Circulatory System 1 Lecture 7-8 PDF

CVS 1, 2  Objectives Define Circulation. Explain the systemic and portal circulations. Enumerate functions of circulatory system. Name the components of vascular system. Give functional classification of vessels. Define artery, vein and capillary ...

CVS 1, 2  Objectives Define Circulation. Explain the systemic and portal circulations. Enumerate functions of circulatory system. Name the components of vascular system. Give functional classification of vessels. Define artery, vein and capillary  Objectives Differentiate between artery and vein and relate their anatomical structure to their functions. Difference between Anatomical & Functional End Arteries. Define Anastomosis with its different types. What are the different types of capillaries. The Cardiovascular System  Consist of heart & blood vessels  Transports blood to and from tissues Functions of Circulatory System  Nutrients distribution.  Transport & Exchange of O2 and CO2.  Removal of waste materials  Distribute Secretions of Endocrine Glands.  Prevent excessive bleeding.  Prevent infection.  Regulate body temperature. THE HEART:  Site: In the middle of thorax, above diaphragm & slightly to left  Size: about individual’s closed fist  Surrounded by a thin membrane called pericardium Divided in to 4 chambers:  Upper 2 champers are  The Right atrium and left atrium  Separated by the interatrial septum  Lower 2 champers  The right ventricle and left ventricle  Separated by the Interventricular septum Valves of the heart  Atrioventricular (cuspid) valves:  Tricuspid valve: between right atrium and right ventricle  Mitral valve: between left atrium and left ventricle  Semilunar valves:  Aortic valve: at the beginning of aorta  Pulmonary valve: at the beginning of pulmonary trunk Circulation  The blood is carried out from the heart in arteries then through the tissues in capillaries and back to the heart in veins. 1. Systemic circulation. 2. Pulmonary circulation. 3. Portal circulation. 4. Coronary circulation Circulation  The blood is carried out from the heart in arteries then through the tissues in capillaries and back to the heart in veins. 1. Systemic circulation. 2. Pulmonary circulation. 3. Portal circulation. 4. Coronary circulation Capillaries in the Head, neck and upper limbs Pulmonary SVC Circulation Rt Lt Heart Lung Heart Liver n Vei l r ta Po IVC Portal GIT Circulation Capillaries in the lower half of the body Systemic Circulation The flow of blood between the heart and the cells of the body  Oxygenated blood is pumped from left ventricle to aorta, then Distributed to body through arteries, arterioles & capillaries  Deoxygenated blood from capillaries passes into venules, veins Returns to right atrium via superior & inferior vena cava Pulmonary Circulation The flow of blood between the heart and the lungs  Deoxygenated blood passes from right atrium into right ventricle  Pumped from right ventricle to pulmonary trunk  Then to lung through 2 pulmonary arteries, arterioles & finally capillaries  Gas exchange around alveoli (CO2 is eliminated & blood is oxygenated)  Oxygenated blood from capillaries passes into venules, veins  Returns to left atrium via 4 pulmonary veins  From left atrium oxygenated blood passes to left ventricle Portal Circulation Flow of blood between two set of capillaries before draining in systemic veins. The venous blood from the digestive system does not return to the heart directly but is received in the portal vein and taken to the liver. Coronary Circulation The circulation of blood in the arteries and veins that supply the heart muscle (myocardium). Arteries, capillaries and veins  Arteries: they are vessels or tubes carrying the blood away from the heart. Like trees, they have branches  Capillaries: Simple vascular endothelial networks between the termination of arteries (arterioles) & beginning of veins (venules) in tissues  Veins: they are vessels or tubes carrying the blood towards the heart. Like rivers, they have tributaries.  ARTERIES VEINS Carry blood away from the heart Carry blood to the heart Divided into (gives) branches Collect from (receive) tributaries Carry oxygenated blood except pulmonary A Carry non-oxygenated blood except pulmonary veins Its wall is rich in smooth muscle and elastic Its wall is poor in smooth muscle and elastic fibers (non- comprisable) fibers (comprisable) Thick wall and narrow lumen Thin wall and wide lumen Do not contain valves Contain valves  Veins Veins are either:  Superficial in the superficial fascia or,  Deep accompanying arteries.  A single vein usually accompanies large arteries.  Medium sized arteries, below elbow and knee, are usually accompanied by two veins (venae comitantes). Veins Valves of the veins: 1. Veins of the limbs have valves. 2. Veins of the neck posses one pair of valves near their termination. 3. Veins of the thorax and abdomen have no valves. Capillaries Sinusoid Fenestrated Contineous Sites of communication between arteries and veins in the tissues: 1. Capillaries (Usually) 2. Arterio-venous anastomosis:  Communications occur directly between arterioles and venules.  Sites: A. The dermis of the skin B. Mucous membrane of the nose. C. The tip of the tongue. D. The intestine (to regulate the rate of absorption by the intestinal villi). E. In the erectile tissue of sex organs (regulate erection). Dermis Nose Ear pinna Tongue and Lips Inteatine Penis Vestibule Sites of communication between arteries and veins in the tissues: 3. Sinusoids, which are wide tubular spaces, lined with phagocytic cells. Sinusoids occur in:  Liver  Spleen.  Bone marrow. 4. Cavernous tissue like that of the penis. This tissue consists of many small spaces lined with endothelium and separated from each other by fibrous septa. ANASTOMOSIS  Definition It is the communication between neighboring vessels (anastomosis = opening).  Types:  Anastomoses may be between arteries and arteries or between arteries and veins. ARTERIAL ANASTOMOSIS  It is between arteries & arteries. Sites: 1. Around joints of the limbs. 2. In the hand and foot. 3. At the base of the brain. 4. In the abdomen (between the arteries of the stomach and intestine). END ARTERIES  They are arteries which do not anastomose with neighboring arteries.  If obstructed, ischemia and necrosis of the supplied region occur  Examples: 1. Arteries of the brain 2. Renal arteries 3. Central Artery of the Retina 4. Coronary arteries End Arteries Collateral Circulation (Anastomosis) Tissue Tissue Ischaemia and Necrosis (infarct) Wavy ARTERIES  These are arteries, which have wavy course, probably because they supply moving organs.  Examples: 1. Uterine artery. 2. Facial artery. 3. Lingual artery 4. Splenic artery. REFERENCE BOOK READING Clinical Anatomy by Regions, 10th edition, (LAWRENCE E. WINESKI). PAGES-93-96 -VESSELS https://next.amboss.com/us/ article/ZK0ZUS?q=blood+ves sels#Ze70cc99757e1ea860c d2529fb952e9f0