Vessel Layers
The three layers of blood vessels
What are the:
Tunica Intima (Inner Layer)
Tunica Media (Middle Layer)
Tunica Externa (External Layer)
This structure is in constant contact with blood
What is the endothelium
These vessels carry blood away from the heart and to the tissues.
What are arteries
These vessels carry blood to the heart and away from tissues.
What are veins?
no really what are they.
This 'tunic' contains smooth muscle.
What is the tunica media
Pores in capillaries
What are fenestrations?
These vessels account for most named arteries.
Elastic Arteries
These vessels carry deoxygenated blood
What are veins
Loose connective tissue most abundant in this tunic.
The tunica externa
This specific, single-cell thick component of the tunica intima serves as a semi-permeable barrier and releases nitric oxide (NO) to regulate vascular tone.
Endothelium
These small veins drain capillaries.
Veinules
These microscopic blood vessels are neither arterial nor veinous and are broadly responsible for gas exchange, leukocyte tissue infiltration, and diffusion of waste into the blood.
What are capillaries?
This structure called the 'vessel of vessels' in Latin is present in the body's larger blood vessels. What does this structure do? Why is it necessary?
What is the vasa vasorum, which is necessary in these larger vessels to supply the energy expensive smooth muscles in these vessel's tunica media.
When you are sick with an upper respiratory disease, many nasal arteries dilate to supply more blood to infected tissues, causing nasal congestion. Why might physiologically arousing activities like aerobic exercise temporarily alleviate congestion?
They are stimulating the sympathetic nervous system which will increase the sympathetic tone of the vessels (cause vasoconstriction) and stimulate downstream release of epinephrine and norepinephrine which will also increase sympathetic tone.
These vessels supply muscles with blood and themselves have thick muscle layers to allow for better control of blood flow into these tissues.
What are distributing/muscular arteries?
These vessels have strong elastic walls to handle higher pressures.
Arteries
Vitamin C is a necessary vitamin for the biosynthesis of the fibrous protein collagen. What tunic would be most impacted by Scurvy (vitamin C deficiency)?
What is the tunic externa.
Increasing the number and size of capillary fenestrations would do what to capillary permeability?
What is increase.
Because transfer of nutrients/gasses/proteins/etc., requires a high surface area of permeable blood vessels, structures such as the hypophysis, liver, kidney, and pancreas use these structures of capillary beds connected by veins.
Portal systems.
Blood samples are usually taken from veins. While there are many reasons to do this, what is the biggest safety concern alleviated by this practice? Why not draw from arteries?