Anatomy and Physiology -A&P 2 Study NOTES (Circulatory System-Blood Flow Tracings)

A&P 2 Lab 4 Circulatory System-Blood Flow Tracings Circulatory system- how the blood from the heart is circulated throughout the body. General blood flow through the body after it leaves the heart follows a mapping system. From the heart, it flows through arteries, then capillaries, and comes back to the heart by way of veins. BLOOD VESSELS IN THE CIRCULATORY SYSTEM: • Arteries- referred to as efferent blood vessel in the circulatory system o They always carry blood away from the heart. o Typically carry oxygenated blood. (except in the pulmonary artery) o 1. Conducting arteries: ▪ very large arteries and typically exit from the heart ▪ They have the need/ability to expand when the heart beats so they withstand the splurge. So, with every heartbeat, blood surges out of the heart into these large vessels. • To do this, they must have a layer of elastic tissue that gives it the ability to stretch and recoil when the heart is relaxing. ▪ EX: aorta and pulmonary trunk o Atherosclerosis- when arteries age and stiffen because plaque builds up in the arteries, they loose that elasticity and the ability to stretch when blood surges into them. ▪ It results in an increase in pressure in those vessels which can lead to an aneurism- a weak point in a artery and with each heartbeat, that little thin walled area will pulsate and it can further and further weaken and eventually rupture which can lead to death or stroke. o 2. Distributing arteries: ▪ A.k.a. medium or muscular arteries ▪ They are direct branches from the conducting arteries ▪ Have a very thick muscular wall (up to 40 layers of smooth muscle) ▪ The muscular wall in a distributing artery makes up 75% of the arterial wall itself. • EX: brachial artery, femoral artery (named for area where they are distributing their blood) o 3. Resistance arteries: ▪ A.k.a. small arteries ▪ Too numerous to name o 4. Metarterioles: ▪ Very short vessels that will link the arteriole system to the capillaries. • AFTER BLOOD FLOWS THROUGH THE ARTERIAL SYSTEM, IT THEN FLOWS INTO A SERIES OF CAPILLARY BEDS. o 5. Capillaries: ▪ Known as the exchange vessels because they have very thin walls that exchange oxygen, glucose, and other nutrients in the body. ▪ They connect the smallest arteries to the smallest veins. • Veins- afferent blood vessels because they bring blood back to the heart o They typically carry deoxygenated blood (except the pulmonary vein) o They are called Capacitance Vessels because they typically control a large amount of volume. o Can stretch more easily than arteries and have thin, flaccid walls and can therefore accommodate a larger volume of blood. o Comparing arteries to veins: ▪ In a resting person, about 11% of the blood is found in the arteries while 54% is found in the veins. ▪ Veins are subject to much lower blood pressure because they are further away from the heart. Because of that, they can have thinner walls compared to the arteries that need more muscular support. ▪ In the arteriole system, we go from large to small vessels and the venous system is opposite. o 6. Post capillary vein: ▪ Very small veins called venules. o 7. Muscular Venules: ▪ Very small and too numerous to name o 8. Medium veins: ▪ They drain blood from specific areas of the body, organs and muscles. ▪ EX: radial and ulnar veins (drain blood out of the forearm) ▪ Unique: they contain valves- flaps of tissue that extend into the lumen and point upwards towards the heart. • Because veins have a very low blood pressure, they don’t have the strength to pump the blood back to the heart against the pull of gravity. • Skeletal muscles that surround the veins also help to pump the blood o EX: when calve muscles contract, they squeeze around the vein and push blood up through the valve. o Kind of like a “milking action” known as the skeletal muscle pump. • When the valves weaken and can’t perform their job, varicose veins will result. They are visible through the skin due to the blood pooling and backflowing into the venous system. o 9. Venous Sinuses: ▪ Large vessels with very thin walls and very large lumens ▪ EX: coronary sinus of the heart where blood that flows through the heart, will dump into the coronary sinus before entering back into the vena cava. ▪ EX: Dural sinuses in the brain. They collect the blood flow from the brain before they return to the heart. o 10. Large veins ▪ EX: Superior/Inferior Vena Cava- will bring blood back to the heart and finally start the system all over again. REVIEW OF BLOOD FLOW THROUGH THE HEART • Inferior Vena Cava: drains from anywhere below the diaphragm • Superior Vena Cava: drains from anywhere above the diaphragm • They both bring blood into the right atrium of the heart • Tricuspid valve • Right ventricle • Pulmonary semilunar valve----pulmonary trunk-----left and right pulmonary arteries----- flow to the lungs • Blood picks up oxygen in the lungs and then to the • Pulmonary veins • Left atrium • Bicuspid valve • Left ventricle • Aortic semilunar valve • Ascending aorta: • Off of the ascending aorta, the branches for the Left and right coronary arteries branch off into the heart to supply the heart muscle with blood. • Once the heart uses the oxygen in the blood, it will flow into the venous system into the coronary sinus which will dump into the right atrium to start the process again BLOOD TRACINGS THROUGH THE BODY • How blood gets to specific organs and regions. • Aorta is the starting point. • ASCENDING AORTA • AORTIC ARCH • DESCENDING: THORACIC AORTA • DESCENDING: ABDOMINAL AORTA • From the aortic arch, there are 3 vessels that branch off and distribute blood to the brain and head and neck region. o R-L: right Brachiocephalic, Left Common Carotid, left subclavian (where finger is pointed) • RIGHT BRACHIOCEPHALIC o further branches into the right subclavian and the right vertebral (in blue). o RIGHT VERTEBRAL o The right subclavian turns into the RIGHT AXILLARY which will distribute blood into the RIGHT ARM . o (one continuous vessel from the subclavian to the axillary; just different names depending on where they are located) • LEFT SUBCLAVIAN o Branches into a LEFT VERTEBRAL and LEFT AXILLARY o The RIGHT AND LEFT VERTEBRAL ARTERIES travel upwards through the neck, through the cervical vertebrae and merge into the BASILAR ARTERY. ▪ BASILAR artery enters directly into the circulation of the brain itself o Basilar artery leads to the Circle of Willis- which is a circular arterial pathway in the brain that will feed the brain tissue with blood. ▪ CIRCLE OF WILLIS provides alternative routes for circulation ▪ o The blood in the brain needs to be drained: by the venous sinus of the dura mater OR occipital region of the brain. ▪ L. VENOUS SINUS OF THE DURA MATER- majority of blood will be drained from here. o From there it goes through the Internal Jugular Vein ▪ INTERNAL JUGULAR VEINS o From the internal jugular veins, blood goes through the Brachiocephalic Veins ▪ BRACHIOCEPHALIC VEINS o From the brachiocephalic veins, it enters the superior vena cava which will enter the right atrium of the heart. ▪ SUPERIOR VENA CAVA o If it doesn’t drain from the venous sinus of the dura mater, it will drain from the Vertebral Vein ▪ VERTEBRAL BRAIN o From the vertebral vein, it will drain into the Subclavian Vein, and then into the brachiocephalic. ▪ BRACHIOCEPHALIC o From the brachiocephalic, it enters into the superior vena cava. o Left Axillary artery (branch off the left subclavian artery) ▪ LEFT AXILLARY ARTERY supplies the left arm with blood. • COMMON CAROTID ARTERIES o The right common carotid branches off from the right brachiocephalic ▪ RIGHT COMMON CAROTID ▪ The right common carotid then branches into a right internal and external carotid artery • R. INTERNAL AND EXTERNAL CAROTID ARTERY o The left common carotid artery branches off into a L internal and external ▪ LEFT COMMON CAROTID o Left common caotid branches into a L external and internal carotid artery ▪ L. INTERNAL AND EXTERNAL CAROTID ARTERY BLOOD THAT DISTRIBUTES TO THE FACE AND SCALP • The right and left external carotid arteries supply blood to the face and the scalp. • So the right and left internal carotids lead into the circle of willis and supply the brain with its own brain supply CIRCULATORY PATHWAY OF THE ARMS • Starts in the left ventricle, then blood flows into the aortic arch • For the right arm, it goes through the R. brachiocephalic artery, and then into the R. subclavian artery, and then it turns into the R. axillary artery, and then through the brachial artery (as it enters the upper arm) o R. BRACHIAL ARTERY • After blood flows through the brachial artery, there is a division at the elbow: radial artery and ulnar artery o R. RADIAL AND R. ULNAR ARTERY • The radial and ulnar veins will flow inferiorly until they hit the wrist which is the deep and superficial palmer arches. (they are networks of overlapping arteries called Anastomosis) o DEEP PALMER ARCH o SUPERFICIAL PALMER ARCH • The deep and superficial palmers arches will then flow into digital arteries to supply the fingers with blood o COMMON PALMAR DIGITAL ARTERY o PROPER PALMER DIGITAL ARTERY • From the digital arteries, the blood enters into the VENOUS SYSTEM o DIGITAL VEINS • From the digital veins, blood goes into the Superficial Venous Palmar Arch and the Deep Venous Palmar Arch o SUPERFICIAL VENOUS PALMAR ARCH o DEEP VENOUS PALMER ARCH • The venous palmer arches then travel laterally into the cephalic vein or medially to the basilic vein. o RIGHT CEPHALIC VEIN o RIGHT BASILIC VEIN • An alternate route from the venous palmer arches would be the radial and ulnar veins o R. RADIAL VEIN o R. ULNAR VEIN • Depending on what side of the arm, the radial and ulnar veins can drain into a cephalic vein or a radial vein laterally or medially into the basilic or ulnar veins. • At this point, the radial vein and the ulnar vein will converge into a larger vein called the brachial vein (at the point where it reaches the elbow). Also hit the Median Cubital Vein at this same point. o R. BRACHIAL VEIN o MEDIAN CUBITAL VEIN small vein across the crease of the elbow and is a good sight for blood draws and allows blood from lateral side of arm to cross over to the medial side • From here, the blood travels superiorly and reaches the shoulder region and the Axillary Vein o RIGHT AXILLARY VEIN • From the right axillary vein, blood will then dump into the right subclavian vein o RIGHT SUBCLAVIAN VEIN area of the clavicle • From the subclavian vein, it drains into the brachiocephalic vein o RIGHT BRACHIOCEPHALIC VEIN • From the brachiocephalic vein, it drains into the super vena cava o SUPER VENA CAVA • From the super vena cava, it then goes into the right atrium of the heart o RIGHT ATRIUM CIRCULATION OF BLOOD THROUGH THE LEGS • Starts at the aorta o DESCENDING AORTA • From the descending aorta, it branches into the common iliac o COMMON ILIAC ARTERY • The common iliac artery has 2 branches and the one that feeds to the leg is the External Iliac Artery o EXTERNAL ILIAC ARTERY ▪ INTERNAL ILIAC ARTERY supplies blood flow to the pelvic organs • From the external iliac artery, the blood flows down to the femoral artery o FEMORAL ARTERY • When the femoral artery hits the knee level, it is now called the Popliteal Artery o POPLITEAL ARTERY • The popliteal artery then branches into an Anterior Tibial Artery and Posterior Tibial Artery o ANTERIOR TIBIAL ARTERY o POSTERIOR TIBIAL ARTERY • The anterior and posterior arteries travel down and connect into the arteries and capillaries of the foot o ARTERIES AND CAPILLARIES OF THE FOOT • How does the blood flow now get out of the foot? • Starting with the veins and capillaries of the foot o VEINS AND CAPILLARIES OF THE FOOT • From the veins and capillaries of the foot, blood will either flow through the Great Saphenous Vein OR through the anterior and posterior tibial veins o GREAT SAPHENOUS VEIN most commonly used vein for bypass o o ANTERIOR TIBIAL VEIN o POSTERIOR TIBIAL VEIN • The great saphenous vein then sends blood through the femoral vein o FEMORAL VEIN • The anterior and posterior tibial veins will send their blood to the popliteal vein o POPLITEAL VEIN and then into the femoral vein • From the femoral vein, blood travels to the external iliac vein o EXTERNAL ILIAC VEIN • The external iliac vein merges into the common iliac vein o COMMON ILIAC VEIN • The common iliac vein to the inferior vena cava o INFERIOR VENA CAVA • From the inferior vena cava to the right atrium of the heart o RIGHT ATRIUM PATHWAY TO SPECIFIC ORGANS: ARTERIES OFF THE THORACIC AORTA o POSTERIOR VIEW OF THORACIC AORTA • First branch is the pericardial artery (not visible on diagram)- supplies the pericardium • Bronchial artery supplies the bronchial tubes, lungs, and the esophagus o BRONCHIAL ARTERY • The Esophageal Artery supplies the esophagus with blood o THE ESOPHAGEAL ARTERY • The Mediastinal Artery supplies the mediastinum (not visible) o The Posterior Intercostal and subcostal arteries drain their blood into a larger region; the intercostal muscles, the pectoral muscles, and abdominal muscles. o POSTERIOR INTERCOSTAL ARTERIES o SUBCOSTAL • From the costal arteries, there are branches • The last thoracic artery is the Superior Phrenic Artery o SUPERIOR PHRENIC ARTERY phrenic= diaphragm VENOUS DRAINAGE FROM THE THORACIC AREA • Venous drainage is always more complex than the arterial • The pericardium is drained by the pericardial vein • Bronchial tubes drained by the bronchial veins • Right esophagus is drained by the esophageal vein • Right mediastinum by the mediastinal vein • The R intercoastal muscles, R pectoral muscles, R abdominal muscles, R mammary gland and R vertebral canal are all drained by the intercostal veins o • There is a difference between the left side and right side drainage. • o All the veins listed will converge onto the Azygos vein (runs along the R side of the aorta and then travels up to drain its blood into the superior vena cava) • Left esophagus is drained by the esophageal vein • L mediastinum by the mediastinal vein • • difference between right and left side. The left side veins must drain into the Hemiazygos Vein first, before entering the azygos vein. • Then to the superior vena cava and the right atrium o SUPERIOR VC R ATRIUM BRANCHES THAT COME OFF THE AORTA IN THE ABDOMINAL CAVITY • ABDOMINAL AORTA • o Celiac artery supplies these organs with blood. • • The left and right Suprarenal Arteries supply blood to the adrenal glands (small glands that sit on top of the kidneys and are essentially part of the endocrine system. o SUPRARENAL ARTERIES • The right and left Renal Arteries supply blood to the kidneys o RENAL ARTERIES • The right and left Gonadal Arteries supply blood to the gonads (testes or ovaries) o GONADAL ARTERIES • The Inferior Mesenteric Artery supplies blood to the left transverse colon, descending and sigmoid colon, and the rectum o INFERIOR MESENTERIC ARTERY • The Lumbar Artery supplies blood to the spinal cord, meninges and lumbar region of the back o LUMBAR ARTERIES • The left and right Common Iliac Arteries are at the very end of the descending aorta. o COMMON ILIAC ARTERIES • The first branch off the common iliac arteries is the left and right Internal Iliac Arteries which supply blood to the uterus, vagina, bladder, vas deferens, and prostate. o INTERNAL ILIAC ARTERIES • The other branch is the External Iliac Arteries which supply blood to the lower extremities. o EXTERNAL ILIAC ARTERIES • The Middle Sacral Artery supplies blood to the sacrum, coccyx, rectum and gluteal muscles o MIDDLE SACRAL ARTERY VENOUS DRAINAGE FROM THE ABDOMINAL AORTA • The internal iliac vein drains the uterus, vagina, bladder, vas deferens and prostate o INTERNAL ILIAC VEIN • They then drain into the common iliac vein o COMMON ILIAC VEIN • Then to the inferior vena cava and into the right atrium o INFERIOR VENA CAVA • The right spinal cord, right meninges and right lumbar region drain into the ascending lumbar veins, and then into the inferior vena cava and the right atrium o ASCENDING LUMBAR VEINS • The left side of the body has an alternate drainage route so the spinal cord, meninges and lumbar region all first drain into the hemiazygos vein and the azygos vein WHICH WILL ULTIMATELY DRAIN INTO THE SUPER VENA CAVA because of its location above the diaphragm. o HEMIAZYGOS VEIN o AZYGOS VEIN • From the right and left gonads, blood drains into the right gonadal vein which is much more direct and right into the inferior vena cava. o RIGHT GONADAL VEIN • The left gonad drains into the left gonadal drain and then into the left renal vein before entering into the inferior vena cava. o LEFT RENAL VEIN • The right and left kidneys drain into the right and left renal veins and then into the inferior vena cava. • The right adrenal glands drain into the right suprarenal vein and into the inferior vena cava. o RIGHT SUPRARENAL VEIN • The left adrenal gland drains into the left suprarenal vein and then into the left renal vein before entering the inferior vena cava o LEFT RENAL VEIN THE DIGESTIVE REGION • The stomach, small intestine, cecum, ascending colon, right transverse colon drain into the superior mesenteric vein o SUPERIOR MESENTRIC VEIN • The left transverse colon, descending colon, sigmoid colon and rectum drain into the inferior mesenteric vein o INFERIOR MESENTRIC VEIN • The spleen, pancreas, stomach and part of the colon drain into the Splenic Vein o SPLENIC VEIN • They all have to enter into the Hepatic Portal Vein o HEPATIC PORTAL VEIN • Which then travel into the liver o LIVER • From the liver, it exits the Hepatic Vein which will then drain into the inferior vena cava. o HEPATIC VEIN ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Show Less