Circulatory System Notes PDF

By: Fikre Bayu (MSc) 1  General objectives  Explain the general function of circulatory system  Describe the components of cardiovascular system  List the different types of blood cells and their functions  Describe the composition of plasma and the specific funct...

By: Fikre Bayu (MSc) 1  General objectives  Explain the general function of circulatory system  Describe the components of cardiovascular system  List the different types of blood cells and their functions  Describe the composition of plasma and the specific functions of the plasma proteins  Describe the location of the heart and its functions  Describe the wall and coverings of the heart  Discuss the blood supply and innervation of heart  Cont.…  Trace the path of blood through the heart, naming its chambers and valves  Name the three types of blood vessels, and describe their structure and function  Discuss the organization of the lymphatic system, including the vessels, principal lymph nodes, thymus, and spleen  Explain the relationship between the lymphatic and circulatory systems, and the role of lymphoid tissue structures and lymphocytes in the body’s defense  Circulatory System  Transports fluids throughout the body.  consists of two interrelated parts,  which function in parallel to transport the body's fluids: 1. Cardiovascular system Heart, blood vessels and blood 2. Lymphatic system Lymphatic organs, lymphatic vessels and lymph Functions of the circulatory system Distributes nutrients Transport and exchange of oxygen and carbon dioxide Removal of waste materials Distributes secretions of endocrine glands Prevent excessive bleeding Prevent infection Regulate body temperature and PH  Major Parts of the Cardiovascular system – Blood Vessels -routes of blood travels – Heart -pumps or pushes blood through body – Blood - is liquid connective tissue  Function of blood – Transportation – Regulation – protection  Blood  Constituted about 8% of the total body weight Its pH range from 7.35 to 7.45 5-6 liters in average adult male and 4-5 liters in adult female The difference in volume is due to differences in body size  blood appears to the unaided eye as a thick, homogeneous liquid, microscopic examination reveals that it has both cellular and liquid components  Components of Blood  Whole blood is composed of two portions: 1. Blood plasma (55%)  liquid extracellular matrix that contains dissolved substances 2. Formed elements (45%)  which are cells and cell fragments - more than 99% of the formed elements are red blood cells (RBCs).  Plasma  Blood plasma is a straw-colored, sticky fluid  Although it is about 90% water, it contains over 100 different kinds of molecules, including ions such as Na+ and Cl- ; nutrients such as simple sugars, amino acids, and lipids; wastes such as urea, ammonia, and carbon dioxide; and oxygen, hormones, and vitamins  Plasma also contains three main types of proteins: albumin, globulin, and fibrinogen  serum is plasma from which the clotting factors have been removed  Cont.…  The percentage of total blood volume occupied by RBCs is termed the hematocrit  WBCs and platelets occupy less than 1% of total blood volume  form a very thin layer, called the buffy coat  Red blood cells (Erythrocytes)  4.3 to 5.2 million cells in a cubic millimeter of blood in women and 5.1 to 5.8 million in men Biconcave discs-discs with depressed centers  mature RBC lacks nucleus and other organelles their cytoplasm is packed with molecules of hemoglobin- the oxygen carrying protein erythrocytes are over 97 % hemoglobin live (life span) 100-120 days much longer than other types of blood cells Erythropoiesis is the production of RBCs starts in the red bone marrow Cont.… White blood cells (Leukocytes)  Unlike red blood cells, white blood cells have nuclei and do not contain hemoglobin , that is why they are colorless  less numerous than erythrocytes, but larger in size  can move in ameboid fashion and protects the body from infectious microorganisms such as bacteria , virus and parasites  can function out side the blood stream  In response, leukocytes leave the capillaries by actively squeezing between the endothelial cells that form the capillary walls, a process called diapedesis  A leukocyte count exceeding 11,000 per cubic millimeter indicates infection or inflammation  The patient is said to have leukocytosis  Cont.…  WBCs are classified as: 1. Granulocytes 2. Agranulocytes  Depending on whether they contain or not conspicuous chemical-filled cytoplasmic granules that are made visible by staining when viewed through a light microscope Granulocytes (granular leukocytes)  There are 3 types of granulocyte  Neutrophils, eosinophils , basophils  are larger and much shorter lived than erythrocytes  Functionally , all granulocytes are phagocytic they engulf and digest foreign cells or molecules  Have variable shaped nuclei Neutrophils 2-6 lobed nucleus the most abundant type of leukocytes (constitutes 60%) Neutrophils respond first to bacterial invasion  Eosinophils accounts for 1-4% of all leukocytes bilobed nucleus phagocytize antigen–antibody complexes Fighting parasites is the most important function of eosinophils, and these cells gather in the wall of the digestive tube, where parasites are most likely to be encountered  Basophils accounts 0.5–1% of all WBCs  bilobed nucleus  release histamine and other mediators of inflammation  Agranular leukocytes (Agranulocytes)  Have no specific granules after staining  There are two types of Agranulocytes 1. lymphocytes 2. monocytes  Lymphocytes 20-45% of all leukocytes are effective in fighting infectious organisms because each lymphocyte recognizes and acts against a specific foreign molecule B cells, T cells and NKCs  Monocytes 12–20µm diameter The largest leukocytes makes up 4-8% of WBC phagocytosis after transforming into fixed or wandering macrophages  Platelets (Thrombocytes)  the smallest formed elements  2–4µm diameter cell fragments of large cells called megakaryocytes  have no nucleus and other organelles  capable of amoeboid movement  blood clotting Hematopoiesis 25 Red bone marrow Summary of formed elements of blood  Heart hollow, muscular, 4 chambered organ Weighs about 250-350 g in adults (about the size of a clenched fist) it rests on the diaphragm near the mid line of the thoracic cavity in the mediastinum 2/3rd portion of the heart is located in the left side of the body  the heart has a pointed end the apex and a broad portion opposite to the apex called base 28 Cont.… 29 Relations and external features of the heart  The heart within the pericardial sac is related anteriorly to: the sternum, costal cartilages and anterior ends of the 3rd -5th ribs on the left side  posteriorly to thoracic vertebrae (T5-T8)  laterally with lungs Inferiorly with diaphragm  Cont.… The heart and pericardial sac are situated obliquely, approximately two thirds to the left and one third to the right of the median plane  The mediastinum  is a space b/n two lungs  It extends from the superior thoracic aperture to the diaphragm inferiorly and from the sternum and costal cartilages anteriorly to the bodies of the thoracic vertebrae posteriorly  The major structures in the mediastinum are also surrounded by blood and lymphatic vessels, lymph nodes, nerves, and fat  It contains all the thoracic viscera and structures, except the lungs  The mediastinum is artificially divided into superior and inferior parts for purposes of description 32  Division of mediastinum 33  The superior mediastinum  extends inferiorly from the superior thoracic aperture to the horizontal plane (transverse thoracic plane) passing through the sternal angle and the IV disc of the T4&T5 vertebrae It contains: the superior vena cava (SVC) brachiocephalic veins arch of the aorta thoracic duct trachea, esophagus, thymus, vagus nerves left recurrent laryngeal nerve, and phrenic nerves 34  The inferior mediastinum  between the transverse thoracic plane and the diaphragm It is further subdivided by the pericardium into : The anterior mediastinum containing remnants of the thymus, lymph nodes, fat, and connective tissue The middle mediastinum containing the pericardium, heart roots of the great vessels, arch of azygos vein, and main bronchi The posterior mediastinum containing the esophagus, thoracic aorta, azygos and hemiazygos veins, thoracic duct, vagus nerves, sympathetic trunks, and splanchnic nerves 35 The Heart: Surfaces and orientation 36 The four borders of the heart are: I. Right border Formed by the right atrium and extending b/n the SVC and the IVC II. Inferior border Formed mainly by the right ventricle and slightly by the left ventricle  Cont.… III. Left border  Formed mainly by the left ventricle and slightly by the left auricle V. Superior border  Formed by the right and left atria and auricles in an anterior view  Coverings of the heart Pericardium (peri = around) is a protective and surrounding membrane of the heart it consists of two principal portion: the superficial fibrous pericardium the deep two layer serous pericardium Fibrous pericardium is tough inelastic, dense irregular connective tissue, which looks like a bag  It rests & attaches to the diaphragm: Function of fibrous pericardium prevents overstretching of the heart protects and anchors the heart in the mediastinum 39  The serous pericardium is a thinner membrane which forms a double layer  parietal layer  is the outer serous pericardium  sensitive to pain  visceral layer The inner serous pericardium adheres tightly to the surface of the heart Insensitive to pain  pericardial fluid  is a fluid In the cavity b/n two layers of pericardium is important to reduce friction b/n the heart and the outer layers and also prevent the heart from external pressure 40 Pericardial Layers of the Heart 42  Layers of the heart wall The heart contain 3 distinct layers: 1. Epicardium (Visceral layer of serous pericardium)  thin, external membrane around the heart  allow protection against friction by rubbing organs 2. Myocardium  thickest layer; consists of cardiac muscle. i.e. the bulk of the heart wall  responsible for the ability of the heart to contract 3. Endocardium a thin innermost layer; a unique type of epithelial tissue that lines the entire circulatory system Fibrous skeleton of the heart – crisscrossing, interlacing layer of connective tissue 43 44  Chambers of the heart The heart has four chambers two upper chambers - atria two lower chambers - ventricles Right atrium forms the right border of the heart it receives deoxygenated rich blood from superior vena cava inferior vena cava and coronary sinus Interatrial septum- is a thin partition between right and left atriums blood passes from the right atrium in to the right ventricle through a valve called tricuspid valve, it consists of three leaflets of cusps Cont.…  Cont.…  Externally the right auricle, a small flap shaped like a dog’s ear projects anteriorly from the superior corner of the atrium  Internally the right atrium has two parts  a smooth-walled posterior part and an anterior part lined by horizontal ridges called the pectinate muscles(pectin comb)  These two parts of the atrium are separated by a large-C shaped ridge called the crista terminalis  The crista is an important landmark in locating the sites where veins enter the right atrium  Additionally, just posterior to this end of the crista is the fossa ovalis, a depression in the interatrial septum that marks the spot where an opening existed in the fetal heart (the foramen ovale Cont.… Left atrium forms most of the base of the heart receives oxygenation rich blood from the lungs through four pulmonary vein (2 right & 2 left) then passes from the left atrium into the left ventricle through the bicuspid (mitral) valve which has two cusps Right ventricle forms most of the anterior surface of the heart left ventricle is separated from the right ventricle by interventricular septum Blood passes from right ventricle through the pulmonary valve to a large artery, pulmonary trunk, which divides in to right and left pulmonary arteries 49 Left ventricle  forms the apex of the heart  The most muscular chamber  Pump blood to the body through aorta  Blood passes through the aortic valve in to the largest artery of the body, aorta, which gives coronary arteries, descending aorta (thoracic and abdominal aorta) and ascending aorta 50  Cont.…  Papillary muscles and trabeculae carneae muscles mark ventricular walls  Myocardium of left ventricle is much thicker than the right 51 Heart Valves:  prevent back flow of blood and ensure that blood flows in the proper direction through the heat The valves function is to maintain blood flow in one direction Valves open and close in response to changes in pressure Four heart valves are: Atrioventricular (AV) valves  tricuspid - the right AV valves  bicuspid valves - the left AV valves Semilunar valves  Aortic valve - Left Ventricle and Aorta Pulmonary valve- Rt Ventricle and Pulmonary Trunk 52  Cont.…  Thin, strong bands called chordae tendineae, the “heart strings,” project superiorly from the papillary muscles to AV valves Cont.… 55  Heart Sounds 1. “Lub”  first heart sound  occurs during ventricular systole/contraction  A-V valves closing 2. “Dup”  second heart sound  occurs during ventricular diastole/relaxation  semilunar valves closing Murmur (Brachycardia and Tachycardia) abnormal heart sound 56 Surface anatomy of Heart: Auscultation sites 57  Cont.…  The sounds can be heard(auscultated) at the following points :  Mitral valve- 5th intercostal space (ICS) at the apex  Tricuspid valve – 5th ICS of right sternal margin  Aortic semilunar valve -2nd ICS right sternal margin  Pulmonary semilunar valve- 2nd ICS of left sternal margin  Blood supply of Heart  The heart is supplied by two major coronary arteries, the right & left coronary arteries  Lt coronary a divides into:  anterior interventricular & circumflex branches 59 Cont.… 60  Cont.…  When the heart is viewed from the back, the most obvious structure lying in the coronary sulcus is the coronary sinus  Coronary sinus receives most of the venous blood from the heart & empties into right atrium  Its tributaries are the small cardiac vein, middle cardiac vein & greater cardiac vein  The arteries seen at the back of the heart are the circumflex coronary artery, terminal part of right coronary artery & its posterior interventricular branch 61 Cont.… Arterial blood supply of heart Venous drainage of heart  Conducting System  Sino atrial (SA) node – pacemaker  atrioventricular (AV) node  AV bundle  right and left bundle branches  Purkinje fibers  Innervations of the Heart Autonomic Innervation (cardiac plexus) Vagus Nerve (parasympathetic) cardio inhibitory center Sympathetic trunks cardioaccelatory center 65 Sequence of Excitation Sequence of Excitation The SA node sends out a stimulus, which cause the atria to contract. When this stimulus reaches the AV node, it signals the ventricles to contract. Impulses pass down the two branches of the atrioventricular bundle to the Purkinje fibers, and thereafter the ventricles contract Congestive Heart Failure (CHF)  Congestive heart failure (CHF) is caused by: – Coronary atherosclerosis – Persistent high blood pressure – Multiple myocardial infarcts – Dilated cardiomyopathy (DCM) – main pumping chambers of the heart are dilated and contract poorly By pass graft Artificial heart Types of circulatory routes pulmonary circulation:  right ventricle --pulmonary artery-- lungs--pulmonary vein -- left atrium systemic circulation: left ventricle --aorta--body-- superior and inferior vena cava--right atrium Coronary circulation:  is part of the systemic circulation and supplies blood to the heart tissues via coronary arteries and veins Cerebral circulation:  the circulation in brain by pair internal carotid and vertebral arteries 71 Pathway of Blood Through the Heart, Lungs and body 72  Hepatic portal system is one in which the veins that drain one group of capillaries delivers blood to another group of capillaries, which in turn are drained by systemic veins that carry blood to the vena cava and then into the right atrium of heart two capillary beds in series: veins that drain blood from capillaries in the internal pancreas, spleen, gallbladder into the capillaries in the liver (sinusoids) right and left hepatic veins that drain the liver into the inferior vena cava 73  Hepatic portal system  Hepatic portal vein – drains blood from GIT  formed by union of superior mesenteric vein (from small intestine) and splenic vein (from spleen)  Splenic vein is formed by convergence of inferior mesenteric vein (from large intestine), pancreatic vein and left gastroepiploic vein  The right gastroepiploic vein from stomach drains directly into the superior mesenteric vein  Three veins drain directly into the portal vein: left and right gastric vein (from lesser curvature) and cystic vein (from gall bladder) 74 75  Fetal Circulation  the circulation of blood in the fetus  No circulation to lungs  Circulation must go to placenta by Umbilical arteries and vein Foramen ovale: blood is shunted from right atrium to left atrium, skipping the lungs through foramen ovale ductus arteriousus  The blood pumped from the right ventricle enters the pulmonary trunk  Most of this blood is shunted into the aortic arch through the ductus 76 arteriousus Umbilical Circulation  Pair of umbilical arteries carry deoxygenated blood & wastes to placenta  Umbilical vein carries oxygenated blood & nutrients from the placenta  The placenta - facilitates gas and nutrient exchange between maternal & fetal blood 77 Adult derivatives of fetal circulation adult fetus  Fossa ovale Foramen ovale  Ligamentum arteriosum Ductus arteriosus  Medial umbilical ligaments Umbilical aa.(within fetus)  Round ligament (ligamentum teres) Umbilical v.(within liver)  Ligamentum venosum Ductus venosus 78 Cont.… 79  Warm Up/Quiz! 10% 1. The apex of the heart rests on the: 2. True/False: The epicardium and the fibrous pericardium are the same structure. 3. What is the correct order of the layers of the heart from outside to inside? 4. The _______ connect the cuspid valves to the papillary muscles. 5. What is an anastomosis? 6. What is also known as the pacemaker of the heart? 7. Why the left ventricle has thickest layer? 8. The arteries that supply heart wall is: 9. Where does blood travel after passing through the aortic semilunar valve? Is this blood oxygenated or deoxygenated? Label the following structures of heart  Blood vessels  Blood vessels are a network of tubes that carry blood throughout the entire body  Are dynamic structures ,that pulsate ,constrict and relax according to the changing needs of the body There are 3 types of Blood Vessels: 1. Arteries 2. Veins 3. Capillaries Arteries  The vessels that carry the blood away from the heart  They carry oxygenated blood 82 Tunics/histological layers of blood vessels  Wall of arteries and veins are composed of three distinct layers (tunics): 1. Tunica intima Composed of simple, squamous epithelium called endothelium It has direct contact with blood Rests on a connective tissue membrane that is rich in elastic and collagen fibers 2.Tunica media Makes up the bulk of the arterial wall Includes smooth muscle fibers, which encircle the tube, and a thick layer of elastic connective tissue 83 3. Tunica adventitia  Is relatively thin  Consists chiefly of connective tissue with irregularly arranged elastic and collagen fibers  Also contains minute vessels that give rise to capillaries and provide blood to the more external cells of the artery wall  Smooth muscles in the walls of arteries and arterioles are innervated by the sympathetic branches of the autonomic nervous system 84  Arteries have more elastin than veins  Types of Arteries Elastic Arteries Largest arteries Largest diameter but walls relatively thin Function as pressure reservoir Help propel blood forward while ventricles relaxing Also known as conducting arteries – conduct blood to medium-sized arteries Ex. aorta, subclavian , brachiocephalic ,common iliac, common carotid , pulmonary … 85 Muscular arteries Tunica media contains more smooth muscle and fewer elastic fibers than elastic arteries Walls relatively thick Capable of great vasoconstriction/ vasodilatation to adjust rate of blood flow Also called distributing arteries Ex. Brachial artery , radial artery , ulnar artery Anastomoses Union of the branches of two or more arteries supplying the same body region Provide alternate routes – collateral circulation 86 Arterioles  An arteriole ( small artery) is a very small, almost microscopic, artery that delivers blood to capillaries.  arterioles consist of little more than a layer of endothelium  covered by a few smooth muscle fibers Abundant vessels in the body Veins  Veins carry blood towards the heart  They carry blood that is  de-oxygenated  They have valves that stop the backflow of blood 87 Venules  Thinner walls than arterial counterparts  Postcapillary venules – smallest venules  Form part of microcirculatory exchange unit with capillaries  Muscular venules have thicker walls with 1 or 2 layers of smooth muscle 88 Capillaries are tiny blood vessels about 10µm diameter that pass blood from the arterioles into the venules Their walls are thin which allows materials to pass into the capillaries Primarily, however, the capillaries are able to profuse the tissues of the body with needed oxygen and important nutrients supplied by blood Lack tunica media and tunica externa Three types of capillary 1. Continuous – most common 2. Fenestrated – have pores 3. Sinusoids(discontinuous) 90  Types of Capillaries Continuous capillaries – intercellular clefts are gaps between neighboring cells – skeletal & smooth, connective tissue and lungs Fenestrated capillaries – plasma membranes have many holes – kidneys, small intestine, choroid plexuses, ciliary process & endocrine glands Sinusoids – very large fenestrations – incomplete basement membrane – liver, bone marrow, spleen, anterior pituitary, & parathyroid gland 92 Principal Arteries of the body ascending aorta ascends from the heart (left ventricle) The coronary arteries are the only branch of the ascending aorta that supplies the heart Aortic arch Three vessels arise from the aortic arch: the brachiocephalic artery–further bifurcates into Right subclavian and common carotid arteries that supply the right upper limbs and head regions left common carotid artery left subclavian artery Descending aorta (thoracic and abdominal) 93 94 Arteries of the neck and head  Common carotid artery ascends upwards in the neck lateral to trachea Divides slightly below the angle of the mandible into the internal carotid artery and the external carotid artery The brain is supplied by four arteries: paired vertebral arteries (i.e., right and left) which forms basal artery and paired internal carotid arteries 95  The vertebral artery  arises from the subclavian artery ascends in the neck through the transverse foramen  enters the cranial cavity through the foramen magnum The right and left vertebral arteries unite to form the basilar artery that supply posterior part of the brain 96 97  The internal carotid arteries  is divided into  the ophthalmic artery  supplies the eye, and  the anterior and middle cerebral arteries  supply the cerebrum The external carotid  branches are named according to the area or structures they supply  Superior thyroid artery supply hyoid, larynx, vocal cords, thyroid gland 98  Ascending pharyngeal artery - supply pharyngeal area  Lingual artery -supply tongue and sublingual gland  Facial artery- supply pharyngeal, palate, chin, lips, nasal region  Occipital artery supply scalp (posteriorly), meninges, mastoid region, some of the posterior neck muscles  Maxillary artery supply teeth, gums, muscles of mastication, nasal cavities, eyelids Superficial temporal artery supply parotid gland, side of the head 99 100 Arteries of the upper limbs  Right subclavian- from brachiocephalic trunk  left subclavian- from aortic arch  It has the several branches in the thorax but becomes the axillary artery as it passes in the axilla  It becomes the brachial artery in the arm Site for BP(blood pressure) measurement 101  The brachial artery bifurcates at the cubital fossa into:  Radial artery- supplies muscles on the radial side of the forearm  It is the site of measuring pulse  Ulnar artery – supplies muscles on the ulnar side of the forearm Both arteries form  palmar arch in the palm and digital arteries supplying the digits 102 103 104 Branches of the thoracic portion of aorta It is a continuation of the aortic arch descends though the thoracic cavity to diaphragm gives branches to the muscles and organs of thoracic region; –esophageal arteries –Bronchial arteries –Pericardial branches –Mediastinal branches –Posterior intercostal arteries –Superior phrenic arteries 105 106 Branches of the abdominal portion of aorta Abdominal aorta is the segment between diaphragm and L4 Has three main unpaired branches Others are paired branches  Unpaired 1. Celiac trunk short, thick, branch, which divides into three vessels: Splenic artery (to spleen) Left gastric artery ( to stomach) Common hepatic (to liver) 107 2. Superior mesenteric artery  to the small intestine (except the duodenum), cecum, appendix, transverse(1/2), and ascending colons 3. Inferior mesenteric artery  last major, anterior, unpaired branch just before bifurcation into the common iliac arteries Supplies half part of the transverse colon, the descending, and sigmoid colons, rectum 108 Paired branches Cont.…  Inferior phrenic artery- to diaphragm  Renal artery– to kidney  Suprarenal artery - to adrenal glands  Testicular artery - to testes  Ovarian artery - to ovaries  Lumbar artery- to lumbar vertebrae and associated tissue Arteries of the pelvis and lower limbs  The abdominal aorta terminates by bifurcating into right common iliac arteries left common iliac arteries  The common iliac divides into the internal iliac and  external iliac arteries 110 111  The internal iliac artery supply gluteal muscles and organs of the pelvic region Urinary bladder , rectum , anal canal branches  Middle rectal - internal visceral organs of the pelvis  Superior, inferior, middle vesicular arteries - urinary bladder  Uterine and vaginal arteries - female reproductive organs  Superior and inferior gluteal arteries - gluteal muscles  Obturator artery - upper medial thigh muscles  Internal pudendal artery - perineum and external genitalia of male and female 112 External and internal iliac arteries 113 The external iliac artery passes out of pelvis beneath the inguinal ligament to become the femoral artery  Femoral artery  passes through the femoral triangle on the upper medial portion of the thigh At this point it is close to the surface, hence for palpation and pressure the femoral artery becomes the popliteal artery as it passes across the posterior aspect of the knee 114 115  The popliteal artery  divides into the anterior tibial and the posterior tibial arteries  the anterior tibial artery at the ankle, becomes  the dorsal pedal artery forms the plantar arch with the lateral plantar artery of the posterior tibial artery The dorsal pedal artery is the site from which the most distal pulse is recorded to get information about circulation 116  The posterior tibial artery  forms the large fibular artery which supplies the peroneal/fibular muscles of the leg At the ankle it bifurcates into the lateral and medial plantar arteries The lateral plantar artery forms the plantar arch and gives off digital arteries to the digits of the foot 117 Venous drainage of the body Veins Draining the neck and head  External jugular vein  from scalp, portions of face, superficial neck region drain into right and left subclavian vein  Internal jugular vein  from brain, meninges, deep regions of face and neck larger and deeper than the external jugular vein passes in carotid sheath with the common carotid and vagus nerve beneath sternocleidomastoid muscle  subclavian vein and internal jugular unite to form the brachiocephalic vein  the two brachiocephalic veins merge to form the superior vena cava, which empties into the right atrium 119  Veins of the upper extremity Consists of superficial and deep venous drainage  Deep veins  accompany the arteries and bear their names / region radial vein & ulnar vein  both drain from deep and superficial palmar arches radial and ulnar veins join in the cubital fossa to form the brachial vein, which continues up on the medial side of the arm. Brachial vein -axiliary → subclavian → internal jugular → brachiocephalic vein 121 Superficial veins of Upper limb 1. Basilic vein drains blood from ulnar side of forearm, medial side of arm merges with brachial vein near the head of the humerus to form the axillary vein 2. Cephalic vein  drains superficial region of hand and forearm on radial side joins axillary vein in the shoulder region median cubital vein ascends from the cephalic vein to join basilic vein on radial side It is a COMMON site of venipuncture 123  Veins of the thorax  Superior vena cava  receives blood from the right and left brachiocephalic veins, which drain head, neck, and upper limb as well as from azygous veins lacks valves which are characteristics of most veins  The azygous vein  extends superiorly along the dorsal abdominal and thoracic walls on the right side of the vertebral column 124  Cont.… joins the superior vena cava at T4 Its tributaries are: ascending lumbar veins - drain from lumbar and sacral regions intercostals veins- from intercostals regions  accessory hemiazygous and hemiazygous veins– from left of the vertebral column Veins of the lower extremity  have a deep and a superficial group  The deep veins  accompany the corresponding arteries 126  posterior and anterior tibial veins  originate in the foot and descend upwards in front of the tibia to the back of the knee where they merge to form the popliteal vein.  Popliteal vein  drains blood from the knee region and above the knee, it becomes the femoral vein  the femoral vein receives blood from the deep femoral vein and above this, receives from the great saphenous vein, then becomes the external iliac vein (as it passes under the inguinal ligament).  the external iliac vein  merges with the internal iliac vein to form the common iliac vein 127 Cont.… The superficial vein  small saphenous vein arises from the lateral side of the foot, courses posteriorly along the surface of the calf of the leg and enters deep into the popliteal vein behind the knee  Great saphenous vein longest vessel in the body, originates at the arch of the foot and ascends superiorly along the medial aspect of the leg and thigh before draining into the femoral vein 129  Veins of the Abdominal Region The inferior vena cava  parallels the abdominal aorta on the right as it ascends through the abdominal cavity It penetrates the diaphragm and empties into the right atrium largest in diameter of all vessels in the body in the abdomen has tributaries corresponding to the branches of the abdominal aorta. (Exceptions: the left testicular vein, left ovarian vein and the left suprarenal vein drain into the left renal vein) 130 Cont.… Cont.… Lymphatic system Lymphatic system disorders 2/15/2019 158