The Cardiovascular System

1. The Cardiovascular System Chapter 12 Human Anatomy & Physiology

2. I. Overview of the Cardiovascular System • The circulatory system can be thought of as the transport system of the body. • A closed system consisting of the heart,blood vessels, and blood • The heart pumps blood • Blood vessels allow blood to circulate to all parts of the body • Function: Deliver oxygen & nutrient-rich blood to body cells and remove carbon dioxide and waste

4. A. Overview of the Heart • The heart is located in the thoracic cavity between the lungs slightly to the left • A hollow, cone-shaped muscle about the size of a fist • Made up of cardiac muscle

6. II. Anatomy of the Heart 1. Coverings: • Pericardium – a double serous membrane • Visceral pericardium (epicardium) • Next to heart • Parietal pericardium • Outside layer • Serous fluid fills the space between the layers of pericardium

7. 2. Heart Walls: • Three layers a] Epicardium • Outside layer • This layer is the visceral pericardium b] Myocardium • Middle and thickest layer • Mostly cardiac muscle c] Endocardium • Inner layer • Made up of simple squamous epithelium

9. 3. Chambers • The heart has 4 chambers • Left & right atria – receive blood • Left & right ventricles -pump blood out • Chambers are separated by a septum

10. 4. Heart Valves • Valves are flaps of connective tissue between the atria and ventricles • Moves the blood through the heart in one direction • Valves open as blood is pumped through • Held in place by chordae tendineae (“heart strings”) • Valves are closed to prevent backflow

11. Four valves a. Atrioventricular valves – between atria and ventricles, open valves • left atrium  bicuspid valve  left ventricle • right atria  tricuspid valve  right ventricle b. Semilunar valves - between ventricle and artery, closed valves • right ventricle  pulmonary semilunar valve  pulmonary artery • left ventricle  aortic valve  aorta

14. 5. Major Vessels • Aorta • Blood leaves left ventricle towards body • Pulmonary arteries • Oxygen-poor blood leaves right ventricle towards lung • Vena cava • Superior and inferior • Blood from the body enters the right atrium • Pulmonary veins (4) • Oxygen-rich blood from lungs enters left atrium

15. IV. Anatomy of Blood Vessels • Blood Vessels are tubes which transport blood A. Function: • Transport blood • Carry out the exchange of gases and waste • Regulate blood pressure • Direct blood flow

16. B. Types of Blood Vessels • 1. Arteries • Blood vessels which carry oxygen-rich blood away from the heart to the body. • The aorta is the largest artery in our body • Thick walls

17. 2.Capillaries • Microscopic blood vessels which connect arteries and veins together • Where exchange of oxygen, carbon dioxide, nutrients, and waste occur • One cell layer thick

18. 3. Veins • Blood vessels which carry oxygen-poor blood from the body back to the heart. • Thin walls • Requires muscles to push blood back to the heart

20. C. Diseases • 1. Arteriosclerosis • The hardening of the arteries due to the formation of scar tissue • Leads to hypertension, heart attack, & stroke • 2. Varicose veins • Valves in the veins become weak leading to abnormal dilations in the superficial veins • 3. Phlebitis • Inflammation of a vein • Very serious because it can lead to thromboembolism and death

21. IV. Circulation of Blood in the Body • Circulation is the transportation of blood A. The goal is to • Send oxygen-poor blood to the the lungs to pick up oxygen and then • To pump oxygen-rich blood from the heart to the body cells

22. B. Three circulation pathways • Pulmonary circulation • From heart to lungs • Systemic circulation • From heart to body • Coronary circulation • From heart to heart muscle

23. 1 6 3 4 4 5 2 1 C. Pulmonary Circulation • Flow of blood from the heart to the lungs • DEOXYGENATED BLOOD must have carbon dioxide removed, so it is sent to the lungs • Body cells > • Veins > • Vena cava (1)> • R Atrium (2)> • Tricuspid valve > • R Ventricle > • Pulmonary Semilunar valve> • Pulmonary ARTERY (3) > • Lungs

24. 1 6 3 4 4 5 2 1 D. Systemic Circulation • Flow of blood from the heart to the body • OXYGENATED BLOOD coming back from the lungs is pumped to the body cells • Lungs > • Pulmonary VEINS (4)> • L Atrium > • Bicuspid (mitral) valve > • L Ventricle (5) > • Aortic Valve > • Aorta (6)> • Arteries > • Body cells

26. Happy Days: Pump your blood • http://www.youtube.com/watch?v=upctPUa6RhA

27. C. Coronary Circulation 1. Flow of blood to the heart tissues • The heart has its own nourishing circulatory system • Coronary arteries – from aorta to myocardium (heart muscle) • Cardiac veins – from the myocardium to the ventricle

28. 2. Coronary disorders a. Atherosclerosis – blockage of the arterial walls due to the build up of cholesterol that can lead to a heart attack b. Thromboembolism – blood clot that breaks away from its origin and is carried to a new location • Can lead to a heart attack if embolus blocks a coronary artery

29. Comparison of Arteries

31. 3. Prevention & Treatment a. Aspirin – reduces stickiness of platelets, therefore prevents clots b. Surgery • i. Balloon Angioplasty – tube is guided through the blood vessel to the blockage where is inflated to open up the vessel or break the clot • ii. Coronary Bypass Operation – a blood vessel from another part of the body is sutured from the aorta to the coronary artery, past the blocked area • Allows blood to flow to cardiac muscle

32. Videos • Balloon Angioplasty • http://www.youtube.com/watch?v=F_gVBK6YkPA • Coronary Bypass • http://www.youtube.com/watch?v=8nbscVKKSm8

33. V. Blood • The only fluid tissue in the human body • Taste, odor, 5x thicker than water • Color range • Oxygen-rich blood is scarlet red • Oxygen-poor blood is dull red • pH must remain between 7.35–7.45 • 5-6 Liters or about 6 quarts/body

34. A. Composition 1. Blood Plasma • Makes up 55% of blood • Composed of 90% of water • Contains nutrients, salts (metal ions), respiratory gases, hormones, proteins, waste products

35. 2. Erythrocytes – Red Blood Cells • The main function is to carry oxygen • Biconcave disks • Anucleate (no nucleus) • Outnumber white blood cells 1000:1 • Each erythrocyte has 250 million hemoglobin molecules • Iron-containing protein • Binds strongly to oxygen

36. 3. Leukocytes – White Blood Cells • Crucial in the body’s defense against disease

37. 4. Platelets • Small fragments produced from ruptured cells (megakaryocytes) • Needed for the clotting process

38. B. Blood Disorders • 1. Anemia – caused by low iron or hemoglobin • Symptoms: fatigue, dizziness, headaches, short of breath • 2. Sickle cell Anemia – recessive genetic disorder • Symptoms: fatigue, bone pain, ulcers, delayed growth, short of breath

39. 3. Hemophilia – recessive sex-linked bleeding disorder • Blood lacks clotting factors • Minor injuries can cause uncontrolled bleeding

40. VI. Physiology of the Heart A. Conduction System of the Heart • Initiates, stimulates, and coordinates the contraction of the atria and ventricles • Makes the heart an effective pump • 2 types of Nodal tissue controls the heartbeat • SA (sinoatrial) Node – found in right atrium • Initiates the heartbeat every 0.85 seconds • Serves as the pacemaker • AV (atrioventricular) Node – bottom of right atrium

41. The impulses travels throughout the ventricles to the Purkinje fibers. The impulse reaches the AV node and travels along the AV bundle. The SA nodesends out an impulse causing the atria to contract. Ventricles contract.

43. B. Cardiac Cycle & Heart Sounds • Cardiac cycle includes all the events that occur in one heartbeat • Heart beats ~70x/minute • L & R atria contract simultaneously • Atria relaxes then L & R ventricles contract simultaneously • Systole – contraction • Diastole - relaxation

44. 1. Atrial systole – 0.15 sec • Atria is systole (contracted) pumping blood into ventricles (diastole-relaxed) • 2. Ventricle Systole - 0.30 sec • Ventricle fills with blood and contracts pumping blood to the aorta and pulmonary arteries • 3. Atrial & Ventricle Diastole – 0.40 sec • Both atria & ventricles are diastole (relaxed) as blood from the body fills the atria

45. Bicuspid Valve • What is that sound? - Lup: closing of the bicuspid and tricuspid valve - Dup: closing of aortic and pulmonary valve

46. C. Measuring the Cardiac Cycle • Electrocardiograms (EKG or ECG) are used to measure the electrical rhythm of the heart’s contraction

47. PQRST Waveform

49. D. Disorders • Damage to AV node = muscles cells in the ventricles do not beat together results in a slower heart beat • Slower heart beat can lead to fibrillation • Fibrillation = lack of blood flow to the heart • Arrhythmia = irregular heart beat • Tachycardia = more than 100 beats/min • Bradychardia = less than 60 beats/min

50. Pacemaker • Used to maintain a consistent heart rate when the body’s natural pacemaker (SA node) is not properly functioning