Human Anatomy Chapter 20 (Blood Vessels) PDF

CHAPTER 20 Blood Vessels Human Anatomy Copyright Copyright©©2011 2011Pearson PearsonEducation, Educatio, Inc. Inc. Structure of Blood Vessels Composed of three layers (tunics) Tunica intima – composed of simple squamous epithelium Tunica media – sheets of smooth muscle Contraction – vasoconstriction...

CHAPTER 20 Blood Vessels Human Anatomy Copyright Copyright©©2011 2011Pearson PearsonEducation, Educatio, Inc. Inc. Structure of Blood Vessels Composed of three layers (tunics) Tunica intima – composed of simple squamous epithelium Tunica media – sheets of smooth muscle Contraction – vasoconstriction Relaxation – vasodilation Tunica externa – composed of connective tissue Lumen – central blood-filled space of a vessel Structure of Arteries, Veins, and Capillaries Tunica intima Endothelium Subendothelial layer Internal elastic membrane Tunica media (smooth muscle and elastic fibers) External elastic membrane Tunica externa (collagen fibers) Lumen Artery Capillary network Valve Lumen Vein Basement membrane Endothelial cells (b) Capillary Structure of Arteries, Veins, and Capillaries Vein Artery (a) Types of Blood Vessels Arteries – carry blood away from the heart Capillaries – smallest blood vessels The site of exchange of molecules between blood and tissue fluid Veins – carry blood toward the heart Types of Arteries Elastic arteries – the largest arteries Diameters range from 2.5 cm to 1 cm Includes the aorta and its major branches Sometimes called conducting arteries High elastin content dampens surge of blood Vasa Lumen vasorum Elastin pressure Tunica Tunica Tunica externa media intima (a) Elastic artery (aorta, 12) Types of Arteries Muscular (distributing) arteries Lie distal to elastic arteries Diameters range from 1 cm to 0.3 mm Includes most of the named arteries Tunica media is thick Unique features Internal and external elastic laminae External elastic membrane Internal Lumen elastic membrane Tunica Tunica externa media (b) Muscular artery (40) Types of Arteries Arterioles Smallest arteries Diameters range from 0.3 mm to 10 µm Larger arterioles possess all three tunics Diameter of arterioles controlled by: Local factors in the tissues Sympathetic nervous system Lumen Endothelium Tunica media (c) Small arteriole (285) Capillaries Smallest blood vessels Diameter from 8–10 µm Red blood cells pass through single file Site-specific functions of capillaries In the lungs – oxygen enters blood, carbon dioxide leaves In the small intestines – receive digested nutrients In endocrine glands – pick up hormones In the kidneys – removal of nitrogenous wastes Capillary Exchange Capillary Beds Network of capillaries running through tissues Precapillary sphincters Regulate the flow of blood to tissues Tendons and ligaments – poorly vascularized Epithelia and cartilage – avascular Receive nutrients from nearby connective tissues Capillary Beds Precapillary sphincters Vascular shunt Metarteriole Thoroughfare channel True capillaries Terminal arteriole Postcapillary venule (a) Sphincters open—blood flows through true capillaries. Capillary Beds Terminal arteriole (b) Sphincters closed—blood flows through metarteriole—thoroughfare channel and bypasses true capillaries. Postcapillary venule Capillary Permeability Endothelial cells—held together by tight junctions and desmosomes Intercellular clefts—gaps of unjoined membrane Small molecules can enter and exit Two types of capillary Continuous—most common Fenestrated—have pores Structure of Capillaries—Cross Section Pericyte Red blood cell in lumen Intercellular cleft Endothelial cell Basement membrane Tight junction Endothelial nucleus (a) Continuous capillary. Least permeable and most common (e.g., skin, muscle). Pinocytotic vesicles Structure of Capillaries—Cross Section Pinocytotic vesicles Red blood cell in lumen Fenestrations (pores) Endothelial nucleus Basement membrane Tight junction (b) Fenestrated capillary. Large fenestrations (pores) increase permeability. Occurs in special locations (e.g., kidney, small intestine). Intercellular cleft Endothelial cell Veins Conduct blood from capillaries toward the heart Blood pressure is much lower than in arteries Smallest veins – called venules Diameters from 8–100 µm Smallest venules – called postcapillary venules Venules join to form veins Tunica externa is the thickest tunic in veins Mechanisms to Counteract Low Venous Pressure Valves in some veins Particularly in limbs Skeletal muscle pump Valve (open) Contracted skeletal muscle Muscles press against thin-walled veins Valve (closed) Vein Direction of blood flow Vascular Anastomoses Interconnections Organs receive blood from more than one arterial source Neighboring arteries form arterial anastomoses Provide collateral channels Veins anastomose more frequently than arteries Vasa Vasorum Tunica externa of large vessels have: Tiny arteries, capillaries, and veins Vasa vasorum (vessels of vessels) Nourish outer region of large vessels Inner half of large vessels receive nutrients from luminal blood Pulmonary Circulation Pulmonary trunk leaves the right ventricle Divides into right and left pulmonary arteries Superior and inferior pulmonary veins Carry oxygenated blood into the left atrium Left pulmonary artery Aortic arch Air-filled alveolus of lung Pulmonary trunk O2 Right pulmonary artery CO2 Three lobar arteries to right lung Gas exchange Pulmonary capillary Two lobar arteries to left lung Pulmonary veins Right atrium Right ventricle Pulmonary veins Left atrium Left ventricle Systemic Circulation Systemic Arteries Carry oxygenated blood away from the heart Aorta – largest artery in the body The Aorta Ascending aorta – arises from the left ventricle Branches – coronary arteries Aortic arch – lies posterior to the manubrium Branches Brachiocephalic trunk Left common carotid Left subclavian arteries The Aorta Right common carotid artery Right subclavian artery Right internal jugular vein Right subclavian vein Right brachiocephalic vein Brachiocephalic trunk Right pulmonary artery Left internal jugular vein Left subclavian artery Left subclavian vein Left brachiocephalic vein Left common carotid artery Aortic arch Left pulmonary artery Ligamentum arteriosum Superior vena cava Thoracic aorta Ascending aorta Pulmonary trunk Right atrium Left atrium Right ventricle Inferior vena cava Left ventricle Major Arteries Arteries of the head and trunk Internal carotid artery External carotid artery Common carotid arteries Vertebral artery Subclavian artery Brachiocephalic trunk Aortic arch Ascending aorta Coronary artery Thoracic aorta (above diaphragm) Celiac trunk Abdominal aorta Superior mesenteric artery Renal artery Gonadal artery Inferior mesenteric artery Common iliac artery Internal iliac artery Arteries that supply the lower limb External iliac artery Femoral artery Popliteal artery Anterior tibial artery Posterior tibial artery Arcuate artery (a) Anterior view Arteries that supply the upper limb Subclavian artery Axillary artery Brachial artery Radial artery Ulnar artery Deep palmar arch Superficial palmar arch Digital arteries Orginally taken from the following website: http://www.smm.org/bodyworlds/video/index.php?size=large Arteries of the Head and Neck Vertebral artery Internal carotid artery External carotid artery Common carotid artery Branches of the external carotid artery Superficial temporal artery Maxillary artery Occipital artery Facial artery Lingual artery Subclavian artery Axillary artery (a) Arteries of the head and neck, right aspect Brachiocephalic trunk Major Arteries Serving the Brain Anterior Cerebral arterial circle (circle of Willis) Middle cerebral artery Internal carotid artery Anterior communicating artery Anterior cerebral artery Posterior communicating artery Posterior cerebral artery Basilar artery Vertebral artery Posterior (c) Major arteries serving the brain (inferior view, right side of cerebellum and part of right temporal lobe removed) Arteries of the Upper Limb and Thorax Vertebral artery Common carotid arteries Right subclavian artery Left subclavian artery Brachiocephalic trunk Axillary artery Descending aorta Brachial artery Deep artery of arm Radial artery Ulnar artery Deep palmar arch Superficial palmar arch Digital arteries Arteries of the Abdominal Aorta Hiatus (opening) for inferior vena cava Hiatus (opening) for esophagus Celiac trunk Renal artery Superior mesenteric artery Abdominal aorta Gonadal (testicular or ovarian) artery Inferior mesenteric artery Common iliac artery The Celiac Trunk and Main Branches Inferior vena cava Celiac trunk Common hepatic artery Hepatic artery proper Splenic artery Abdominal aorta Superior mesenteric artery (a) The celiac trunk and its major branches. The left half of the liver has been removed. Distribution of the Superior and Inferior Mesenteric Arteries Celiac trunk Superior mesenteric artery Branches of the superior mesenteric artery Middle colic artery Intestinal arteries Right colic artery Ileocolic artery Aorta Inferior mesenteric artery Branches of the superior mesenteric artery Left colic artery Sigmoidal arteries Superior rectal artery Ascending colon Right common iliac artery (b) Distribution of the superior and inferior mesenteric arteries. The transverse colon has been pulled superiorly. Arteries of the Pelvis and Lower Limbs Common iliac artery Internal iliac artery External iliac artery Deep artery of thigh Obturator artery Femoral artery Popliteal artery Anterior tibial artery Posterior tibial artery Fibular artery Dorsalis pedis artery (a) Anterior view Arteries of the Pelvis and Lower Limbs Popliteal artery Anterior tibial artery Posterior tibial artery Lateral plantar artery Medial plantar artery Fibular artery (b) Posterior view of leg Internal Iliac Artery Middle rectal artery (to rectum) Medial umbilical ligament (obliterated umbilical artery of fetus) Superior vesical artery (to bladder) Common iliac artery External iliac artery Internal iliac artery Gluteal arteries Obturator artery Inferior vesical artery (to bladder) and vaginal artery Uterine artery Internal pudendal artery (to perineum) (b) Medial view of the right pelvis of a female Flow Chart Summarizing Main Systemic Arteries Systemic Veins Three major veins enter the right atrium Superficial veins lie just beneath the skin Multivein bundles – venous plexuses Unusual patterns of venous drainage Dural sinuses Hepatic portal system Venae Cavae and Tributaries Superior vena cava Returns blood from body regions superior to the diaphragm Inferior vena cava Returns blood from body regions inferior to the diaphragm Superior and inferior vena cava Join the right atrium Major Veins of the Systemic Circulation Veins of the head and trunk Dural venous sinuses External jugular vein Vertebral vein Internal jugular vein Right and left brachiocephalic veins Superior vena cava Great cardiac vein Hepatic veins Veins that drain the upper limb Subclavian vein Axillary vein Cephalic vein Brachial vein Basilic vein Median cubital vein Ulnar vein Radial vein Splenic vein Hepatic portal vein Digital veins Renal vein Veins that drain the lower limb External iliac vein Femoral vein Great saphenous vein Popliteal vein Posterior tibial vein Anterior tibial vein Small saphenous vein Dorsal venous arch Dorsal metatarsal veins Superior mesenteric vein Inferior mesenteric vein Inferior vena cava Common iliac vein Internal iliac vein Veins of the Head and Neck Dural Sinuses Superior and inferior sagittal sinuses Straight sinus Transverse sinuses Superior sagittal sinus Sigmoid sinus Falx cerebri Inferior sagittal sinus Straight sinus Cavernous sinus Confluence of sinuses Transverse sinuses Sigmoid sinus Jugular foramen Right internal jugular vein (b) Dural venous sinuses of the brain Veins of the Head and Neck Venous drainage Ophthalmic vein Superficial temporal vein Internal jugular veins Facial vein Occipital vein External jugular veins Posterior auricular vein External jugular vein Vertebral veins Vertebral vein Internal jugular vein Superior and middle thyroid veins Brachiocephalic vein Subclavian vein Superior vena cava (a) Veins of the head and neck, right superficial aspect Veins of the Upper Limbs Deep Veins Follow the paths of companion arteries Have the same names as the companion arteries Superficial veins Visible beneath the skin Cephalic vein Basilic vein Median cubital vein Median vein of the forearm Veins of the Right Limb Internal jugular vein External jugular vein Left subclavian vein Superior vena cava Azygos vein Accessory hemiazygos vein Hemiazygos vein Brachiocephalic veins Right subclavian vein Axillary vein Brachial vein Cephalic vein Inferior vena cava Median cubital vein Cephalic vein Radial vein Ulnar vein Veins of the Thorax Azygos vein Hemiazygos vein Accessory hemiazygos vein Veins of the Abdomen The Hepatic Portal System A specialized part of the vascular circuit Picks up digested nutrients Delivers nutrients to the liver for processing The Basic Scheme of the Hepatic Portal System Veins of the Hepatic Portal System Hepatic veins Liver Hepatic portal vein Inferior vena cava (not part of hepatic portal system) Gastric veins Spleen Inferior vena cava Splenic vein Right gastroepiploic vein Inferior mesenteric vein Superior mesenteric vein Small intestine Large intestine Rectum (b) The veins of the hepatic portal system Veins of the Pelvis and Lower Limbs Deep veins Share the name of the accompanying artery Superficial veins Great saphenous vein empties into the femoral vein Small saphenous vein empties into the popliteal vein Veins of the Right Lower Limb and Pelvis Common iliac vein Internal iliac vein External iliac vein Femoral vein Great saphenous vein (superficial) Popliteal vein Fibular vein Anterior tibial vein Dorsalis pedis vein (a) Anterior view Veins of the Right Lower Limb and Pelvis Great saphenous vein Popliteal vein Anterior tibial vein Fibular vein Posterior tibial vein Plantar veins (b) Posterior view of leg Flow Chart Summarizing Main Veins of Systemic Circulation Fetal and Newborn Circulation Compared Fetus Aortic arch Superior vena cava Ductus arteriosus Ligamentum arteriosum Pulmonary artery Pulmonary veins Heart Lung Foramen ovale Fossa ovalis Liver Ductus venosus Ligamentum venosum Hepatic portal vein Umbilical vein Ligamentum teres Inferior vena cava Umbilicus Abdominal aorta Common iliac artery Umbilical arteries Medial umbilical ligaments Urinary bladder Umbilical cord Placenta (a) High oxygenation Moderate oxygenation Low oxygenation Very low oxygenation Fetal and Newborn Circulation Compared Newborn Aortic arch Superior vena cava Ductus arteriosus Ligamentum arteriosum Pulmonary artery Pulmonary veins Heart Lung Foramen ovale Fossa ovalis Liver Ductus venosus Ligamentum venosum Hepatic portal vein Umbilical vein Ligamentum teres High oxygenation Moderate oxygenation Low oxygenation Very low oxygenation Inferior vena cava Umbilicus Abdominal aorta Common iliac artery Umbilical arteries Medial umbilical ligaments Urinary bladder (b) Abdominal Aneurysm Aortic aneurysm