week 6 heart Flashcards
The valves between the atrium and ventricles are called:
AV Valves
The valves between the ventricle and outgoing vessels are called:
Semilunar valves
The steps of blood flow :
deoxygenated blood comes from IVC and SVC-> blood enters right atrium-> blood then flows through the tricuspid valve->then to the right ventricle-> flows through the pulmonary artery-> then to the lungs where it becomes oxygenated->flows through the pulmonary veins->fills the left atrium-> then flows through the bicuspid valve-> into the left atrium->then goes through the aortic valve-> into the aorta and leaving to the rest of the body
The _______________ initiates & distributes the electrical impulses through the heart in an orderly fashion
conduction system
The ___________ starts the impulse & spreads it to both the Atria. This causes both atrias to Contract.
SA node
The ________________ Receive impulse from the AV node and gives it to the PJ
fibers.
Bundles of hiss
The _____________ receive impulse and spreads it among the Ventricles, this in turn causes Ventricles to Contract
Purkinje fibers
The _________ slows the impulse down (by holding on to it) thereby allowing Ventricles to fill with blood. The impulse then travels to the next segment.
AV node
Steps of SA node action potential (LONG):
- Pacemaker potential: begins at -60mv, opening of Na+ channels closing of K+ channels, membrane reaches threshold(-40mv) 2. Depolarization begins ( Ca+2 channels open causing an influx of calcium), when +5mv is reached Ca+2 channels close 3. Repolarization begins (Ca+2 channels close and K+ channels open causing K+ to efflux(exit) which bring membrane potential back to its most negative voltage (-60 mv RMP)
What are the three steps of SA node potential? (SHORT)
- Pacemaker potential 2. Depolarization 3. Repolarization
What are the steps to myocardial cell action potential? (SHORT)
Phase “0” Depolarization, Phase “1” early repolarization, Phase “2” plateau, Phase “3” repolarization, & Phase “4” resting membrane potential (-90mv)
What is resting membrane potential for SA node action potential ?
-60 mv
What is resting membrane potential for myocardial cell action potential ?
-90 mv
Phase “0” – Depolarization:
Opening of fast
Voltage Gated Sodium Channels →Sodium enters cell → membrane becomes positive
Phase “1” – Early Repolarization:
Opening of Voltage
Gated Potassium Channels → Potassium leaves cell → membrane becomes negative
Phase “2” – Plateau:
Opening of Voltage
Gated Calcium Channels → Calcium enters cell and Potassium leaves cell (ch is still open)→ membrane is stable
Phase “3” – Repolarization:
Voltage Gated
Potassium Channels are open→ Potassium leaves cell → membrane becomes negative
Phase 4 – Resting Membrane Potential:
-90 mv (Resting membrane potential reached), Closure of Voltage
gated Potassium Channel.
_____________ prevent tetanic contractions and stops the heart pumping.
Re-factory Periods, Last 250ms
Unipolar leads:
leads on the chest, 5 total
Bipolar leads:
4 total, aVR (right wrist), aVL (left wrist), aVF (left foot), N (right foot)
Atrial depolarization is represented by :
P waves
Ventricular depolarization is represented by:
the QRS complex
Ventricular repolarization is represented by :
T waves
Atrial repolarization is hidden within the :
QRS complex
Atrial depolarization, initiated by the __ ____, causes the _ _____
SA node, P wave
After atrial depolarization, the impulse is delayed at the __ _____. This is the __ segment.
AV node, PR
ventricular depolarization begins at the ____, causing the ___ _____. Atrial repolarization occurs.
apex, QRS complex
Ventricular depolarization is complete at the __ segment.
ST segment
Ventricular repolarization begins at the ____ , causing the T wave.
apex
The cardiac cycle:
- Atrial and ventricular diastole, semilunar valves closed, AV valves open (0.4 sec). 2. Atrial systole, ventricular diastole (0.1 sec). 3. Ventricular systole, atrial diastole, semilunar valves open, AV valves closed (0.3 sec)
S1 is the ___ noise, __ valves are closed.
Lub, AV
S2 is the ___ noise, _______ valves are closed.
Dub, Semilunar
Frank-Starling law
greater stretch = greater contraction
