circulatory system LYMPHATIC SYSTEM AND DETAILS

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1. CIRCULATORY SYSTEM AND LYMPHATIC SYSTEM

2. Overview of the circulatory system Function of the Circulatory system Transportation Regulation Protection Major components of the circulatory system Cardiovascular system Lymphatic system Blood Composition Structure of the Heart Blood Circulation Pulmonary and Systemic circuit

3. Valves of the Heart Pathway of Blood flow through the heart The cardiac cycle Pressure changes during the cardiac cycle: Systole & Diastole Cardiac Output Heart sounds Cardiac Conduction System Blood vessels Arteries and Arterioles Capillaries and Types Veins and Venules Lymphatic System Conclusion

4. The circulatory system consists of Blood Blood vessels The Heart Lymphatic vessels It works together with other systems in maintaining Homeostasis Respiratory Urinary Digestive Endocrine Integumentary systems

5. Major Components of the Circulatory System The circulatory system is divided into two major subdivisions: The Cardiovascular system and the Lymphatic system Cardiovascular system consist of: Heart Blood vessels: Form a tubular network that permits the flow of blood Arteries , arterioles, veins, capillaries

6. Cont. Lymphatic system consists of: Lymphatic vessels Lymphoid tissues Found in the spleen, thymus, tonsil and lymph nodes

7. Composition of the Blood It consist of formed elements that are suspended and carried in fluid know as plasma. The formed element of the blood consist of: Erythrocyte (RBC) Leukocyte ( WBC) Platelets Hematopoiesis is the formation of blood cells Hematopoietic stem cells

8. The Constituents of Blood The constituents of blood. Blood cells become packed at the bottom of the test tube when whole blood is centrifuged, leaving the fluid plasma at the top of the tube.

9. Blood Composition cont. Erythropoiesis refers to the formation of erythrocytes Leukopoesis refers to the formation of leukocytes These processes occur in two classes of tissues after birth Myeloid and lymphoid

10. The Heart Structure Located in the thoracic cavity in the mediastinum, between the lungs and deep to the sternum Contains four chamber Its about the size of a fist , the hollow, cone-shaped There is a layer of dense connective tissues b/t the atria and ventricle

11. Blood Circulation Movement  of blood through the vessels of the body that is induced by the pumping action of the heart and serves to distribute oxygen to and remove wasted products from all parts of the body. Two types: Pulmonary circulation Systemic circulation

12. Blood Circulation Cont. Pulmonary circuit carries deoxygenated blood away from the heart to the lungs and returns oxygenated blood to the heart. Systemic circuit carries oxygenated blood away from the heart to body system and returns deoxygenated blood to the heart. Pulmonary circuit begins in the right ventricle and ends in the left atrium Systemic circuit beings in the left ventricle and ends in the right atrium

13. Valves of the Heart Two (2) main types: Atrioventricular Valves Semilunar Valves

14. Atrioventricular Valves Found between the atria and ventricles Constitutes ; Tricuspid valve Bicuspid valve Tricuspid valve: right AV valve that prevents blood from flowing back into the right atrium when the right ventricle contract. It has three flaps of tissues. Bicuspid valves: left AV valve that prevents blood from flowing back into the left atrium when the left ventricle contract.

15. Semilunar Valves Shaped like half moons Constitutes; Pulmonary valve Aortic valve Pulmonary valve: beginning of the pulmonary truck. Prevents blood from flowing back into the right ventricle Aortic valve: beginning of the aorta. Prevents blood from flowing back into the left ventricle.

16. Transportation- Transport substances essential for cellular metabolism. These substances can be categorized as follows: Respiratory- Oxygen (RBC), Carbon dioxide (blood) Nutritive- Absorbed products of digestion (blood, lymphatics ) Excretory- Metabolic wastes (such as urea), excess water and ions, etc. (blood into kidneys = urine) Function of The Circulatory System

17. Cont. Regulation- contributes to both hormonal and temperature regulation Hormonal- hormones (blood) Temperature- diversion of blood from deeper to more superficial cutaneous vessels or vice versa

18. Protection- protects against blood loss from injury and against pathogens, including foreign microbes and toxins introduced into the body. These substances can be categorized as follows: Clotting - prevents blood loss when blood vessels are damaged. Immune function- protect against many disease-causing agents (pathogens). Performed by leukocytes (white blood cells ).

19. Conduction system of heart

20. Conductive system of the heart is formed by the modified cardiac muscle fibers. These fibers are the specialized cells, which conduct the impulses rapidly from SA node of the atrium. Conductive tissues of the heart are also called junctional tissues.

21. components AV Nodes Bundle of His Right and Left Bundle Branches Purkinje Fibers

22. Impulses starts from SA node are conducted through right and left atrium and reaches the AV nodes via some specialize fibers called internodal fibers. After this bundle of his arises and devides into right and left branches. From each branches of bundle of his many Purkinje fibers that arises and spread impulses all over the ventricular myocardium.

23. Cardiac cycle

24. Definition Cardiac cycle is defined as the succession of (sequence of) coordinated events taking place in the heart during each beat. Each heartbeat consists of two major period called systole and diastole.

25. During systole heart contracts and pump the blood through arteries. During diastole, heart relaxes and blood is filled in the heart. All these changes are repeated during every heartbeat, in a cyclic manner. When the heart beat at a normal rate of 72/minute, duration of each cycle is about 0.8 second.

26. Cont. Events of cardiac cycle Atrial events Atrial systole = 0.1 sec. Atrial diastole = 0.7 sec. Ventricular events Ventricular systole = 0.3 sec Ventricular diastole = 0.5 sec.

27. Atrial systole Also known as last rapid filling phase or presystole . It is also considered as last phase or ventricular diastole. In this period, only small amount of blood is forced from atria into ventricles.

28. Atrial diastole After arterial systole, the atrial diastole starts. Simultaneously, ventricular systole also starts. Atrial diastole lasts for 0.7 sec. which is necessary that atrial filling takes place.

29. Ventricular events Isovolumetric contraction– As the ventricles begin their contraction, the intraventricular pressure rises. Closure of atrioventricular valves at the beginning of this phase produces first heart sound (LUB ) . At this time, the ventricles are neither being filled with blood (because the AV valves are closed) nor ejecting blood (because the intraventricular pressure has not risen sufficiently to open the semilunar valves ).

30. Ejection- Blood is pumped out of the ventricles. When the pressure in the left ventricle becomes greater than the pressure in the aorta, the phase of ejection begins as the semilunar valves open . Protodiastole - It is the first stage of ventricular diastole. Due to the ejection of blood, the pressure in aorta and pulmonary artery increases and pressure in ventricular drops. It indicates end of systole and beginning of diastole.

31. Isovolumetric relaxation– In this period once again all the valves of the heart are closed. Both ventricles closed without change in volume and length of muscle fibers. Intraventricular pressure decreases during this period. Closure of semilunar valves during this phase produces second heart sound(DUB). Rapid  filling– When the pressure in the ventricles falls below the pressure in the atria, the AV valves open and a phase of rapid filling of the ventricles occurs. About 70 % of filling takes place during this phase.

32. Slow filling phase- A fter the sudden rush of blood, the ventricular filling become slow. Now it is called slow filling. It is also called diastasis. About 20 % filling occurs in this phase and is about 0.19 second. Last Rapid Filling Phase- L ast rapid filling phase occurs because of atrial systole. After slow filling period the atria contracts and push a small amount of blood into ventricles. About 10% of ventricular filling takes place during this period. Flow of additional amount of blood into ventricles due to atrial systole is called atrial kick.

33. Cardiac output

34. Defined  as the amount of blood pumped from each ventricle per minute. It refers to left ventricular output through aorta. It is important factor that shows the rate of blood. Determined by : Stroke volume Minute volume Cardiac index

35. Stroke volume is the amount of blood pumped out by each ventricle during each beat. Normal volume: 70 ml (60 to 80 ml) when the heart rate is normal (72 beat/minute). Minute volume is the amount of blood pumped out by eqch ventricle in one minute. It is the product of stroke volume and heart rate: Minute volume = stroke volume x heart rate Normal value: 5 L /ventricle/minute Cardiac index is defined as the amount of blood pumped out per ventricle/minute/square meter of the body surface area. Normal: 2.8 + 0.3 L/square meter of body surface area/minute.

36. 26.  Heart Sounds • There  are 4 heart sounds, 3 normal, 2 of which are easily heard • The 4th heart sound may normally be heard in a young child, but is abnormal in adults • The 1st and 2nd heart sounds are associated with the closure of valves

37. 27.  Heart Sound Cont’d…   1st Heart Sound ( Lubb ) • When the ventricle contract, the tricuspid and bicuspid valves snap shut  2nd Heart Sound ( Dubb ) • When the atria contract and the pulmonary and aortic valves snap shut

38. 28.  Heart Sound Cont’d…   3rd Heart Sound • Produced during diastole • Heard when the two inlet valves opens • Not usually audible, may be heard in young child  4th Heart Sound • Caused by contraction of both atria • It’s heard when there is atrial hypertrophy • Thickening of the wall of the atria

39. 29.  The Heart: Cardiac  Conduction System • Group of structures that send electrical impulses through the heart • Sinoatrial node (SA node) • Wall of right atrium • Generates impulse • Natural pacemaker • Sends impulse to AV node • Atrioventricular node (AV node) • Between atria just above ventricles • Atria contract • Sends impulse to the bundle of His • Bundle of His • Between ventricles • Two branches • Sends impulse to Purkinje fibers • Purkinje fibers • Lateral walls of ventricles • Ventricles contract

40. 30.  Cardiac Conduction System Figure 1.10  The conduction system of the heart. The conduction system consists of specialized myocardial cells that rapidly conduct the impulses from the atria into the ventricles.

41. 31.  Blood Vessels • Blood  vessels form a tubular network throughout the body that permits blood to flow from the heart to all the living cells of the body and then back to the heart • Blood leaving the heart passes through vessels of progressively smaller diameters, referred to as arteries, arterioles, and capillaries • Blood returning to the heart from the capillaries passes through vessels of progressively larger diameters, called venules and veins.

42. 32.  Blood Vessels: Arteries  and Arterioles • Strongest of the blood vessels • Carry blood away from the heart • Under high pressure • Vasoconstriction • Vasodilation • Arterioles • Small branches of arteries • Aorta • Takes blood from the heart to the body • Coronary arteries • Supply blood to heart muscle

43. The Microcirculation The  microcirculation. Metarterioles ( arteriovenous anastomoses) provide a path of least resistance between arterioles and venules . Precapillary sphincter muscles regulate the flow of blood through the capillaries.

44. Blood Vessels Capillaries The arterial system branches extensively to deliver blood to over 40 billion capillaries in the body. The tiny capillaries provide a total surface area of 1,000 square miles for exchanges between blood and tissue fluid. The amount of blood flowing through a particular capillary bed depends primarily on the resistance to blood flow in the small arteries and arterioles that supply blood to that capillary bed. Vasoconstriction in these vessels thus decreases blood flow to the capillary bed, whereas vasodilation increases blood flow

45. Types of Capillaries In terms of their endothelial lining, these capillary types include those that are continuous, those that are fenestrated, and those that are discontinuous. Continuous capillaries are those in which adjacent endothelial cells are closely joined together. These are found in muscles, lungs, adipose tissue, and the central nervous system. Fenestrated capillaries occur in the kidneys, endocrine glands, and intestines. They are characterized by wide intercellular pores that are covered by a layer of mucoprotein , which serves as a basement membrane over the capillary endothelium Discontinuous capillaries are found in the bone marrow, liver, and spleen

46. Blood Vessels: Veins and Venules Most of the total blood volume is contained in the venous system. Unlike arteries, which provide resistance to the flow of blood from the heart, veins are able to expand as they accumulate additional amounts of blood. Average pressure in the veins is only 2mmHg compared to a much higher arterial pressure of about 100mmHg The low venous pressure is insufficient to return blood to the heart, particularly from the lower limbs. Veins, however, pass between skeletal muscle groups that provide a massaging action as they contract.

47. The Action of The One-way Venous Valves Figure 1.13 The action of the one-way venous valves. Contraction of skeletal muscles helps to pump blood toward the heart, but the flow of blood away from the heart is prevented by closure of the venous valves.

48.   Lymphatic System • Lymphatic  vessels absorb excess interstitial fluid and transport this fluid—now called lymph—to ducts that drain into veins. • The lymphatic system has three basic functions: • It transports interstitial (tissue) fluid, initially formed as a blood filtrate, back to the blood • It transports absorbed fat from the small intestine to the blood • It cells—called lymphocytes —help provide immunological defenses against disease-causing agents 39.  Lymphatic System Cont’d… •  The smallest vessels of the lymphatic system are the lymphatic capillaries. • Microscopic closed-ended tubes that form vast networks in the intercellular spaces within most organs • Once fluid enters the lymphatic capillaries, it is referred to as lymph. Figure 1.14 The relationship between blood capillaries and lymphatic capillaries 40.  Lymphatic System Cont’d… •  Before the lymph is returned to the cardiovascular system, it is filtered through lymph nodes • Lymph nodes contain phagocytic cells, which help remove pathogens, and germinal centers, which are sites of lymphocyte production. Figure 1.15 The relationship between the circulatory and lymphatic systems 41.  Location of Lymph Node  Along the Lymphatic Pathways Figure 1.16 The location of lymph nodes along the lymphatic pathways. Lymph nodes are small bean shaped bodies, enclosed within dense connective tissue capsules.