The Cardiovascular System

1. The Cardiovascular System • The cardiovascular system includes the heart and blood vessels (arteries, veins, capillaries) • A functional cardiovascular system is vital to survival Animation

2. HEART • hollow, muscular pump found between the lungs • main function is to propel blood throughout the body • An adult heart pumps ~4,000 gal (~7,000 L) of blood daily

4. Structure of Heart • The pericardium is a double layered sac that encloses the heart

5. The pericardium consists of: • visceral pericardium - inner layer that covers the entire heart; also known as the epicardium • parietal pericardium - outer layer; tough fibrous sac • A small amount of serous fluid lies between the two layers to prevent friction Visceral Pericardium (epicardium) Parietal Pericardium

6. Walls of the Heart • Epicardium – outermost layer • Myocardium – thick middle layer; responsible for the pumping action of the heart • Endocardium - smooth inner layer; continuous with the inner lining of blood vessels

7. Heart Chambers & Valves • The heart has four chambers enclosed by thick, muscular walls • The upper part is divided into right and left atria, which receive blood entering the heart • The bottom is divided into right and left ventricles, which pump blood out of the heart

8. The interventricular septum acts as a wall that separates the right side of the heart from the left side Interventricular Septum

9. Cardiovascular SystemNotes Page 1 Class Work • Chapter 13 vocabulary

10. The left side of the heart is thicker and stronger than the right side because the left side supplies blood to all body tissues • Right side sends blood to the lungs

11. Valves of the heart open and close to control and ensure one way blood flow through the heart • tricuspid valve separates the right atrium and right ventricle • (bicuspid) mitral valve separates the left atrium and left ventricle See Your Heart Valves at Work Animation

12. MVP (mitral valve prolapse) – mitral valve does not close properly, which causes blood to flow backwards into left atrium • Symptoms include fatigue and chest pain

13. The heartbeat is produced by the closure of valves when blood is pushed through chambers of the heart Animation

14. Blood Flow through the Heart • Blue = oxygen poor blood; Red = oxygen rich blood • Carbon dioxide is dropped off and oxygen is picked up in the lungs • Oxygen is dropped off and carbon dioxide is picked up at the capillaries right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → arteries → arterioles → capillaries → venules → veins → superior and inferior vena cava→ back to right atrium

15. The coronary arteries supply blood to heart muscle • right coronary artery supplies both left and right sides of the heart • left coronary artery supplies left side of the heart

16. Plaque may build-up in a coronary artery at the site of a tear in the lining of the vessel

17. Animation • A heart attack or acute myocardial infarction (MI) occurs when one of the coronary arteries becomes blocked by spasm or by clot formation • The blockage results in damaged tissue and a permanent loss of contraction of this portion of the heart muscle

18. Symptoms of a possible heart attack include chest pain and pain that radiates down the shoulder and arm.

19. Coronary artery disease is a narrowing of the small blood vessels that supply blood and oxygen to the heart Animation Directional Coronary Atherectomy (DCA) is a minimally invasive procedure to remove the blockage from the coronary arteries and allow more blood to flow to the heart muscle and ease the pain caused by blockages.

20. Percutaneous transluminal coronary angioplasty (PTCA) is a minimally invasive procedure to open up blocked coronary arteries, allowing blood to circulate unobstructed to the heart muscle. Animation

21. Angina is a specific type of pain in the chest caused by inadequate blood flow through the coronary vessels of the myocardium Coronary Artery Bypass Graft Animation

22. Atherosclerosis is another disorder of the arteries. • Fat, cholesterol, and other substances collect in the walls of arteries, • which can damage artery walls and block blood flow. • These plaque deposits severely restricted blood flow in the heart muscle, resulting in chest pain.

23. BLOOD VESSESLS • Arteries • Veins • Capillaries

24. Vasoconstriction is constriction or narrowing of a blood vessel. • When a blood vessel constricts, the flow of blood is restricted or slowed.

25. Arteries carry blood away from the heart; thickest blood vessels • All arteries, with the exception of the pulmonary arteries, carry oxygenated (oxygen-rich) blood. • The pulmonary artery carries oxygen-poor blood from the right ventricle to the lungs. • Arterioles are small arteries that connect to capillaries.

26. The aorta is the largest artery • The aorta originates in the left ventricle of the heart and carries oxygen rich blood to the rest of the body.

27. The carotid arteries deliver oxygen-rich blood to the head and brain; located in the neck • The jugular veins return oxygen-poor blood from the head and brain to the heart.

28. An aneurysm is a sac-like protrusion of an artery caused by a weakened area within vessel wall • If a cerebral (brain) aneurysm ruptures, the escaping blood within the brain may cause severe neurologic complications or death. • A person who has a ruptured cerebral aneurysm may complain of the sudden onset of "the worst headache of my life“.

29. Abdominal aortic aneurysm involves a widening, stretching, or ballooning of the aorta • There are several causes of abdominal aortic aneurysm, but the most common results from atherosclerotic disease • As the aorta gets progressively larger over time there is increased chance of rupture. Animation

30. Blood Pressure is the measurement of force applied to the artery walls The pressure is determined by: Force behind blood Amount of blood pumped Size and flexibility of the arteries Animation

31. HEART ACTIONS Atrial Systole – atria contract Ventricular diastole – ventricles relax • Normal blood pressure – 120/80 • Hypertension is a disorder characterized by chronically high blood pressure (exceeding 140/90) • Hypertension is called "the silent killer" because it often causes no symptoms for many years, even decades, until it finally damages critical organs

32. BLOOD PRESSURE (BP) 2 Factors: • Cardiac output: rate of blod flow produced by the heart • Systemic vascular resistance (SVR): the resistance of the blood vessels to blood flow • BP = cardiac output x SVR • So what two factors could serve to increase blood pressure? Why would BP increase with age?

33. BLOOD PRESSURE CONTROL: • Autonomic nervous system responses • Baroreceptors – pressure sensitive nerve endings in the carotid sinus and aortic arch • Decreased BP causes activation of the sympathetic nervous system • Capillary shift mechanism – low BP makes fluid move from interstitial space into circulation • Hormonal responses – • Sympathetic stimulation → adrenaline/noradrenaline • Renin and angiotensin produced by kidney → vasoconstriction AND fluid retention • Kidney and fluid balance mechanisms

35. Hypotension • low blood pressure • symptoms include lightheadedness, dizziness, and fainting • Low blood pressure is blood pressure that is low enough that the flow of blood to the organs of the body is inadequate • Unlike high blood pressure, low blood pressure is defined primarily by signs and symptoms of low blood flow not by a specific blood pressure number • Common causes of low blood pressure include a reduced volume of blood, heart disease, and medications

36. Veins are blood vessels that return blood to the heart • All veins, with the exception of the pulmonary vein, carry deoxygenated (oxygen poor) blood • Veins: • are not as strong as arteries • are thinner and less flexible than arteries • contain valves to prevent backflow of blood • Venules are small veins that connect to capillaries • Lumen of the vein  • Valve

37. Superior Vena Cava • The superior and inferior vena cava function to return oxygen poor blood to right atrium • The pulmonary vein returns oxygen-rich blood from the lungs to the left atrium Pulmonary Veins Inferior Vena Cava

38. Varicose veins are enlarged, twisted, painful superficial veins resulting from poorly functioning valves; usually occur in the veins of the legs

39. Jugular Vein – located in the neck; drain blood from the head, brain, face and neck; joins the subclavian vein • Brachiocephalic Vein - two veins that drain blood from the head, neck, and upper limbs; unite to form the superior vena cava

42. PICC Line – Peripherally Inserted Central Catheter

44. In medicine, a port is a small medical appliance that is installed beneath the skin. A catheter connects the port to a vein. • Under the skin, the port has a septum through which drugs can be injected and blood samples can be drawn many times, usually with less discomfort for the patient than a more typical "needle stick".

45. Hickman Catheter

47. The capillaries are networks of tiny, thin blood vessels that connect arterioles to venules • Gases, nutrients, and metabolic by-products (CO2) are exchanged in capillaries Capillaries are so small that it would take 10 to equal the thickness of a human hair

48. Cardiac Conduction System • The sinoatrial node (SA node) is a group of cells that generates electrical current; these "sparks" cause the right atrium to contract • The SA node is located in the right atrium; called the pacemaker • The SA node sets the pulse rhythm Animation

49. A pacemaker is a battery-operated electronic device which is inserted under the skin to help the heart beat regularly and at an appropriate rate The pacemaker has leads that travel through a large vein to the heart, where the wires are anchored The leads send the electrical impulses to the heart to tell it to beat

50. The atrioventricular node (AV node), located between the right atrium and right ventricle, is the secondary pacemaker • The AV node sets the rhythm of your heart contractions • The AV node receives impulses from the SA node and delays the signal, giving the atrium time to contract first • If the atrium and the ventricle contracted at the same time, the ventricles would push out their blood before they were totally full, resulting in low blood pressure