Blood Vessel Histology Human Arteries and Veins BIOL 204 – Week 3 Lab Blood Vessel Histology Human Arteries and Veins

Objective 1 Blood Vessel Histology Arteries and Veins have three tunics, or tissue layers: Tunica intima (interna) Inner layer of endothelium and subendothelial areolar CT Tunica media smooth muscle and elastic tissue Tunica adventitia (externa) Dense irregular connective tissue

Comparison of arteries and veins: Small artery: thick tunica media, thin Small vein: thin tunica media tunica externa thick tunica externa maintains its shape collapsible

Objective 2 Some Human Arteries:

Objective 3 Major Veins of the Body

Objective 4 Pulmonary Circulation Functions to bring deoxygenated blood to the lungs for gas exchange and to bring oxygenated blood back to the heart for distribution to body systems Unlike systemic circulation, pulmonary circulation: 1. is a low pressure pathway 2. arteries carry deoxygenated blood; veins carry oxygenated blood

Objective 5 Trace The Flow of Blood In Pulmonary Circulation

Objective 6 Cerebral Circulation Arteries

Vessels of the Circle of Willis

Sheep’s Brain: Structures of the Circle of Willis

Venous Drainage

Objective 7 and 8 Hepatic Portal Circulation Hepatic portal circulation consists of veins that drain blood from digestive viscera, the spleen and pancreas and deliver that blood to the liver for processing: Remove, store and bioconvert sugars, fatty acids and amino acids Detoxification of the blood Remove bacteria and other debris

Hepatic Portal System in the Cat: Superior Mesenteric Vein C. Hepatic Portal Vein Inferior Mesenteric Vein D. Gastrosplenic Vein

Objective 9 and 10 Fetal Circulation The structures of fetal circulation allow the placenta to function as an organ for nutrient, waste and gas exchange Note that the: Umbilical arteries carry deoxygenated blood and that the umbilical veins carry oxygenated blood The ductus venosus allows most blood to bypass the nonfunctional fetal liver The foraman ovale and the ductus arteriosus allows most blood to bypass the nonfunctional fetal lungs

Umbilical Arteries and Umbilical Vein of a Fetal Umbilical Cord