3.1.5 Control of the Cardiac Cycle L.O: to label and describe the 3 structures involved in...

3.1.5 Control of the Cardiac Cycle

L.O: to label and describe the 3 structures involved in controlling the cardiac cycle

Starter: If systole means to contract and diastole means to relax, can you put these into the correct order of the cardiac cycle…

• Ventricular systole• Diastole• Atrial systole

Diastole!

Multiple-choice quiz

Diastole

Diastole!

Atrial Systole

Ventricular Systole

http://www.youtube.com/watch?v=xVofKdXOa4M

What does a doctor hear when they listen to a patients’ heart?

Listening to a beating heart: lub-dub

The “lub” is caused bythe closing of the valves leading to the ventricles.

The “dub” is caused by the closing of the valvesleading out of the heart.

lub-dub,

The sound of a heartbeat is the sound of the heart valves.

lub-dub, lub-dub, lub-dub, lub-dub, lub-dub…

Cardiac CycleStage Atrioventricular

valvesSemi lunar

valves

Diastole

Atrial Systole

Ventricular Systole

Cardiac CycleStage Atrioventricular

valvesSemi lunar

valves

Diastole Open Closed

Atrial Systole

Open Closed

Ventricular Systole

Closed Open

Blood Pressure• Systolic pressure is the

pressure at which the blood leaves the heart through the aorta.

• Diastolic pressure is the minimum blood pressure in the aorta.

• Blood pressure can be measured with a sphygmomanometer: first reading is systolic and second is diastolic then represented as a fraction.

Systolic Diastolic

< normal < 100 < 60

Normal 100-139 60-89

Borderline 140-159 90-94

Hyper-tension

>159 >94

1.

2.

3.

?

4.

5.

6.

Control of the Cardiac CycleThree stages of the cardiac cycle are

controlled by three structures:

Control of the Cardiac CycleThe three stages of the cardiac cycle are

controlled by three structures:

1. Sinoatrial node

2. Atrioventricular node

3. Bundle of His

Control of the Cardiac Cyclehttp://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter22/

animation__conducting_system_of_the_heart.html

http://www.bbc.co.uk/learningzone/clips/the-human-heart/12225.html

Past Exam Question Jan 2010

7 (a) The cardiac cycle is controlled by the sinoatrial node (SAN) and the atrioventricular node (AVN). Describe how. (5 marks)

Casualty Keywords!‘He’s tachycardic!’

A fast heart rhythm that originates in one of the ventricles of the heart. Can lead to ventricular fibrillation (a ‘quiver’ rather than a full contraction), asystole (no cardiac activity) and sudden death.

‘We need to defib NOW!’

Defibrillation consists of delivering a therapeutic dose of electrical energy to the affected heart with a device called a defibrillator. This should terminate the dysrhythmia, and allows the sinoatrial node of the heart to re-establish the correct rhythm.

Keyword Quiz!Unjumble the keywords about the heart to solve the hidden message at the bottom of your sheet! Then solve the picture clue!