Messerli BIOL325 Exam 3 Questions with
Verified Correct Answers
What three layers make up arteries and veins?
1. Tunica intima (endothelial lining)
2. Tunica media (smooth muscle and elastin)
3. Tunica externa (collagen fibers)
4 things about elastic arteries...
1. Have elastin in all three tunics
2. Large lumen to offer low resistance
3. Inactive in vasoconstriction
4. Aorta and its major branches
3 things about muscular arteries...
1. Downstream from elastic arteries
2. Active in vasoconstriction
3. Thick tunica media with lots of smooth muscle
What is an aneurysm?
Local weakening of the artery wall. Stents are grafted inside the vessels to reinforce the wall.
2 things about arterioles...
1. Contain smooth muscle for controlling flow into capillary beds
2. Uses vasoconstriction and vasodialation
5 things about capillaries...
1. Make up about 80% of the length of blood vessels
2. Vary in permeability
3. Diameter allows only one RBC to pass at a time
4. Walls of tunica intima are very thin (doesn't have the other tunicas)
5. Exchanges gasses, nutrients, wastes, hormones
3 things about venules...
, 1. Formed when capillary beds unite
2. Larger venules have one or two layers of smooth muscle cells
3. Postcapillary venules are very porous and allow fluids and WBCs into tissues, similar to
capillaries
6 things about veins...
1. Formed when venules converge
2. Have thin walls and large lumens
3. The tunica media is thin but still undergoes constriction via smooth muscle
4. Thick tunica externa
5. Blood pressure is lower than arteries
6. Venous valves prevent backflow of blood
What does "capacitance vessel" mean?
Referring to veins - "blood reservoirs" containing up to 60% of blood supply
Resistance formula
R = 8(length of vessel)(blood viscosity) / Pi(radius of vessel)^4
___ is the greatest influence on resistance.
Blood vessel diameter
___ are the major determinants of peripheral resistance
Small-diameter arterioles
Flow rate ___ with more branches
Decreases
___ x ___ = blood pressure
Cardiac output, peripheral resistance
___ x ___ = blood pressure
Blood flow, peripheral resistance
___ / ___ = blood flow
Blood pressure, peripheral resistance
Blood pressure near the heart is ___
Verified Correct Answers
What three layers make up arteries and veins?
1. Tunica intima (endothelial lining)
2. Tunica media (smooth muscle and elastin)
3. Tunica externa (collagen fibers)
4 things about elastic arteries...
1. Have elastin in all three tunics
2. Large lumen to offer low resistance
3. Inactive in vasoconstriction
4. Aorta and its major branches
3 things about muscular arteries...
1. Downstream from elastic arteries
2. Active in vasoconstriction
3. Thick tunica media with lots of smooth muscle
What is an aneurysm?
Local weakening of the artery wall. Stents are grafted inside the vessels to reinforce the wall.
2 things about arterioles...
1. Contain smooth muscle for controlling flow into capillary beds
2. Uses vasoconstriction and vasodialation
5 things about capillaries...
1. Make up about 80% of the length of blood vessels
2. Vary in permeability
3. Diameter allows only one RBC to pass at a time
4. Walls of tunica intima are very thin (doesn't have the other tunicas)
5. Exchanges gasses, nutrients, wastes, hormones
3 things about venules...
, 1. Formed when capillary beds unite
2. Larger venules have one or two layers of smooth muscle cells
3. Postcapillary venules are very porous and allow fluids and WBCs into tissues, similar to
capillaries
6 things about veins...
1. Formed when venules converge
2. Have thin walls and large lumens
3. The tunica media is thin but still undergoes constriction via smooth muscle
4. Thick tunica externa
5. Blood pressure is lower than arteries
6. Venous valves prevent backflow of blood
What does "capacitance vessel" mean?
Referring to veins - "blood reservoirs" containing up to 60% of blood supply
Resistance formula
R = 8(length of vessel)(blood viscosity) / Pi(radius of vessel)^4
___ is the greatest influence on resistance.
Blood vessel diameter
___ are the major determinants of peripheral resistance
Small-diameter arterioles
Flow rate ___ with more branches
Decreases
___ x ___ = blood pressure
Cardiac output, peripheral resistance
___ x ___ = blood pressure
Blood flow, peripheral resistance
___ / ___ = blood flow
Blood pressure, peripheral resistance
Blood pressure near the heart is ___
