heart 3 Flashcards
(27 cards)
Lymphatic Vessels
return lymph to veinous circulation
Lymph
excess fluid returned to the blood, important for immune function
capillaries
site of exchange of gases and nutrients
blood pressure is highest in the __
Aorta
Blood pressure is lowest in __
Vena Cava
Tunica Externa
outermost layer of the blood vessel
Tunica Media
middle layer w/smooth muscle
changes the size of lumen, altering flow and pressure
Tunica Interna (Endothelium)
innermost layer of simple squamous tissue
Lumen
hole that blood flows through
blood vessel structure in arteries
thicker in tunica media, narrow lumen
more elastic and collagen fibers to resist blood pressure changes
blood vessel structure in veins
thicker in tunica externa and larger lumen
if no blood it collapses
Blood vessel structure in capillaries
Tunica intima, connect arteries to veins, consist of endothelial layer and basement membrane for rapid exchange of gases and nutrients
Elastic Arteries
largest arteries, Aorta and major branches transport blood to muscular arteries
Muscular Arteries
Thicker tunica media, provide blood to organs
Arterioles
supply blood to capillary beds
blood flow in capillaries
one cell layer thick
red blood cells pass one at a time (rouleau)
precapillary sphincters control flow of blood through bed
Venules
drain capillary beds, merge to form veins
Systolic pressure
pressure during ventricular contraction
Diastolic pressure
pressure during ventricular relaxation
foramen ovalve
connects right atrium to left atrium
Ductus arteriosus
connects pulmonary trunk to aorta
ductus venosus
connect umbilical cord to inferior vena cava
Shunt closure
first breath changes pressure gradients forcing closure
first new born breath changes
ductus arteriosus–ligamentum arteriosum
foramen ovale– fossa ovalis
ductus venosus– ligament venosum
