Cardiovascular System Lecture 6 PDF

 Faculty of Dentistry Cardiovascular System By A.Prof./Rabab Amer  To know different components of cardiovascular system To compare between arteries and veins To know normal position and size of the heart To describe structure of the heart and its outer...

 Faculty of Dentistry Cardiovascular System By A.Prof./Rabab Amer  To know different components of cardiovascular system To compare between arteries and veins To know normal position and size of the heart To describe structure of the heart and its outer covering (pericardium) Identify chambers of the heart. Identify the main arteries and veins of the body To know different types of circulations  Resource & References Book: Gray’s student anatomy Netter F: Atlas of Human Anatomy Link of snell’s clinical anatomy: https://drive.google.com/file/d/1Q8fPdGiIt9FPD_J_H1XVrErQtmaGN66V/view?u sp=sharing\ Media: https://www.youtube.com/watch?v=xpe7nIC_B6Y  Cardio-vascular system 1. Heart 2. Blood vessels Arteries Veins Capillaries 3. Lymphatic vessels  Arteries 1. definition: The vessels that carry the blood away from the heart 2. They carry oxygenated blood except pulmonary artery. 3. They have thicker walls than veins to withstand Main arteries: as aorta blood pressure. Medium sized (muscular) arteries are 4. They have no valves accompanied by venae comitants. Smallest arteries are called arterioles  Arterial Anastomosis Definition: the joining of branches of arteries Advantage: provide alternative pathways called collateral circulation If one arterial branch is occluded  1. Veins carry blood towards the heart 2. They carry non-oxygenated Blood except pulmonary veins 3. They have valves to stop the backflow of blood The smallest veins are called venules The veins have tributaries. Note: When the valves become incompetent, dilatation and tortuosity of the veins occur (Varicose veins). Note: the arterial wall is much thicker than the veins  Arteries Veins 1.Carry bl. From the heart To the heart 2.Oxygenated (except pulmonary De-oxygenated except pulmonary a) veins 3.Thicker walls Thinner walls- 4.narrower lumen wider lumen 5. Open Collapse when cut 6.No valves Valves 7.Has branches Has tributaries 8.Connection Connection (plexuses) (anastomosis)  Branches of smallest arterioles Its wall is formed by one layer (endothelial ) the average diameter is 7 m Sinusoids They are wider than capillaries. They have extremely thin wall. Present in liver, spleen, bone marrow and endocrine glands. 1. Which of the following is true regarding arteries? a. Have thinner walls b. Have narrower lumen c. Usually contain valves d. Collapse when cut 2. Which of the following is true regarding veins? a. Have no anastomoses b. Contain valves c. Begin by branches d. Are thick walled  Heart A hollow muscular organ about the size of a closed owner’s fist Of average weight of 300 gm. Lies obliquely in middle mediastinum between 2 lungs. Its base directed upwards & to the right and its apex directed downwards & to the left.  pericardium 1.fibrous 2. serous a. visceral b. parietal  Pericardium Fibrous pericardium: is a fibrous sac surrounding the heart and attached to the diaphragm inferiorly Serous pericardium: is a Serous sac invaginated by the heart Has two layers: -Visceral pericardium: covering the heart - Parietal pericardium: lining the fibrous pericardium Pericardial cavity space between visceral and parietal Diaphragm pericardium Contains film of pericardiac fluid External features Borders 1. Superior border: Formed by the two atria masked by the roots of the great blood vessels 2. Right border: Convex and formed by the right atrium. 3. Left border: Convex and formed by the left ventricle. 4. Inferior border: concave and formed by right ventricle and the apical part of the left ventricle. The heart is formed of 4 chambers. 2 atria and 2 ventricles (right atrium, left atrium, right ventricle and left ventricle). 1. The right atrium: it lies in the upper right part of the heart. It receives the venous drainage of the whole body through the superior vena cava and the inferior vena cava which open in the right atrium. The right atrium receives also the opening of the coronary sinus which carries the venous drainage of the heart tissue to the cavity of the right atrium. 2. The right ventricle: it lies in the lower right half of the heart. It communicates with the right atrium above through a passage called the tricuspid atrio- ventricular opening. This opening is guarded with the tricuspid valve. The venous blood passes from the right atrium to the right ventricle through this opening. Then right ventricle pumps the blood through the pulmonary trunk to the lungs. 3. The left atrium: it lies in the upper left half of the heart; the main part is present in the posterior surface of the heart. It receives the oxygenated blood from the lungs through the 4 pulmonary veins. The 4 pulmonary veins (2 pulmonary veins from the left lung and 2 from the right lung) open in the left atrium. The left atrium communicates with the left ventricle through the mitral opening; which is guarded by the bicuspid mitral valve. 4. The left ventricle: it lies in the lower left half of the heart. The wall of the left ventricle is 3 times thicker than the wall of the right ventricle. It receives the oxygenated blood from the left atrium through the mitral opening. The left ventricle then pumps blood to the whole body through the aorta. Arterial supply of the heart: The heart is supplied by the coronary arteries. 1- The left coronary artery gives two branches, circumflex artery and the anterior inter-ventricular artery. 2- The right coronary artery gives, marginal artery and the posterior inter-ventricular artery. Both coronaries anastomose with each other. Venous drainage of the heart: All veins of the heart drain in the coronary sinus which drains in the right atrium. 1- Which of the following is an opening of the left atrium? A- coronary sinus. B- bicuspid opening C- Pulmonary trunk D- superior vena cava 2- The inferior border of the heart is formed by which of the following? A- right atrium B- left atrium C- pulmonary veins D- right ventricle 1- Aorta: It has 3 parts; ascending aorta, arch of aorta, and descending aorta. A- Ascending aorta : Branches : 1- Right coronary artery. 2- Left coronary artery. B- Arch of aorta : Branches : 1-Brachiocephalic ; which gives the right common carotid and right subclavian artery. 2-Left common carotid. 3-Left subclavian  Arteries of the head & neck : - Common carotid artery : Passes upwards and divides into : Internal carotid : Enters the interior of the skull through the carotid canal. External carotid : Supplies the outer surfaces of the head & neck. - Subclavian artery : It passes behind the clavicle to enter the axilla where it becomes the axillary artery.  Arteries of the thorax Descending Thoracic Aorta : It is the continuation of the aortic arch. It ends by passing through the diaphragm to continue as the abdominal aorta. It gives 2 groups of branches : -Visceral branches; Pericardial , bronchial, esophageal - Parietal branches; Posterior intercostal arteries.  Descending Abdominal Aorta It gives 2 groups of branches : Single branches 1-Coeliac artery 2-Superior mesenteric 3-Inferior mesenteric 4-Median sacral a. Paired branches : 1-Inferior Phrenic arteries 2-Middle suprarenal arteries. 3-Renal arteries 4-Genital arteries (testicular or ovarian) 5-Lumbar arteries 6-Common iliac arteries These are the two terminal branches of descending aorta. Each divides into : Internal iliac artery : Passes to the pelvis. External iliac artery : Pass under the inguinal ligament to become the femoral artery.  Arteries of the upper limb - -Axillary artery : Is the main artery of the upper limb. At the lower Axilla border of axilla, it becomes the brachial artery. - Brachial artery : It runs down the arm till the elbow where it divides into radial & ulnar arteries. - Radial artery : Follows the radius. It becomes superficial in its lower part just above the wrist where the pulse is usually felt. - Ulnar artery : Follows the ulna. - Palmar arches : From these arches digital branches run to the digits. Arteries of the lower limb : - Femoral artery : It is the continuation of the external iliac a. It descends to the popliteal fossa at the back of the knee where it becomes the popliteal artery. - Popliteal artery : It gives off the anterior and posterior tibial arteries. - Anterior tibial artery : It supplies the front of the leg and is continued downwards on the dorsum of the foot as the Dorsalis pedis artery. - Posterior tibial artery : It supplies the back of the leg. - Plantar arches : Digital branches arise from the arch to supply the toes.  Main Veins of the Body 1- Superior Vena Cava and its Tributaries : It is formed by union of right and left brachiocephalic (innominate) veins and collects venous blood from the head & neck and upper limbs. Veins of the head & neck : External jugular vein Internal jugular vein : - It receives the veins of the brain. - It unites with the subclavian vein to form the innominate (brachiocephalic) vein. 2-Inferior vena cava and its Tributaries: - Formed by the union of common iliac veins of both sides. It runs upwards to the right of the aorta and receives : - Right genital vein (the left one joins the left renal vein). - Renal veins - Hepatic veins  Circulation 1. Systemic circulation: Heart → to the aorta to be distributed to various parts of the body → arteries, arterioles and the capillary meshwork → blood is collected into venules → into veins which collect to form the superior vena cava which drains the upper part of the body and inferior vena cave which drains the lower half of the body. These 2 venae cavae end in the right atrium.  Circulation 2. Pulmonary circulation: A single pulmonary artery from the heart divides into two vessels, one for each lung, The finer arterioles supply the capillary network around the lung alveoli. Venules collect the blood from the capillaries and join to form larger veins which leave the lung as the four pulmonary veins which open directly into the left atrium of the heart.  Portal circulation - The venous blood from the digestive system does not return to the heart directly but is received in the portal vein (which is formed by union of splenic and superior mesenteric veins) and taken to the liver. - In the liver the portal vein breaks up finally into a second set of capillaries (sinusoids) where the digested food stuff come in contact with the liver cells for further chemical treatment or storage. - So, the portal vein begins and ends by capillaries. - These second set of capillaries reunite to form the hepatic veins which leave the liver to join the inferior vena cava. - Obstruction of the portal vein e.g. by cirrhosis causes portal hypertension which result in esophageal varices and hemorrhoids. 1- What is the termination of the anterior tibial artery? A- Popliteal artery B- Femoral artery. C- Dorsalis pedis artery D- Planter arches 2- Which of the following arteries is a single branche from the aorta? A- Coeliac trunk B- Renal C- Lumbar D- Gonadal 3- Which of the following veins is a tributary of the inferior vena cava? A- Hepatic B- Splenic 40 C- Superior mesenteric D- internal jugular