Coverings of the heart (pericardium) from superficial to deep
Fibrous pericardium: dense irregular connective tissue
serous pericardium: parietal layer. mesothelium (sheet of mesothelial cells on a basement membrane)
pericardial cavity: fluid filled
visceral layer of serous pericardium: mesothelium
help cells move as one by connecting their actin filaments
macula adherens (desmosomes)
help prevent cells from pulling apart by connecting intermediate filaments
made of specialized modified cardiomyocytes
- larger in size
- need lots of stored energy
Ventricularis/atrialis = Layer rich in elastin at the inflow surface. Elastin facilitates rapid recoil to close the valve quickly. Lined on the outside with endothelium.
Spongiosa = Central core of loose CT with loosely arranged collagen and elastic fibers. Dampens vibrations from valve closing.
Fibrosa = Dense irregular connective tissue at the outflow surface that is an extension of the fibrous skeleton. Lined with endothelium on the outside. Note: cordae tendineae in AV valves are extensions of the fibrosa.
Inflow surface: ventricularis or atrialis. Depending on where the blood is coming from. Lots of eleastic fibers to snap valve back in place.
Internal elastic lamina present in
small arteries but not arterioles
tunica media in arteriole vs small artery
small artery: 4-10 layers of smooth muscle
arteriole: 1-3 layers of smooth muscle
pre-capillary sphincter= smooth muscle enlargement in the areriole.