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35 Cards in this Set

  • Front
  • Back
2 functional components of circulatory system
blood, lymph
List the basic structures of circulatory tystem (3 parts)
Tunica intima (inner)
Tunica media (middle)
Tunica adventitia (outer)
2 major functions of circulatory system
deliver blood to tissues, exchange substances between tissues and blood
Describe lymphatic vessel
Blind-ended collecting vessels with valves. Return tissue fluids, lymphocytes and large molecular weight substances (eg.antibodies) to the blood
Tunica intima
Innermost layer. "Endothelium." Specialized simple squamous epithelium. Rests on basement membrane and subendothelial (loose) connective tissue and internal elastic lamina.
Tunica media
middle layer. Circumferentially arranged smooth muscle and connective tissue (Usually collagen III, IV, or elastin)
Tunica adventitia
outer layer. Connective tissue (Collagen I and elastin), fibroblasts, adipocytes, GAGs, etc. Blends into connective tissue of tissue being supplied. In larger vessels has vasa vasorum
vasa vasorum
"vessels in vessels." Found in tunica adventitia
Elastic arteries
Large, rigid. helps pumping.
Intima - thick (b/c of subendothelial connective tissue layer).
Media - elastic lamellae.
Adventitia - connective tissue and vasa vasorum
Muscular arteries
"distributing arteries." Deliver blood to specific regions or organs. Allows body to control blood flow.
Intima- thin subendothelial layer, prominent internal elastic lamina.
Media-thick, smooth muscle with prominent elastic lamellae or fibers
Adventitia - unremarkable
Small diameter. responsible for 50% of flow resistance. May have pericyte.
Intima - thin subendothelium, barely discernible internal elastic lamina

Media - 5-8 cells thick
Adventitia - thin
5 functions of endothelium
Exchange, vasoregulation, promote clotting, inhibit platelet adhesion, stimulate angiogenesis (during wound healing)
Functions of: 1) T. Intima, 2)T. Media, and 3) T. Adventitia
1) Maintain smooth luminal surface and tissue seal
2) Controlling peripheral blood pressure
3) Support
Which vessels have holes in the walls and what is that called?
Fenestration. (EDIT) Capillaries
Layers of the heart
endocardium - simple squamous, thin connective tissue
myocardium - cardiac muscle, blood supply
epicardium - connective tissue w/ adipose, coronary vessels, simple squamous (mesothelium)
List the 3 arteriole classifications
continuous, fenestrated, sinusoidal (discontinuous)
Where do lymphatic vessels drain into?
Thoracic duct
Veins hold ______% of systemic blood and are therefore referred to as ___________ __________
70%; "capacitance vessels"
Histological differences between veins and arteries
Veins: have a larger, more irregular lumen, smaller smooth muscle cell/collagen fiber ratio, no distinct elastic laminae, thicker adventitia than media, and valves.
Large veins
Intima: thin
Media: thin
Adventitia: thick
Medium/Small veins
Similar to large, but intima may be relatively thick.
Intima: only endothelium and basal lamina
Media: thin (a few muscle cells)
Adventitia: thick
SA node
sinoatrial. beneath epicardium on medial wall of rt atrium near superior vena cave opening
AV node
atrioventricular. In atrioventricular septum
Bundle of His
pass from AV node through interventricular septum
Purkinje fibers
branch from bundle of His into the subendocardium. Transmits impulses to rest of myocardium
Classification of blood vessels by function (5)
Elastic --> conducting
muscular --> distributing
arterioles --> resistance
capillaries --> exchange
veins --> capacitance
direct connection from one BV (?) to another
End arteries
one arteriole, such as in the retina, which supplies blood. If damaged, blood supply is cut off
Properties that effect the passing of substances through capillary walls
nature of the endothelium, hydrostatic vs osmotic pressures, physiochemical properties of the substance in the blood and interstitial fluid
continuous capillaries
completely sealed by endothelial cells w/ junctions (tight, desmosomes). Passive diffusion through BM and cell, or pinocytosis
fenestrated capillaries
Junctions btw endothelial cells, but with semi-closed gaps. Continuous BM. Easy passage from lumen to EC space. eg - endocrine organs releasing hormones, small intestine (absorption), kidneys (secretion)
Discontinuous capillaries
"sinusoidal." Larger gaps, holes in BM. Easy diffusion. eg - liver
AV shunts
arteriovenous shunts. Allows blood to bypass capillary bed. eg - fingers in cold weather
Portal system
capillary bed to capillary bed, no intermediate pump. (uses portal veins)