Ex 3 Lecture: vasculature and thermodynamics Flashcards
Which blood vessels carry blood to the tissues?
Aorta
Arteries
Arterioles
Capillaries
Which blood vessels carry blood back toward the heart?
Capillaries
Venules
Veins
Vena Cava
Do arteries or veins have a thicker wall?
arteries
Which blood vessel has a smaller lumen?
arteries
Do both arteries and veins contain a smooth muscle layer?
Yes
Do capillaries have a smooth muscle layer?
No
What are the 3 layers of blood vessels?
Tunica intima
Tunic media
Tunic externa
What are the components of tunic intima?
endothelium
What are the components of tunic media?
smooth muscle, controlled by sympathetic nervous system
What are the components of tunic externa?
mostly fibrous connective tissue
What are the two types of capillaries?
True capillaries
Vascular shunt
Define true capillaries?
directly connects an arteriole to a venule
What are the three types of structures for capillaries?
Continuous capillaries
Fenestrated capillaries
Sinusoidal capillaries
Which structure of capillaries has the tightest junction?
continuous
Which capillary is the most common?
continuous
Where are continuous capillaries located?
skin, muscle, lung, CNS
Which vessel has a high pressure conduit?
arteries
Which vessel are the gatekeepers to capillaries?
arterioles
Where does the biggest gradient in pressure occur?
the capillaries
Where are the areas of highest pressure in the cardiovascular system?
left ventricle, aorta, arteries, arterioles
How is Ohm’s law applied to the cardiovascular system?
pressure differentials along the vessels allow blood flow
What is Ohm’s law?
Q=(change in pressure)/(resistance)
What is blood flow directly proportional to?
the pressure difference between two points of the blood vessel
What is blood flow inversely proportional to?
vascular resistance
Blood flow is equal to what?
volume/time
cardiac output (CO)
What is cardiac output equal to?
stroke volume x heart rate
What is the blood volume distribution on the pulmonary side?
25%
What is the blood volume distribution on the systemic side?
75%
What is the equation for Flow?
area (cm squared) x velocity (cm/min)
What is velocity equal to?
flow/area
If flow remains constant, the velocity of blood flow across circulation is inversely related to what?
total cross-sectional area
What are the two types of blood flow?
laminar and turbulent
What are the properties of laminar blood flow?-
-velocity is constant over time
higher velocity in the center
little flow near wall
increased shear near wall
fewer cells toward the wall
Parabolic flow profile
What are the properties of turbulent blood flow?
disorganized
velocity varies
“eddy” currents (whorls)
increase friction of blood flow
increase resistance to flow
turbulence occurs with increased flow velocity, obstruction, vessel turn
When the critical number exceeds ____ you will see turbulence
2000
What do you hear with the first heart sound (s1)?
closure of the atrioventricular valves
What do you hear with the second heart sound (s2)
closure of the aortic and pulmonic valves
What would you (if you could) hear with the third heart sound? (s3)
turbulence associate with rapid ventricular filling
What would you hear (if able) with the fourth heart sound?
movement of blood associate with atrial systole
Which cardiac valves can you hear on the left side of the thorax and where?
pulmonic, aortic, mitral
behind the shoulder and dorsal to the point of the elbow (olecranon)
Turbulent blood flow can cause what?
murmers
Turbulent blood flow can occur from what?
anemia
What happens to the blood during anemia?
blood viscosity drops due to low PCV and hypoproteinemia
What 3 factors includence resistance?
viscosity of fluid
length of vessel/tube
radius of tube
What is the equation of Poiseuille’s law?
R=8nI/(pi)r^4
What is Poiseuille’s law calculating?
hemodynamic principles of flow resistance
What is resistance directly related to?
viscosity
What is resistance inversely related to?
to the fourth power of the tube
What has the greatest effect of blood flow and pressure?
width of the vessel
Which blood vessel has the greatest compliance?
veins
Which blood vessel provides the most resistance to flow?
arterioles
What is the equation for vascular compliance?
change in volume/ change in pressure
What does vascular compliance mean?
increase in volume/increase in pressure (NOT STIFF)
Why do arterioles present the greatest resistance to flow?
diameter
What does the presence of smooth muscle do?
regulate the flow of blood and cause the biggest change in arterial pressure due to changes in resistance
Describe the characteristics of the venous “pump”?
1 way valves
action of surrounding tissues
What are the blood storage areas?
veins expand at low pressure
spleen
As wall thickness increases
lumen decreases, vessel less compliant, resistance to blood flow increases
What are three characteristics of arterioles?
strong muscular walls
greatest increase in vascular resistance
acts as control valves for flow to tissue
When can you hear audible vibrations (murmurs)?
over 2000
What factors promote turbulence
High flow velocity
large vessel diameter
decrease in viscosity
sudden change in vessel diameter
pulsatile flow
Which are the most common factors that promote turbulence?
high flow velocity
decrease in viscosity
What is Reynold’s number?
a measure of the tendency for turbulence to occur
What is Reynold’s number?
(fluid density/fluid viscosity) * (average velocity of fluid) * (tube diameter)
Describe the diffusion at capillary beds?
exchange of Oxygen and Carbon dioxide gases, nutrients, and waste products occur due to pressure difference
Which capillary structure is the leakiest?
sinusoidal capillaries
What are examples continuous capillaries?
skin, muscle, lung, CNS
What are examples of fenestrated capillaries?
exocrine glands, renal glomeruli, intestinal mucosa
What are examples of sinusoidal capillaries?
liver, spleen, bone marrow
How does the venous blood return to heart?
milking action of skeletal muscles
How is arterial blood exported throughout the body?
Arterial blood is pumped by the heart
What is the smallest type of blood vessel?
capillaries
What do capillaries connect?
arterioles to venules
Which vessel is only one cell layer thick?
Capillary
Do capillaries have a smooth muscle layer?
No
Define vascular shunt?
bypass connection of an arteriole to a venule
What vessel expands easily at low pressure, have thin walls, and are 1 way valves?
veins
What is vascular stiffness? (equation)
1/compliance
