Circulatory Flashcards
(44 cards)
What is perfusion?
flow of blood through tissue
What is Ischemia?
inadequate blood flow. Waste builds up
what is Hypoxia?
reduced supply of oxygen in the blood
Does exchange happen in arterioles?
No
What is angiogenesis?
Formation of new blood vessels by proliferation of epithelial cells
What prevents backflow of blood?
Venous Valves
What happens during diastole?
ventricles relax, blood flows in from atria. Atria contract
What happens during systole?
ventricles contract, AV valves shut
Which is longer Diastole or Systole?
Diastole
What is stroke volume?
amount of blood pumped with each systole
what is cardiac output?
total amount of blood pumped per minute
What does cardiac output equal?
stroke volume x heart rate
Is the cardiac output the same in the left and right ventricles?
Yes. So backup does not occur
What are ways to increase cardiac output?
increase venous return and arterioles dilating
What are fast sodium channels?
Open first in response to depolarization to allow sodium to enter
What are slow calcium channels?
Open in response to threshold voltage and allow calcium down its gradient. Stay open longer creating plateau phase
What feature maximizes calcium entry into cardiac muscle cells once an action potential arrives?
T-Tubules
In the heart what releases calcium?
Sarcoplasmic reticulum
Which have longer refractory periods neurons or cardiac muscle?
Cardiac muscle
What are the three phases of the SA node?
Phase 0, Phase 3, Phase 4
Why does the SA node have unstable resting potential?
Due to phase 4 and sodium leak channels allowing sodium in to push for threshold
What happens at phase 0?
VG Calcium channels open
What happens at phase 3?
Repolarization. Closure of Calcium channels and opening of potassium channels.
Which node sets the rate of heart contraction?
SA node
