C3.1 Integration of body systems - written task
This structured extension question addresses the control of the heart rate and stroke volume.
It uses the "outline" command term.
Outline answers are only slightly different from explain or describe.
The answers should include reasons why something happens or structures and functions, they can combine description and explanation, as well as definition.
Answers to a ‘describe question’ only require details about the subject of the question not necessarily reasons why.
The speed and output volume of the heart beat is controlled by complex interactions between the autonomic nervous system, the endocrine system and by the heart itself.
Outline the ways of increasing the volume of blood the heart can pump per minute.
(2 marks)
Outline the function of Chemoreceptors in the control of the pulse rate.
(2 marks)
Outline the role of the central nervous system in the control of heart rate.
(3 marks)
Teachers note - These responses interact forming complex feedback loops controlling heart function. but the IB Biology guide only mentions the following simple roles.
The terms 'respiratory centre' and 'cardiovascular centre' are not mentioned in the biology guide.
- This could be a classroom task, a revision moment or a homework activity.
- There is a hidden model answer which appears when the answer is submitted.
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