Blood and circulation

Question 1

describe plasma

Answer 1

• yellow liquid

- transports dissolved food molecules, carbon dioxide, urea

Question 2

describe red blood cells

Answer 2

• contain hemoglobin

- transport oxygen

Question 3

describe white blood cells

Answer 3

• defend body against microbes
• lymphocytes produce antibodies to destroy microorganisms and form memory cells
• phagocytes engulf and digest microorganisms

Question 4

what are platelets

Answer 4

• cell fragments that help clot the blood

Question 5

describe the stages of blood clotting

Answer 5

injury –> platelets arrive –> platelets break open –> if calcium ions are present, THROMBIN is formed –> thrombin acts on FIBRINOGEN to turn it into FIBRIN –> fibrin forms mass of insoluble protein threads which forms a clot –> scabs once red blood cells are trapped in it

Question 6

describe how heart rate increases with exercise

Answer 6

1. muscles release more energy
2. aerobic desperation requires increased oxygen
3. stroke volume increases

Question 7

describe how stress increases heart rate

Answer 7

1. flight or flight response is triggered by the secretion of adrenaline
2. extra blood goes to muscles

Question 8

describe how the medulla is involved in changing heart rate

Answer 8

1. exercise takes place
2. more CO2 is produced
3. sensors in the aorta and carotid artery detect this
4. send nerve impulses to medulla
5. medulla passes on to accelerator nerve
6. CO2 goes back to normal

Question 9

list some ways in which antibody can destroy a pathogen

Answer 9

• making them stick together so that they can be engulfed more easily by the phagocyte
• act as a label so that the phagocyte can recognize the pathogen more easily
• causes bacterial cells to burst open
• neutralizer toxins produced by the bacteria
• form memory cells