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ABDOMINAL VESSELS

ABDOMINAL VESSELS. I. Introduction/General Information A. Uses for ultrasound 1. Screening procedure for abdominal abnormalities 2. Localize/Characterize masses 3. Measurement, rate, direction of blood flow via Doppler .

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ABDOMINAL VESSELS

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  1. ABDOMINAL VESSELS

  2. I. Introduction/General Information • A. Uses for ultrasound • 1. Screening procedure for abdominal abnormalities • 2. Localize/Characterize masses • 3. Measurement, rate, direction of blood flow via Doppler

  3. General Information, continued … B. Heart: 1. CVT used on adults 2. Ultrasound used in utero • C. Abdominal vessels • 1. Abdominal aorta • a. Ultrasound can delineate contour, course & size

  4. General Information, continued … b. Can evaluate entire course c. Used to diagnose, follow progress of aneurysms d. Can distinguish between normal and aneurysm aortic pulsations

  5. Abdominal Vessels, continued … 2. Celiac axis (trunk, artery) a. First unpaired branch off abdominal aorta (~ L-1) b. Originates from ventral surface c. Gives rise to splenic, common hepatic, & left gastric arteries

  6. Arteries of the Abdominal Aorta Figure 19.11

  7. Abdominal Vessels, continued … 3. Superior Mesenteric Artery a. Second, unpaired branch of abdominal aorta b. Originates ~ lower L-1 body c. 1 – 2 cm below celiac axis d. Supplies small intestines, pancreas, omentum, ascending and transverse colon

  8. Arteries of the Abdominal Aorta Figure 19.11

  9. Abdominal Vessels, con’t… 4. Inferior Mesenteric Artery a. Arises just above the bifurcation of the aorta (~L-3/4) b. Last unpaired branch of aorta c. Supplies jejunum, descending and sigmoid colon, rectum

  10. Distribution of the Superior and Inferior Mesenteric Arteries Figure 19.13

  11. Abdominal Vessels, continued … 4. Renal arteries a. First major paired branches from aorta b. Arise opposite each other 1-2 cm below SMA (~L-2) c. Multiple renal arteries occur in 20% of patients

  12. Renal Arteries Figure 19.11

  13. Abdominal Vessels, continued … 5. Common Hepatic Artery a. Right branch of celiac a. b. Continues to GDA, then… 6. Proper Hepatic Artery a. Branches within liver b. Begin at ~porta hepatis

  14. Blood Supply to Liver

  15. Abdominal Vessels, continued … 7. Inferior Vena Cava a. Formed at ~ L-5 b. by union of Common Iliac Veins c. Largest vein in body d. Dilation may be due to: 1. right-sided CHF 2. Portal hypertension

  16. Major Veins of the Abdomen L-5 Figure 19.21

  17. Abdominal Vessels, continued … 8. Veins of Portal Circulation a. SMV: joins with splenic vein 1. runs parallel to SMA 2. On right side of abdomen b. IMV: terminates in splenic vein c. Portal Vein: enters liver

  18. Veins of the Hepatic Portal System Figure 19.23

  19. Abdominal Vessels, continued … d. Renal Veins – run parallel to renal arteries

  20. Major Veins of the Abdomen Figure 19.21

  21. Veins of the Right Lower Limb and Pelvis e. Femoral Veins - run parallel to femoral arteries f. Popliteal Veins – run parallel to popliteal arteries Figure 19.24a

  22. II. Detailed Anatomy • Arteries • 1. Size: • a. ~ 2.5 cm – 0.5 mm • b. inside diameter • c. Arbitrary designation • 2. Structure: 3 coats or tunics

  23. Detailed Anatomy, con’t… • a. Tunica intima • 1. aka: tunica interna • 2. innermost layer • 3. = endothelium • 4. thin: 1 cell layer + basement membrane

  24. Vascular Tunics: Tunica Intima Tunica Intima Artery Capillary Vein

  25. Structure, Arteries, continued … b. Tunica media 1. thickest layer 2. smooth muscle & connective tissue (mostly elastic) 3. in lamina 4. fibers circularly arranged around lumen

  26. Vascular Tunics: Tunica Media Tunica Media

  27. Structure arteries, continued … c. Tunica externa 1. thinner than media 2. thicker than intima 3. white fibrous C. T. 4. A few smooth muscle fibers, arranged longitudinally

  28. Vascular Tunics: Tunica Externa Tunica Externa

  29. Arteries, continued … 3. Variability of arteries a. larger elastic arteries: 1. aorta, pulmonary, carotids 2. have thicker tunica intima 3. increased elastic tissue

  30. Arteries, variability, continued … 4. very thick tunica media a. smooth muscle b. obscured by elastic tissue 5. tunica externa is a. thin but strong b. limits stretch

  31. Structure, arteries, continued 6. Serve as “shock absorbers” a. expand & contract b. accommodate the pressure from pumping of the heart c. Maintain blood flow

  32. Structure, arteries, continued 7. arteriosclerosis leads to: a. decreased elasticity b. increased blood pressure c. High B.P., aneurysm, rupture of vessels

  33. Variability, Arteries, continued … b. Muscular arteries 1. farther from the heart 2. tunica media a. more smooth muscle b. Less elastic tissue c. controlled by ANS

  34. Elastic vs. Muscular Arteries Elastic Artery Muscular Artery

  35. Variability, Muscular Arteries, continued … 3. actively influence blood flow, pressure 4. ANS: a. triggers smooth muscle contraction b. Sympathetic and parasympathetic responses

  36. Variability, arteries, continued … 5. have capacity to establish collateral circulation 6. Especially coronary arteries 7. contract when injured a. ANS reaction b. Prevents blood loss

  37. Detailed anatomy, continued … • B. Arterioles: small arteries < 0.5 mm • 1. Lie close to capillary beds • 2. Muscular • 3. Primary function: regulate capillary blood flow • 4. Allows for exchange of materials between blood and tissues

  38. Detailed anatomy, continued … • C. Capillaries (sinusoids) • 1. Size: 1 mm long x 10 micrometers diameter • 2. Structure • a. Wall: 1 cell layer thick (endothelium) • b. inner surface contacts blood

  39. Blood Vessel Anatomy: Capillaries Capillary

  40. Capillaries, continued … c. outer surface rests on basement membrane d. Beyond basement membrane: 1. loose connective tissue 2. contains tissue fluid ( = plasma outside of blood stream)

  41. Capillaries, continued … • 3. Organization of capillaries: • a. Form vast, complex networks • b. Penetrate to reach most tissues • c. Pre-capillary sphincter: • 1. smooth muscle rings • 2. regulate blood flow between arterioles & capillary beds

  42. Capillaries, continued … • d. Capillary beds: (~ 60,000 miles) • 1. Specialized for exchange of materials • 2. each pound of adipose tissue contains 200 miles of capillaries

  43. Capillary Networks • Capillaries connect arterioles to venules • Blood flow is from the arterial to the venous vessels • Every millimeter of tissue has capillary blood supply

  44. Blood Vessel Anatomy, con’t… • D. Venules • 1. Vessels closest to capillary beds • 2. carry deoxygenated blood • 3. Small venules: structurally similar to large capillaries • 4. Medium venules: contain a few circular muscle fibers • 5. Large venules: have a tunica externa

  45. Blood Vessel Anatomy, con’t… • E. Veins • 1. Structure: same tunics, but not as distinct • a. Tunica media may be absent • b. Tunica externa: usually thickest • 1. Provides strength to outer wall • 2. Lots of smooth muscle fibers • 3. Less elastic tissue

  46. Vascular Tunics: Veins Tunica Externa Tunica Media Tunica Interna

  47. Veins, continued … • Valves: in veins carrying blood against gravity • a. Folds of tunica intima • b. Prevent backflow • c. Absent in venae cavae, pulmonary & portal veins

  48. Valves in Veins Venous Valve

  49. Valves, continued … • 2. Internal jugular veins have valves • a. are “upside down” • b. blood is flowing back to heart c. when heart contracts, pushes blood up into SVC • d. valves keep -O2 blood from going back up into brain

  50. Valves Assisted by Skeletal Muscles • Skeletal muscle contraction, especially in the extremities, assists the flow of blood back to the heart • Varicose Veins…..

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