Cardio Physiology Intro Flashcards
Where is the apex of the heart?
At the bottom of it
Two-thirds of the heart lies _____ of the midline.
left
The two pumps of the heart are arranged in ________ (series or parallel).
series
Do both ventricles squeeze in a similar manner?
No, not really. The right squeezes against the septum and the left squeezes concentrically.
Which side of the heart is the tricuspid valve found?
Right
What is another name for the bicuspid valve? What side is it on?
Mitral - left side
What are the fibrous strands called that attach to the AV valves? What do the other ends of these attach to?
Chordae tendinae attach to papillary muscles on the ventricle walls.
When the ventricles contract, papillary muscles ______ to prevent valve _______.
contract to prevent valve eversion
How many layers of fibers make up the myocardium?
5
What is the fiber arrangement of all the myocardial layers?
Inner (endocardium) is longitudinally arranged
2nd is oblique
3rd (middle) is circumferentially arranged
4th is oblique
Outer (epicardium) is longitudinally arranged
The end-to-end connections of the myocardial cells are called the _________.
intercalated disks
A drop in pressure at the capillary level is due to high ________ in the arterioles.
resistance
How does fluid flow (Q) relate to pressure drop and resistance?
Q = ΔP / R
Define cardiac output.
The volume of flow through the entire systemic or pulmonary circulation.
What does Poiseuille’s law state regarding the radius of a cylinder and flow resistance? What is the equation?
That there is a 4th power relationship between changes in radius and fluid flow (a 2-fold change in resistance changes fluid flow by 16x).
Q = ΔPπr^4 / 8ηL
What is the simple equation for mean arterial pressure?
MAP = DP + (SP - DP) / 3
What is pulse pressure?
The difference between systolic and diastolic pressures
Why does fluid velocity actually decrease in the capillaries of the body? Does Q change throughout the different sectors of the vascular system?
Because the total cross sectional area of the capillaries is much larger than in the large arteries. Total fluid flow does not change
What is the mathematical relationship among velocity, flow, and cross-sectional area?
V = Q/A
Doppler ultrasound measures the ________ _______ in sound waves reflected off RBCs.
frequency change
Do large arteries have a physiologic role in BP regulation?
No, not really.
Which vessels are the primary vessels involved in BP regulation? What is another name for these?
Small arteries and arterioles are. Also called resistance vessels.
Does solute exchange happen in the post-capillary venules?
Yeah, for macromolecules and fluid especially.
What purpose does smooth muscle in venules serve?
To help regulate capillary pressure (by reducing or increasing outflow speed)
_______ hold 70-80% of the body’s blood volume.
Veins
How does one calculate the total peripheral resistance for vessel segments in series?
Add them up
How does one calculate the total peripheral resistance for vessel segments in parallel?
Sum the reciprocals of the resistances:
1/TPR = 1/R1 + 1/R2 + 1/R3…
What is the LaPlace equation and what does the law help explain?
T ( vessel wall tension) = P (pressure) x r (radius)
Explains how the thin capillaries can withstand relatively high pressure without bursting.
