1. DR—Noha Elsayed 2015--2016 The Circulatory System

2. The Circulatory System: Anatomy Also called cardiovascular system – Completely closed Two circuits: – Systemic circulation in body – Pulmonary circulation in lungs

3. The Heart Muscular organ that pumps blood throughout the body Located behind sternum About size of closed fist Heart muscle is called myocardium Pericardium is membrane surrounding heart

4. The Heart Four chambers: – Two atria – Two ventricles – Each side of the heart contains one atrium and one ventricle. Atria receive blood returned to heart. Ventricles pump blood out of heart.

5. Valves of the Heart Tricuspid valve separates right atrium from right ventricle Mitral valve separates left atrium from left ventricle Pulmonary valve regulates blood flow from right ventricle to pulmonary artery Aortic valve regulates blood flow from left ventricle to aorta

6. The Cardiac Cycle Process that creates the pumping of the heart Systole= Contraction – Pumping of blood into systemic circulation Diastole=Relaxation phase of cycle

7. The Cardiac Cycle Pulse pressure = systolic pressure − diastolic pressure Afterload: pressure in aorta against which left ventricle pumps blood Stroke volume: amount of blood ejected per contraction Cardiac output = stroke volume × heart rate

8. The Vascular System Arteries carry blood away from the heart. Veins carry blood back to the heart. Arteries branch into arterioles divide into capillaries enlarge venules merge to form veins.

9. The Vascular System the heart Supplied by right and left coronary arteries Pulmonary circulation – Carries blood from right side of heart to lungs – Carries blood back to left side of heart – Carries blood from systemic circulation throughout body

10. Blood Flow Within the Heart Deoxygenated blood returns to the right atrium via superior vena cava and inferior vena cava. Freshly oxygenated blood returns to the left atrium through pulmonary veins.

11. Blood Flow Within the Heart Blood flows through mitral valve into the left ventricle. Left ventricle pumps oxygenated blood into aorta, and then to entire body

12. The Vascular System Systemic arterial circulation – Oxygenated blood leaves heart via the aorta. – Aorta distributes blood to all parts of body Systemic venous circulation – Drains deoxygenated blood and returns it to the heart. – Veins accompany major arteries, and often have the same names.

13. The Circulatory System: Anatomy

14. Heart Sounds Created by contraction and relaxation of heart and flow of blood – Heard during auscultation with stethoscope S1 and S2 are normal sounds. – S3 and S4 are not

15. The Electrical Conduction System Electrical stimulus controls mechanical pumping action Conduction system components: – Sinoatrial (SA) node – Atrioventricular (AV) node – Bundle of His – Right and left bundle branches – Purkinje fibers

16. The Electrical Conduction System

17. Regulation of Heart Function Autonomic nervous system, endocrine hormones, and heart tissue, control: – Rate of contraction (chronotropic state) – Rate of electrical conduction (dromotropic state) – Strength of contraction (inotropic state)

18. Regulation of Heart Function Baroreceptors – Respond to changes in pressure Chemoreceptors – Sense changes in chemical composition of blood Stimulation of receptors affects heart rate and contractility.

19. The Circulatory System: Physiology Pulse is created by blood pumping out of left ventricle into major arteries Blood pressure is the pressure blood exerts against artery walls. – Sphygmomano-meter measures high/low points

20. The Circulatory System: Physiology Systemic vascular resistance is how dilated or constricted the blood vessels are. – Average adult has about 5 L of blood – Infants 300 mL, children 2 to 3 L

21. Normal Circulation in Adults Circulatory system normally adjusts and readjusts automatically Perfusion is the circulation of blood in an organ or tissue in adequate amounts. Loss of blood pressure means cells, tissues, and whole organs may die. – Loss of normal blood indicates blood is no longer circulating effectively to every organ. Shock – Inadequate circulation involving entire body

22. Inadequate Circulation in Adults Heart automatically adjusts to lower blood volume as patient loses blood – Heart attempts to maintain adequate pressure by constricting vessels – Heart pumps more rapidly to circulate lower amount of blood Pulse increases as pressure falls.

23. The Distribution of Blood Hydrostatic pressure – Moves plasma and nutrients from capillaries into interstitial space Oncotic pressure – Moves plasma and wastes from interstitial space into capillaries

24. The Vascular System

25. Arteries of the head and neck Arteries of the upper extremity

26. The Vascular System Branches of the abdominal aorta

27. The Vascular System Arteries of the lower extremity Arteries of the pelvis and thigh

28. The Vascular System Veins of the head and neck

29. The Vascular System Veins of the upper extremity Hepatic portal system

30. The Vascular System Veins of the lower extremity