1. Co 23 Chapter 23 Vessels and Circulation

2. Arteries travel away from the heart –Arterioles are smallest arteries Capillaries are smallest vessels –one red blood cell wide –thin walls so oxygen, carbon dioxide, and water can move in or out of vessels Veins return to the heart –Venules are the smallest veins Types of Blood Vessels 2

3. Fig. 23.1 Walls of a Blood Vessel Tunica media Valves Artery Vein Tunica externa Vasa vasorum Internal elastic lamina Subendothelial layer Endothelium Tunica intima Arteries and veins have 3 tunics (layers) Tunica intima is inner layer –endothelium (simple squamous) –areolar connective tissue –in muscular arteries, includes internal elastic lamina

4. Fig. 23.1 Walls of a Blood Vessel Tunica media Valves Artery Vein External elastic lamina Tunica media –layers of smooth muscle –in muscular arteries, includes external elastic lamina

5. Fig. 23.1 Walls of a Blood Vessel Tunica media Artery External elastic lamina Tunica media in arteries –thickest layer; mostly smooth muscle –enables vasoconstriction and vasodilation Lumen

6. Fig. 23.1 Walls of a Blood Vessel Tunica media Artery Vein Tunica externa Vasa vasorum Tunica intima Tunica externa –areolar connective tissue with elastic and collagen fibers –anchors vessel to other structures –includes vasa vasorum, blood supply for very large blood vessels –thickest layer in veins

7. Fig. 23.1 Walls of a Blood Vessel Tunica media Lumen Valves Artery Endothelium Basement membrane Capillary Capillary bed Vein Tunica externa Vasa vasorum External elastic lamina Internal elastic lamina Subendothelial layer Endothelium Tunica intima Arteries –lumen is narrow –lots of elastic and collagen fibers in tunics stay open; withstand changes in blood pressure Veins –lumen is wide –valves within lumen prevent blood flow in wrong direction

8. Fig. 23.1 Walls of a Blood Vessel Lumen Artery Endothelium Basement membrane Capillary Capillary bed Vein Capillaries – connect arteries and veins –only have tunica interna thin walls enable gas exchange

9. Fig. 23.2 Tunica intima Tunica media Tunica externa Vein Blood in the lumen Artery LM 100x Tunica intima Tunica media Tunica externa

10. Types of Arteries Fig. 23.3 Elastic artery Arteries Pulmonary trunk (artery) Ascending aorta Tunica intima Tunica media Tunica externa Descending aorta Elastic arteries –largest –AKA conducting arteries— conduct blood from heart to smaller arteries –ex. aorta, pulmonary, brachiocephalic, common carotid, subclavian, common iliac arteries

11. Types of Arteries Elastic arteries –very thick tunica media with elastic fibers throughout –elastic fibers enable stretching during ventricular contraction, return to original shape Fig. 23.3 Lumen LM 100x 23.4 (a) Elastic artery Tunica intima Tunica media Elastic fibers throughout tunica media Tunica externa

12. Types of Arteries Muscular arteries –AKA distributing arteries—distribute blood to body organs and tissues –most named arteries, ex. brachial, anterior tibial, coronary, inferior mesentery Fig. 23.3 Tunica intima Internal elastic lamina Tunica media External elastic lamina Tunica externa Muscular artery

13. Fig. 23.3 Tunica intima Tunica media Tunica externa Arteriole Types of Arteries Arterioles –smallest –larger arterioles have 3 tunics; small arterioles have endothelium and one layer of smooth muscle

14. Fig. 23.3 Endothelium Basement membrane Capillary Capillaries Connect arterioles to venules usually 1 mm long, 8-10 micometers wide –diameter of one red blood cell –erythrocytes must pass through one at a time

15. Fig. 23.3 Capillaries Basement membrane and endothelium only –gases and nutrients diffuse easily across capillary wall into extracellular fluid –gases then move from ECF to cells

16. Fig. 23.5 Endothelium Venous end True capillaries Arterial end Smooth muscle cells Metarteriole Arteriole Postcapillary venule Thoroughfare channel Relaxed precapillary sphincters (a) Sphincters relaxed; capillary bed well perfused Capillary beds Metarteriole flows into capillary bed, venule flows out White blood cells travel through metarteriole, bypass capillaries

17. Fig. 23.5 (b) Sphincters contracted; blood bypasses capillary bed Contracted precapillary sphincters Capillary beds Precapillary sphincter is circle of smooth muscle around proximal end of capillary –can cut off blood flow –cycle on and off to meet tissue’s nutrient need

18. Fig. 23.3 Endothelium Elastic artery Arteries Pulmonary trunk (artery) Ascending aorta Tunica intima Tunica media Tunica externa Tunica intima Internal elastic lamina Tunica media External elastic lamina Tunica externa Tunica intima Tunica media Tunica externa Arteriole Muscular artery Descending aorta Inferior vena cava Large vein Veins Superior vena cava Tunica intima Valve Tunica media Tunica externa Tunica intima Valve Tunica media Tunica externa Tunica intima Tunica media Tunica externa Venule Small to medium- sized vein Basement membrane Capillary

19. Fig. 23.3 Tunica intima Tunica media Tunica externa Venule Types of Veins Venules –smallest veins –travel with and correspond to arterioles –smallest are postcapillary venules drain capillaries similar to capillaries but slightly wider lumen –largest venules have all 3 tunics Postcapillary venule

20. Fig. 23.1 Tunica media Lumen Valves Tunica externa Vasa vasorum Subendothelial layer Endothelium Tunica intima Veins –Lumen is wide –Thick tunica externa –Contain valves to prevent backflow of blood formed from tunica intima strengthened by elastic and collagen fibers Vein

21. Fig. 23.3 Inferior vena cava Large vein Veins Superior vena cava Tunica intima Valve Tunica media Tunica externa Tunica intima Valve Tunica media Tunica externa Small to medium- sized vein Veins Large veins –Travel with and correspond to elastic arteries Small to medium-sized veins –Travel with and correspond to muscular arteries

22. Fig. 23.7 Blood flow from tissues To heart Increased pressure opens valve Contracted skeletal muscles Valve closed (to prevent blood backflow) Vein Skeletal muscle pump Contraction of muscles squeezes veins, forcing blood through Works more efficiently when a person is active When a person is inactive, blood may pool in lower extremities

23. Fig. 23.7 (b) Inhalation Increases blood flow into thoracic veins Decreased intrathoracic pressure Diaphragm contracts Blood moves superiorly Increased intra-abdominal pressure Compression Thoracic cavity Abdominopelvic cavity Respiratory pump Exhalation Increases blood flow into heart and abdominal veins Increased intrathoracic pressure Diaphragm relaxes Decreased intra-abdominal pressure Release of compression Respiratory pump contraction of diaphragm compresses abdominal cavity, squeezes vessels, pushes blood through relaxation of diaphragm decreases pressure in abdominal cavity, draws blood into vessels of abdomen

24. Fig. 23.3 Endothelium Elastic artery Arteries Pulmonary trunk (artery) Ascending aorta Tunica intima Tunica media Tunica externa Tunica intima Internal elastic lamina Tunica media External elastic lamina Tunica externa Tunica intima Tunica media Tunica externa Arteriole Muscular artery Descending aorta Inferior vena cava Large vein Veins Superior vena cava Tunica intima Valve Tunica media Tunica externa Tunica intima Valve Tunica media Tunica externa Tunica intima Tunica media Tunica externa Venule Small to medium- sized vein Basement membrane Capillary

25. Page 688 Varicose veins Veins with nonfunctional valves Blood pools in one area, vein swells Causes: genetics, aging, long periods of standing, obesity, pregnancy Compression stockings prevent the vessels from swelling Treatment: –sclerotherapy—irritant injected into vein; vein scars and seals off –phlebectomy—vein removal

26. From heart, blood pumped through ascending aorta Right and left coronary arteries branch off first Brachiocephalic trunk is first of 3 large branches on aortic arch Branches into –right common carotid: supplies right side of head and neck –right subclavian: supplies right arm and some thoracic structures Systemic circulation Right common carotid artery Right subclavian artery Left common carotid artery Left subclavian artery Brachiocephalic trunk Right coronary artery Left coronary artery

27. Left common carotid is next branch off aortic arch –supplies left side of head and neck Left subclavian is last –supplies left arm and some thoracic structures After arch, aorta becomes descending aorta Systemic circulation Right common carotid artery Right subclavian artery Left common carotid artery Left subclavian artery Brachiocephalic trunk Right coronary artery Left coronary artery Ascending aorta Descending aorta Aortic arch

28. Fig. 23.10ab (a) Arteries, right lateral view Common carotid artery Branches of common carotid artery Internal carotid artery External carotid artery Common carotid artery splits above thyroid cartilage –internal carotid artery supplies internal skull structures –external carotid artery supplies external skull structures Head and neck circulation

29. Fig. 23.10ab (b) Veins, right lateral view Right subclavian vein Right brachiocephalic vein Internal jugular vein External jugular vein Veins from head and neck drain through internal and external jugular veins, into subclavian, then brachiocephalic vein Systemic circulation

30. Fig. 23.11 Superior sagittal sinus Inferior sagittal sinus Cavernous sinus Superior petrosal sinus Inferior petrosal sinus Ophthalmic veins Straight sinus Occipital sinus Marginal sinuses Transverse sinus Sigmoid sinus Internal jugular vein (b) Cranial and facial veins, right superior anterolateral view Facial vein Dural venous sinus system drains into internal jugular veins Venous draining from head

31. Fig. 23.19ab Subclavian artery Axillary artery Subclavian arteries supply blood to upper limbs After passing over first rib, becomes axillary artery After passing teres major muscle, becomes brachial artery Brachial artery

32. Fig. 23.19ab Brachial artery Ulnar artery Radial artery Deep palmar arch Superficial palmar arch Digital arteries (a) Arteries of right upper limb In cubital fossa, brachial artery splits into radial artery and ulnar artery anastomose into two arches in palm: superficial palmar arch and deep palmar arch digital arteries supply fingers

33. Fig. 23.19ab Radial veins Cephalic vein Basilic vein Ulnar veins Dorsal venous network Superficial veins Deep veins (b) Veins of right upper limb On hand dorsal venous network drains into basilic vein and cephalic vein basilic veins becomes axillary vein in armpit cephalic vein joins inferior to subclavian Median cubital vein connects cephalic and basilic veins usual site for blood donations or samples Median cubital vein

34. Fig. 23.19ab On hand superficial and deep palmar venous arches drain into 2 radial veins and 2 ulnar veins (deep) Radial and ulnar veins merge at cubital fossa to form 2 brachial veins Radial veins Cephalic vein Basilic vein Ulnar veins Superficial venous arch Superficial veins Deep veins Deep venous arch Brachial veins

35. Fig. 23.19ab Subclavian vein Axillary vein Cephalic vein Basilic vein Brachial veins Radial veins Cephalic vein Median cubital vein Basilic vein Ulnar veins Deep palmar venous arch Superficial palmar venous arch Dorsal venous network Brachial veins merge to form axillary vein Basilic vein joins at about level of teres major Cephalic vein joins near clavicle After passing lateral border of first rib, renamed subclavian vein

36. Fig. 23.12 Descending thoracic aorta Left renal artery Common iliac artery Left internal iliac artery Left external iliac artery Left femoral artery Right renal artery Descending abdominal aorta Descending thoracic aorta becomes descending abdominal aorta below diaphragm Major arteries

37. Fig. 23.12 Renal arteries supply kidneys Gonadal arteries supply gonads Blood returns through veins with same names Renal veins drain kidneys Gonadal veins drain gonads Left renal artery Right renal artery Left gonadal artery Right gonadal artery

38. Fig. 23.12 Common iliac artery Left internal iliac artery Left external iliac artery Left femoral artery Above sacrum, aorta splits into common iliac arteries Common iliac branches into internal and external iliac arteries Below inguinal ligament, external iliac artery renamed femoral artery Major arteries

39. Fig. 23.20b Posterior view Femoral vein Popliteal vein curves to anterior thigh, becomes femoral vein, becomes external iliac vein above inguinal ligament External iliac vein

40. Fig. 23.13 Left common iliac vein Left external iliac vein Left internal iliac vein Left femoral vein Inguinal ligament External iliac vein and internal iliac vein merge into common iliac vein Left and right common iliac veins merge to form inferior vena cava Inferior vena cava

41. Digestive System

42. Fig. 23.15 celiac trunk branches off aorta arteries that branch off celiac trunk supply stomach, part of duodenum, liver, part of pancreas, spleen Pancreas Duodenum Spleen Stomach Esophagus Celiac trunk Liver

43. Abdominal Arteries Inferior vena cava Descending abdominal aorta Superior mesenteric artery Spleen Stomach Celiac trunk Left gastric artery Splenic artery Common hepatic artery Hepatic artery proper Right gastric artery Liver Celiac trunk branches from abdominal aorta, branches into: Left gastric artery supplies stomach Splenic artery supplies spleen Common hepatic artery supplies liver

44. Fig. 23.15 Transverse colon Superior mesenteric artery Celiac trunk Descending colon Inferior mesenteric artery Superior mesenteric artery located inferior to celiac trunk supplies most of small intestine, pancreas, proximal large intestine

45. Fig. 23.15 Transverse colon Superior mesenteric artery Celiac trunk Descending colon Inferior mesenteric artery Inferior mesenteric artery branches from aorta superior to common iliac arteries supplies inferior colon and rectum

46. Hepatic portal vein Superior mesenteric vein Inferior mesenteric vein Splenic vein Hepatic portal vein receives blood from GI tract; formed from inferior mesenteric vein drains from distal large intestine splenic vein drains spleen superior mesenteric vein drains small intestine and part of large intestine Liver Fig. 23.16

47. Page 702 Hepatic portal vein Superior mesenteric vein Splenic vein Inferior mesenteric vein The configuration of the veins of the hepatic portal system resembles the side view of a chair.

48. Fig. 23.16 Blood leaves liver through hepatic veins, drains into inferior vena cava Splenic vein Diaphragm Liver Inferior vena cava Hepatic veins Hepatic portal vein

49. Page 706 LM 20xLM 50x Blood in narrowed lumen Lumen Normal artery Atherosclerotic artery Atheroma occluding lumen Affects elastic and muscular arteries Tunica intima thickens; lumen narrows Causes: injury to tunica intima: infection, trauma, or hypertension injury attracts white blood cells and immune response cholesterol proteins (LDL and VLDL) enter tunica intima, stick to vessel wall other cells attracted, create foam cells, which develop into plaques Atherosclerosis

50. Page 706 1 ArteryAtheromaCatheter An uninflated balloon and compressed stent are passed through a catheter to the area of the artery that is obstructed. 2 Stent Balloon Balloon inflates, which expands the stent and inserts it in place and also compresses the atheroma. 3 The stent remains in the vessel as the balloon is deflated and the catheter is withdrawn. Treatment: angioplasty Stent inserted into artery and expanded Stent compresses plaques, becomes new wall of artery, expanding artery

52. Page 713 Abdominal aneurysm Localized, abnormal dilation of blood vessel May be caused by atherosclerosis Felt as pulsating mass if in abdominal aorta Visualized by x-ray or ultrasound If ruptures, rarely survived Aneurysm

53. Page 713 Blood flows through stent graft Endovascular stent graft in place Aorta Abdominal aortic aneurysm Plaque Common iliac artery Stent graft released from catheter Abdominal aneurysm Catheter insterted into femoral artery Treatment possible for abdominal aneurysm Stent graft replaces inner artery Aneurysm