Date | November 2018 | Marks available | 3 | Reference code | 18N.2.SL.TZ0.4 |
Level | Standard level | Paper | Paper 2 | Time zone | TZ0 / no time zone |
Command term | Explain | Question number | 4 | Adapted from | N/A |
Question
Label X and Y on the diagram of the heart.
Explain how the circulatory system is able to transport the blood under high pressure from the heart to the rest of the body.
The heart responds quickly to physical activity. Describe how heart rate is controlled to meet the increased circulatory demands.
Markscheme
X: pulmonary artery ✔
Y: left atrium ✔
Accept auricle
a. contraction of ventricle creates high pressure ✔
b. blood at high pressure is carried out of the heart through arteries ✔
c. thick muscular walls of arteries resist pressure/prevent leaks ✔
d. elastic recoil of arterial walls helps to push blood ✔
e. narrow lumen of arteries maintain pressure ✔
Features require an explanation, a list is inadequate
a. nerve impulse from medulla/brain acts on heart/right atrium ✔
b. pacemaker/sinoatrial node/SAN increases/controls contraction of heart ✔
c. epinephrine/adrenaline «rapidly» increases heart rate ✔