Chapter 13 Anatomy And Physiology Of The Vascular System PDF

ANATOMY AND PHYSIOLOGY CHAPTER 13 THE VASCULAR SYSTEM  FUNCTIONS EXCHANGE OF MATERIALS BETWEEN THE BLOOD AND TISSUES. MAINTENANCE OF THE BLOOD PRESSURE  ARTERIES CARRY BLOOD FROM THE HEART TO CAPILLARIES SMALL ARTERIES ARE ARTERIOLES. OUTER AND...

ANATOMY AND PHYSIOLOGY CHAPTER 13 THE VASCULAR SYSTEM  FUNCTIONS EXCHANGE OF MATERIALS BETWEEN THE BLOOD AND TISSUES. MAINTENANCE OF THE BLOOD PRESSURE  ARTERIES CARRY BLOOD FROM THE HEART TO CAPILLARIES SMALL ARTERIES ARE ARTERIOLES. OUTER AND MIDDLE LAYERS THICK. 3 LAYERS OF ARTERIES TUNICA INTIMA TUNICA MEDIA TUNICA EXTERNA  VEINS CARRY BLOOD FROM CAPILLARIES BACK TO THE HEART. SMALLER VEINS ARE VENULES. SAME THREE LAYERS AS ARTERIES BUT INNER LAYER HAS VALVES. THESE VALVES PREVENT BACKFLOW. MIDDLE AND OUT LAYER IS THIN BECAUSE BP IS LOW IN VEINS.  ANASTOMOSES CONNECTION OR JOINING, OF VESSELS, ARTERY TO ARTERY OR VEIN TO VEIN. PURPOSE IS TO PROVIDE ALTERNATE PATHWAYS FOR THE FLOW OF BLOOD IF ONE VESSEL BECOMES OBSTRUCTED. ARTERIAL VENOUS  CAPILLARIES CARRY BLOOD FROM ARTERIOLES TO VENULES. WALLS ONLY 1 CELL IN THICKNESS BLOOD FLOW IS REGULATED BY PRECAPILLARY SPHINCTERS. CONSTRICT AND DILATE ACCORDING TO THE NEEDS OF THE TISSUES. SINUSOIDS ARE LARGER AND MORE PERMEABLE THAN OTHER CAPILLARIES. PERMIT LARGER SUBSTANCES SUCH AS PROTEINS AND BLOOD CELLS TO ENTER OR LEAVE THE BLOOD.  SINUSOIDS ARE FOUND IN HEMOPOIETIC TISSUES SUCH AS RED BONE MARROW AND SPLEEN, LIVER AND PITUITARY GLAND.  EXCHANGES IN CAPILLARIES SITES FOR EXCHANGE OF MATERIALS BETWEEN THE BLOOD AND TISSUE FLUID SURROUNDING CELLS. GASES MOVE BY DIFFUSION FROM THEIR AREA OF GREATER CONCENTRATION TO THE AREA OF LOWER CONCENTRATION. BP IN ARTERIOLES IS 30-35 MHG, AND THE PRESSURE OF THE SURROUNDING TISSUE FLUID IS MUCH LOWER, ABOUT 2 MMHG.  BECAUSE CAPILLARY BLOOD PRESSURE IS HIGHER, THE PROCESS OF FILTRATION OCCURS, WHICH FORCES PLASMA AND DISSOLVED NUTRIENTS OUT OF THE CAPILLARIES AND INTO TISSUE FLUID. BP DECREASES AS IT REACHES THE VENOUS END OF CAPILLARIES.  ALBUMIN CONTRIBUTES TO COLLOID OSMOTIC PRESSURE OF BLOOD THIS IS A PULLING PRESSURE. AT THE VENOUS END OF CAPILLARIES, THE PRESENCE OF ALBUMIN IN THE BLOOD PULLS TISSUE FLUID INTO THE CAPILLARIES WHICH ALSO BRINGS INTO THE BLOOD THE WASTE PRODUCTS PRODUCED BY CELLS.  THE TISSUE FLUID THAT RETURNS TO THE BLOOD ALSO HELPS MAINTAIN NORMAL BLOOD VOLUME AND BLOOD PRESSURE. EXCESS TISSUE FLUID ENTERS LYMPH CAPILLARIES TO BE RECYCLED AS PLASMA.  PULMONARY CIRCULATION RIGHT VENTRICLE PUMPS BLOOD INTO THE PULMONARY ARTERY, WHICH DIVIDES INTO THE RIGHT AND LEFT PULMONARY ARTERIES, ONE FOR EACH LUNG. WITHIN THE LUNGS EACH ARTERY BRANCHES EXTENSIVELY INTO SMALLER ARTERIES AND ARTERIOLES, THEN TO CAPILLARIES. THE PULMONARY CAPILLARIES SURROUND THE ALVEOLI OF THE LUNGS.  THE ALVEOLI ARE WHERE THE EXCHANGES OF OXYGEN AND CARBON DIOXIDE TAKE PLACE. THE CAPILLARIES UNITE TO FORM VENULES, WHICH MERGE INTO VEINS, AND FINALLY INTO THE TWO PULMONARY VEINS FROM EACH LUNG THAT RETURN BLOOD TO THE LEFT ATRIUM. THIS OXYGENATED BLOOD WILL THEN TRAVEL THROUGH THE SYSTEMIC CIRCULATION.  NOTICE THAT THE PULMONARY VEINS CONTAIN OXYGENATED BLOOD; THESE ARE THE ONLY VEINS WITH HIGH OXYGEN CONTENT.  SYSTEMIC CIRCULATION LEFT VENTRICLE PUMPS BLOOD INTO THE AORTA. ASCENDING AORTA AORTIC ARCH THORACIC AORTA ABDOMINAL AORTA  THE BRANCHES OF THE AORTA TAKE THE BLOOD INTO ARTERIOLES AND CAPILLARY NETWORKS THROUGHOUT THE BODY. CAPILLARIES MERGE TO FORM VENULES AND VEINS. THE VEINS FROM THE LOWER BODY TAKE BLOOD TO THE INFERIOR VENA CAVA THE VEINS FROM THE UPPER BODY TAKE BLOOD TO THE SUPERIOR VENA CAVA. THESE RETURN BLOOD TO THE RIGHT ATRIUM.  CIRCLE OF WILLIS CIRCLE OF ARTERIES AROUND THE PITUITARY GLAND. THE BRAIN MUST HAVE A CONSTANT FLOW OF BLOOD TO SUPPLY OXYGEN AND REMOVE WASTE PRODUCTS.  THE SYSTEMIC VEINS DRAIN BLOOD FROM ORGANS OR PARTS OF THE BODY AND OFTEN PARALLEL THEIR CORRESPONDING ARTERIES.  HEPATIC PORTAL CIRCULATION SUBDIVISION OF THE SYSTEMIC CIRCULATION IN WHICH BLOOD FROM THE ABDOMINAL DIGESTIVE ORGANS AND SPLEEN CIRCULATES THROUGH THE LIVER BEFORE RETURNING TO THE HEART. BLOOD FROM THE CAPILLARIES OF THE STOMACH, SMALL INTESTINE, COLON, PANCREAS, AND SPLEEN FLOWS INTO TWO LARGE VEINS, THE SUPERIOR MESENTERIC VEIN AND THE SPLENIC VEIN, WHICH UNITE TO FORM THE PORTAL VEIN.  THE PORTAL VEIN TAKES BLOOD INTO THE LIVER, WHERE IS EMPTIES BLOOD INTO THE SINUSOIDS, THE CAPILLARIES OF THE LIVER. FROM THE SINUSOIDS, BLOOD FLOWS INTO HEPATIC VEINS TO THE INFERIOR VENA CAVA AND BACK TO THE RIGHT ATRIUM. PURPOSE IS TO ENABLE THE LIVER TO MODIFY THE BLOOD FROM THE DIGESTIVE ORGANS AND SPLEEN.  SOME NUTRIENTS MAY BE STORED OR CHANGED, BILIRUBIN FROM THE SPLEEN IS EXCRETED INTO BILE, AND POTENTIAL POISONS ARE DETOXIFIED BEFORE THE BLOOD RETURNS TO THE HEART AND THE REST OF THE BODY. DETOXIFY’S ALCOHOL, AND IF GLUCOSE IS HIGH, CHANGES IT TO GLYCOGEN TO STORE.  FETAL CIRCULATION FETUS IS DEPENDENT ON MOTHER FOR OXYGEN AND NUTRIENTS AND FOR REMOVAL OF CARBON DIOXIDE AND WASTE PRODUCTS. SITE OF EXCHANGE IS PLACENTA, WHICH CONTAINS FETAL AND MATERNAL BLOOD VESSELS THAT ARE VERY CLOSE TO ONE ANOTHER. HOWEVER, THE BLOOD DOESN’T MIX SUBSTANCE ARE EXCHANGED BY DIFFUSION AND ACTIVE TRANSPORT.  UMBILICAL CORD UMBILICAL ARTERIES UMBILICAL VEIN DUCTUS VENOSUS  THE FETAL LUNGS ARE DEFLATED AND DON’T PROVIDE FOR GAS EXCHANGE, BLOOD IS SHUNTED AWAY FROM THE LUNGS AND TO THE BODY. THE FORAMEN OVALE IS AN OPENING IN THE INTERATRIAL SEPTUM THAT PERMITS SOME BLOOD TO FLOW FROM THE RIGHT ATRIUM TO THE LEFT ATRIUM.  THE BLOOD THAT DOES ENTER THE RIGHT VENTRICLE IS PUMPED INTO THE PULMONARY ARTERY. THE DUCTUS ARTERIOSUS IS A SHORT VESSEL THAT DIVERTS MOST OF THE BLOOD IN THE PULMONARY ARTERY TO THE AORTA, TO THE BODY. BOTH THE FORAMEN OVALE AND THE DUCTUS ARTERIOSUS PERMIT BLOOD TO BYPASS THE FETAL LUNGS.  JUST AFTER BIRTH, THE BABY BREATHES AND EXPANDS ITS LUNGS, WHICH PULLS MORE BLOOD INTO THE PULMONARY CIRCULATION. MORE BLOOD THEN RETURNS TO THE LEFT ATRIUM, AND A FLAP ON THE LEFT SIDE OF THE FORAMEN OVALE IS CLOSED. THE DUCTUS ARTERIOSUS CONSTRICTS, AND PULMONARY CIRCULATION BECOME FULLY FUNCTIONAL WITHIN A FEW DAYS.  VELOCITY OF BLOOD FLOW CIRCULATION TIME IS THE TIME IT TAKES FOR BLOOD TO GO FROM THE RIGHT VENTRICLE TO THE LUNGS, BACK TO THE HEART TO BE PUMPED BY THE LEFT VENTRICLE TO THE BODY, AND RETURN TO THE HEART AGAIN. THIS IS ABOUT 1 MINUTE OR LESS.  BLOOD PRESSURE FORCE THE BLOOD EXERTS AGAINST THE WALLS OF THE BLOOD VESSELS. FILTRATION DEPENDS UPON BLOOD PRESSURE. THE PUMPING OF THE VENTRICLES CREATES BLOOD PRESSURE, WHICH IS MEASURED IN MMHG. SYSTOLIC DIASTOLIC  MAINTENANCE OF SYSTEMIC BLOOD PRESSURE VENOUS RETURN SKELETAL MUSCLE PUMP CONSTRICTION OF THE VEINS RESPIRATORY PUMP HEART RATE AND FORCE PERIPHERAL RESISTANCE ELASTICITY OF THE LARGE ARTERIES VISCOSITY OF THE BLOOD LOSS OF BLOOD HORMONES  INTRINSIC MECHANISMS OF REGULATION OF BP HEART – STARLINGS LAW KIDNEYS – BLOOD FLOW RENIN-ANGIOTENSIN MECHANISM  NERVOUS MECHANISMS OF REGULATION OF BP HEART PERIPHERAL RESISTANCE  AGING AND THE VASCULAR SYSTEM AGING OF BLOOD VESSELS, ESPECIALLY ARTERIES, BEGINS IN CHILDHOOD, ALTHOUGH THE EFFECTS ARE NOT APPARENT FOR DECADES. ARTHEROSCLEROSIS IS EXPECTED WITH AGE. AVERAGE RESTING BLOOD PRESSURE MAY INCREASE, WHICH FURTHER DAMAGES ARTERIAL WALLS. MAY RESULT IN STROKE AND LEFT SIDED HEART FAILURE.  VEINS DETERIORATE WITH AGE; THEIR THIN WALLS WEAKEN AND STRETCH, MAKING THEIR VALVES INCOMPETENT. MOST LIKELY IN VEINS OF LEGS. VARICOSE VEINS AND PHLEBITIS RESULT.