Cardiac cycle and conduction Flashcards
Cardiac cycle made of two alternating states, __ and __
systole; diastole
In cardiac cycle, this means contraction
systole
In cardiac cycle, this means relaxation
diastole
____% passes from atrium to ventricle passively
70
Three steps to cardiac style
- atrial systole/ventricular diastole
- ventricular systole/atrial diastole
- brief moment of nothing
valves open and close in the heart due to changes in __
pressure
During atrial systole, the ____ valves are open and the ___ valves are closed
AV; semilunar
During ventricular systole, the ____ are open and the ___ are closed
semilunar; AV
pacemaker of the heart
SA (sinoatrial) node
what are the 7 stops of impulses through the heart?
- SA node
- Atrial syncytium
- Junctional fibers
- AV node
- AV bundle (Bundle of His)
- Bundle branches
- Purkinje fibers
this structure in the cardiac cycle delays passing on the impulse until the atria have finished contracting
AV node
these structures in the cardiac cycle spreads impulses to the ventricular wall and causes the ventricles to contract
Purkinje fibers
these structures in the cardiac cycle divide into left and right pathways down the septum
bundle branches
A. SA node
B. AV node
C. Bundle branches
D. Purkinje fibers
What is an ECG?
Recording of electrical changes that occur during cardiac cycle
3 parts of ECG
- P wave
- QRS complex
- T wave
In this section of an ECG, the atria depolarize
P wave
In this part of an ECG, the ventricles depolarize and the atria repolarize
QRS
In this part of an ECG, the ventricles repolarize
T
What is happening during the first heart sound?
Ventricular systole - AV valves close
What is happening during the second heart sound?
Semilunar valves close
what is a heart murmur?
abnormal heart sound; happens because of valve damage
As blood is pushed out of the heart, what happens to ventricular pressure?
Increases
As blood gets pushed out of the heart, what happens to ventricular volume?
Decreases
What is the average adult heart rate?
70-75
When a person’s heart rate is over 100 bpm, it’s called
tachycardia
When a person’s heart rate is below 60, it’s called
bradycardia
How does an increased body temperature affect heart rate?
Increeas
condition where there is too much K+; decreases heart rate and force contraction; can be life-threatening
Hyperkalemia
condition where there is too much Ca+; increases heart rate
hpercalcemia
condition where there is too little calcium; decreases heart rate
hypocalcemia
