1. Chapter 21 Blood Vessels

2. Direction of Flow Heart to aorta to arteries to arterioles to capillaries. Capillaries to venules to veins to vena cava to heart.

3. Arteries Veins

5. Capillaries form Microcirculation Microscopic vessels that connect arterioles to venules Found near every cell in the body but more extensive in highly active tissue (muscles, liver, kidneys & brain) entire capillary bed fills with blood when tissue is active lacking in epithelia, cornea and lens of eye & cartilage Function is exchange of nutrients & wastes between blood and tissue fluid Structure is single layer of simple squamous epithelium and its basement membrane

6. Capillaries: 1. Continuous 2. Fenestrated 3. Sinusoid

7. Venous valves

8. Blood Distribution 12% pulmonary vessels 8 % = heart 15% = systemic arteries and arterioles 5% = capillaries 60% = systemic veins and venules

10. Venous flow occurs by: 1. muscle contraction 2. respiratory pump 3. valve assistance 4. Ventricular relaxation

11. Varicose Veins Twisted, dilated superficial veins –caused by leaky venous valves congenital or mechanically stressed from prolonged standing or pregnancy –allow backflow and pooling of blood extra pressure forces fluids into surrounding tissues nearby tissue is inflamed and tender Deeper veins not susceptible because of support of surrounding muscles

12. Anastomoses Union of 2 or more arteries supplying the same body region –blockage of only one pathway has no effect circle of willis underneath brain coronary circulation of heart Alternate route of blood flow through an anastomosis is known as collateral circulation –can occur in veins and venules as well Alternate routes to a region can also be supplied by nonanastomosing vessels

14. Pulse Pressure Pulse pressure = systole - diastole MAP = diastolic pressure + pulse pressure/3 MAP = mean arterial pressure MAPB = diastole + 1/3 (systole – diastole) MAPB = mean arterial blood pressure

17. Blood Pressure Influenced by: Peripheral resistance Heart efficiency Blood viscosity Total blood vessel length Arteriole elasticity Blood volume

20. Hormones that affect BP Renin angiotensin Epinephrine and norepinephrine Antidiuretic hormone Atrial natriuretic peptide

22. Autoregulation of BP Physical changes Vasodilating and constricting chemicals

27. Major Branches of the Aorta Coronary arteries Brachiocephalic Left common carotid Left subclavian Celiac Superior mesenteric artery Renals Ovarian / testicular Inferior mesenteric

28. Minor Branches of the Aorta PericardialThoracic BronchialLumbar EsophagealSuprarenal Mediastinal Intercostal Phrenic

33. Celiac circulation

34. Abdominal arteries

44. Arterial supply and venous drainage of the liver

51. Hypertension Systole > 140 Diastole > 90 Causes: diet high in fat and sodium, obesity, older age, race, heredity, stress, and smoking.

52. Words to Learn AneurysmShock AngiogramSphygmomanometer DiureticKorotkoff sounds PhlebitisAngiogenesis PhlebotomyHypotension ThrombophlebitisOcclusion SyncopeWhite Coat Hypertension TachycardiaEdema