-
Veins and arteries (excluding capillaries and venules) are made up of what primary components
- Endothelial Cells
- Elastic Fibers
- Smooth muscle
- Collagen fibers
-
What are the three layers of most blood vessels
- Tunica intima
- Tunica media
- Tunica adventitia
-
Capillaries only contain what layer
Tunica intima of endothelial cells lying on a basal lamina
-
What is the tunica intima made up of
Single layer of epithelial cells (aligned parallel), loose connective tissue, and a few scattered smooth muscle cells
-
What does the tunica media consist of
- Losts of smooth muscle cells
- Elastic fibers, Coll. III, and proteoglycans between the smooth muscle cells
-
What is the tunica adventitia composed of
Mainly fibroblasts, type I Coll., and longitudinally oriented elastic fibers
-
The tunica adventitia becomes continuous with what
With the connective tissue elements surrounding the blood vessel
-
What do large vessels have in them that other vessels lack
The tunica advantitia and outer part of the tunica media has vessels called the vaso vasorum that supply blood to the walls
-
What are the three types of arteries and how do they differ
- Elastic Arteries (Biggest, closest to the heart)
- Muscular Arteries (2nd biggest)
- Arterioles (Smallest arteries)
-
What are the alternate names for the three types of arteries
- Elastic (Conducting)
- Muscular (Distributing)
- Arterioles (Includes metarterioles)
-
What is it called when the elastic arteries contract for continual blood flow while the heart is resting
Windkessel effect
-
What properties make the elastic arteries recoil
The tunica media is formed by layer of smooth muscle with elastic lamins in between them
-
In an elastic artery, what makes the collagen and elastin
Smooth muscle cells, fibroblasts are only in the tunica adventitia
-
Smooth muscle in both elastic and muscular arteries in the tunica media are connected how
Gap junctions
-
Elastic arteries have holes in the elastic lamellae allowing what
Nutrients and oxygen to diffuse through, as well as allow smooth muscle cells to contact each other across layers
-
Smooth muscle cells in the elastic vessels have the ability to proliferate and repair intima in response to what
Growth factors secreted by the endothelial cells
-
In elastic vessels, what is the thicker layer
Tunica media is thicker then the tunica adventitia because of the large amount of elastic laminas
-
In large muscular arteries what separates the tunica media from the tunica adventitia
External elastic lamina or membrane
-
How is the internal elastic lamina different, and in what vessels is it found
It is only in the arteries (mainly muscular), and it separates the tunica media from the tunica intima. It is made up of elastin
-
Internal elastic lamina is well developed in what vessels
In the muscular arteries
-
What is a good way to determine if it is a muscular artery from a histological view
There is one definative row of internal elastic lamina in muscular vessels, Elastic vessels have many rows of it
-
Most vessels arising from the aorta are what kind of vessels
Muscular (distributing) arteries
-
If a vessel has a large tunica media with a lot of smooth muscle cells, and a small tunica intima, what is it
Muscular artery
-
What is the tunica adventitia of the muscular vessels made up of
- Fibroblasts
- Elastic fibers
- Collagen fibers
- Ground substance
- Blood vessels
- Nerves
-
What is found in the layers of arterioles
- In very small arterioles there is no external or internal elastic lamina
- The media is composed of 1-2 layers of smooth muscle
- The advantitia is very thin
-
What are the layers found in metarterioles
They are surrounded by a discontinuous layer of smooth muscle, no external or internal elastic lamina
-
What is the difference between the capillaries and a metarteriole
Metarterioles have discontinuous smooth muscle, capillaries have none
-
What is the important function of the arterioles and how do they achieve it
They regulate blood pressure by constriction or relaxing the smooth muscle cells tightly arranged around them
-
Veins have a much smaller what then arteries
Tunica media, but a large lumen
-
Veins are able to help move blood due to what
Valves, Smooth muscle in the tunica adventitia
-
Valves in a vein are part of what layer, reinforced by what
Tunica intima, reinforced by collagen and elastic fibers
-
What causes varicose veins
This is when the valves in the veins don't close properly
-
Where does the gas exchange happen
Capillaries
-
How is blood flow regulated from reaching the capillaries
By the smooth muscle cells and sphincters on the arterioles and metarterioles
-
Nitric oxide and norepinephrine have what effects on the capillaries
- NO dilates
- Norepinephrine Constricts
-
When the precapillaries sphincters are closed where does the blood flow
Through the thoroughfare channel bypassing the true capillaries
-
How do the capillaries assist in the release of heat from the body
The metarteriole sphincters open letting the blood pass to the capillaries putting them susceptible to the periphery the body
-
Capillaries are all made of
Single layer of Endothelium attached to a basal lamina
-
What are the three different types of capillaries
- Continuous (No gaps)
- Fenestrated (Small gaps)
- Discontinuos/Sinosoidal (large gaps)
- All but discontinuous are on a continuous basal lamina.
-
What is important about pericytes and where are they found
They contain actin, myosin, and tropomyosin, and can therefore contract. They are found on some capillaries and post capillary venules
-
Pericytes are surrounded by what
A basal lamina that is continuous with the basal lamina of the endothelial cells
-
Continuous capillaries are found in what tissues
- Muscle
- Connective
- Exocrine glands
- Nervous tissue
-
How does the transportation of molecules happen in continuous capillaries
They contain numerous pinocytotic vesicles with the ability to transfer large macromolecules in both directions
-
Capillaries are endothelial cells but differ from many others with the lower amount of what
Zonula occludens, allowing diapedesis
-
What organs contain fenestrated capillaries
- Kidneys
- Intestine
- Endocrine Glands
-
The pores in the fenestrated capillaries are bridged by what
An ultrathin diaphragm (thinner then the plasma membrane)
-
Renal glomerulus fenestrated capillaries lack what
Diaphragms
-
Sinusoidal/Discontinuous capillaries are found in what organs
- Liver
- Bone marrow
- Spleen
- (Where large cells have to pass)
-
What is the primary difference between fenestrated and discontinuous capillaries
Discontinuous don't have diaphragms, endothelial cells are more separated, they conform to the shape of the structure to which they are located and holes are large enough for whole cells to pass through
-
What vesicles can capillaries use to transport large substances across the membrane
Caveolae
-
What is the size of a large pore in a capillary
50-70nm found in fenestrae and transport vesicles
-
What is the size of a small pore in capillaries
9-11nm
-
Calveolae transportation has names for the sides of the lumen, what are they
- Adluminal - side facing the lumen
- Abluminal - side facing away from the lumen
-
What are the different ways that a capillary can transport material
- Diffusion (lipid soluble substances)
- Leaky tight junctions (water soluble substances)
- Movement through fenestrations (water soluble substances)
- Vesicles (large subtances)
-
How do the capillaries in the BBB limit transportation
- Very extensive tight junctions
- Very few pinocytic vesicles
-
What is the role of astrocytes in the BBB
They wrap around the endothelial cells and secrete factors that induce capillary cells to produce tight junctions
-
What is an ateriovenous anastomosis
- Direct communication between arterioles and venules (no capillaries)
- Found in penis and clitoris
-
What is a arterial portal system and where can it be found
- Arteriole to capillary to arteriole
- In the kidneys
-
What is a venous portal system and where can it be found
Venule to capillary to venule, found in the liver
-
What are the different layer of the heart
- Endocardium
- Myocardium
- Epicardium
-
What makes up the endocardium
- Simple squamous epithelium
- Fibroelastic connective tissue
- Subendothelial layer (Dense connective tissue)
-
What is found in the subendothelial layer of the heart
Dense connective tissue with blood vessels, nerves, and perkinje fibers
-
What is the thickest layer of the heart an what does it contain
The myocardium (center layer) contains cardiac muscles arranged in complex spirals around the chambers
-
What does the epicardium contain
The coronary heart vessels, nerves, ganglia, and fat
-
Arteriosclerosis
A chronic disease characterized by the thickening and hardening of the arterial walls (hardening of the arteries)
-
Atherosclerosis
A form of Arteriosclerosis with deposits of fatty substances, and fibrosis of the inner layer of the arteries (Intima layer)
-
Artheroma
Lipid deposits in the intima of arteries
-
What are the steps to atherosclerosis formation
- Monocytes migrate to damaged site
- Monocytes become macrophages taking up excess LDL forming foam cells
- Smooth muscles cells respond to the release of GF's secreted by the foam cells surrounding them
- Smooth cells form fibrous tissue forming a muscle cap
-
Where does the fibrous cap form in artherosclerosis
Under the endothelial cells
-
HDL is good because it has what effect
It romoves LDL's from the blood stream
-
What differentiates into foam cells
Smooth muscle cells and macrophages
-
In what ways does smoking lead to atherosclerosis
- Production of carbon monoxide
- Nicotine is a potent vasoconstrictor
- Smoking promotes oxidation of LDL
|
|
