Anatomy and physiology

This is Cardiovascular system anatomy and physiology class. 

This class is for GNM, ANM and Bsc nursing students first yr syllabus.

This class will enrich the students knowledge on Cardiovascular system anatomy and physiology. 

The topics covered in this system 

1. The heart is a roughly cone shaped hollow muscular organ.  Length: 10 cm  Weight: 225 g in women  310 g in men  Position/location: the heart lies in the thoracic cavity in the mediastinum( the space between two lungs).  It lies obliquely little more to the left that right and presents a base above and apex below. INTRODUCTION
2. 3.  Inferiorly: the apex rests on the central tendon of the diaphragm.  Superiorly: the great blood vessels e.g. aorta, superior venacava, pulmonary artery and pulmonary veins  Posteriorly: the oesophagus, trachea, left and right bronchus, descending aorta, inferior venacava and thoracic vertebra  Laterally: the lungs- the left lungs overlaps the left side of the heart  Anteriorly: the sternum , ribs and intercostal muscles. ORGANS ASSOCIATED WITH THE HEART
3. 4.  The heart wall:  The heart wall is composed of three layers of the tissue. 1. Pericardium 2. Myocardium 3. endocardium STRUCTURE OF THE HEART
4. 5.  The pericardium is the outermost layer of the heart and is made up with two sacs.  Outer sac consist of : fibrous tissue  Inner sac consists of : continues double layer of serous membrane  Outer layer is known as parietal pericardium  Inner layer is known as visceral pericardium.  the space between two sacs is known as pericardial space, which is filled with serous fluid, which is secreted from serous membrane of inner sac. 1. PERICARDIUM
5. 6.  The myocardium is composed of specialised cardiac muscles founded only in heart.  It is not under voluntary control but striated like skeletal muscle. Each fibres cells has nucleus and one or more braches.  The sheet arrangements of the myocardium enables the atria and ventricular to contract in a co ordinated and efficient manner.  Myocardium is network of specialised conducting fibres responsible for transmitting the heart electrical signals.  Myocardium is thickest at the apex and thins out towards the base. 2. MYOCARDIUM
6. 7.  This lines the chambers and valves of the hearts.  It is a thin smooth membrane to ensure smooth flow of blood through the heart. It consists of flattened epithelial cells and it is continuous with the endothelium lining the blood vessels. 3. ENDOCARDIUM:
7. 8.  The heart is divide into right and left sided by the septum, a partition consisting of myocardium converted by endocardium.  Each side is divide by an antrioventricular valve into upper atrium and the ventricle below.  Atrioventricular valve: these are formed by double layer of endocardium.  Strengthen by a little fibrous tissue. INTERIOR OF THE HEART
8. 9.  AV VLAVES: right side AV valve has three flaps is known as tricuspid valve, which separates right atrium and right ventricle.  Left sided AV valve has two flaps is called as mitral valve or bicuspid valve, which separates left atrium and left ventricle.
9. 10.  There are four chambers of the heart.  1. right atrium – 2- 3 mm size  2.rigth ventricle-4-5 mm  3. left atrium – 2-3 mm  Left ventricle- 10-15 mm CHAMBERS OF THE HEART
10. 11.  The two largest veins of the body, the superior vencava and inferior vencava empty their contents into the right atrium.  This blood passes via right atrioventriculer vlave into right ventricle and from there blood is pumped out into the pulmonary artery( the only artery in the body which caries deoxygenated blood). BLOOD FLOW THROUGH THE HEART
11. 12.  At the opening of pulmonary artery pulmonary valve is present which prevents backflow of the blood into right ventricle , it is also known as semi-luner valve.  After leaving the heart the pulmonary artery divides into left and right pulmonary arteries, which carry the blood to the lungs where exchange of gases takes place, carbon dioxide excreted and oxygen is absorbed.
12. 13.  After purification of blood in the lungs two pulmonary veins carry oxygenated blood back to the left atrium.  Blood than passes through left atrioventriculer valve ( mitral valve, bicuspid valve) into the left ventricle and from there blood Is pumped out into the aorta( the first artery of general circulation).  The opening of aorta is guarded by the aortic valve.( at the opening of aorta there are valve present which is called as semilunar or aortic valve.
13. 14.  However , it should be noted that both atria contract at the same time and this followed by the simultaneous contraction of both ventricles.
14. 15. arterial supply: the heart I supplied with arterial blood by the right and left coronary arteries. The coronary arteries branch from the ascending aorta. The coronary arteries receives about 5% of the blood pumped from the heart. Large amount of blood supply especially to the left ventricle. There are two coronary arteries : 1. Right coronary artery 2. Left coronary artery

1. BLOOD CIRCULATION TO THE HEART/ CORONARY CIRCULATION
2. 16.  1. right coronary artery:  It supplies small branches to the right side heart. Right arteries having two branches:  Posterior inter ventricular branch  Marginal branches  The posterior inter ventricular branches supplies blood to the wall of two ventricles.  The marginal branches supplies blood to the right ventricles.
3. 17.  2. left coronary artery:  The left coronary artery passes inferior to the left circle & divides into the anterior inter ventricular branch & the circumflex branches.  The anterior inter ventriculer branches will supplies oxygenated blood to the walls of both ventricles.  The circumflex branch will supplies oxygenated blood to the walls of the left ventricle & left atrium.
4. 18.  Venous drainage: most of venous blood is collected into number of cardiac veins that join to form the coronary sinus, which opens into the right atrium.