Download HCB Objectives 13

HCB Objectives 13
1.
Elastic artery:
Large vein:
Muscular artery:
Medium/small vein:
Arteriole:
Venule:
2.
Types of capillaries:
a.
Continuous: endothelial cells sealed with tight junctions, no perforations,
surrounded by complete basal lamina, transport across membrane is
transcytosis (pinocytosis). Found in CNS, lungs, muscles, and CT
b.
Fenestrated: endothelial cells sealed with tight junctions, pierced by
fenestrae, surrounded by complete basal lamina. Found in choroid plexus,
gall bladder, intestine, and endocrine glands
c.
Sinusoidal: endothelial cells with gaps to permit direct exchange, pierced
by fenestrae without diaphragms, basal lamina is missing at pore areas.
Found in liver, lymph nodes, and adrenal cortex.
3.
Function of arteriovenous anastomoses: direct connection of arteries and veins
(bypassing capillaries). When anastomoses are open, blood is shunted from
capillaries back to the cardiovascular system; therefore, arteriovenous
anastomoses takes blood to the areas where it is needed most and away from
where it isn’t immediately needed (fight/flight AV anastomoses close in skeletal
muscle to provide blood to muscle; AV anastomoses open in gut to shunt blood
away)
4.
Histological organization of the heart:
a.
Pericardium: tissue surrounding the heart, used to protect and support the
heart
b.
Epicardium: collagenous CT with elastic fibers, fat cells, nerves, ganglia,
lymphatic vessels, and blood vessels. Externally covered by simple
squamous epithelium (mesothelium). Borders the visceral pericardium.
c.
Myocardium: cardiac muscle cells, thickest part of the heart.
d.
Endocardium: collagenous CT with elastic fibers and smooth muscles
covered by an endothelial layer with a continuous basement membrane.
Where Purkinje fibers reside.
 Note: Heart valves are endocardium, and are made of dense fibrous
CT bordered by endothelial layers. Valve bases attach to fibrous
skeleton rings which are attached to myocardium to allow electrical
conduction of valves.
Structure as a modified blood vessel: Epicardium = Tunica Adventitia,
Myocardium = Tunica Media, Endocardium = Tunica Intima
5.
Lymphatic vessel cross-section:
Lymph flow from tissues to blood: Lymphatic capillaries → lymphatic vessels
→ lymphatic ducts → veins