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Cardiovascular System

Cardiovascular System. Circulatory Site of Sites. The Circle of Blood. PBS NOVA Heart Site. The Virtual Body. BLOOD. Functions : Transportation of 1) 2) 3) 4). O 2 & CO 2. nutrients. wastes. hormones. Regulation of 1) 2) 3). pH. temperature.

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Cardiovascular System

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  1. Cardiovascular System Circulatory Site of Sites The Circle of Blood PBS NOVA Heart Site The Virtual Body

  2. BLOOD Functions: Transportation of 1) 2) 3) 4) O2 & CO2 nutrients wastes hormones Regulation of 1) 2) 3) pH temperature water content by clotting Protection: 1) 2) against disease

  3. Contents of Blood circulatory system link Liquid part : made up of PLASMA (55%) Solid part: made up of CELLS & CELL FRAGMENTS (45%) 99% Red Blood Cells (RBC’s) 1% White Blood Cells (WBC’s) Blood Plasma 92% water & 8% solutes Solutes may be antibodies, enzymes, hormones, nutrients, waste products, and electrolytes (i.e. Na, Ca, K, Cl, etc…

  4. BLOOD CELLS circulatory system link 1 Erythrocytes– RBC’s -hematocrit – measurement of RBC’s in blood volume; 38-46% females 40-54% males • have no nuclei - cannot reproduce 2 Leukocytes – WBC’s • have nuclei - fight invaders 3 Thrombocytes – platelets (cell fragments) - used in clotting

  5. circulatory system link Hematopoiesis • formation of blood cells • originate from stem cells Erythropoiesis – RBC formation; stimulated by erythropoietin Red Blood Cells carry O2 attached to hemoglobin molecules. Each hemoglobin can carry 4 O2 molecules. There are 280 million hemoglobin molecules per RBC = 1,120,000,000 O2 molecules per RBC

  6. White Blood Cells (5 types) circulatory system link attacks antigen-antibody complexes& destroys certain parasitic worms 1) Eosinophils – 2) Basophils – release histamine which causes inflammatory response 3) Neutrophils - phagocytosis 4) Lymphocytes – mediate immune responses (T-cells), kill cancer cells, attacks transplanted tissue cells macrophages 5) Monocytes -

  7. CBC – Complete Blood Count circulatory system link immune system failure Low WBC High WBC  ongoing infection Clotting of Blood Hemostasis – stopping of bleeding (3 steps) 1 Blood vessel spasm – smooth muscle contraction 2 Platelet plug formation 3 Blood clotting - coagulation

  8. Platelet plug formation: circulatory system link A platelet plug can stop blood loss completely if the hole in a blood vessel is small enough (3 steps)… 1 Platelets stick to parts of damaged vessel. 2 Platelets change from disc shaped to an irregular shape that extend with projections that allow it to interact with other platelets.

  9. circulatory system link 3 Due to chemicals released, other platelets become sticky and stick to other platelets causing a platelet plug. reinforcing fibrin threads

  10. Blood clotting circulatory system link 13 chemical clotting factors If one is not present, blood does not clot = Hemophilia

  11. HEART circulatory system link Mediastinum • located in the of the chest Pericardium • enclosed in a pericardial sac, called the… Heart contains 4 chambers: 1) Right Atrium collects blood from… 3) Left Atrium receives blood from… the lungs the body 2) Right Ventricle sends blood to… 4) Left Ventricle sends blood to… the body the lungs

  12. Heart Valves… circulatory system link Atrioventricular valves (AV) separate what? the atriums and ventricles The valve found on the left side is known as the… bicuspid The valve found on the right side is known as the… tricuspid The chordae tendinae (tendon-like cords) connect the AV valves to the papillary muscle

  13. HEART circulatory system link Also know *CORONARY ARTERY* circulatory system link APEX SEPTUM EPICARDIUM MYOCARDIUM ENDOCARDIUM

  14. Heart Song http://www.dgs.k12.il.us/heart.htm

  15. HEART’s own blood supply circulatory system link Coronary arteries: • we have a left and a right that surround the heart like a… • branches off of the… • supplies heart cells w/ O2 and other nutrients Crown surrounds a person’s head Ascending aorta Coronary sinus: returns blood to the heart

  16. circulatory system link HEART PROBLEMS: Often due to… Poor coronary circulation FYI…the heart tries to avoid these problems with the use of artery connections called… Anastomoses – connections / arteries, that provide alternate routes for blood to supply a particular tissue/organ This would be useful when what type of problem may occur? Heart problem examples: Ischemia Can cause hypoxia- reduced O2 supply that weakens heart cells without killing them

  17. circulatory system link Heart problem examples: Angina chest pain, often caused from ischemia Myocardial infarction heart attack due to… • heart cells dying, • which leaves scar tissue, • therefore, the heart cannot pump Heart Conduction System • stimulates the heart to contract - due to autorhythmic fibers self-excitable cells, repeatedly generate and trigger heart contractions Provide 2 main functions: • Pace maker • 2. Conduction system • sets rhythm • carries impulses throughout the heart

  18. circulatory system link Heart Conduction System continued 0 The conduction system ensures that the cardiac chambers contract in a coordinated manner… Any problem w/this pathway and the heart will not beat properly SA (sinoatrial) node/pace maker - atria contract AV node AV bundle (Bundle of His) Bundle branches – move through the interventricular septum toward the apex Purkinje fibers - ventricles contract Conduction sequence: http://a1977.g.akamai.net/f/1977/1448/1d/webmd.download.akamai.com/1448/Anatom-E-Tools/Heart/Heart_Tool.swf

  19. circulatory system link Blood flow in the heart is directly related to pressure. - the chambers change size because of the contracting valves opening and closing The SA node starts the contractions The contraction is slowed considerably at the AV node for two reasons: 1. Fibers have a much smaller diameter 2. It allows the atria to empty fully and the ventricles to fill

  20. circulatory system link Sometimes we experience an ectopic pacemaker • a site in the heart other than the SA node can develop self-excitability • can be due to… Caffeine, nicotine, drugs, dehydration, or hypoxia EKG(ECG)  ELECTROCARDIOGRAM A diagnostic tool used to record the electrical charges associated with the heart beat P wave – atrial contraction  SA node P-Q interval – impulse travels through conduction system QRS complex – ventricular contraction  impulse through the ventricles T-wave – restoring potential of ventricle

  21. circulatory system link http://a1977.g.akamai.net/f/1977/1448/1d/webmd.download.akamai.com/1448/Anatom-E-Tools/Heart/Heart_Tool.swf This is our heart beat… Consisting of both atria contracting and then both ventricles contracting

  22. circulatory system link Systole Contraction&Diastole  Relaxation 1 cardiac cycle consists of: NOVA Online | Cut to the Heart | Map of the Human Heart atrial systole/ventricular diastole atrial diastole/ventricular systole During the cardiac cycle, SOUNDS can be heard. The lubb-dubb (or lubb-dupp) sound that is heard is from the closing of the valves. http://www.bioscience.org/sound/normal.wav Heart Sounds LUBB– AV valves closing (after ventricular systole begins) DUPP – semilunar valves closing (after ventricular systole ends)

  23. circulatory system link Doctors listen to the sounds because they can tell if there is a problem of blood flow through the heart Heart murmur– flow noise before, between, or after lubb-dupp http://www.bioscience.org/sound/ms3.wav Mitral stenosis – narrowing of the mitral valve Mitral valve prolapse– inherited; portion of mitral valve is pushed back into the atria 10-15% of the population; 65% female http://www.med.ucla.edu/wilkes/intro.html http://www.medstudents.com.br/cardio/heartsounds/heartsou.htm

  24. circulatory system link Fetal Circulation: Blood does not need to go to the lungs, so it goes from the right atrium directly to the left atrium via the foramen ovale (fossa ovalis after birth). If the hole does not close after birth (which is what normally happens) it may need to be surgically repaired.

  25. circulatory system link Autonomic control - autonomic nervous system (we do not control) consists of two parts: 1.Sympathetic increases heart rate and the force of the contractions due to the release of norepinephrine and epinephrine (Fight or Flight response) 2. Parasympathetic decreases heart rate due to the release of acetylcholine Both work together to maintain homeostasis

  26. Following a Drop of Blood To the brain and back… • Left atrium • Bicuspid/mitral valve • Left ventricle • Aortic semilunar valve • Aorta • Common carotid • Internal & external carotid • To the brain • Sigmoid sinus • Internal & external jugular • Brachiocephalic • Superior vena cava • Right atrium • Tricuspid valve • Right ventricle • Pulmonary semilunar valve • Pulmonary arteries • Lungs • Pulmonary veins

  27. Following a Drop of Blood To the left hand and back… • Aorta • Lt. subclavian • Lt. axillary • Lt. brachial • Lt. ulnar & lt. radial • Lt. ulnar & lt. radial • Lt. brachial • Lt. axillary • Lt. subclavian • Superior vena cava • Right atrium • Tricuspid valve • Right ventricle • Pulmonary semilunar valve • Pulmonary arteries • Lungs • Pulmonary veins • Left atrium • Bicuspid/mitral valve • Left ventricle • Aortic semilunar valve

  28. Following a Drop of Blood To foot and back… • Aorta • Common iliac • External iliac • Femoral • Popliteal • Anterior & posterior tibial • Anterior & posterior tibial • Popliteal • Femoral • External iliac • Common iliac • Inferior vena cava • Right atrium • Tricuspid valve • Right ventricle • Pulmonary semilunar valve • Pulmonary arteries • Lungs • Pulmonary veins • Left atrium • Bicuspid/mitral valve • Left ventricle • Aortic semilunar valve

  29. Anatomy of the BLOOD VESSELS circulatory system link The heart pumps the blood through a series of “pipes” or vessels through a closed system Arteries carry the blood away from the heart Veins bring the blood back to the heart heart Arteries Arterioles CapillariesVenulesVeins

  30. ARTERIES circulatory system link Tunics – coats (3 layers) of an artery • Tunica Interna – inside; lines the lumen; is an endothelium that lines the entire inner surface of • the circulatory system • Tunica Media – middle; thickest layer; made of muscle and elastic tissue which allows for high compliance*; • helps propel the blood 3. Tunica Externa - outside

  31. Sympathetic fibers send impulses to smooth muscles of the artery walls circulatory system link Vasoconstriction – smooth muscle contracts causing a Narrowing of the lumen; causing an increase in… B.P. Vasodilation – smooth muscle relaxes which causes the diameter of the lumen to increase Vasospasm limits blood loss in the event of an injured vessel by constricting and limiting blood flow Elastic Arteries – largest arteries that serve as a pressure reservoir*; helps to propel blood while the ventricles are relaxed Examples include: aorta, brachiocephalic, common carotid, subclavians, vertebrals, pulmonary, and common iliac are all elastic arteries

  32. circulatory system link Muscular Arteries – contain more smooth muscle than elastic fibers allowing for more vasoconstriction and vasodilation to help control blood flow Arterioles – deliver blood to the capillaries Capillaries – smallest of the vessels; responsible for microcirculation (blood flow from arterioles to venules through capillaries); found near almost every cell in the body • muscles, liver, kidneys, nervous tissue - contain a large # of capillaries • tendons, ligament – contain few • cornea and lens of the eye, cartilage – contain none

  33. Capillary Function: circulatory system link • Exchange of materials • only one cell thick (endothelium) • lots of branches to increase… surface area Venules – small veins formed by united capillaries • collects blood from capillaries and drains into veins Veins – also have the tunica interna, media, and externa • lack muscle and elastic fibers • contain large diameter lumen • contain valves that project into the lumen and toward the heart; to prevent backflow

  34. circulatory system link Veins (continued) • serve as blood reservoirs 60% of the body’s blood is found in them • thus blood can quickly be diverted to other parts of • the body when necessary (via venoconstriction) Blood flow velocity (speed) FAST Aorta fastest slowest – why and what is the benefit? Capillaries Vena cavas faster Normal circulation time for 1 drop of blood is SLOW about 1 minute

  35. CAPILLARY EXCHANGE circulatory system link Diffusion • all materials move from areas of HIGH to LOW • movement of materials (CO2, O2, glucose, hormones • and amino acids) Bulk Flow: Filtration & Reabsorption • help to maintain fluid balance and is based on pressure differences (high to low) • Filtration – fluid movement from capillaries to cells • Reabsorption – fluid movement from cells to capillaries Swelling (Edema) – occurs when… there is excessive filtration or inadequate reabsorption

  36. BLOOD PRESSURE circulatory system link • The farther from the left ventricle, the • lower the blood pressure • BP depends on the following… • 1. Volume of blood (5 liters) • increase in blood volume • (water retention)  high BP • decrease in blood volume • (hemorrhaging)  low BP 2. Vessel resistance • vessel radius – smaller radius greater resistance

  37. blood viscosity • high viscosity = low viscosity = circulatory system link high BP (dehydration) low BP (anemia) • blood vessel length • longer the vessel, greater the resistance (high B.P.) each extra pound of fat = (200 miles) BLOOD PRESSURE systole diastole Considered normal, but may vary among individuals. 120 80 *Women are often 8-10 mm Hg lower

  38. Regulation of Blood Pressure circulatory system link Baroreceptors • specialized cells that line the walls of arteries, veins, and the right atrium • sense change in pressure and stretch in vessels 3 most important: 1. Carotid sinus 2. Aortic arch 3. Right atrium tors inus tors aorta • Carotid sinus • located within the internal carotids • regulate brain blood pressure

  39. if stretched (BP increases) circulatory system link To combat this… • A message is sent to the medulla oblongata • An increase in parasympathetic impulses (SA node) • Heart rate is slowed • Cardiac output is decreased • Vasodilation is increased • Blood pressure lowers • if blood pressure drops • 1. Baroreceptors are stretched less • 2. A decrease in parasympathetic impulses occurs • 3. An increase in sympathetic impulses occurs • 4. Increase in epinephrine and norepinephrine • 5. Heart rate increases • 6. Vasoconstriction occurs • 7. Vascular resistance increases • 8. Blood pressure raises

  40. Chemoreceptors circulatory system link • located next to baroreceptors • measures changes in chemicals in blood • i.e. oxygen, carbon dioxide, H+ (acid) lowered O2 availability • Hypoxia – • Hypercapnia – • Acidosis – excess CO2 increase in H+ concentration (will cause increased sympathetic impulses which will increase heart rate and cause vasoconstriction) THE END

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