The Blood Vessels And Blood Pressure (Physiology) Flashcards
What is meant by pressure gradient?
The pressure difference between the beginning and end of a blood vessel.
Three factors that determine vascular resistance?
Blood viscosity
Vessel length
Vessel radius
What is the relationship btwn flow of blood and pressure and resistance?
The rate of blood flow is directly proportional to the pressure gradient and inversely proportional to the vascular resistance.
What is the proportionality of resistance with respect to radius
Resistance is proportional to 1/r^4
Describe the BV of the vascular tree in coordination as well as which type of blood each carry.
Arteries- oxygenated
Arterioles- oxygenated
Capillaries- oxygenated
Venules- deoxygenated
Veins- deoxygenated
What do we call the microscopic exchange vessels with all cells, offering blood that supplies the metabolic needs of the cells?
Capillaries
What drives the flow of blood during cardiac relaxation?
The elastic coil in the walls of arteries
What happens in the arteries when blood is pumped into them?
They temporarily expand and when the heart relaxes, they passively recoil.
What is the mean arterial pressure?
It is the diastole pressure plus 1/3 of the pulse pressure
What are the major resistance vessels?
Arterioles
What are the local chemical and physical influences of resistance of arterioles?
Local metabolic changes and histamine release (chemical), Local heat and cold and myogenic responses to stretch ( physical).
Factors causing vasoconstriction(5)
-Increased myogenic activity.
- Increased oxygen
-Decreased CO2 and other metabolites
-Cold
-Vasopressins, angitensin 2, sympathetic stimulation.
Factors causing vasodilation
-Decreased myogenic activity.
- Decreased oxygen.
-Increased Co2 and other metabolites.
-Decreased sympathetic stimulation, vasopressins and angiotensin 2.
-Heat
What are the two influences or determinants of blood viscosity
Number of RBC.
Concentration of plasma proteins.
How does NA cause vasoconstriction in arterioles
By binding to the alpha 1 receptors.