A&PII Lab 6: The Cardiovascular System - The Blood Vessels Flashcards
Tunica interna (tunica intima)
innermost layer of arteries; simple squamous epithelium that establishes a smooth inner surface of the vessel
Endothelium
smooth inner surface of arteries
Basement membrane
connective tissue portion of arteries
Internal elastic membrane
thin elastic connective tissue layer of arteries; enables the lumen of the vessel to stretch open to accommodate surges in blood volume that occur during the cardiac cycle
Tunica media
bordering the internal elastic membrane in arteries; thickest layer; contains smooth muscle cells and elastic fibers
Vasoconstriction
contraction of the smooth muscle causing a decrease in the diameter of the lumen
Vasodilation
relaxation of the smooth muscle causing a relaxation and an increase in the lumen diameter
Tunic externa (tunica adventitia)
outermost layer of an artery wall; composed of loose connective tissue that provides support and protection; its collagen fibers anchor arteries to nearby structures
Elastic arteries
the largest arteries; named so due to the large amount of elastic fibers present in the tunica media; must stretch under the pressure exerted during ventricular contraction to accommodate a large bolus of blood with each cardiac cycle
Muscular arteries
smaller tributaries from the elastic arteries; more smooth muscle cells and fewer elastic fibers in the tunica media
External elastic membrane
the elastic fibers are concentrated to form this distinct layer between the tunica media and tunica externa
Arterioles
after branching into smaller tributaries, the muscular arteries eventually give rise to small arteries, and finally these, which carry blood to capillaries
Capillary networks
capillaries are usually found in these complex branching patterns
Precapillary sphincters
tiny sphincter muscles of smooth muscle are present at this union between the arteriole and capillary
Venules
small tubes that are intermediary between capillaries and larger veins; wall consists of a thin endothelium and a tunica media with only a few smooth muscle cells
Veins
venules converge to form these larger vessels; 3 tunics; however, the thickness of the wall is much thinner in these, and the lumen is much larger
Valves
one-way extensions of the tunic intima; present in the veins of the limbs and elsewhere to prevent the backflow of blood
Systemic circulation
primary blood delivery system of the body, carrying oxygenated blood from the heart to all body tissues except the lungs; also includes the capillaries within all tissues of the body except the lungs, and the veins outside of the lungs that carry deoxygenated blood back to the right atrium
Pulmonary circulation
route of blood flow to the lungs from the right ventricle, the capillary distribution within the lungs, and the vessels that carry oxygenated blood from the lungs to the left atrium
Hepatic portal circulation
blood is carried from the large intestine, small intestine, stomach, spleen, and pancreas to the liver
Placenta
the exchange between mother and fetus is made possible by the presence of this, which contains capillaries from the mother
Umbilical vein
vein that carries oxygen-rich blood through the umbilical cord to the fetus
Ductus venosus
within the fetus, this vessel carries blood from the umbilical vein to the inferior vena cava
Foramen ovale
in order to bypass circulation to the lungs, this hole permits blood to flow between the atria
Ductus arteriosus
shunts blood from the pulmonary trunk into the aorta
Umbilical arteries
to remove deoxygenated blood, 2 of these arteries channel it from their origin at the internal iliac arteries, through the umbilical cord, and to the placenta
