestion

Question 8

What is plasma?

Answer 8

A yellow liquid within blood that

transports substances around the body.

Question 9

What is the purpose of red blood cells in blood?

Answer 9

Transport of oxygen around the body

Question 10

How are red blood cells adapted for their function?

Answer 10

● Biconcave shape - increased surface area to volume ratio.
● No nucleus - more room for haemoglobin to bind to oxygen.
● Contain haemoglobin - binds to oxygen.

Question 11

What is the purpose of white blood cells in blood?

Answer 11

They form part of the immune system, which protects the body from invading pathogens.

Question 12

How are white blood cells adapted for their function?

Answer 12

● Have a nucleus - contains DNA which codes for proteins
● Can produce antibodies
● Can produce antitoxins
● Can engulf and digest pathogens (phagocytosis)

Question 13

What is the purpose of platelets in blood?

Answer 13

Platelets are small cell fragments which aid the clotting of blood at the site of a wound.

Question 14

Why is the function of platelets important?

Answer 14

● Platelets aid in the process of blood clotting
(conversion of fibrinogen to fibrin). As a result, red
blood cells are trapped in the fibrin network,
forming a clot which prevents excessive bleeding.
Scab formation (after the clot has dried) prevents
bacteria from entering the wound