Anatomy of Arteries, Veins and Capillaries Lab 4 Anatomy of Arteries, Veins and Capillaries Identification of major blood vessels Blood Flow Lymphatic System 2/6/2010 M. Dufilho

Precapillary sphincter Venous system Arterial system Large veins (capacitance vessels) Heart Elastic arteries (conducting vessels) Large lymphatic vessels Lymph node Muscular arteries (distributing vessels) Lymphatic system Small veins (capacitance vessels) Arteriovenous anastomosis Lymphatic capillary Sinusoid Arterioles (resistance vessels) Postcapillary venule Terminal arteriole Metarteriole Thoroughfare channel Capillaries (exchange vessels) Precapillary sphincter 2/6/2010 M. Dufilho Figure 19.2

• Subendothelial layer Internal elastic lamina Tunica intima • Endothelium Valve • Subendothelial layer Internal elastic lamina Tunica media (smooth muscle and elastic fibers) External elastic lamina Tunica externa (collagen fibers) Lumen Vein Lumen Artery Capillary network Basement membrane Endothelial cells (b) Capillary 2/6/2010 M. Dufilho Figure 19.1b

2/6/2010 M. Dufilho Table 19.1 (1 of 2)

2/6/2010 M. Dufilho Table 19.1 (2 of 2)

Systolic pressure Mean pressure Diastolic pressure 2/6/2010 M. Dufilho Figure 19.6

Factors Aiding Venous Return Respiratory “pump”: pressure changes created during breathing move blood toward the heart by squeezing abdominal veins as thoracic veins expand Muscular “pump”: contraction of skeletal muscles “milk” blood toward the heart and valves prevent backflow Vasoconstriction of veins under sympathetic control 2/6/2010 M. Dufilho

Valve (open) Contracted skeletal muscle Valve (closed) Vein Direction of blood flow 2/6/2010 M. Dufilho Figure 19.7

Blood Pressure What is blood pressure? How is it measured? Where is it measured? Systolic vs. Diastolic? 2/6/2010 M. Dufilho

Consists of three parts Lymphatic System Consists of three parts A network of lymphatic vessels (lymphatics) Lymph Lymph nodes 2/6/2010 M. Dufilho

Lymphatic System: Functions Returns interstitial fluid and leaked plasma proteins back to the blood Once interstitial fluid enters lymphatics, it is called lymph Together with lymphoid organs and tissues, provide the structural basis of the immune system 2/6/2010 M. Dufilho

lymphatic duct into vein Regional lymph nodes: Internal jugular vein Cervical nodes Entrance of right lymphatic duct into vein Entrance of thoracic duct into vein Axillary nodes Thoracic duct Cisterna chyli Aorta Inguinal nodes Lymphatic collecting vessels Drained by the right lymphatic duct Drained by the thoracic duct (a) General distribution of lymphatic collecting vessels and regional lymph nodes. 2/6/2010 M. Dufilho Figure 20.2a

Venous system Arterial system Heart Lymphatic system: Lymph duct Lymph trunk Lymph node Lymphatic collecting vessels, with valves Tissue fluid Blood capillaries Lymphatic capillary Tissue cell Blood capillaries Lymphatic capillaries (a) Structural relationship between a capillary bed of the blood vascular system and lymphatic capillaries. Filaments anchored to connective tissue Endothelial cell Flaplike minivalve Fibroblast in loose connective tissue (b) Lymphatic capillaries are blind-ended tubes in which adjacent endothelial cells overlap each other, forming flaplike minivalves. 2/6/2010 M. Dufilho Figure 20.1

Internal jugular veins Esophagus Right lymphatic duct Right jugular trunk Internal jugular veins Esophagus Right lymphatic duct Right subclavian trunk Trachea Left subclavian trunk Right subclavian vein Left jugular trunk Right broncho- mediastinal trunk Left subclavian vein Brachiocephalic veins Entrance of thoracic duct into vein Superior vena cava Left bronchomediastinal trunk Azygos vein Ribs Thoracic duct Hemiazygos vein Cisterna chyli Right lumbar trunk Left lumbar trunk Inferior vena cava Intestinal trunk (b) Major lymphatic trunks and ducts in relation to veins and surrounding structures. Anterior view of thoracic and abdominal wall. 2/6/2010 M. Dufilho Figure 20.2b

Lymph Transport Lymph is propelled by Pulsations of nearby arteries Contractions of smooth muscle in the walls of the lymphatics 2/6/2010 M. Dufilho

Principal lymphoid organs of the body Lymph Nodes Principal lymphoid organs of the body Embedded in connective tissue, in clusters along lymphatic vessels Near the body surface in inguinal, axillary, and cervical regions of the body 2/6/2010 M. Dufilho

(a) Longitudinal view of the internal structure of a lymph Cortex • Lymphoid follicle Afferent lymphatic vessels • Germinal center • Subcapsular sinus Efferent lymphatic vessels Hilum Medulla: • Medullary cord • Medullary sinus Trabeculae Capsule (a) Longitudinal view of the internal structure of a lymph node and associated lymphatics 2/6/2010 M. Dufilho Figure 20.4a

lymphatic duct into vein Regional lymph nodes: Internal jugular vein Cervical nodes Entrance of right lymphatic duct into vein Entrance of thoracic duct into vein Axillary nodes Thoracic duct Cisterna chyli Aorta Inguinal nodes Lymphatic collecting vessels Drained by the right lymphatic duct Drained by the thoracic duct (a) General distribution of lymphatic collecting vessels and regional lymph nodes. 2/6/2010 M. Dufilho Figure 20.2a

Figure 20.5 Lymphoid organs. Tonsils (in pharyngeal region) Thymus (in thorax; most active during youth) Spleen (curves around left side of stomach) Peyer’s patches (in intestine) Appendix 2/6/2010 M. Dufilho