1. The Heart Circulatory System Ms. Lowrie Advanced Biology 11

2. 7.5 – The Mammalian Heart  Muscular pump In circulatory system Technically:  Two parallel pumps Synchronized Separated by a thick wall of muscle  Septum

3. Two Pumps Right Side  Right atrium & ventricle  Pulmonary circulation: Receives deoxygenated blood from body Sends to lungs Think: LUNGS! Left Side  Left atrium & ventricle  Systemic circulation: Receives oxygenated blood from lungs Sends to body tissues and cells Think: BODY!

4. Heart Chambers  Four chambers or “rooms” Two atria and two ventricles  Atria Thin walls Receive blood from veins Pump blood to ventricles  Ventricles Thick walls Receive blood from atria Pump blood out of heart  To body or lungs

5. Blood Flow in Heart Into heart Atria Ventricles Leaves heart Like the alphabet … A comes before V

6. The heart has valves too!? Just like veins!  Prevents backflow of blood  Atrioventricular (AV): Between artia & ventricles  Semilunar: Between ventricles & arteries

7. Major Veins & Arteries  Vena cava are VeINs Come INto heart from body  Superior vena cava From upper body  Inferior vena cava From lower body  Aorta is an Artery Go Away from heart to body  Aorta To upper body  Descending aorta To lower body  Coronary arteries Supply heart with oxygen and nutrients

8. Label Heart Diagram (pg 257) L pulmonary vein R atrium (from upper body) (from lower body) (to upper body) semilunar AV (to lower body)

9. Task  Use notes & pages 256–258 & 261–262  Answer: A: Practice Questions: #1-4 (pg 258) B: Practice Questions: #2, 3 (pg 263) C: Section Questions: # 1, 5 & 6 (pg 263)

10. Questions?

11. Blood Flow Blood Flow in the Heart Grab blue & red colouring utensils!

12. 7.6 – Setting the Heart’s Tempo  Cardiac muscle is different from skeletal muscles  Composed of myogenic muscle Muscles that contract without external nerve stimulation

13. The Heart’s Tempo  “Node” = bundle of specialized nerves  Sinoatrial (SA) node Located where vena cava enter right atrium Acts as pacemaker Sends nerve impulse to AV node  Atria contract

14. The Heart’s Tempo (cont.)  Atrioventricular (AV) node Located at AV valve in right atrium Sends nerve impulse through septum to ventricles  Through Purkinje fibres  Ventricles contract

15. Heart Rate & Communication  Controlled by autonomic nervous system  Sympathetic nervous system: Increases rate under stress  Prepares for increased energy demands  Parasympathetic nervous system: Decreases rate after stress Controls rate during rest

16. Electrocardiogram (ECG)  Electrical impulses displayed on a graph  P wave = atrial contraction  QRS wave = ventricular contraction  T wave = ventricular recovery  Flat lines = @ rest

17. Abnormal ECG  What has gone wrong? normal ECG

18. 7.7 – Heart Sounds  lubb-dubb caused by heart valves closing  Diastole (relaxation): Atria fill with blood & contract AV valves open Blood enters ventricles & contract AV valves close  lubb Blood pushed into arteries through semilunar valves

19. Heart Sounds  Systole (contraction): Ventricles relax & increase in volume Blood drawn toward ventricles from arteries Semilunar valves close  dubb Blood stays in arteries

20. 7.8 – Blood Pressure  Measured by a sphygmomanometer “Blood pressure cuff”

21. Blood Pressure (cont.)  Measures 2 pressures: When ventricles contract (systolic) When ventricles relax (diastolic)  Normal blood pressure = 120/80 Systolic = 120mm Hg Diastolic = 80mm Hg

22. Blood Pressure Can Change  Varies by artery Decreases with distance from ventricles

23. Blood Pressure Regulation 1. Cardiac output Any increase = increase blood pressure 2. Arteriolar resistance Arteriole diameter:  Constriction (more blood in artery)  Increase blood pressure  Dilation (less blood in artery)  Decrease blood pressure

24. Blood Pressure Regulation (cont.)  If CO 2 & lactic acid build-up Anaerobic respiration  Smooth muscles relax Arterioles dilate  Delivers more oxygen to tissues  Homeostasis!

25. Blood Pressure Problems If too low:  Reduces capacity to move blood Circulation problems  Adjustment: Sympathetic (speed up) increased  Cardiac output increased Arterioles constrict  Decrease outflow from arteries

26. Blood Pressure Problems If too high:  Can weaken artery May rupture vessel  Adjustment: Sympathetic (speed up) decreased Parasympathetic (slow down) increased  Cardiac output decreased Arterioles dilate  Increase outflow from arteries

27. Concept Map Use terms: 1. Capillaries 2. Diastolic 3. Heart 4. Pulmonary artery 5. Pulmonary vein 6. Sphygmomanometer 7. Systolic 8. Vein 9. Vena cava

28. Any Questions???