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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Vessels  Blood is carried in a closed system of vessels that begins and.

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Presentation on theme: "Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Vessels  Blood is carried in a closed system of vessels that begins and."— Presentation transcript:

1 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Vessels  Blood is carried in a closed system of vessels that begins and ends at the heart  The three major types of vessels are arteries, capillaries, and veins  Arteries carry blood away from the heart, veins carry blood toward the heart  Capillaries contact tissue cells and directly serve cellular needs

2 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Generalized Structure of Blood Vessels  Arteries and veins are composed of three tunics – tunica interna, tunica media, and tunica externa  Lumen – central blood-containing space surrounded by tunics  Capillaries are composed of endothelium with sparse basal lamina

3 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Generalized Structure of Blood Vessels Figure 19.1b

4 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Vessel Anatomy Table 19.1

5 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Elastic (Conducting) Arteries  Thick-walled arteries near the heart; the aorta and its major branches  Large lumen allow low-resistance conduction of blood  Contain elastin in all three tunics  Withstand and smooth out large blood pressure fluctuations  Serve as pressure reservoirs

6 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscular (Distributing) Arteries and Arterioles  Muscular arteries – distal to elastic arteries; deliver blood to body organs  Have thick tunica media with more smooth muscle  Active in vasoconstriction  Arterioles – smallest arteries; lead to capillary beds  Control flow into capillary beds via vasodilation and constriction

7 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Capillaries  Capillaries are the smallest blood vessels  Walls consisting of a thin tunica interna, one cell thick  Allow only a single RBC to pass at a time  Pericytes on the outer surface stabilize their walls  There are three structural types of capillaries: continuous, fenestrated, and sinusoids

8 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Vascular Components Figure 19.2a, b

9 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Continuous Capillaries  Continuous capillaries are abundant in the skin and muscles  Endothelial cells provide an uninterrupted lining  Adjacent cells are connected with tight junctions  Intercellular clefts allow the passage of fluids

10 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Continuous Capillaries  Continuous capillaries of the brain:  Have tight junctions completely around the endothelium  Constitute the blood-brain barrier

11 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Continuous Capillaries Figure 19.3a

12 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fenestrated Capillaries  Found wherever active capillary absorption or filtrate formation occurs (e.g., small intestines, endocrine glands, and kidneys)  Characterized by:  An endothelium riddled with pores (fenestrations)  Greater permeability than other capillaries

13 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fenestrated Capillaries Figure 19.3b

14 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sinusoids  Highly modified, leaky, fenestrated capillaries with large lumens  Found in the liver, bone marrow, lymphoid tissue, and in some endocrine organs  Allow large molecules (proteins and blood cells) to pass between the blood and surrounding tissues  Blood flows sluggishly, allowing for modification in various ways

15 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sinusoids Figure 19.3c

16 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Beds  A microcirculation of interwoven networks of capillaries, consisting of:  Vascular shunts – metarteriole–thoroughfare channel connecting an arteriole directly with a postcapillary venule  True capillaries – 10 to 100 per capillary bed, capillaries branch off the metarteriole and return to the thoroughfare channel at the distal end of the bed

17 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Beds Figure 19.4a

18 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Beds Figure 19.4b

19 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Flow Through Capillary Beds  Precapillary sphincter  Cuff of smooth muscle that surrounds each true capillary  Regulates blood flow into the capillary  Blood flow is regulated by vasomotor nerves and local chemical conditions

20 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Venous System: Venules  Venules are formed when capillary beds unite  Allow fluids and WBCs to pass from the bloodstream to tissues  Postcapillary venules – smallest venules, composed of endothelium and a few pericytes  Large venules have one or two layers of smooth muscle (tunica media)

21 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Venous System: Veins  Veins are:  Formed when venules converge  Composed of three tunics, with a thin tunica media and a thick tunica externa consisting of collagen fibers and elastic networks  Capacitance vessels (blood reservoirs) that contain 65% of the blood supply

22 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Venous System: Veins  Veins have much lower blood pressure and thinner walls than arteries  To return blood to the heart, veins have special adaptations  Large-diameter lumens, which offer little resistance to flow  Valves (resembling semilunar heart valves), which prevent backflow of blood  Venous sinuses – specialized, flattened veins with extremely thin walls (e.g., coronary sinus of the heart and dural sinuses of the brain)

23 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Vascular Anastomoses  Merging blood vessels, more common in veins than arteries  Arterial anastomoses provide alternate pathways (collateral channels) for blood to reach a given body region  If one branch is blocked, the collateral channel can supply the area with adequate blood supply  Thoroughfare channels are examples of arteriovenous anastomoses

24 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Flow  Actual volume of blood flowing through a vessel, an organ, or the entire circulation in a given period:  Is measured in ml per min.  Is equivalent to cardiac output (CO), considering the entire vascular system  Is relatively constant when at rest  Varies widely through individual organs

25 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Pressure (BP)  Force per unit area exerted on the wall of a blood vessel by its contained blood  Expressed in millimeters of mercury (mm Hg)  Measured in reference to systemic arterial BP in large arteries near the heart  The differences in BP within the vascular system provide the driving force that keeps blood moving from higher to lower pressure areas

26 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Resistance  Resistance – opposition to flow  Measure of the amount of friction blood encounters  Generally encountered in the systemic circulation  Referred to as peripheral resistance (PR)  The three important sources of resistance are blood viscosity, total blood vessel length, and blood vessel diameter

27 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Aiding Venous Return  Venous BP alone is too low to promote adequate blood return and is aided by the:  Respiratory “pump” – pressure changes created during breathing suck blood toward the heart by squeezing local veins  Muscular “pump” – contraction of skeletal muscles “milk” blood toward the heart  Valves prevent backflow during venous return PLAY InterActive Physiology ®: Anatomy Review: Blood Vessel Structure and Function, pages 3–27

28 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Aiding Venous Return Figure 19.6

29 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Blood Pressure  Maintaining blood pressure requires:  Cooperation of the heart, blood vessels, and kidneys  Supervision of the brain

30 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Blood Pressure  The main factors influencing blood pressure are:  Cardiac output (CO)  Peripheral resistance (PR)  Blood volume  Blood pressure = CO x PR  Blood pressure varies directly with CO, PR, and blood volume

31 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Temperature Regulation  As temperature rises (e.g., heat exposure, fever, vigorous exercise):  Hypothalamic signals reduce vasomotor stimulation of the skin vessels  Heat radiates from the skin  Sweat also causes vasodilation via bradykinin in perspiration  Bradykinin stimulates the release of NO  As temperature decreases, blood is shunted to deeper, more vital organs

32 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Circulatory Pathways  The vascular system has two distinct circulations  Pulmonary circulation – short loop that runs from the heart to the lungs and back to the heart  Systemic circulation – routes blood through a long loop to all parts of the body and returns to the heart

33 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Differences Between Arteries and Veins ArteriesVeins Delivery Blood pumped into single systemic artery – the aorta Blood returns via superior and interior venae cavae and the coronary sinus Location Deep, and protected by tissue Both deep and superficial PathwaysFair, clear, and definedConvergent interconnections Supply/drainagePredictable supply Dural sinuses and hepatic portal circulation

34 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pulmonary Circulation Figure 19.18b

35 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Systemic Circulation Figure 19.19

36 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19.20b (b) Common carotid arteries Subclavian artery Aortic arch Coronary artery Thoracic aorta Branches of celiac trunk: Renal artery Superficial palmar arch Radial artery Ulnar artery Internal iliac artery Deep palmar arch Left gastric artery Splenic artery Common hepatic artery Internal carotid artery Vertebral artery Brachiocephalic trunk Axillary artery Brachial artery Abdominal aorta Superior mesenteric artery Gonadal artery Common iliac artery External iliac artery Digital arteries Femoral artery Popliteal artery Inferior mesenteric artery Ascending aorta External carotid artery Anterior tibial artery Posterior tibial artery Arcuate artery

37 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19.21b (b) Superficial temporal artery Ophthalmic artery Maxillary artery Occipital artery Facial artery Lingual artery Superior thyroid artery Larynx Thyroid gland (overlying trachea) Clavicle (cut) Brachiocephalic trunk Internal thoracic artery Basilar artery Vertebral artery Internal carotid artery Subclavian artery Axillary artery External carotid artery Common carotid artery Thyrocervical trunk Costocervical trunk

38 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19.21c,d (d)(c) Frontal lobe Optic chiasma Middle cerebral artery Internal carotid artery Pituitary gland Temporal lobe Occipital lobe Cerebral arterial circle (circle of Willis) Anterior Posterior cerebral artery Basilar artery Vertebral artery Cerebellum Posterior communicating artery Pons Anterior cerebral artery Anterior communicating artery Arteries of the Brain

39 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19.22b (b) Vertebral artery Common carotid arteries Left axillary artery Right subclavian artery Left subclavian artery Anterior intercostal artery Internal thoracic artery Lateral thoracic artery Descending aorta Brachiocephalic trunk Posterior intercostal arteries Costocervical trunk Thoracoacromial artery Axillary artery Subscapular artery Posterior circumflex humeral artery Anterior circumflex humeral artery Common interosseous artery Radial artery Ulnar artery Deep palmar arch Superficial palmar arch Digitals Brachial artery Deep artery of arm Suprascapular artery Thyrocervical trunk

40 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Arteries of the Abdomen Figure 19.23b (b) Liver (cut)Diaphragm Esophagus Left gastric artery Superior mesenteric artery Left gastroepiploic artery Spleen Pancreas (major portion lies posterior to stomach) Splenic artery Stomach Inferior vena cava Celiac trunk Hepatic artery proper Common hepatic artery Right gastric artery Gallbladder Abdominal aorta Gastroduodenal artery Right gastroepiploic artery Duodenum

41 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Arteries of the Abdomen Figure 19.23c (c) Opening for inferior vena cava Diaphragm Inferior phrenic artery Middle suprarenal artery Renal artery Superior mesenteric artery Inferior mesenteric artery Median sacral artery Common iliac artery Ureter Gonadal (testicular or ovarian) artery Hiatus (opening) for esophagus Celiac trunk Kidney Abdominal aorta Lumbar arteries

42 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Arteries of the Abdomen Figure 19.23d (d) Celiac trunk Transverse colon Superior mesenteric artery Intestinal arteries Left colic artery Inferior mesenteric artery Aorta Sigmoidal arteries Descending colon Left common iliac artery Sigmoid colon Rectum Middle colic artery Right colic artery Ileocolic artery Ascending colon Ileum Superior rectal artery Appendix Cecum

43 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Arteries of the Lower Limbs Figure 19.24b, c (b) (c) Common iliac artery Deep artery of thigh Lateral circumflex femoral artery Medial circumflex femoral artery Obturator artery Femoral artery Adductor hiatus Popliteal artery Anterior tibial artery Posterior tibial artery Fibular artery Dorsalis pedis artery Arcuate artery Metatarsal arteries Internal iliac artery Superior gluteal artery External iliac artery Popliteal artery Anterior tibial artery Fibular artery Plantar arch Dorsalis pedis artery (from top of foot) Posterior tibial artery Lateral plantar artery Medial plantar artery

44 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19.25b Renal vein Splenic vein Basilic vein Brachial vein Cephalic vein Dural sinuses External jugular vein Vertebral vein Internal jugular vein Superior vena cava Axillary vein Great cardiac vein Hepatic veins Hepatic portal vein Superior mesenteric vein Inferior vena cava Ulnar vein Radial vein Common iliac vein External iliac vein Internal iliac vein Digital veins Femoral vein Great saphenous vein Popliteal vein Posterior tibial vein Anterior tibial vein Fibular vein Dorsal venous arch Dorsal digital veins Inferior mesenteric vein Median cubital vein Right and left brachiocephalic veins Subclavian vein (b)

45 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Veins of the Head and Neck Figure 19.26b (b) Ophthalmic vein Superficial temporal vein Facial vein Occipital vein Posterior auricular vein External jugular vein Vertebral vein Internal jugular vein Superior and middle thyroid veins Brachiocephalic vein Subclavian vein Superior vena cava

46 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Veins of the Brain Figure 19.26c (c) Superior sagittal sinus Falx cerebri Inferior sagittal sinus Straight sinus Cavernous sinus Junction of sinuses Transverse sinuses Jugular foramen Right internal jugular vein Sigmoid sinus

47 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Veins of the Upper Limbs and Thorax Figure 19.27b Right subclavian vein Brachiocephalic veins Axillary vein Brachial vein Cephalic vein Basilic vein Median cubital vein Median antebrachial vein Basilic vein Internal jugular vein External jugular vein Left subclavian vein Superior vena cava Azygos vein Inferior vena cava Ascending lumbar vein Accessory hemiazygos vein Hemiazygos vein Posterior intercostals Ulnar vein Deep palmar venous arch Superficial palmar venous arch Digital veins Cephalic vein Radial vein (b)

48 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Veins of the Abdomen Figure 19.28b (b) Hepatic veins Inferior phrenic vein Left suprarenal vein Left ascending lumbar vein Lumbar veins Left gonadal vein Common iliac vein Internal iliac vein Renal veins Inferior vena cava Right suprarenal vein Right gonadal vein External iliac vein

49 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Veins of the Abdomen Figure 19.28c (c) Hepatic veins Liver Spleen Gastric veins Inferior vena cava Splenic vein Right gastroepiploic vein Inferior mesenteric vein Superior mesenteric vein Large intestine Hepatic portal vein Small intestine Rectum

50 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19.29b, c (c) Popliteal vein Common iliac vein Fibular (peroneal) vein Anterior tibial vein Dorsalis pedis vein Dorsal venous arch Metatarsal veins Internal iliac vein External iliac vein Inguinal ligament Femoral vein Great saphenous vein (superficial) Great saphenous vein Popliteal vein Anterior tibial vein Fibular (peroneal) vein Small saphenous vein (superficial) Posterior tibial vein Plantar veins Plantar arch Digital veins (b)


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