Essential Idea: Internal and external factors influence heart function
Understandings:
Structure of cardiac muscle cells allows propagation of stimuli through the heart wall
Signals from the sinoatrial node that cause contraction cannot pass directly from atria to ventricles
There is a delay between the arrival and passing on of a stimulus at the atrioventricular node
This delay allows time for atrial systole before the atrioventricular valves close
Conducting fibres ensure coordinated contraction of the entire ventricle wall
Normal heart sounds are caused by the atrioventricular valves and semilunar valves closing causing changes in blood flow
Applications:
Use of artificial pacemakers to regulate the heart rate
Use of defibrillation to treat life-threatening cardiac conditions
Causes and consequences of hypertension and thrombosis
Skills:
Measurement and interpretation of the heart rate under different conditions
Interpretation of systolic and diastolic blood pressure measurements
Mapping of the cardiac cycle to a normal ECG trace
Analysis of epidemiological data relating to the incidence of coronary heart disease
Nature of Science: Developments in scientific research followed improvements in apparatus or instrumentation: the invention of the stethoscope led to improved knowledge of the workings of the heart.
Copy of Topic D.4 The heart
Copy of Topic D.4 The Heart Skeleton Notes STUDENT