Blood Vessels & Circulation 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.

Martini pg. 711

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.

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

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

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

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

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

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

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

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

Muscular Arteries

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

Arteriole end = endothelial cell nucleus n = smooth muscle nucleus rbc = red blood cells end = endothelial cell nucleus n = smooth muscle nucleus rbc = red blood cells

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

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

Veins Medium-sized veins: Large 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

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

Large Vein

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

Vein Artery

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

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

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

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

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

Circle of Willis Internal Carotid Vertebral External carotid

Arteries of the head and neck

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

Anterior cerebral Internal Carotid Middle cerebral Posterior cerebral

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

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

Spleen Splenic a. Renal a.

Thigh Anterior Posterior External Iliac Femoral Deep Femoral

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

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

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

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

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

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

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

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

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

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

Fetal Circulation Lungs of fetus are non functional. Oxygen and nutrients move from the maternal side of the placenta to the fetal bloodstream and CO2 and wastes moves from the fetal blood to the placenta

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

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.

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.

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

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

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

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

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

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

Measuring Blood Pressure WRONG TECHNIQUE Measuring Blood Pressure 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 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.

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.

Video Demonstration for Measuring Blood Pressure http://www.uams.edu/csc/programs/orientation/bloodPressure/TakingBP1.mov

Normal Blood Pressure For adults 18 and older who: Reference: August 2004, National Heart Lung and Blood Institute – Diseases and Conditions Index http://www.nhlbi.nih.gov/health/dci/Diseases/Hbp/HBP_WhatIs.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

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.

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

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 mmHg. 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 mmHg, even if the absolute value is still 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

Pulse Radial Pulse Carotid Pulse Brachial Pulse

Pulse Posterior Tibial Pulse Dorsalis Pedis Pulse

The End The End