1. Lab 4: Heart sounds and vessels

2. Overview Review Heart sounds Blood supply to the heart Blood vessels –Veins Portal systems New lab website: http://isu.indstate.edu/~jowhitak/cmritzi.htm Practical lab review: Sunday 2-5 pm

3. Review How do volume and pressure in the ventricles change during atrial contraction? What region of the heart controls the electrical signal through the heart? Which standard limb lead has a negative lead on the right arm and a positive lead on the left arm?

4. Overview Review Heart sounds Blood supply to the heart Blood vessels –Veins Portal systems

5. Heart sounds “lubb-dubb” S1: longer and louder S2: softer and shorter S3: found in children and juveniles S1 & S2 occur in conjunction with the opening and closing of valves Actually caused by turbulence of blood

6. Valvular troubles Valvular Insufficiency: valve failure causing backwards flow Any defect in the valves can lead to heart failure Defective valves can be replaced with artificial valves or with pig valves

7. Valvular Troubles (cont) Mitral valve prolapse: tri- or bicuspid cusps bulge back into the atrium. –Symptoms: chest pain, fatique, shortness of breath –Cause: hereditary Valvular Stenosis: cusps of the valve are stiff and opening is constricted by scar tissue –Results from autoimmune disease –Causes enlarged heart –Blood moving backwards through the valves causes a heart murmur

8. Break for Dynamic Human

9. Blood supply to the heart muscles The endocardium prevents blood from seeping through the heart How is blood supplied to the myocardium and the pericardium? –Coronary arteries originating from the aortic arch

10. Arteries in the heart Aorta Right Coronary Left Coronary Marginal artery Circumflex Artery Posterior IV Artery Anterior IV Artery Anastomoses

11. Point where two arteries join to reach a common destination If one artery becomes blocked, the other can take blood to the appropriate destination

12. Arteries of the heart

13. Veins in the heart Greater Cardiac VeinSmall Cardiac Vein Middle Cardiac Vein Coronary Sinus Right Atrium

14. Coronary Veins

15. Artherosclerosis Contributes to over 710,000 heart attack and stroke, and peripheral vascular disease deaths each year. Fatty blockage in coronary artery

16. Artherosclerosis Cause: Abundance of low-density lipids and defective receptors for LDL in the coronary arteries. –LDL: cholesterol, free fatty acids and phospholipids –Arterial cells with defective receptors will take in too much cholesterol –Results in obstruction of the arterial lumen

17. Cardiac Ischemia and Infarction Ischemia: Loss of blood flow Infarction: Death of myocardial cells; heart attack Cause: Artheriosclerosis blocks a cardiac artery. The downstream region does not receive enough oxygen causing cell death. The death of these cells weakens the heart wall disrupting electrical pathways leading to fibrillation.

18. Break for Dynamic Human

19. Overview Review Heart sounds Blood supply to the heart Blood vessels –Veins Portal systems

20. Blood Vessels Arteries Capillaries Veins

21. Structure of Blood Vessels Tunica externa: loose connective tissue Tunica media: smooth muscle, elastin, collagen Tunica interna: endothelium

22. Types of Arteries Conducting (elastic) –Passively accommodate blood flow Distributing (muscular) –High smooth muscle content –Deliver blood to specific organs Arterioles –Control blood flow –Link to capillaries

23. Capillaries Pre-capillary sphincters –Open and close capillary beds –¾ of all capillaries are ususally closed Structure: endothelium only

24. Types of Capillaries Continuous: uninterrupted tube –Only allow small solutes such as glucose to enter –Blood-brain barrier Fenestrated: riddled with pores –Allow rapid passage of small molecules –Hold proteins in the vessels –Important in organs that engage in rapid filtration

25. Veins Venules: Collect blood from capillaries –Porous Veins: –Lower pressure than the arteries –Thinner walls (little tunica media or externa) but larger lumens –Walls expand easy and accomadate more blood than arteries

26. How does blood travel in veins? 1. Messaging action of skeletal muscle 2. Pressure gradient in the body: –Positive pressure in the abdominal cavity and negative in the thoracic cavity draws blood up

27. Venous Valves 3.Venous valves prevent backflow Failure of valves results in varicose veins

28. Special Circulations: Portal Systems Portal systems: Blood flows between two consecutive capillary beds before returning to the heart Artery Capillary 1 Capillary 2 Vein

29. Hepatic Portal System Connects capillaries of the intestines to capillaries of the liver Delivers newly absorbed nutrients to the liver

30. Hypothalamo-hypophyseal portal system Connects hypothalamus to pituitary gland Responsible for transporting hormones

31. Dynamic Human

32. Overview Review Heart sounds Blood supply to the heart Blood vessels –Valves Portal systems Cat heart and human heart

33. Cat Dissection Finish identifying arteries and veins Remove cat heart and dissect in half –Valves and chambers –Chordae Tendinai –Coronary Arteries