HEART
Dicribe:
- The heart is a muscular oragan.which pumps blood throgh the blood vessels of th circulartary system.blood provides the body oxygen and nutrients as well as assists and removal metabolic waste.It is about 12cm long ,9cm wide and 6cm thick size of owner's fist.its weighing about 225gram in female and is heavier in male 310gram.the heart has four chamber of heart.Ra,Rv,la.lv(right atrium,right ventricle,left atrium,left ventricle)
Position:
- The heart lies in the thoracic cavity in the medistinum and the space between the lungs.heart lies obliquely,a little more to the left than right.it extend at the level of T5 toT8(2nd rib)The heart wall:
- The heart wall is a composed of three layers of tissue
- Pericardium:outer most layar of heart
- Myocardium:middle layer of heart.it composed of specilized cardiac muscle found only in the heart.
- Endocardium:this lines the chamber and valves of the heart and innermost layer.it is thin smooth,glistening membrane that permits smooth flow of the blood inside the heart.
The cardiac cycle :
- The healthly adult heart is likely to beat at a rate of 60-80bpm.during each heartbeat,the heart is contracts and relaxes.systole is a contraction and relaxtion is a diastole.
- Normal blood pressure 120/80bpm