Working of Heart The cardiac events that occur from the beginning of one heart beat to the begning of the next constitute a cardiac cycle. it consists 3 phases 1 . atrial systole  (0.1) 2. ventricular systole  (0.3) 3. Joint diastole  (0.4) Click Here For Complete Lecture Cardiac Output : The volume of blood pumped out by each ventricle, for each heart beat, is known as the stroke volume . the volume of blood pumped out by the heart from each ventricle per minute is termed cardiac output Stroke volume X No.of beats per minute  = 70 ml/beat X 72 beats/min  = 5040 ml/min (5 liters) 

 Structure of Heart Heart is mesodermal in origin. located in mediastinum upper 2 chambers (atria) are known as receiving chambers lower 2 chambers (ventricles) known as pumping chambers heart is covered by 2 (pericardial) layers percardial space filled with pericardial fluid. Click here for Complete Lecture the groove which divides atria and ventricles is known as coronary sulcus. in which coronary blood vessesls are embeded.  both atria separated by inter atrial septum. as like ventricles also divided by inter ventriclular septum.

 Regulation of respiratory movements & Disorders Regulation of respiratory movements:   1.  A Special center present in the medulla region of brain, called Respiratory rhythm centre is primarily responsible for this regulation.  2. another center present in the pons of the brain stem called Pneumotaxic Center  can moderate the functions of the  Respiratory rhythm centre  3. A Chemo-sensitive area is situated adjacent to the respiratory rhythm center. which is highly sensitive to CO2 and Hydrogen ions.  Disorders of the Respiratory System 1. Emphysema, chronic bronchitis and asthma come under Chronic Obstructive Pulmonary Diseases. (COPDs) Occupational Respiratory Disorders:   1. Asbestosis (asbestosis industry) 2 Silicosis (mining industries, quarries) 3. Siderosis: (inhaled iron particles) 4. Black lung diseases (coal mine workers) https://youtu.be/pzqBHY698l8

 Transport of Carbon dioxide CO2 Is transported in 3 ways.  1. Dissolved state : 7 % 2. As carbamino compounds: 20 - 25 % 3. As Bicarbonates : 70 % Chloride Shift Exchange of chloride and bicarbonate ions between RBC and plasma at the tissues is called #Chloride shift of Hamburger's Phenomenon/ Hamburger's shift. click here for complete lecture

 Transport of Oxygen Oxygen is transported from the lungs to the tissues through the plasma and RBC of the blood. 100ml of oxygenated blood can deliver 5 ml of O2 to the tissues. under normal conditions.  Transport of oxygen through plasma : 3 % Transport of oxygen by RBC                : 97% Bohr Effect the effect of pCO2 and H+ concentration on the oxygen affinity of haemoglobin is called Bohr Effect.