Circulatory system - blood

Question 1

Red blood cells

Answer 1

• Make up half of our blood by volume
• Carry oxygen from lungs to body tissues for use in respiration
• Haemoglobin

Question 2

Adaptations of red blood cells

Answer 2

1. Don’t have a nucleus -> More space for haemoglobin
2. Shaped like a biconcave disc -> Larger surface area for absorbing oxygen

Question 3

White blood cells (circulatory system)

Answer 3

• Defend from infection
• Make up less than 1% of blood volume in the body
• Do have a nucleus

Question 4

Platelets (circulatory system)

Answer 4

• Small fragments of cells (no nucleus)
• Float around in blood
• When wounded, they rush to the cut and clot - acting as a glue to patch it up and preventing from infection

Question 5

Plasma

Answer 5

Make up ≈50% of blood volume
Makes the blood watery so that it can flow

Question 6

Substances carried by plasma

Answer 6

• Red blood cells
• White blood cells
• Platelets
• Nutrients (glucose and amino acids)
• Waste products (CO2 and Urea)
• Hormones
• Proteins
• Antibodies
• Antitoxins

Question 7

Artificial blood (salt water)

Answer 7

• Adds volume to blood
• However, contains 0 red blood cells

Question 8

Blood transfusions

Answer 8

• Has red blood cells