Transcript CIRCULATION
CIRCULATION CIRCULATION • THE CIRCULATORY SYSTEM ASSOCIATES INTIMATELY WITH ALL BODY TISSUES – CIRCULATORY SYSTEM • A SYSTEM OF INTERNAL TRANSPORT; TRANSPORTS OXYGEN AND CARBON DIOXIDE, DISTRIBUTES NUTRIENTS TO BODY CELLS, AND CONVEYS THE WASTE PRODUCTS OF METABOLISM TO SPECIFIC SITES FOR DISPOSAL CIRCULATION • SEVERAL TYPES OF INTERNAL TRANSPORT HAVE EVOLVED IN ANIMALS – SIMPLE ANIMALS HAVE NO TRUE CIRCULATORY SYSTEM (WHY DON’T THEY NEED ONE??) • EX. HYDRA – BLOOD • SPECIALIZED CIRCULATORY FLUID FOUND IN MORE COMPLEX ANIMALS – TWO BASIC TYPES OF SYSTEMS • OPEN CIRCULATORY SYSTEM • CLOSED CIRCULATORY SYSTEM CIRCULATION • TWO BASIC TYPES OF SYSTEMS CIRCULATION • TWO BASIC TYPES OF SYSTEMS – OPEN CIRCULATORY SYSTEM • BLOOD LEAVES THE VESSELS AND BATH THE CELLS DIRECTLY (EX. GRASSHOPPER) – CLOSED CIRCULATORY SYSTEM (A.K.A. CARDIOVASCULAR SYSTEM) • CONSISTS OF A HEART AND TUBE-LIKE VESSELS; THE BLOOD IS ALWAYS CONFINED TO THESE VESSELS (EX. FISH, HUMANS) CIRCULATION • CLOSED CIRCULATORY SYSTEM – THREE KINDS OF VESSELS • ARTERIES – CARRY BLOOD AWAY FROM THE HEART – ARTERIOLES SMALL VESSELS, OFF ARTERIES, THAT GIVE RISE TO CAPILLARIES • VEINS – CARRY BLOOD TO THE HEART – VENULES RESULT OF CONVERGING CAPILLARIES THAT EVENTUALLY FORM VEINS • CAPILLARIES – CONVEY BLOOD BETWEEN ARTERIES AND VEINS WITHIN EACH ORGAN – CAPILLARY BEDS NETWORKS OF CAPILLARIES THAT INFILTRATE EVERY ORGAN AND TISSUE IN THE BODY CIRCULATION • VERTEBRATE CARDIOVASCULAR SYSTEMS REFLECT EVOLUTION CIRCULATION • VERTEBRATE CARDIOVASCULAR SYSTEMS – PULMONARY CIRCUIT • CARRIES BLOOD BETWEEN THE HEART AND THE GAS EXCHANGE TISSUES IN THE LUNGS – SYSTEMIC CIRCUIT • CARRIES BLOOD BETWEEN THE HEART AND THE REST OF THE BODY CIRCULATION • HUMAN HEART AND CARDIOVASCULAR SYSTEM TYPIFY THOSE OF MAMMALS CIRCULATION • FOLLOWING THE PATH OF BLOOD – – – – – – – – – – RIGHT VENTRICLE *PULMONARY ARTERIES* CAPILLARIES IN LUNGS *PULMONARY VEIN* LEFT ATRIUM LEFT VENTRICLE AORTA ARTERIES BRANCH OFF AORTA SUPERIOR VENA CAVA / INFERIOR VENA CAVA RIGHT ATRIUM – *VAVA L VAVA* CIRCULATION • THE STRUCTURE OF BLOOD VESSELS FITS THEIR FUNCTION – ARTERIES • THICKEST – VEINS • VALVES – CAPILLARIES • THINNEST CIRCULATION • THE HEART CONTRACTS AND RELAXES RHYTHMICALLY – CARDIAC CYCLE • A COMPLETE SEQUENCE OF FILLING AND PUMPING OF THE HEART • DIASTOLE – ENTIRE HEART IS RELAXED; BLOOD FLOWS INTO ALL FOUR CHAMBERS » AV VALVES ARE OPEN, ALLOWING BLOOD TO GO FROM ATRIUM TO VENTRICLES • SYSTOLE – BRIEF CONTRACTION THAT FORCES ALL BLOOD INTO VENTRICLES (0.1 SEC) – VENTRICLES CONTRACT FOR ABOUT 0.3 SEC, CLOSING AV VALVES AND OPENING SEMI-LUNAR VALVES WHICH PUMPS BLOOD INTO ARTERIES CIRCULATION • THE HEART CONTRACTS AND RELAXES RHYTHMICALLY – CARDIAC OUTPUT • THE VOLUME OF BLOOD PER MINUTE THAT THE LEFT VENTRICLE PUMPS INTO THE SYSTEMIC CIRCUIT – VALVES PREVENT BACKFLOW AND KEEP BLOOD FLOWING IN RIGHT DIRECTION • RESPONSIBLE FOR “LUB-DUB” SOUND HEART MAKES • WHEN DEFECTIVE, RESULTS IN A MURMUR – EXTRA HEART SOUNDS CIRCULATION • THE PACEMAKER SETS THE TEMPO OF THE HEARTBEAT CIRCULATION • THE PACEMAKER SETS THE TEMPO OF THE HEARTBEAT – PACEMAKER A.K.A. SA (SINOATRIAL) NODE; SPECIALIZED REGION OF CARDIAC MUSCLE THAT MAINTAINS THE HEARTS PUMPING RHYTHYM BY SETTING THE RATE AT WHICH ALL THE MUSCLE CELLS OF THE HEART CONTRACT • PACEMAKER GENERATES ELECTRICAL SIGNALS • SIGNALS SPREAD THROUGHOUT ATRIA; 0.1 SEC TO REACH AV (ATRIOVENTRICULAR) NODE • SPECIALIZED MUSCLE FIBERS RELAY SIGNALS AND CAUSE VENTRICLE CONTRACTION THAT PUMPS BLOOD – ARTIFICIAL PACEMAKER • A TINY ELECTRONIC DEVICE SURGICALLY IMPLANTED NEAR THE AV NODE; EMIT ELECTRICAL SIGNALS THAT TRIGGER NORMAL HEARTBEATS CIRCULATION • WHAT IS A HEART ATTACK? – HEART ATTACK • FAILURE OF THE HEART TO FUNCTION PROPERLY; DUE TO LACK OF OXYGEN BEING DELIVERED TO CARDIAC CELLS – CARDIOVASCULAR DISEASE • DISEASES OF HEART AND BLOOD VESSELS; ACCOUNTS FOR 40% OF ALL DEATHS IN U.S. – ATHERIOSCLEROSIS • GROWTH OF PLAQUE DEVELOPS ON THE INNER WALLS OF THE ARTERIES, NARROWING THE PASSAGES THROUGH WHICH BLOOD CAN FLOW CIRCULATION • BLOOD EXERTS PRESSURE ON VESSEL WALLS – BLOOD PRESSURE • THE FORCE THAT BLOOD EXERTS AGAINST THE WALLS OF OUR BLOOD VESSELS – PULSE • THE RHYTHMIC STRETCHING OF THE ARTERIES CIRCULATION • MEASURING BLOOD PRESSURE CAN REVEAL CARDIOVASCULAR PROBLEMS – HYPERTENSION • HIGH BLOOD PRESSURE; MAY INDICATE A SEVERE CARDIOVASCULAR DISEASE CIRCULATION • SMOOTH MUSCLE CONTROLS THE DISTRIBUTION OF BLOOD – SPHINCTERS EXIST THAT LIMIT BLOOD FLOW THROUGH CAPILLARY BEDS IF BLOOD IS NOT NEEDED IN THOSE AREAS (EX. DIGESTIVE TRACT DURING EXERCISE) CIRCULATION • CAPILLARIES ALLOW THE TRANSFER OF SUBSTANCES THROUGH THEIR WALLS – THE THIN WALLS MAKE THIS THE ONLY VESSEL WHERE TRANSFER OF SUBSTANCES CAN TAKE PLACE CIRCULATION • BLOOD CONSISTS OF CELLS SUSPENDED IN PLASMA CIRCULATION • BLOOD CONSISTS OF CELLS SUSPENDED IN PLASMA – ADULT HUMAN ON AVERAGE HAS 4 – 6 LITERS OF BLOOD – 4 PARTS TO BLOOD • • • • PLASMA RED BLOOD CELLS WHITE BLOOD CELLS PLATELETS CIRCULATION • PLASMA – LIQUID MADE UP OF 90% WATER, 10% INORGANIC SALTS • 55% OF BLOOD IS PLASMA • WORKS TO MAINTAIN OSMOTIC BALANCE AND PH CIRCULATION • RED BLOOD CELLS – A.K.A. ERYTHROCYTES – MOST NUMEROUS BLOOD CELLS – LACK NUCLEI AND MITOCHONDRIA – FORMED IN BONE MARROW – CYCLE FOR 3-4 MONTHS BEFORE BROKEN DOWN AND RECYCLED IN THE LIVER – *ANEMIA* • AN ABNORMALLY LOW AMOUNT OF HEMOGLOBIN OR A LOW NUMBER OF RED BLOOD CELLS CIRCULATION • WHITE BLOOD CELLS – A.K.A. LEUKOCYTES – HELP DEFEND THE BODY – 5 TYPES • BASOPHILS – RELEASE CHEMICALS TO FIGHT INFECTION • NEUTROPHILS – PHAGOCYTES • MONOCYTES – PHAGOCYTES • EOSINOPHILS – KILL PARASITIC WORMS, HELP REDUCE ALLERGIES; NOT FULLY UNDERSTAND • LYMPHOCYTES – KEY CELL IN IMMUNITY – WILL DISCUSS IN MORE DETAIL DURING “IMMUNE SYSTEM” CIRCULATION • PLATELETS – BITS OF CYTOPLASM PINCHED OFF FROM LARGE CELLS IN THE BONE MARROW – IMPORTANT IN BLOOD CLOTTING CIRCULATION • BLOOD CLOTTING – PLATELETS AND THE PLASMA PROTEIN FIBRINOGEN ACT AS SEALANTS – PROTHROMBIN IS CONVERTED TO THROMBIN WHICH CONVERTS FIBRINOGEN TO FIBRIN • FIBRIN – THREAD-LIKE PROTEIN THAT TRAPS BLOOD CELLS; FORMING PATCH UNTIL CONNECTIVE TISSUE CAN HEAL – CLOTTING MECHANISM DEFECTS CAN BE SERIOUS • HEMOPHILIA • THROMBOSIS CLOTS WHEN THERE IS NO INJURY CIRCULATION • STEM CELLS OFFER A POTENTIAL CURE FOR LEUKEMIA AND OTHER BLOOD CELL DISEASES – STEM CELLS • UNSPECIALIZED CELLS – LEUKEMIA • CANCER OF THE WHITE BLOOD CELLS (LEUKOCYTES) CIRCULATION • SPEAKING OF DISEASES…HOW DOES THE HUMAN BODY PROTECT ITSELF?? • THE IMMUNE SYSTEM IS NEXT!!!