cardiovascualr system and heart of human .pptx

cardiovascular system

1. CARDIO VASCULAR SYSTEM INTRODUCTION- William Harvey ( 1578 to 1657) was inventor of process that organ of blood circulatory system is the heart .Cardio vascular system is called as the blood vascular system or circulatory system it consists of heart which is a muscular pumping device ,and a closed system of vessels called arteries , veins , capillaries. As the name implies, blood contained in the  circulatory system  is pumped by the heart around a closed circle or circuit of vessels as it passes again and again through the various "circulations" of the body. The blood vessels that take blood from the heart to various tissues are called arteries. The smallest arteries are called arterioles. Arterioles open into a network of capillaries which constitute the microcirculation.

2. POSITIONING OF HEART IN HUMAN BODY

3. The heart is a fist sized organ weighing approx. 300 gm. that pumps blood throughout the body. It is main organ of circulatory system and is a marvelous organ. Position of the heart: The human heart is located within the thoracic cavity medially between the lungs and behind the Sternum/ Brest bone in the space known as the mediastinum. Heart is a conical hollow muscular organ enclosed within the pericardium. It is positioned posteriorly to the body of sternum with one/third situated on the right and two/thirds on the left of mid line and hence lies slanting a little to the left. The base of the heart is directed upwards and points towards the person`s right shoulder. The apex points downwards towards the front as well as left . The movements of apex can be felt while the heart beats between the 5 th & 6 th left ribs. The apex is situated 8-9cm away from the midline, a little below the nipple & slightly towards mid line

4. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the  pericardial cavity .

5. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and also when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch

6. ANATOMICAL HEART

7. functional anatomy of heart The heart is a muscular pump designed to ensure the circulation of blood through the tissues of the body. The human heart weighs approximately 300 g and it consists of two halves, right and left. The right heart circulates blood through the lungs for the purpose of oxygenation (i.e. through pulmonary circulation). The left heart circulates blood to the tissues of the entire body (i.e. through the systemic circulation) CHAMBERS OF HEART Each half of the heart consists of an inflow chamber called the atrium and an outflow chamber called the ventricle Thus, there are four chambers in the heart.

8. Atria Interatrial septum separates the right and left atria which are thin walled chambers. Right atrium receives deoxygenated blood from the tissues of the entire body through the superior and inferior vena cavae. This blood passes into the right ventricle through the right atrioventricular orifice which is guarded by a tricuspid valve. The right atrium has got the pacemaker known as sinoatrial node that produces cardiac impulses and atrioventricular node that conducts these impulses to the ventricles. Left atrium receives oxygenated blood from the lungs through the four pulmonary veins (two right and two left). This blood passes into left ventricle through the left atrioventricular orifice which is guarded by the mitral valve.

9. Ventricles Interventricular septum separates the right ventricle from the left ventricle. Interior of each ventricle has an inflow part and an out flow part. Papillary muscles are finger-like processes attached to the ventricular wall at one end but free at the other. They are functionally related to the atrioventricular valves. Right ventricle receives blood from the right atrium and pumps through the pulmonary trunk (which divides into right and left pulmonary arteries) into the lungs. The pulmonary valve is present at the junction of right ventricle and pulmonary trunk. Left ventricle receives blood from the left atrium and pumps out into systemic circulation through the aorta. Aortic valve is present at the junction of left ventricle and the ascending aorta. The wall of left ventricle is three times thicker than of the right ventricle (Physiological hypertrophy) as left ventricle has to do more work to pump the blood to whole body

10. VALVES OF HEART There are four valves in a human heart, two atrioventricular valves and two semilunar valves. Valves allow unidirectional flow of blood. The atrioventricular valves open towards the ventricles and close towards the atria. They allow blood to flow from atria to ventricles. But when ventricles contract, they are closed and thus prevent backflow of blood from ventricles to atria. These valves passively open and close due to pressure gradient. The right atrioventricular valve is known as tricuspid valve and is made of three cusps: anterior, posterior and septal The left atrioventricular valve is called mitral valve or bicuspid valve and is made of two cusps: anterior and posterior At the periphery, the cusps (flaps) of the atrioventricular valves are attached to the atrioventricular ring, which is the fibrous connection between the atria and ventricles. The free edges of the cusps are attached to the papillary muscles through the cord-like structures called the chordae tendinea

11. Valves of the heart Bicuspid valve attached with papillary muscles and chordae tendineae

12. Semilunar valves Aortic valve is the semilunar valve present at the opening of aorta in the left ventricle. It is made of three semilunar cusps: one anterior and two posterior. These valves are adapted to withstand physical trauma of high pressure in aorta and high velocity of blood flow during the ventricular systole (rapid ejection phase). Pulmonary valve is the semilunar valve present at the opening of pulmonary trunk into the right ventricle. It is also made of three semilunar cusps: one posterior and two anterior Semilunar valves open away from the ventricles and close towards ventricles These valves open when ventricles contract allowing the blood to flow from the left ventricle to aorta and from the right ventricle to the pulmonary trunk. Semilunar valves close when ventricles relax thus preventing backflow of blood from aorta or pulmonary trunk into the ventricles. Opening of the semilunar valves is a slow process. While closure is a sudden process causing neighbouring fluid to vibrate resulting in noise which is heard as heart sounds

13. STRUCTURE OF THE WALLS OF HEART Walls of the heart are composed of thick layer of cardiac muscle, the myocardium , covered externally by the epicardium and lined internally by the endocardium . Walls of the atrial portion of the heart are thin. Walls of the ventricular portion of the heart are thick. Skeleton of the heart consists of fibrous rings that surround the atrioventricular, pulmonary and aortic orifices and are continuous with the membranous part of the ventricular septum. The fibrous rings around the atrioventricular orifices separate the muscular walls of the atria from those of the ventricles but provide attachment for the muscle fibers The fibrous rings support the bases of the valve cusps and prevent the valves from stretching and becoming incompetent.

14. Pericardium The heart and roots of the great vessels are enclosed by a fibro serous sac called pericardium. Its function is to restrict excessive movements of the heart as a whole and to serve as a lubricated container in which different parts of the heart can contract. Pericardium consists of two layers: outer fibrous and inner serous . Fibrous pericardium surrounds the heart like a bag and is attached with the surrounding structures. Serous pericardium has parietal and visceral layers. The parietal layer of serous pericardium lines the fibrous pericardium and is reflected around the roots of the great vessels to become continuous with the visceral layer of serous pericardium that closely cover the heart and is often called the epicardium. The slit-like space between the parietal and the visceral layers of the serous pericardium is called pericardial cavity which contains small amount of pericardial fluid (5–30 mL) that acts as a lubricant to facilitate movement of the heart.

15. Myocardium The myocardium (muscular tissue of the heart) is the main tissue constituting the walls of the heart. It consists of three types of muscle fibers Cardiac muscles forming the walls of the atria and ventricles. Muscle fibers forming the pacemaker which is the site of origin of cardiac impulse. Muscle fibers forming the conducting system which transmits the impulse to the various parts of the heart. Endocardium Endocardium is thin, smooth and glistening membrane lining the myocardium internally. It consists of a single layer of endothelial cells. The endocardium continues as the endothelium of great vessels opening in the heart.