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81 Cards in this Set
- Front
- Back
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What is the objective of the vascular system?
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To mainatin the QUALITY and VOLUME of the extracellular fluid.
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Where is the site of exchange for replenishing oxygen and nutrients in the EC space?
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In the Microvascular capillary bed of each tissue
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How close to a nurturing capillary are all cells?
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Within 200 um
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How many "tunics" in vessels?
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3
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What are the 3 tunics of blood vessels?
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1. Tunica Adventitia
2. Tunica media 3. Tunica intima |
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What is the outermost covering of blood vessels? What is it made of?
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Tunica adventitia - made of connective tissue.
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2 Important structures housed within the Tunica Adventitia:
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-Vasa vasorum
-Nervi vascularis |
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What is Vasa Vasorum?
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The vasculature of the vasculature - the blood supply to the vessels themselves.
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What is Nervi vascularis?
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The blood vessel's nerve supply
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What is Tunica Media? What is it made up of?
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The most variable layer - made up of Smooth muscle cells + CT
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What is the Tunica Media made of it it's in the heart?
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Cardiac myocytes + CT
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What is the innermost covering of the blood vessel?
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Tunica intima
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What does the tunica intima consist of? (3 things)
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-Endothelium
-Basal lamina of the endothelium -some CT |
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What type of epithelium is the endothelium of tunica intima?
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Simple squamous
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What feature of the tunica intima endothelial cells KEEPS blood IN the tube vessel?
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Tight junctions
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How does the tunica intima change at the capillary beds?
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The tight junctions become leaky to allow exchange of fluids.
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What are the three very highly modified vascular tunics in the heart called?
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-Epicardium
-Myocardium -Endocardium |
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What is the Epicardial layer made up of in the heart? (cell types)
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Simple squamous mesothelium + some CT
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Why is the epicardium important?
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Because innervation and coronary vessels enter the heart here.
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What 2 cell types make up the myocardium?
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-Cardiac myocytes
-Cardiac fibroblasts |
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What type of cells make up the cardiac endocardium?
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Simple squamous endothelium + basal lamina + some CT
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What important component of the heart is located in the sub-endocardium?
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Purkinje fibers - the conduction system.
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Which has a thicker wall; arteries or veins?
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Arteries
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Why are the walls of arteries thicker?
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They have a more highly developed tunica media
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What fiber is prominent in the tunica media of arteries?
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Elastin
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How is the lumen different in arteries versus veins?
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It's smaller in arteries
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What is the thickest layer in veins in contrast to arteries?
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The tunica ADVENTITIA is thickest in veins; and their lumen is much larger than arteries.
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What are the arrangements of elastin fibers in large vessels called?
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lamellae
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3 important features of the Tunica Intima in large vessels:
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-Tight junctions
-Pinocytotic vesicles -EC cells that secrete Fx VIII |
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Function of the large arteries:
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To maintain BP during diastole
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What is an Aneurysm?
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Outpocketing of the tunica media in large arteries
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What distinguishes large veins from large arteries?
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Their thick tunica adventitia
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What are the 2 prominent features that distinguish MEDIUM ARTERIES?
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-Prominent layer of 40 SMCs in the tunica media
-Internal lamina is ELASTIC |
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Function of the medium arteries?
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To regulate blood pressure
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What pathology develops in medium arteries?
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Atherosclerosis
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2 Cell types that form atherosclerotic plaques:
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-Macrophages
-Smooth muscle cells |
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How do macrophages form atherosclerotic plaques?
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They ingest lipid and become lodged in the endothelial wall.
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How do SMCs form atherosclerotic plaques?
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They migrate to the tunica intima, proliferate, and take up LDL.
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What is the combination of Lipid-laden Macrophages and SMCs called?
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Foam cells
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Aside from simply blocking the arteries, what do foam cells do?
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Bind platelets - form pathological thrombosies that cause STROKE and/or MI
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What feature of Medium AND small veins allows them to direct the flow of blood to the heart?
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Valves
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What are the valves in medium and small veins made of?
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Infoldings of the tunica intima.
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How wide are SMALL blood vessels? How many RBCs can fit through?
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Less than 50 um in diameter
Allows ~6-7 RBCs to pass through at a time. |
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What is the prominent layer in small arteries/arterioles?
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Their tunica media
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How many layers of SMCs are in
-Arteries? -Arterioles? |
Arteries = 8 layers
Arterioles = 2 layers |
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What results when SMCs in the media wall of small arteries and arterioles take up lipid?
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Hypertension
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What is the function of the small arteries and arterioles?
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To regulate bloodflow to the vascular capillary bed.
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What important inflammatory process occurs at venules?
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Diapedesis of leukocytes
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How are capillaries prominently different from all other vessels?
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They have no tunica adventitia or media - only the intima
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How wide in diameter are capillaries?
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~10 um
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So how many RBCs can fit through a capillary at one time?
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1-2
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What is a capillary composed of?
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A single layer of endothelial cells + its basal lamina
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Are capillaries active or passive?
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Very active
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What makes capillaries tissue specific?
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Expression of tissue-specific growth factors
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3 morphological types of capillaries:
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-Continuous
-Fenestrated -Sinusoidal |
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4 tissues that have Continuous capillaries:
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-Heart
-Skeletal muscle -CNS -Lung |
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What makes these capillaries "continuous"?
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Tight junctions
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How do continuous capillaries transport stuff from the vessel lumen to connective tissue?
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Via pinocytosis
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Do CNS vessels have pinocytosis?
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No
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What tissues have Fenestrated capillaries (3)?
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-Endocrine organs
-GI tract -Kidneys |
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What is the predominant feature of fenestrated capillaires?
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100 nm wide windows that allow passage of large molecules
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Where are Sinusoidal capillaries found? (3 places)
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-bone marrow
-liver -spleen |
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What are sinusoidal capillaries for?
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Letting whole RBCs pass through.
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What is the function of capillaries in general?
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Exchange of gases and nutrients.
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What size of molecules can pass through the intercellular junctions of endothelial cells in capillaries w/out needing transporters/pinocytosis?
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<10,000 kDa
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Do endothelial cells in capillaries just exchange gases and nutrients?
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No; they also SECRETE STUFF.
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What are some things that capillary endothelial cells secrete?
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-Endothelin (vasoconstrictor)
-Nitric oxide (vasodilator) -Growth factors -PDGF -Interleukins |
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Where are LYMPHATICS present?
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Everywhere except bone marrow and the CNS
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What is special about lymphatic vessels?
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they are very very very very very leaky
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What is the function of lymphatics?
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One way drainage of lymphatic fluid to veins and venules.
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What is lymphatic fluid composed of?
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WBCs and Lipid
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How is lymphatic fluid circulated?
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By skeletal muscle contractions
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What is vasculogenesis?
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Development of blood vessels in the embryo
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What is angiogenesis?
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REgeneration of blood vessels in adults.
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What vascular Endothelial cell receptor is necessary for angiogenesis?
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VEGEF (thank you deb donahoe)
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Well actually 3 receptors needed for angiogenesis:
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-VEGEF receptor
-FGFR (fibroblast grwth factor) -TIE2 |
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What do VEGEF, FGF, and TIE2 do?
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Stimulate angiogenesis
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What inhibits angiogenesis? (2 things)
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Angiostatin
Endostatin |
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When would you want to stimulate angiogenesis?
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After an MI or in diabetics with ischemic tissue diseases.
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When would you want to inhibit and prevent angiogenesis?
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In tumor situations
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Other than directly inhibiting angiogenesis with Angiostatin or Endostatin how can you limit tumor angiogenesis?
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By giving an antibody against VEGF.
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