Exercise 21 Blood Vessels Circulation Portland Community College

Exercise 21 Blood Vessels & Circulation Portland Community College BI 232

Blood vessels • Conduits that carry oxygen and nutrients to cells and remove wastes • Arteries transport blood away from the heart. • Deliver blood to capillary beds where gas and nutrient exchange occurs. • Veins transport blood toward the heart. 2

Martini pg. 711 3

General Circulatory Patterns • Two main circuits: • Pulmonary circulation: Blood goes from the heart to the lungs and returns to the heart. The pulmonary trunk and its branches; leave the right ventricle of the heart and contain deoxygenated blood. • Systemic Circulation: Blood goes from the heart to rest of the body. The aorta and its branches; leave the left ventricle of the heart and contain oxygenated blood. 4

Artery and Vein Histology • Walls have 3 layers: • Tunica intima • Tunica media • Tunica externa 5

Tunica Intima • Is the innermost layer near the lumen • Includes: • The endothelial lining • Connective tissue layer • Internal Elastic Membrane: In arteries, is a thick layer of elastic fibers in the outer margin of the tunica intima 6

Tunica Media • Is the middle layer • Contains concentric sheets of smooth muscle in loose connective tissue • Binds to inner and outer layers 7

Tunica Externa (aka: Tunica Adventitia) • • Is outer layer Contains connective tissue sheath Anchors vessel to adjacent tissues In arteries: • Contain collagen • Elastic fibers • In veins: • Contain elastic fibers • Smooth muscle cells 8

Elastic Arteries • Also called conducting arteries, these are the largest arteries • Tunica media has many elastic fibers and few muscle cells • Elasticity evens out pulse force • Examples: • Pulmonary trunk • Aorta • Common carotid arteries • Subclavian arteries • Common iliac arteries 9

Aorta n = smooth muscle cell TI = tunica intima el = elastic fibers 10 end = endothelial cells TA = tunica adventitia TM = tunica media

Vasa Vasorum • “Vessels of Vessels” • Small arteries and veins in the walls of large arteries and veins • Supply cells of tunica media and tunica externa Vasorum Aorta 11

Muscular Arteries • Also called distribution arteries, are medium -sized (most arteries) • Tunica media has many muscle cells • Examples: • External carotid arteries • Brachial arteries • Femoral arteries 12

Muscular Arteries 13

Arterioles • • The smallest branches of arteries Feed into capillaries Have little or no tunica externa Have thin or incomplete tunica media 14

Arteriole end = endothelial cell nucleus e n = nsmooth muscle nucleus rbc d= red blood cells 15

Capillaries • The smallest vessels • Structure: Simple squamous epithelium tube • Lumen side has a thin basal lamina • No tunica media, No tunica externa • Location of exchange between blood and interstitial fluid. • Gasses and chemicals diffuse across their walls 16

Veins • Carry blood to the heart • Are larger in diameter than arteries • Have thinner walls • Contain valves • Folds of tunica intima that prevent blood from flowing backward • Venules: The smallest veins that carry blood away from the capillaries 17

Veins • Medium-sized veins: • Thin tunica media and few smooth muscle cells • Tunica externa with longitudinal bundles of elastic fibers • Large veins: • Have all 3 tunica layers • Thick tunica externa • Thin tunica media • Example: Inferior and Superior vena cava 18

Venous Valve in Medium Vein ad = adipose tissue TA = tunica adventitia TM = tunica media v = valve 19

Large Vein 20

Arteries Vs. Veins • Arteries and veins run side-by-side • Arteries have thicker walls and higher blood pressure • Collapsed artery has small, round lumen • Vein has a large, flat lumen 21

Vein Artery 22

Aortic Arch Left Coronary A. Ascending Aorta Right Coronary A. 23

Aortic Arch External carotid Internal Carotid Common Carotid R. Vertebral R. Axillary a. R. Subclavian a. L. Subclavian a. Brachiocephalic Trunk 24

Right Common Carotid R. Subclavian Vertebral L. . Subclavian Brachiocephalic Trunk Left Common Carotid 25

Descending aorta • Thoracic aorta: above the diaphragm • Includes the intercostal arteries which run between the ribs • Abdominal aorta: below the diaphragm 26

Axillary Artery R. Axillary a. Brachial a. Radial a. Ulnar a. 27

Circle of Willis Internal Carotid Vertebral External carotid 28

Arteries of the head and neck 29

Circle of Willis Anterior communicating Anterior cerebral Internal Carotid (cut) Middle cerebral Posterior communicating Posterior cerebral R. Vertebral Basilar L. Vertebral 30

Anterior cerebral Internal Carotid Middle cerebral Posterior cerebral 31

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Abdominal Aorta Celiac Trunk Superior Mesenteric Renal A. Gonadal Inferior Mesenteric Common Iliac External Iliac Internal Iliac 33

Abdominal Common Hepatic Aorta Celiac Trunk Left Gastric Splenic Superior Mesenteric Inferior Mesenteric 34

Spleen Splenic a. Renal a. 35

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Thigh Anterior Posterior External Iliac Femoral Deep Femoral 37

Lower Leg Femoral Popliteal Fibular Dorsalis Pedis Anterior tibial Fibular Posterior tibial 38

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Axillary vein Cephalic vein Brachial vein Basilic vein Median Cubital vein Cephalic vein Radial vein Basilic vein Ulnar vein 40

Brachiocephalic Right Left Subclavian vein Axillary vein Cephalic vein Brachial vein Basilic vein Azygos Hemiazygos 41

Petrosal sinus Superior Sagittal sinus Cavernous sinus Straight sinus Transverse sinus Sigmoid sinus Internal Jugular Brachiocephalic Vertebral Vein Right Left External Jugular Subclavian vein Superior Vena 42 Cava

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Popliteal Great Saphenous Small Saphenous Femoral Small Saphenous Anterior Tibial Fibular Posterior Tibial 44

Deep Femoral Great Saphenous Popliteal Small Saphenous Anterior Tibial Posterior Tibial Small Saphenous Fibular 45

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Hepatic veins Inferior Vena Cava Renal vein Common iliac vein Internal iliac vein External iliac vein 47

Inferior Vena Cava Hepatic veins Hepatic Portal vein Splenic vein Superior Mesenteric Inferior Mesenteric 48

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Hepatic Portal Circulation • Veins that flow into the liver before returning to the heart • Blood from digestive organs and spleen travel to capillaries of the liver. • The liver processes the blood before sending it through the hepatic vein. • Blood then travels to the inferior Vena Cava 50

Thoracic Veins • Intercostal veins which drain the intercostal muscles • Azygos and hemiazygos veins which drain blood from the thoracic region 51

Fetal Circulation • Lungs of fetus are non functional. • Oxygen and nutrients move from the maternal side of the placenta to the fetal bloodstream and CO 2 and wastes moves from the fetal blood to the placenta 52

Fetal Circulation • Blood flow • From the umbilical cord blood travels through the ductus venosus which shunts the blood to the inferior vena cava • From the VC blood travels to the right atrium of the heart 53

Fetal Circulation • Blood can then move either to the right ventricle or through a hole in the right atrium called the foramen ovale (bypass route) • Blood in the right ventricle moves into the pulmonary trunk where another shunt vessel, the ductus arteriosus carries blood to the aortic arch, bypassing the lungs. • Closing to the foramen ovale leaves the fossa ovalis which we learned about in the heart lab. 54

Blood Pressure • Maintenance of bp is important for the health of the heart and proper functioning of various organs • The force exerted by blood on the walls of blood vessels. • A function of the pumping action of the heart and the resistance to flow as blood moves through the blood vessels. 55

Blood Pressure • In large elastic arteries, the BP fluctuates between a max. and min. value • Systolic pressure is the maximum pressure exerted on bv walls. • Diastolic pressure is the minimum level 56

Blood Pressure • Measured in units called millimeters of mercury (mm. Hg) • If the pressure in a bv is 95 mm Hg, it means that the force exerted by the blood will cause a column of mercury to rise 95 mm 57

Blood Pressure Cuffs • BP cuffs come in Large Adult different sizes. • Be sure to choose the one that is appropriate for the patient Infant 58

Measuring Blood Pressure • Most cuffs are marked with an O or an arrow. This should be placed near the artery. 59

Measuring Blood Pressure • Place the BP cuff snugly on the patient's arm. • Check to make sure you have found the artery. • Line the mark on the cuff up with the artery 60

Measuring Blood Pressure • Stethoscope: Note how the ear pieces slant slightly in one direction. • Make sure the ear pieces on the stethoscope are point away from you when you put them on. • Place stethoscope on the artery, tucked slightly under the cuff 61

Measuring Blood Pressure WRONG TECHNIQUE • The cuff should be placed at the level of the heart. • The patients arm (or leg) should be completely relaxed. • Resting on the table or in their lab is helpful 62 CORRECT TECHNIQUE

Inflate the Cuff • A Grasp the bulb so that your thumb can easily access the valve. • Turn the valve to the right to tighten it and pump up the cuff, turn it to the left to loosen it and deflate the cuff. 63

Measuring Blood Pressure • Pump up the cuff until the sphygmomanometer reads 180 to 200. • Loosen the valve to let a little of the air out. • Listen for the first heartbeat, that is the top number (systolic BP) • Continue to listen until there are no more heartbeats. The last beat you hear is the bottom number (diastolic BP) • Let the air all the way out and remove the cuff. 64

Video Demonstration for Measuring Blood Pressure • http: //www. uams. edu/csc/programs/orientati on/blood. Pressure/Taking. BP 1. mov 65

Normal Blood Pressure • Reference: • August 2004, National Heart Lung and Blood Institute – Diseases and Conditions Index • http: //www. nhlbi. nih. gov/health/dci/Diseases/Hbp/HBP_What. Is. html • For adults 18 and older who: • Are not on medicine for high blood pressure • Are not having a short-term serious illness • Do not have other conditions such as diabetes and kidney disease • Systolic BP: Less than 120 • Diastolic BP: Less than 80 66

Pre-Hypertension • Systolic BP: between 120 -139 • Diastolic BP: between 80 -89 • Examples: 118/82, 128/89, or 130/86 • If your blood pressure is in the pre-hypertension range, it is more likely that you will end up with high blood pressure unless you take action to prevent it. • Note: When systolic and diastolic blood pressures fall into different categories, the higher category should be used to classify blood pressure level. 67

Hypertension • Stage 1 • Systolic BP: between 140 -159 • Diastolic BP: between 90 -99 • Stage 2 • Systolic BP: 160 or higher • Diastolic BP: 100 or higher 68

Hypotension • Hypotension is a subnormal arterial pressure. • There is not enough pressure to adequately perfuse the tissues. • There is usually a mean arterial pressure (MAP) below 60 mm. Hg. • MAP= diastolic + 1/3(systolic-diastolic) Example: BP= 120/70 MAP= 70 + 1/3(120 -70)= 86. 6 • People who are chronically hypertensive may feel symptoms of hypotension if their mean arterial pressure drops by 40 mm. Hg, even if the absolute value is still 69 over 60.

Pulse • The rhythmic expansion and recoil of the arteries is known as the pulse. • Can be found in various locations • Diminish in smaller arteries and are absent in capillaries and veins 70

Pulse Radial Pulse Carotid Pulse Brachial Pulse 71

Pulse Posterior Tibial Pulse Dorsalis Pedis Pulse 72

The End 73