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

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Presentation on theme: "Cardiovascular System The Circle of Blood PBS NOVA Heart Site The Virtual Body Circulatory Site of Sites."— Presentation transcript:

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

2 BLOOD Functions:Transportation of 1) 2) 3) 4) O 2 & CO 2 Regulation of1) 2) 3) pH Protection:1) 2) nutrients wastes hormones temperature water content by clotting against disease

3 Contents of Blood Liquid part : Solid part: 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… made up of PLASMA (55%) made up of CELLS & CELL FRAGMENTS (45%) circulatory system link

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

5 Hematopoiesis Erythropoiesis – Red Blood Cells carry O 2 attached to hemoglobin molecules. There are 280 million hemoglobin molecules per RBC = 1,120,000,000 O 2 molecules per RBC Each hemoglobin can carry 4 O 2 molecules. RBC formation; stimulated by erythropoietin formation of blood cells originate from stem cells circulatory system link

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

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

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

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

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

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

12 Heart Valves… 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 circulatory system link


14 Heart Song

15 HEART’s own blood supply Coronary arteries: we have a left and a right that surround the heart like a… branches off of the… supplies heart cells w/ O 2 and other nutrients Crown surrounds a person’s head Ascending aorta circulatory system link Coronary sinus: returns blood to the heart

16 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 Heart problem examples: Ischemia  Can cause hypoxia - This would be useful when what type of problem may occur? circulatory system link reduced O 2 supply that weakens heart cells without killing them

17 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: 1.Pace maker 2. Conduction system - sets rhythm - carries impulses throughout the heart circulatory system link

18 Heart Conduction System continued The conduction system ensures that the cardiac chambers contract in a coordinated manner… Conduction sequence: 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 Any problem w/this pathway and the heart will not beat properly circulatory system link

19 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 circulatory system link

20 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 circulatory system link

21 This is our heart beat… Consisting of both atria contracting and then both ventricles contracting circulatory system link

22 Systole  Contraction & Diastole  Relaxation 1 cardiac cycle consists of: atrial systole/ventricular diastole atrial diastole/ventricular systole NOVA Online | Cut to the Heart | Map of the Human Heart 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. normal.wa v LUBB – AV valves closing (after ventricular systole begins) DUPP – semilunar valves closing (after ventricular systole ends) circulatory system link Heart Sounds

23 Doctors listen to the sounds because they can tell if there is a problem of blood flow through the heart bioscience.o rg/sound/m s3.wav Heart murmur – flow noise before, between, or after lubb-dupp Mitral stenosis – narrowing of the mitral valve med.ucla.ed u/wilkes/intr o.html Mitral valve prolapse – inherited; portion of mitral valve is pushed back into the atria 10-15% of the population; 65% female circulatory system link ardio/heartsound s/heartsou.htm

24 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. circulatory system link

25 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 circulatory system link

26 Following a Drop of Blood To the brain and back…  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  Left atrium  Bicuspid/mitral valve  Left ventricle  Aortic semilunar valve

27 Following a Drop of Blood To the left hand and back…  Aorta Lt. subclavian Lt. axillary Lt. brachial 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  Aorta Common iliac External iliac Femoral Popliteal Anterior & posterior tibial Popliteal Femoral External iliac Common iliac Inferior vena cava  Right atrium To foot and back… Following a Drop of Blood  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 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 Arteries  Arterioles  Capillaries  Venules  Veins heart circulatory system link

30 ARTERIES Tunics – coats (3 layers) of an artery 1.Tunica Interna – inside; lines the lumen; is an endothelium that lines the entire inner surface of the circulatory system 2.Tunica Media – middle; thickest layer; made of muscle and elastic tissue which allows for high compliance*; helps propel the blood 3. Tunica Externa - outside circulatory system link

31 Sympathetic fibers send impulses to smooth muscles of the artery walls 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 circulatory system link

32 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 circulatory system link

33 Capillary Function: 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 circulatory system link

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

35 CAPILLARY EXCHANGE movement of materials (CO 2, O 2, glucose, hormones and amino acids) all materials move from areas of HIGH to LOW Diffusion Bulk Flow: Filtration & Reabsorption help to maintain fluid balance and is based on pressure differences (high to low) Filtration – Reabsorption – Swelling (Edema) – occurs when… there is excessive filtration or fluid movement from capillaries to cells fluid movement from cells to capillaries inadequate reabsorption circulatory system link

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

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

38 Regulation of Blood Pressure Baroreceptors Carotid sinus located within the internal carotids regulate brain blood pressure tors inus tors aorta 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 circulatory system link

39 1.A message is sent to the medulla oblongata 2.An increase in parasympathetic impulses (SA node) 3.Heart rate is slowed 4.Cardiac output is decreased 5.Vasodilation is increased 6.Blood pressure lowers if stretched (BP increases) To combat this… 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 circulatory system link

40 Chemoreceptors located next to baroreceptors measures changes in chemicals in blood i.e. oxygen, carbon dioxide, H + (acid) Hypoxia – Hypercapnia – Acidosis – lowered O 2 availability circulatory system link excess CO 2 increase in H + concentration (will cause increased sympathetic impulses which will increase heart rate and cause vasoconstriction) THE END

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