The Cardiovascular System Dale Embleton

1. THE BODY IN ACTION The Cardiovascular System Dale Embleton

2. The cardiovascular system What you need to learn … • The structure of the cardiovascular system • The blood • The heart and valves • The blood vessels • The functions of the cardiovascular system • Heart contraction • Cardiac cycle • Pathway of blood

3. The cardiovascular system The cardiovascular system The cardiovascular system consists of the heart, blood and blood vessels, and is also referred to as the circulatory system of the body.

4. The cardiovascular system The circulatory system consists of three parts • The blood – in which materials are carried to and from the tissues • The heart – the muscular pump that pushes blood to the working muscles • The blood vessels (venules, veins, arteries, arterioles and capillaries) – the routes by which the blood travels to and through the tissues, and back to the heart

5. The cardiovascular system Key points • Arteries carry oxygenated blood away from the heart • Veins carry de-oxygenated blood back to the heart • Capillaries connect veins and arteries

6. STRUCTURE

7. The cardiovascular system: BLOOD Functions of blood • Carries nutrient substances absorbed from the intestine to the tissues • Carries oxygen to the tissues • Carries waste products from the tissues to the kidneys and liver • Returns carbon dioxide from the tissues to the lungs • Regulates body temperature • Distributes hormones and other agents • Fights bacterial infection through the white cells and antibodies

8. The cardiovascular system: BLOOD A closer look at the structure of blood … • Plasma • Liquid • Erythrocytes • O2 and CO2 • Leucocytes • Immune • Platelets • Blood clots See Handout and complete worksheet 45

9. The cardiovascular system: HEART The heart • Situated in the left-hand side of the chest • Muscular pump whose purpose is to drive the blood into and through the arteries, to deliver it to the tissues and working muscles • Considered as two separate pumps • Two chambers on the right, and two chambers on the left side • What are they?

10. The cardiovascular system: HEART Structure of the Heart • Surrounded by sac known as the pericardium, which prevents friction as the heart beats. • Heart wall is made of: • Epicardium (outer layer) • Myocardium (strong middle layer) • Endocardium (inner layer) • Right separated from left by Septum

11. The cardiovascular system: HEART The structure of the heart and blood vessels Task • In pairs research and complete work sheets 42, 43 and 44

13. The cardiovascular system: HEART The heart functions (continued) • Right atrium receives de-oxygenated blood from the body • Right ventricle pumps it to the lungs • Left atrium receives oxygenated blood from the lungs • Left ventricle pumps oxygenated blood to the body

14. The cardiovascular system: HEART Circulation of Blood

15. The cardiovascular system: HEART The heart valves • The heart has 4 valves • Choose 1 • Using books/web, draw these valves • Identify their location • What is their function? • When will they open and close? • Present to the class

16. The Cardiovascular System: BLOOD VESSELS • Complicated network of blood vessels • 96 kilometres of arteries, arterioles, capillaries, venules and veins. • Their structure relates to their function • Next two slides and handout have more information on the blood vessels • Page 218-19

17. The cardiovascular system: BLOOD VESSELS SRUCTURE • 3 groups • Explain the structure of these blood vessels using a diagram and labels

18. The cardiovascular system: BLOOD VESSELS Main blood vessels and their functions • Aorta – Main artery of the body carrying oxygenated blood to the body tissues • Pulmonary artery – Carries deoxygenated blood from the lungs back to the heart • Superior vena cava – Receives deoxygenated blood from the upper body to empty into the right atrium of the heart • Inferior vena cava – Receives deoxygenated blood from the lower body to empty into the right atrium of the heart See Handout for further information and complete worksheet 45

19. FUNCTIONS OF THE CARDIOVASCULAR SYSTEM

20. THE HEART’S CONTRACTION • Contraction causes blood to move • The SA (sinoatrial) node is the pacemaker • Endocardial of right atrium • 60-100 beats per minute • AV node (septal wall of right atria) slows impulse between the atria and ventricles to allow time for contracting atria to fill ventricles. • What would happen otherwise?

21. CARDIAC CYCLE • “The period from the beginning of one heart beat to the beginning of the next” • Two distinct phases • Systole • diastole • Using textbook handout, complete Worksheet 47,question 1 and 2

22. Cardiac output = rate at which blood leaves the heart • Stroke volume = volume of blood that leaves the heart with each beat • CO = SV X HR • Complete worksheet 47 and 48

23. PATHWAY OF BLOOD • There are 3 modes of circulation that transports blood through the body. • Pulmonary • Systemic • Coronary • Summarise these in a few sentences on your Handout • Now complete worksheets 46

24. PATHWAY OF BLOOD…cont…. Blood Pressure • The blood is always under pressure • Without it where would the blood in your body be? • It therefore enables the blood to gravitate upwards in the body and through capillaries. • Worksheet 49

25. THE PULSE • Where can you find a pulse? • Why? • What is it a measure of? • Healthy adults = ______ - _______ bpm

26. BLOOD POOLING • This is where blood is not returned to the heart and lungs for re-oxygenation. • Fainting may occur……… • Why?......what has this got to do with gravity? • Blood may pool in your cardiovascular system • Low blood pressure • Terminating activity without a recovery phase.

27. The cardiovascular system What you need to learn … • The structure of the cardiovascular system • The blood • The heart and valves • The blood vessels • The functions of the cardiovascular system • Heart contraction • Cardiac cycle • Pathway of blood