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37 Cards in this Set
- Front
- Back
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Right ventricle
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Low pressure circuit/ high volume
(no resistance to flow) |
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Left Ventricle
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High pressure circuit
(5x more resistance to flow) |
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Right ventricle
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we only need to send blood to one place--the lungs! (don't need resistance to blood flow)
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Artery
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carries blood away from heart
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Vein
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carries blood back to heart
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Why is the left Systemic Circuit a high pressure circuit?
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Necessity of partitioning CO to various organs under rest vs. exercise obligates systemic circuit to use resistance vessels (small arteries)to partition blood flow on a beat to beat basis.
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Blood flows through heart by..
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pressure gradient!
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Surface area and velocity...
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are inversely related
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Arteries constrict..
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where we don't want blood to go
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Pulmonary pumps @
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1/5 the pressure head of the systemic system
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Endothelial lining
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gets damaged with pressure above 90 mmHg
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2 things that change pressure in circuit
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volume and blood compliance
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Compliance
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its ability to give (not get stiff)
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How do we know what blood pressure is low enough for ourselves?
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whatever level you can function @ normally is how low you go
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Low blood pressure
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The lower the better (can't die from pressure too low)
Lower the pressure head = more energy efficient |
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Windkessel vessels
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change pulsatile patterns to continual patterns down circuits
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Resistors (small arteries)
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repartition blood flow to various organ structures
arranged parallel don't think for themselves |
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increase more than 32-33 mmHg..
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too much fluid & blood will leave and cause swelling
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Venules
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small veins
vast amount of exchange in capillary beds we absorb things--hormones, waste products, heat |
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Venules
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17mmHg
low pressure circuit out high pressure in |
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Small veins (capacitors)
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have lots of elastic tissue
store blood here |
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Vena cavae
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We have two
drain blood back to right side of heart decrease surface area increase velocity |
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Blood moves from
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high pressure to low pressure
Aorta 100mmHg Vena cavae 2-3 mmHg |
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Need conduction tissue to
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signal contractile tissue when to contract
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Conduction tissue
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paces contractions
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EKG maps 3 waves of conduction activity:
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P wave
QRS complex T wave |
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P wave
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atrial depolarization
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QRS complex
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ventricular depolarization
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T wave
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ventricular repolarization
(resets ion channels back to resting levels) Potassium channels open N gates open, potassium leaves We drive down membrane potential |
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EKG tracing does not correlate to
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mechanical activity (pumping/contraction)
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ECG or EKG
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membrane potential map of the electrical activity of all cardiac tissues
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P-R interval
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impulse is delayed at the AV node.
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S-T segment
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complete ventricular depolarization
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Components of the EKG
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P wave, P-R segment, QRS complex, S-T segment, T wave
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SA node
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is the pacemaker
it paces the heart to contract |
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Under resting conditions..
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external control predominates (vagal tone)
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Intrinsic control of contractile tissue
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1. SA node
2. AV node 3. AV bundle 4. Bundle branches 5. Purkinje fibers |
