The Circulatory System

1. The Circulatory System Chapter 18-19

2. The Heart • Size of your fist • In thoracic cavity between lungs • Rests on diaphragm

3. Structure -hollow, cone-shaped -enclosed in pericardium (fibrous membrane)

4. Pericardium Visceral pericardium (epicardium) -layer of pericardium that is in contact with the heart Parietal Pericardium -outer layer of pericardial sac Paricardial Cavity -layer between visceral and parietal, contains serous fluid to help reduce friction

5. Pericarditis – inflammation of pericardium -caused by bacterial or viral infections -layers stick together and interfere w/ heart movements

6. Wall of Heart Epicardium – protective layer -connective tissue covered by epithelium Myocardium – thick layer of cardiac muscle -richly supplied with blood

7. Wall of Heart Endocardium – consists of epithelium and connective tissue -many elastic and collagenous fibers

8. Chambers and Valves The heart has 4 chambers : 2 left, 2 right Atria (Atrium) – upper chambers -thinner walls -receive blood from veins, or returning to the heart

9. Chambers and Valves Ventricles – lower chambers that pump blood through arteries to the rest of the body. -thicker muscle or wall b/c they pump blood further Septum – separates the right and left sides.

10. Right Side of Heart -Right atrium receives blood from superior vena cava, inferior vena cava, and coronary sinus -Tricuspid valve guards opening between R. ventricle (chordae tendineae) and R. atria -Right ventricle pumps blood to the lungs -thinner muscular wall than left ventricle Chordae tendinae -orignates from the sm muscle tissue (papillary muscles) and projects inward from the walls of the ventricle.

11. Left side of Heart -Left atrium receives blood from the lungs through 4 pulmonary veins -Bicuspid (mitral) valve guards opening between L. atrium and L. ventricle -Left ventricle pumps blood to the rest of the body through the aorta. The R and L coronary arteries branch off of the aorta to supply the heart muscle. -thick muscular wall -aortic valve (semilunar valve) prevents blood from flowing back into heart

12. Pathway of Blood Right side receives blood low in O2 and high in CO2 Right ventricle pumps blood to the lungs (pulmonary circuit) Left side receives blood from Lungs: high in O2 and low in CO2 http://www.medtropolis.com/VBody.asp http://www.pbs.org/wgbh/nova/heart/heartmap.html

13. Heart Blood Flow 1. From superior and inferior vena cava 2. Into the R. atrium 3. Past the tricuspid valve into the R. ventricle 4. Through the semilunar valve into the pulmonary artery to the lungs 5. From the lungs through the pulmonary veins into the L. atrium 6. Through the bicuspid valve (mitral) into the L. ventricle 7. From the L. ventricle past the semilunar valve to the aorta 8. Blood is transported to the body through arteries, arterioles, and capillaries. 9. Venous blood travels back through venules and then veins O2 rich O2 poor blood

14. Blood Supply to Heart/Coronary Circulation -Heart needs a steady supply of oxygenated blood -Right and left coronary arteries branch off of aorta and supply blood to the muscle cells of the heart -Coronary sinus empties into R. atrium (carries venous blood)

15. Angina Angina http://www.bidmc.org/YourHealth/ProceduresInMotion.aspx

16. Important Things to Be Aware of!! • Angina – severe chest pain • Ischemia – reduced blood flow to tissue • Coronary Artery Disease (CAD) • – reduced blood flow to myocardial tissue due to clogged • or blocked arteries. • Atherosclerosis – hardening of arteries, calcifying of lipids • in blood vessels making them hard and • brittle. • Myocardialinfarction – tissue death often leads to heart • attack b/c blood clot or clogged. • Treatments – angioplasty, stents, bypass surgery http://www.hhmi.org/biointeractive/stemcells/video.html

19. Heart Attack http://wn.kktv.com/category/60673/medical-3d-animation-heart-attack http://www.heartinfo.org/ms/animations/13/main.html http://www.nhlbi.nih.gov/health/health-topics/topics/heartattack/causes.html http://www.hhmi.org/biointeractive/media/heart_attack-lg.mov Heart Attack, Cholesterol, Laser Angioplasty http://health.india.com/diseases-conditions/what-is-a-heart-attack-animation/

20. Heart Sounds (Dub – Dub) Lubb = 1st part of sound (systolic) -ventricles contract…empty -tricuspid and bicuspid valves close (A-V valves) Dupp = 2nd part of sound (diastolic) -ventricles relax…fill -pulmonary and aortic semi-lunar valves close *Heart murmurs – abnormal sounds that may indicate problems with valves

21. Cardiac Cycle Cardiac cycle = one complete heartbeat -Takes about .8 seconds -The atria contract while the ventricles relax -Ventricles contract while atria relax R. Ventricle lungs L. Ventricle body

22. Cardiac Cycle Cont. Sinoatrial Node (SA Node) -Small mass of tissue that stimulates contractions in the heart (interatrial fibers stimulate the left atria) -Called the pacemaker of the heart -Responsible for the rhythmic contractions -Stimulates atria to contract p565 Fig 18-11, p595 Fig 19-1

23. Cardiac Cycle Cont. Atrioventricular node – (AV Node) -Specialized muscle tissue in the floor of the R. Atrium -Internodal fibers connect the SA Node to the AV Node -Delayed impulse allows the atria to empty and ventricles to refill. -As impulse travels through the AV bundle (bundle of His) the impulse travels more rapidly

24. Cardiac Cycle Cont. -Purkinje fibers: function in transmitting the impulse from the AV bundle to ventricular muscles to contract and force the blood into the arteries -The Purkinje fibers stimulate the papillary muscles

25. Electrocardiogram (ECG) -A recording of electrical chgs occuring within the heart -Electrodes placed on the skin and connected by wires -A pen records any electrical changes

26. P Wave – depolarization of atria… “atrial contraction” QRS – depolarization of ventricles and atrial repolarization “ventricular contraction” T Wave – repolarization of ventricles http://www.getbodysmart.com/ap/circulatorysystem/heart/electricalevents/ecg/tutorial.html http://www.ecgrhythmcourse.com/look_inside.cfm P599 Fig 19-4

27. Regulation of Cardiac Cycle -Parasympathetic fibers secrete acetylcholine -slows down heart, dec rate of contractions -Sympathetic fibers secrete norepinephrine -increases rate of contractions -Cardiac center is located in medulla oblongata -receives sensory info from various parts of circulatory system -responds to anxiety, fainting, temp change, ion concentration (K+, Ca+2)

28. Blood Vessels Arteries – strong, elastic vessels that carry oxygenated blood away from heart under high pressure…exception p. artery -thick walls -arterioles : small arteries that join to capillaries Vasoconstriction – muscle fibers contract and decrease vessel diameter Vasodilation– muscle fibers relax and increase vessel diameter

29. Both tunica media and tunica adventitia are absent in veins and capillaries

30. Blood Vessels Venules & Veins Veins – deoxygenated blood to the heart..exception p. veins *thinner walls *blood reservoir *low pressure Venules – small veins, that join to capillaries. Sinuses - lg venous spaces

31. Blood Vessels Capillaries -microscopic vessels that carry blood from arterioles to venules *thin endothelium- allows for ease of transport across membranes *Blood pressure dec as the distance from the heart inc.

32. Blood Pressure -The force blood exerts against the inner walls of blood vessels Systolic pressure - maximum pressure achieved during ventricular contraction (arterial pressure). (pressure while heart is beating) Diastolic pressure - the lowest pressure that remains in the arteries before the next ventricular contraction. (resting stage between beats)

33. Ventricles are filling up/relaxed Ventricles are emptying/ contracting

34. 120 Systolic 80 Diastolic 120-139 80-89 140 or more 90 Normal Prehypertension Hypertension Pulse pressure = diff between systolic and diastolic pressures

35. Congestive heart failure – (left side failure) left ventricle decreases pumping pressure in systemic circulation which then causes fluid to build up Cardiomyopathy -is a weakening of the heart muscle or a change in heart muscle structure. It is often associated with inadequate heart pumping or other heart function abnormalities. Congenital heart disease - Congenital heart disease refers to a problem with the heart's structure and function due to abnormal heart development Aneursym – is a bulge or ballooning of the artery which can grow and burst and possibly cause death.

37. Happy Mothers Day from our Lab Friends!!!! Geogina – “Whatever” Wilber – “Whity / asian” Phil – “The Butcher’s son” Babe – “Demented” possibly TOURETTS Ethel – “Spacy” Moo The green runt Lafawnda “The best behaved” Pork chop Lunch!! ELLE – THE BOSS!!!

38. Don’t forget to wish you mother Happy Mother’s Day on Sunday!!!