ANPS 20: Anatomy of Blood Vessels
-By function 1) Elastic Arteries 2) Muscular Arteries 3) Resistance Vessels (Arterioles) 4) Exchange Vessels (Capillaries) 5) Capacitane Vessels (Veins)
How can blood vessels be categorized? what are the different categories?
1) Through epithelial cell membrane [diffusion (passive), pinocytosis (active)] 2) Through Pores (fenestrations) in epithelial cell membranes (size filter) 3) Through spaces between epithelial cells (bulk flow)
How do substances pass through capillary wall?
Veins - because veins have little muscle and few elastic fibers in their wall, they have little ability to resist stretch and often hold much of the circulating blood.
What are Capacitance vessels?
-Have complete endothelial lining -are found in all tissues except epithelia and cartilage -permit diffusion of water, small solutes and lipid-soluble materials -Block RBC and plasma proteins -Specialized continuous capillaries are found in the CNS and create the "blood-brain barrier"
What are Continuous Capillaries? What are their functions? Where are they found?
Largest arteries closest to the heart. Contain a lot of elastic fibers, and swell with blood each time the heart pumps
What are Elastic Arteries?
Capillaries are the only vessels where materials move through the vessel wall.
What are Exchange Vessels?
-Have small pores in endothelial lining -permit rapid exchange of water and larger solutes between plasma and interstitial fluid -Found in areas requiring MORE exchange: Choroid plexus, Endocrine organs, Kidneys, Intestinal Tract
What are Fenstrated Capillaries? What are their functions? Where are they found?
Smaller diameter arteries distributing to ogans
What are Muscular Arteries?
Arterioles often have areas of extra muscles in their wall as they branch into a capillary network. These sphincters contract to decrease blood flow into a capillary bed.
What are Pre-capillary sphincters?
-Have large gaps between adjacent endothelial cells -Permit free exchange of water and large plasma proteins between blood and interstitial fluid. -Found in: Liver, Spleen, Bone Marrow, Endocrine organs -Phagocytic cells monitor blood at sinusoids
What are Sinusoidal Capillaries? What are their functions? Where are they found?
-Aortic Arch -Thoracic Aorta (into the thoracic cavity) -Abdominal Aorta
What are some of the major parts of the aorta?
Leakiness
What are the degrees of capillaries based on?
1) Elastic Artery 2) Muscular Artery 3) Arteriole 4) Capillary
What are the sizes of arteries, from largest to smallest?
1) Large Vein 2) Small-to medium sized veins 3) Venule 4) Capillary
What are the sizes of veins, from largest to smallest?
Arteries have stronger, thicker walls than the vein of the same size. ARteries generally contain more smooth muscle and often more elastic fibers.
What are the structural differences between arteries and veins?
1) Continuous Capillaries 2) Fenstrated Capillaries 3) Sinusoidal Capillaries
What are the three degrees of capillaries?
Tunica Intima: innermost Tunica Media: middle layer Tunica Externa: outer layer
What are the three layered wall (tunics) of blood vessels?
1) Above the diaphragm, blood returns through the superior vena cava 2) Below the diaphragm, blood returns through the inferior vena cava
What are the two large unpaired veins that blood returns to the heart in?
Arterioles - because they are small diameter with a few layers of smooth muscle; contraction or relaxation of that muscle creates great changes in diameter, and thus great changes in resistance to blood flow.
What blood vessels are Resistance vessels?
Valves, formed from foldings of tunica intima. Skeletal muscle activity around deep veins compresses veins and pushes blood toward heart: the "muscular pump"
What do veins contain to prevent blood from flowing backward? What forms/aids this?
Allows blood to pool in veins and creates distension in the vein walls. Valve failure may be due to genetic factors or to locally high venous pressure.
What happens during venous valve failure?
Tunica Intima (endothelium)
What is labeled
Lumen
What is labeled?
Tunica Externa (collagen fibers)
What is labeled?
Tunica Media (smooth muscle and elastin)
What is labeled?
named so because it doesn't have visible striations in it's cytoplasm. Does contain actin and myosin and contracts in the presence of calcium.
What is smooth muscle?
A simple squamous epithelium that lines the interior of blood vessels
What is the Endothelium?
Outer layer of blood vessels. -connective tissue
What is the Tunica Externa?
Innermost layer of blood vessel -lined by the endothelium -supported by connective tissue (collagen)
What is the Tunica Intima?
Middle layer of blood vessel -Smooth muscle with various amounts of elastic fibers
What is the Tunica Media?
-a capillary is little more than a tube of endothelial cells supported by a basal lamina -thin wall allows exchange of materials between bloodstream and tissues
What is the anatomy of capillaries?
30-35% of blood volume is contained in heart, arteries and capillaries 60-65% of blood is in the venous system
What is the general distribution of blood?
Connective tissue which anchor the blood vessels to surrounding tissues
What is the outermost layer of blood vessels comprised of?
The Aorta
What is the single vessel that leaves the left side of the heart?
Arterial Lumen
What structure is labeled?
Basement Membrane
What structure is labeled?
Capillary bed
What structure is labeled?
Elastic Fibers
What structure is labeled?
Endothelium
What structure is labeled?
Lumen
What structure is labeled?
Subendothelial Layer
What structure is labeled?
Tunica Externa
What structure is labeled?
Tunica Intima
What structure is labeled?
Tunica Media
What structure is labeled?
Valve
What structure is labeled?
Vasa vasorum
What structure is labeled?
Venous Lumen
What structure is labeled?
Smooth muscle, When the smooth muscle layer contracts the vessel diameter narrows (vasoconstriction), when the smooth muscle layer relaxes the vessel diameter increases (vasodilatation)
What type of muscle occurs in blood vessels?
diffusely spread out within the muscle layer. These nerves are important for controlling blood diameter.
Where are nerves in blood vessels?
closest to the heart
Where are the blood vessels of largest diameter?
