CARDIOVASCULAR 10 Flashcards
Blood vessel anatomy: three layers
Tnuca Intima
Tunia media
Tunica extrerna
1) Tunica intima
2) Tunia media
3) Tunica externa
1) Endothelium
2) Smooth muscle, controlled by sympathetic nervous system
3) Most fibrous connnective tissue
Windkessel effect?
Steps:
Elastic walls?
Elastic arteries expand and store energy during ventricular ejection
1) Ventricle contracts
2) Semilunar valve opens
3) Aorta and arteries expand and store pressure in elastic walls
Create PE in the Walls
Elastic recoil of arteries?
Steps:
Keep blood moving during ventricular relaxation
1) Isovolumic ventricular relaxation
2) Semilunar valve shuts, preventing flow back into ventricle
3) Elastic recoil of arteries send blood forward into rest of circulatory system
Systolic pressure ?
Diastolic pressure?
Pulse pressure ?
Maximum pressure
Minimum pressure
Max-Min
Major blood vessels: thickest to thinest
Artery, Arteriole, capillary, Venule, veins
Most fibrous tissue, smooth muscle , elastic tissue & endothelium to least
Artery, Vein, arteriole, venule and capillary
The veins
1) Venules
2) Contents:
3) Carry ?% of the body’s blood
4) During hemorrhage?
1) Drain blood from the capillaries
2) Less smooth muscle and connective tissue than arteries + valves (prevent backflow of blood)
3) 70%
4) Act as a reservoir
Anatomy of the Capillary bed
1) Capillaries?
2) Consists of two types of vessels?
1) Capillaries have walls only one cell thick
2) Vasuclar shunt and true capillaries
1) Vascular shunt
2) True capillaries
1) Directly connect an arteriole to venule: metarteriole
2) Exchange vessels: O2 and nutrients cross to cell and CO2 and metabolic waste products cross into blood
What determines flow?
Directly proportional to the pressure gradient
Inversely proportional to the resistance to flow
Fluid flow through a tube depends ?
The higher the pressure gradient ?
Fluid flows only if there is?
Pressure gradient
The greater the fluid flow
Positive pressure gradient
Flow depends on the pressure gradient not?
Absolute pressure
Blood pressure gradient in blood vessels
1) Greatest?
2) Ventricles?
1) In the aorta
2) The wall of the left ventricle is thicker than the right ventricle
What creates pressure needed for blood flow?
The heart is a simple pump: with a cardiac contraction: most arterial blood is pumped by the heart
Resistance of a vessel can affect flow?
If resistances increases, flow decreases
Poiseuille’s Law
1) Length
2) Viscosity
3) Tube radius to the 4th power
1) Resistance increases as length increases
2) Resistance increases as viscosity increases
3) Resistance decreases as radius increases
Vessel radius changes?
As the radius of a tube decreases, the resistance to flow increases
Velocity of blood flow
Velocity of flow depends on total cross-sectional area of all the vessels
Resistance: blood vessels
Small change in radius
1) Vasoconstriction
2) Vasodilation
Enormous effect on resistance to blood flow
1) A decrease in blood vessel diameter/radius and decreases blood flow
2) An increase in blood vessel diameter/radius and increases blood flow
Factors that alter arteriolar resistance
1) Myogenic “autoregulation”
2) Paracrines (local): active and reactive hyperemia
3) Sympatheic control: SNS; norepinephrine, adrenal medulla: eprineprine
1) Effect on blood flow Active-Hyperemia: Locally Mediated?
2) Effect on tissue metabolism
3) Release of metabolic vasodilators into ECF?
4) Vasodilators?
5) Arterioles?
6) Resistance?
7) Nutrient supply?
1) Increases blood flow
2) Increases
3) Increase
4) Adenosine, low O2, high 5) CO2 acidic
dilate
6) Decrease
7) Increases
Reactive Hyperemia: Locally Mediated Increase in Blood flow caused by?
1) Tissue blood flow?
2) Metabolic vasodilators?
3) Arterioles?
4) Resistance?
5) As vasodilators wash away, arterioles ?
Physical Blockage (occlusion)
1) Decreases
2) Accumulate in ECF
3) Dilate
4) Decreases
5) Constrict
Sympathetic regulation
1) Release of ?
2) Autonomic control of arteriolar diameter?
1) Norepinephrine
20 Arteriolar diameter
GPCRs promote?
Calcium-mediated smooth muscle cell contraction without excitation-contraction coupling
Norepinephrine binds
alpha-adrenergic receptors
Calcium oscillations?
Control smooth muscle cell contractions.
Arteriolar diameter
Affects flow between venous and artery bags
Flexible filaments allow for?
Large Changes in length during contraction
