1. Blood Vessels

2. Types of Blood Vessels
Arteries - vessels that transport blood away from the heart
Veins - return blood back to the heart
Capillaries - microscopic blood vessels that allow exchanges between blood and tissues

3. Structure of a blood vessel
Tunica externa (adventitia) - outermost layer made of loose connective tissue. Serves to anchor, protect and prevent overstretching
Tunica media - middle layer composed of smooth muscle; functions in dilation and constriction of blood vessels
Tunica interna(intima) - innermost layer made of endothelium (s.squamous epithelium)

8. Blood flow through tissues
From the heart blood flows into
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
Superior/ Inferior Vena Cava
Back to the heart

9. Arteries Elastic (conducting) arteries
Larger arteries
Muscular ( distributing) arteries
Medium arterties
Arterioles
Tiny , tiny arteries
Metarteriole

11. Capillaries Microscopic vessels that connect arterioles and venules
Walls consist of a single layer of simple squamous epithelial cells that allow the exchange of gases
Precapillary sphincters regulate blood flow
Continuous/Fenestrated capillaries

12. Veins Venules merge to form veins
Have 3 distinct layers; thinner walled than arteries due to thin tunica interna and media
Large lumens and posses valves
Varicose veins
Blood reservoir

13. Systemic Circulation The aorta and its major branches
Arterial supply to neck and head
Arterial supply to upper extremities
Arterial supply to thorax
Arterial supply to abdomen
Arterial supply to pelvic region and lower extremities

14. Systemic Veins Venous drainage of the head and neck
Major tributaries of the inferior vena cava
Venous drainage of the upper extremities
Venous drainage of the lower extremities

15. Hepatic Portal System
Routes blood from the stomach, spleen, pancreas, small and large intestines to the liver
Blood from these structures all drain into the hepatic portal vein, then into the liver
Blood is returned to the inferior vena cava via the hepatic vein

16. Fetal Circulation
Placenta - site where exchange of materials between fetus and mother occur
Umbilical arteries (2) - carry fetal blood high in CO2 / low in O2 to the placenta
Umbilical vein - returns oxygenated blood from the placenta to the fetus

17. Fetal Circulation Ductus venosus - allows blood to bypass the liver
Foramen ovale - opening in interatrial septum allowing blood to bypass the lungs Blood flows from r.atrium ->l.atrium
Ductus arteriosus - vessel connecting pulmonary artery to the aorta

18. A. Great Vessels
1. superior vena cava 2. inferior vena cava 3. pulmonary veins 4. pulmonary trunk (p. artery, p. aorta) 5. systemic aorta

20. Branches of systemic aorta
1. from ascending aorta, right and left coronary artery 2. from aortic arch, brachiocephalic artery a. right subclavian artery (1) r. axillary artery (a) r. brachial artery r. ulnar artery r. radial artery

23. Branches of systemic aorta
3. superficial and deep palmar arches (anastomoses) (b) deep brachial artery (c) posterior circumflex (2) r. vertebral artery

24. Branches of systemic aorta
b. right common carotid artery (a) r. external carotid artery (b) r. internal carotid artery c. (cat, not human) left common carotid artery (a) l. external carotid artery (b) l. internal carotid artery

27. Branches of systemic aorta
3. from aortic arch (human, not cat), left common carotid artery a. l. external carotid artery b. l. internal carotid artery

28. Branches of systemic aorta
4. from aortic arch, left subclavian artery (cat and human) a. l. axillary artery (1) l. brachial artery (a) l. ulnar artery (b) l. radial artery (c) superficial and deep palmar arches (anastomoses)

29. Branches of systemic aorta
(2) deep brachial artery (3) posterior circumflex b. l. vertebral artery
5. from descending thoracic aorta a. paired bronchial arteries b. paired intercostal arteries

30. Branches of systemic aorta
6. from abdominal aorta a. celiac trunk (1) splenic artery (2) l. gastric artery (3) hepatic artery

33. Branches of systemic aorta
b. superior mesenteric artery c. paired renal arteries d. paired gonadal arteries e. paired lumbar arteries f. inferior mesenteric artery

35. Branches of systemic aorta
g. right and left common iliac arteries (1) internal iliacs (2) external iliacs->femorals-> popliteal->tibial->dorsalis pedis-> plantar arches

38. C. Major veins
A. coronary circulation: coronary sinus B. pulmonary circulation: pulmonary veins C. hepatic portal circulation: hepatic portal vein drains 1. inferior mesenteric which drains splenic vein 2. superior mesenteric vein

40. D. Cranial Circulation:
cranial venous sinuses

41. E. Systemic Circulation:
1. superior vena cava drains a. azygos system b. right and left brachiocephalic veins c. internal jugular and subclavian vein d. external jugular and axillary e. cephalic vein (superficial) and brachial vein (deep) which drains radial, ulnar, median cubital and basilic veins

44. 2. inferior vena cava drains. a. hepatic vein. b. phrenic vein. c
2. inferior vena cava drains a. hepatic vein b. phrenic vein c. paired renal veins d. paired gonadal veins

46. e. paired common iliac veins which drain
e. paired common iliac veins which drain (1) paired internal iliac veins (2) paired external iliac veins which drain (a) femoral veins which drain popliteal veins which drain a peroneal vein b anterior and posterior tibial veins (b) great saphenous veins

49. Capillary Exchange

51. Mechanisms of Exchange
Diffusion - major method used to exchange substances such as O2, CO2, glucose, and amino acids
Vesicular transport - endocytosis and exocytosis of lipid-insoluble molecules
Bulk flow - involves filtration and reabsorption

52. Arteries Veins Pressures promoting filtration
Blood hydrostatic pressure***
Interstitial fluid osmotic pressure
Pressures promoting reabsorption
Blood colloid osmotic pressure***
Interstitial fluid hydrostatic pressure

53. Physiology of Circulation

54. Important Terms
Blood Flow
Blood pressure
Resistance

55. Blood Flow
Blood flow - is the amount of blood flowing through a tissue in a given period of time
Velocity of blood flow is inversely related to the diameter of the blood vessel
Blood flows most slowly in areas of greatest width

56. Blood Pressure
Force that the blood exerts against the walls of a blood vessels
Factors affecting BP include cardiac output, blood volume, viscosity, resistance, and the elasticity of the arteries

57. Cardiac Output CO=Stroke volume X Heart Rate
Any factor that increases SV or HR will increase blood pressure

58. Peripheral Resistance
Resistance to blood flow due to the force of friction between vessel wall and blood
Resistance affected by blood viscosity, vessel length and vessel radius

59. Sources affecting Resistance
Blood viscosity- how thick or thin the blood is. Measured by hematocrit.
Vessel length- longer the vessel, the greater the resistance, the greater the BP
Vessel radius- smaller the vessel the greater the resistance

60. Blood Volume  Blood volume ,  Blood pressure
Blood volume & blood pressure monitored by the cardiovascular center in the medulla (ANS), baroreceptors and chemoreceptors and by hormonal regulation

61. Hormonal Regulation of Blood Pressure
Renin- angiotensin pathway
Angiotensin II - powerful vasoconstrictor thus raising resistance
Stimulates secretion of aldosterone from the adrenal gland promoting sodium retention
ADH - antidiuretic hormone from the pituitary causing the kidneys to reabsorb more water

62. Hormone lowering BP ANP - atrial natriutic peptide
released by atrial cells promoting the loss of salt and water in the urine , thus  blood volume and causing vasodilation which then  blood pressure
PTH - parathyroid hormone causes vasodilation

63. Endothelin = potent vasoconstrictor responds to low blood flow
NO (nitrous oxide) = powerful vasodilator; balances endothelin and dilates vessels in response to high blood flow.

64. Normal Blood Pressure Newborn = 90/55 mm Hg Adults = 120/80 mm Hg
Old Age = 150/90
Systolic Pressure = peak pressure during systole
Diastolic pressure = lowest pressure during diastole (filling of ventricles)