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Cardiovascular System

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Presentation on theme: "Cardiovascular System"— Presentation transcript:

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 Protection: 1) 2) by clotting against disease

3 Contents of Blood Blood Plasma Liquid part : made up of PLASMA (55%)
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 1 Erythrocytes – RBC’s - hematocrit –
circulatory system link 1 Erythrocytes – RBC’s - hematocrit – measurement of RBC’s in blood volume; % females % males have no nuclei - cannot reproduce 2 Leukocytes – WBC’s have nuclei - fight invaders 3 Thrombocytes – platelets (cell fragments) - used in clotting

5 Hematopoiesis formation of blood cells originate from stem cells
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 1) Eosinophils – attacks antigen-antibody complexes & destroys certain parasitic worms 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 5) Monocytes - macrophages

7 CBC – Clotting of Blood Complete Blood Count Hemostasis – Low WBC 
circulatory system link Low WBC  High WBC  immune system failure 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 reinforcing fibrin threads
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 13 chemical clotting factors
circulatory system link 13 chemical clotting factors If one is not present, blood does not clot = Hemophilia

11 HEART located in the of the chest Mediastinum
circulatory system link 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… 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… Atrioventricular valves (AV) separate what?
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 Also know *CORONARY ARTERY* APEX SEPTUM EPICARDIUM MYOCARDIUM
circulatory system link Also know *CORONARY ARTERY* circulatory system link APEX EPICARDIUM SEPTUM MYOCARDIUM ENDOCARDIUM

14 Heart Song

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 HEART PROBLEMS: Often due to… Poor coronary circulation
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 Heart Conduction System
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 Heart Conduction System continued
circulatory system link Heart Conduction System continued 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 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

19 Blood flow in the heart is directly related to pressure.
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 EKG (ECG)  ELECTROCARDIOGRAM
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 Consisting of both atria contracting and then both
circulatory system link This is our heart beat… Consisting of both atria contracting and then both ventricles contracting

22 Systole  Contraction & Diastole  Relaxation
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. Heart Sounds LUBB – AV valves closing (after ventricular systole begins) DUPP – semilunar valves closing (after ventricular systole ends)

23 Doctors listen to the sounds because they can tell if there
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 Mitral stenosis – narrowing of the mitral valve Mitral valve prolapse – inherited; portion of mitral valve is pushed back into the atria % of the population; % female

24 Blood does not need to go to the lungs, so it goes
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 Both work together to maintain homeostasis
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 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 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 Tunics – coats (3 layers) of an artery
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 Muscular Arteries – contain more smooth muscle than
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 only one cell thick (endothelium) lots of branches to increase…
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 Blood flow velocity (speed)
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 Capillaries slowest – why and what is the benefit? Vena cavas faster Normal circulation time for 1 drop of blood is SLOW about 1 minute

35 CAPILLARY EXCHANGE Diffusion Bulk Flow: Filtration & Reabsorption
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 The farther from the left ventricle, the
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 PRESSURE 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) To combat this…
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 THE END located next to baroreceptors
circulatory system link located next to baroreceptors measures changes in chemicals in blood i.e. oxygen, carbon dioxide, H+ (acid) Hypoxia – Hypercapnia – Acidosis – lowered O2 availability 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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