L7 Flashcards
what is the role of the circulatory system
to provide O2/nutrients to every cell in the body and remove CO2/waste products from every cell in the body
what are the 2 things that the circulatory system requires
a driving force i.e. pump = heart
conduit system = vascular bed
what is the vascular bed
capillaries
what are the 2 juxtaposed systems in the heart
systemic and pulmonary circulation
describe the systemic circuit
from the left side of the heart, around the body, and back into the right side of the heart
describe the pulmonary circuit
the right ventricle to the lungs and back to the left side of the heart
what is the route blood takes in the systemic circuit
left ventricle -> aorta -> arteries -> arterioles -> capillaries -> venules -> veins -> vena cava _ right atrium and ventricle
what kind of circuit is the systemic circuit
parallel
what is the route blood takes in the pulmonary circuit
right ventricle -> pulmonary artery -> arterioles -> capillaries -> venules -> pulmonary veins -> left atrium and ventricle
what kind of circuit is the pulmonary circuit
series as 100% of the CO ges through pulmonary circulation
what structures are in the delivery system
arteries, arterioles and capillaries
what structures are in the waste removal system
venules and veins
the different blood vessels are made up of a range of different tissues. what layer do all the blood vessels have
an endothelial cell layer
what makes up the microvasculature
The terminal arterioles, capillaries and the small venules
describe the structure of the capillaries
The capillaries have an endothelial cell layer and a basement membrane
It only having that one cell layer means that there is a really small diffusion distance
what is blood flow
CO
what is flow dependent on
Q = pressure difference / resistance
what is the poiseuille relationship
it relates pressure, radius and viscosity to blood flow
if you increase the length of the vessel what happens to the resistance
it increases
what could be a reason where the viscosity of the blood could increase
if you were severally dehydrated
this increase in viscosity could increase resistance
what happens to the cross sectional area of the individual vessels as you travel towards the capillaries
what does this mean in terms of resistance
The cross sectional area get smaller and smaller as you go towards the capillaries and away from the aorta meaning that resistance increases
what happens to the TOTAL cross sectional area of the individual vessels as you travel towards the capillaries
the capillaries have the largest net cross sectional area
if the capillaries have the largest total cross sectional area how come the blood is stored in the veins
because veins are compliance vessels
what does cross sectional area have to do with velocity
Large CSA the velocity is low
Low CSA –> Velocity to increase
The flow in terms of volume is the same but the area has increased (capillaries) therefore velocity decreases
when looking at the pressure of the systemic arterial network, where will you see a large pressure drop
the arterioles
what features of the capillaries make them perfect for exchange
Large capillary network =
large cross sectional area
Capillaries thin wall =
small diffusion distance
Low velocity =
time for diffusion
Non-Pulsatile flow =
continuous blood movement
what happens to blood flow in the venous system
total CSA goes down therefore velocity goes up
Although the CSA goes down the pressure is not going to go up because of the distance from the heart
where is the pressure lowest
in the right atrium
describe the pulmonary circuit
Branching towards
capillaries then decreased
again on way back to heart
Similar effects on the CSA
and velocity
Blood pressure much lower!
Decreasing pulsatile flow
Low pressure circuit
the pulmonary circuit is a ________ circuit
low pressure
What is the correct blood flow order through the pulmonary system starting at the vena cava
A: LA, LV, pulmonary artery, capillaries,
pulmonary vein, RA, RV, aorta
B: RA, RV, pulmonary vein, capillaries,
pulmonary artery, LA, LV, aorta
C: RA, RV, pulmonary artery, capillaries,
pulmonary vein, LA, LV, aorta
D: RV, RA, pulmonary artery, capillaries,
pulmonary vein, LA, LV, aorta
C
The resistance to blood flow through the arterioles is higher than in the aorta BECAUSE
resistance is proportional to radius^4 .
The first is true and the second is false
because it should say inversely proportional
Which of the following is not a type of blood vessel?
A: Artery
B: Vein
C: Ventricle
D: Venule
C
If a blood vessel decreased in radius by 3 times, the resistance would _____ by a factor of _______?
A: Decrease; 81
B: Increase; 81
C: Decrease; 12
D: Increase; 12
B
The velocity of blood flow is slowest through the capillaries
BECAUSE
the cross sectional area of the individual capillary is the smallest.
both are true but not causal
Blood flow in the pulmonary vein is pulsatile
BECAUSE
the blood only exits the right ventricle into the pulmonary circulation during systole.
the first statement is false but the second statement is true
