PART 1 Blood Vessels

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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Structure of Arteries, Veins, and Capillaries Figure 19.1a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries – carry blood away from the heart 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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Elastic arteries – the largest arteries 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 pressure Figure 19.2a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Muscular (distributing) arteries Types of Arteries Muscular (distributing) arteries Lie distal to elastic arteries Diameters range from 1 cm to 0.3 mm Includes most named arteries Tunica media is thick Unique features Internal and external elastic laminae Figure 19.2b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

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 Figure 19.2c Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Smallest blood vessels Capillaries Smallest blood vessels Diameter from 8–10 µm Red blood cells pass through single file Site-specific functions of capillaries Lungs – oxygen enters blood, carbon dioxide leaves Small intestines – receive digested nutrients Endocrine glands – pick up hormones Kidneys – removal of nitrogenous wastes Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

RBCs in a Capillary Figure 19.3 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Network of capillaries running through tissues Precapillary sphincters 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 CT PLAY Anatomy Review: Blood Vessel Structure and Function Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Capillary Beds Figure 19.4a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Capillary Beds Figure 19.4b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Capillary Permeabillity 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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Structure of Capillaries – Cross Section Figure 19.5a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Structure of Capillaries – Cross Section Figure 19.5b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Routes of Capillary Permeability Four routes into and out of capillaries Direct diffusion Through intercellular clefts Through cytoplasmic vesicles Through fenestrations Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Low Permeability Capillaries Blood-brain barrier Capillaries have complete tight junctions No intercellular clefts are present Vital molecules pass through Highly selective transport mechanisms Not a barrier against Oxygen, carbon dioxide, and some anesthetics Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Wide, leaky capillaries found in some organs Sinusoids Wide, leaky capillaries found in some organs Usually fenestrated Intercellular clefts are wide open Occur in bone marrow and spleen Sinusoids have a large diameter and twisted course Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Sinusoids Figure 19.5c Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Conduct blood from capillaries toward the heart 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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Mechanisms to Counteract Low Venous Pressure Valves in some veins Particularly in limbs Skeletal muscle pump Muscles press against thin-walled veins Figure 19.6 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Vessels interconnect to form vascular anastomoses Organs receive blood from more than one arterial source Neighboring arteries form arterial anastomoses Provide collateral channels Veins anastomose more frequently than arteries Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Tunica externa of large vessels have Vasa vasorum vessels of vessels 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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Pulmonary Circulation Figure 19.7 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Systemic Circulation Systemic Arteries Carry oxygenated blood away from the heart Aorta – largest artery in the body Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Major Arteries Figure 19.8a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Ascending aorta – arises from the left ventricle 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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Aorta Figure 19.9 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Descending aorta – continues from the aortic arch The Aorta Descending aorta – continues from the aortic arch Thoracic aorta – in the region of T5–T12 Abdominal aorta – ends at L4 Divides into right and left common iliac arteries Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

PART 2 Blood Vessels

Arteries of the Head and Neck Figure 19.10a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Major Arteries Serving the Brain Cerebral arterial circle Figure 19.10c Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries of the Upper Limb and Thorax Figure 19.11 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries of the Abdominal Aorta Inferior phrenic arteries Celiac trunk Superior mesenteric artery Suprarenal arteries Renal arteries Gonadal (testicular or ovarian) arteries Inferior mesenteric artery Common iliac arteries Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries of the Abdominal Aorta Figure 19.12 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Celiac Trunk and Main Branches Figure 19.13 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

PART 3 Blood Vessels

Distribution of the Superior and Inferior Mesenteric Arteries Figure 19.14 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries of the Pelvis and Lower Limbs Internal iliac arteries External iliac artery Femoral artery Popliteal artery Anterior tibial artery Posterior tibial artery Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Internal Iliac Artery Figure 19.15b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries of the Pelvis and Lower Limbs Figure 19.16a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Arteries of the Pelvis and Lower Limbs Figure 19.16b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Flow Chart Summarizing Main Systemic Arteries Figure 19.17 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Fenestrated Capillary Describe relevance of pulse points to clinical anatomy Figure 19.5b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Three major veins enter the right atrium 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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Abdominal Cavity Showing Vasculature Figure 19.19 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Major Veins of the Systemic Circulation Figure 19.18 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

PART 4 Blood Vessels

Veins of the Head and Neck Dural Sinuses Superior and inferior sagittal sinuses Straight sinus Transverse sinuses Sigmoid sinus Figure 19.20b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Veins of the Head and Neck Venous drainage Internal jugular veins External jugular veins Vertebral veins Figure 19.20a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Veins of the Right Limb Figure 19.21a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Form anastomese frequently Antecubital Fossa Form anastomese frequently Median cubital vein is used to obtain blood or administer IV fluids Figure 19.22 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Accessory hemiazygos vein Veins of the Thorax Azygos vein Hemiazygos vein Accessory hemiazygos vein Figure 19.21b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Gonadal (testicular or ovarian) veins Renal veins Suprarenal veins Veins of the Abdomen Lumbar veins Gonadal (testicular or ovarian) veins Renal veins Suprarenal veins Hepatic veins Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Tributaries of the Inferior Vena Cava Figure 19.23 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Hepatic Portal System A specialized part of the vascular circuit Picks up digested nutrients Delivers nutrients to the liver for processing Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Basic Scheme of the Hepatic Portal System Figure 19.24 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

PART 5 Blood Vessels

Veins of the Hepatic Portal System Figure 19.25 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

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 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Veins of the Right Lower Limb and Pelvis Figure 19.26a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Veins of the Right Lower Limb and Pelvis Figure 19.26b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Flow Chart Summarizing Main Veins of Systemic Circulation Figure 19.27 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Disorders of the Blood Vessels Aneurysm Deep vein thrombosis of the lower limb Venous disease Microangiopathy of diabetes Arteriovenous malformation Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Blood Vessels Throughout Life Fetal Circulation All major vessels in place by month three of development Differences between fetal and postnatal circulation Fetus must supply blood to the placenta Very little blood is sent through the pulmonary circuit Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Vessels to and from the Placenta Umbilical vessels run in the umbilical cord Paired umbilical arteries Unpaired umbilical vein Fetal vessels and structures Ductus venosus Ligamentum teres Ligamentum venosum Medial umbilical ligaments Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Shunts Away from the Pulmonary Circuit Foramen ovale Ductus arteriosus Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Fetal and Newborn Circulation Compared Figure 19.28a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Fetal and Newborn Circulation Compared Figure 19.28b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Blood Vessels in Adulthood Atherosclerosis begins in youth Consequences evident in middle to old age Males More atherosclerosis than females between ages 45 – 65 Females Experience heart disease and atherosclerosis later in life Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings