1. Control of Heart Rate in Humans

2. Starter
Label heart diagrams

3. Structure of the heart deoxygenated blood to the lungs
oxygenated blood to the body
deoxygenated blood from the body
oxygenated blood from the lungs

4. Learning Objective Success Criteria
Know how we control heart rate
Outline the hormonal and nervous mechanisms involved in the control of heart rate

5. Cardiac Cycle
Using the key words below in pairs write a paragraph to describe the cardiac cycle
Pacemaker, Atrio-Ventricular node, myogenic, Sino-Atrial node, Atria, Ventricles, Purkyne Tissue
When finished swap with another pair and see if you can improve their work

7. Think about what happens:
when you walk down a quiet road late at night and you’re afraid your being followed Or
before an exam.

8. sympathetic Nervous System
Increases the heart rate, to increase oxygen supply to the muscles.
Increases the ventilation rate, so that more oxygen can be absorbed in the lungs.
Decreases peristalsis in the gut so there is more blood available for the heart and lungs.
Other parts of the body also respond to enable increased sensory awareness eg pupils dilate

9. Parasympathetic Nervous System
Relaxing responses - decreases over all physical activity, so it is associated with rest.
It decreases heartbeat rate
It decreases ventilation rate
It increases peristalsis in the gut, so that food can be digested

10. Nervous Control of Heart Rate
Nerves from cardiovascular centre in medulla oblongata (in brain) supply heart
Connect to SAN
Effect frequency of beats
Action potentials sent down the accelerator nerve (sympathetic NS) increase heart rate
Action potentials sent down the vagus nerve (parasympathetic NS) decrease heart rate

11. Hormonal Control of Heart Rate
Heart muscle responds to adrenaline in blood

12. Normal conditions Resting heart rate controlled by SAN
Varies from person to person
Frequency of beats per min
This can be controlled by the cardiovascular centre in the medulla oblongata

13. Factors that affect Heart Rate
Movement of limbs
detected by stretch receptors in muscles
Send impulse to cardiovascular centre
Increases heart rate
Production of CO2 during exercise
Reduces blood pH
Detected by chemoreceptors in carotid arteries, aorta and brain

14. Factors that affect Heart Rate
Decrease in CO2 after exercise
Reduces activity of accelerator nerve
Decrease in heart rate
Adrenaline secretion
Increases heart rate
Blood pressure
Monitored by stretch receptors in walls of carotid sinus
Blood pressure too high, impulse sent to cardiovascular centre, impulse sent down vagus nerve

15. Artificial Pacemaker
Read a section of information on artificial pacemakers and make notes about its development, forming a timeline

16. Heart Rate Jan 11
[5]

17. Heart Rate Jan 11 Markscheme