Anatomy PDF - Cardiovascular and Pulmonary Systems

# Introduction of Anatomy ## Cardiovascular System * The cardiovascular system consists of the heart and blood vessels. ## Heart * **Site:** * It lies behind the sternum and costal cartilages, extending from the 2nd to the 6th costal cartilages. * About 2/3 of the heart lies to the left...

# Introduction of Anatomy ## Cardiovascular System * The cardiovascular system consists of the heart and blood vessels. ## Heart * **Site:** * It lies behind the sternum and costal cartilages, extending from the 2nd to the 6th costal cartilages. * About 2/3 of the heart lies to the left and 1/3 of the heart lies to the right of the median plane. * **Chambers of the heart:** It is formed of two atria and two ventricles. * **Right atrium:** Receives the deoxygenated blood from all parts of the body by 2 large veins; the superior vena cava (SVC) and the inferior vena cava (IVC). It sends its blood to the right ventricle through the tricuspid valve. * **Right ventricle:** Sends the deoxygenated blood through the pulmonary valve to the pulmonary trunk which divides into 2 pulmonary branches (right and left), one for each lung where oxygenation of the blood occurs. * **Left atrium:** Receives the oxygenated blood from both lungs through 4 pulmonary veins and pumps it to the left ventricle via mitral valve. * **Left ventricle:** It pumps its oxygenated blood to all parts of the body through the aortic valve, to the aorta and its branches. * **Types of the blood in the heart:** 1. Right 1/2 of the heart contains deoxygenated (venous) blood. 2. Left 1/2 of the heart contains oxygenated (arterial) blood. * The heart is covered by the pericardial sacs. ### Heart and Major Blood Vessels | | | | | --------------------- | --------------------- | --------------------- | | **Pulmonary artery** | **Aorta** | **Pulmonary artery** | | **Anterior vena cava** | | | | **Right atrium** | | **Left atrium** | | **Pulmonary veins** | | **Pulmonary veins** | | **Semilunar valve** | **Semilunar valve** | **Atrioventricular valve** | | **Atrioventricular valve** | | | | **Posterior vena cava** | | | | **Right ventricle** | **Left ventricle** | | ## Pulmonary Circulation * This circulation transmits venous blood from GIT to the liver in order to metabolize digested nutrients and to detoxify the blood. * The venous blood from stomach, spleen, pancreas and intestine, is collected into the portal vein which enters the liver (through the porta hepatis) and divides into many branches which end in liver sinusoids. * The blood leaves the liver sinusoids by the hepatic veins which end in inferior vena cava. ## Blood Circulation * **Lt. ventricle** → aortic valve → aorta and its branches which supply upper and lower parts of the body → venous blood returns via S.V.C and I.V.C → Rt. atrium → tricuspid valve → Rt. ventricle → pulmonary valve → pulmonary trunk → Rt. and Lt. pulmonary arteries to Rt. and Lt. lungs, where oxygenation of blood occurs. The oxygenated blood returns via 4 pulmonary veins → Lt. atrium → mitral valve → Lt. ventricle. ## Types Circulation * **Systemic circulation:** * Oxygenated blood in the left ventricle passes through the aorta and its branches to reach all the tissues of the body, where exchange of gases and nutrients occur. * Deoxygenated blood is collected by small veins, then by large veins and finally by superior and inferior venae cava into the right atrium. * The blood passes from the right atrium to the right ventricle where this circulation ends and a new cycle starts. * **Pulmonary circulation:** * Deoxygenated blood from the right ventricle passes through the pulmonary artery and its 2 branches to reach both lungs, where oxygenation of the blood occurs.