Exam 3: Lecture 10 Flashcards
What is aortic valve stenosis?
When the aortic valve opening is reduced and blood flow through is diminished
What are the two major factors that affect pulse pressure and what is their equation?
Stroke volume output of the heart
Compliance of the arterial tree
Pulse Pressure=Stroke volume/Arterial compliance
What does atherosclerosis cause?
Reduced compliance of vessel walls
What is patent ductus arteriosus?
Occurs due to ductus arteriosus not closing in fetus
Half or more of cardiac output flows back into pulmonary artery and lungs causing diastolic pressure to fall very low before next heart beat
What is aortic regurgitation?
Aortic valve is absent or will not close completely
Aortic pressure may fall to 0 before next heartbeat
What is Central Venous Pressure equal to?
Pressure in right atrium
What are the 2 factors that regulate right arterial pressure?
Ability of heart to pump blood out of right atrium/ventricle
Tendency of blood to flow into right atrium
What are the 3 factors that increase venous return (right atrial pressure)?
Increased blood volume
Increased peripheral venous pressure due to increased large vessel tone
Dilation of arterioles
T/F: When a person is lying down, pressure in peripheral veins is 4-6 mmHg greater than right atrial pressure.
True
T/F: When intra-abdominal pressure increases, venous pressure in legs must decrease below abdominal pressure before blood can flow from legs to heart through abdominal veins.
False, venous pressure in legs must increase above abdominal pressure
Describe arterioles
Highly muscular (until metarteriole)
Small ones control blood flow to each tissue
Local tissue conditions control diameters of arterioles
Are capillaries surrounded by skeletal or smooth muscle at origination point from metarteriole?
Smooth (precapillary sphincter)
Describe the capillary wall
Unicellular layer of endothelial cells
Thin basement membrane
0.5µm think with 4-9µm diameter
Describe slit pores
Intercellular clefts
Allow for rapid diffusion of water, water-soluble ions, and small solutes
Describe plasmalemmal vesicles
Formed from caveolins
Play role in endocytosis and transcytosis
What is the most important factor regulation vasomotion?
[Oxygen] in tissues
What is the most important role of diffusion between blood and interstitial fluid?
Exchange substances
What type of substances can diffuse readily through the capillary cell membranes?
Lipid-soluble
Oxygen
CO2
What type of substances diffuses through the pores/clefts?
Non-lipid-soluble substances
T/F: The rate of water diffusion is 100x faster than flow of plasma within capillary.
False, 80x faster
What do Starling forces do?
Determine direction of diffusion into or out of capillary
What are the two outward Starling forces?
Capillary pressure = Hydrostatic pressure of blood
Interstitial fluid colloid osmotic pressure = Osmotic pressure of interstitial fluid
What are the two inward Starling forces?
Interstitial fluid pressure = Hydrostatic pressure of interstitial fluid
Capillary plasma colloid osmotic pressure = Osmotic pressure of blood
What does the sum of the 2 outward forces and 2 inward forces equal?
Net filtration pressure
What does the capillary coefficient take into consideration?
The number and size of pores
T/F: Lymph vessel contraction is NOT large enough force to be considered a Starling force?
True
What are the 2 major descriptions of lymph return?
Lymph vessels have 1-way valves
Lymph flow is maximum when interstitial pressure rises above atmospheric pressure
What are the factors that increase lymph flow (and interstitial fluid pressure)?
Elevated capillary hydrostatic pressure
Decreased plasma colloid osmotic pressure
Increased interstitial fluid colloid osmotic pressure
Increased permeability of capillaries
