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Atrial Presure Curve:
A wave
C wave
V wave
- A wave: (atrial contraction), pressure low, then P wave comes, the pressure goes up a little, squeezing the 30% of blood into ventricle
- C wave: (ventricular contraction), ventricular pressure goes up really high--->AV valve shuts off, creats lub, ventricular pressure shoots up, bulges the valve up into the atrial, the this increases the pressure in atria stil
- V wave (slow pressure build-up in atria): Ventrical contraction, but relaxation of atria--->Blood return from venous return
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What happens when ventrical relaxes and ventricle pressure goes below atria pressure?
- 1. AV valves open
- 2. 70% blood falls back to ventricle, venus return, blood goes to atria, ventricle pressure below atria
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ventricle pressure
- Ventricular pressure (Systole)
- AV shuts (lub) pressure builes up, blood is trapped, isometric contraction
- -When the pressure in ventricle is above aorta, aortic valve opens,
- blood squeezes through to aorta, T wave, and ventricle relaxes, pressure goes down to zero, blood starts to come back to ventricle, aorta snaps shut
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Autonomic Nerves on Pacemaker potential in SA node
- Increase the slope with sympathetic
- Decreae the slope with parasympathetic- longer hypopolarization, slows the heart rate
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IMPORTANT: Parasympathetic DOES NOT CHANGE THE FORCE of the contraction, it is a chronotropic change, meaning it CHANGES the rate by slowing it
-Sympathetic: Makes the force stronger
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Sympathetic innervation of the SA
- 1. Opens the HCN by epi and norepi stimulation( That means Na and Ca channels
- -Hyperpolarization
- -More cardiac cycles per minute)
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4 Extrinic regulation of the heart
- 1. Neurally controlled
- 2. Major center in CNS is locatd in medulla (Pool of neurons there with same function)
- 3. Endocrine
- 4. Frank Starling Law (Sympathetic)
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Know Stroke Volume
The amount of blood squeezed out of heart during a contraction
- Stroke volume= end-diastolic - end-systolic
- (135-65=70ml)
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End diastolic
The volume of blood in ventricle at the end of diastolic (Just before it contracts) 135ml
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End-systolic
- After contraction volume
- -65 ml in heart
- This is due to the backflow before the semilunar shuts
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Valsalva maneuver
Forced expiration on closed glottis, put a lot of pressure in thoracic cavity-Closed the great vein off
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hyperkalemia
Potassium is up, decrease contraction
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Temperature up-->heart rate up
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Korotkoff sound
- When the cuff is above systolic pressure, the artery is constricted,
- When it's between systolic and diastolic, blood flow is turbulent and Korotkoff sounds are heart with each systole.
- No sound at 140
- First sound at 120, that's the systolic pressure
- Second sound, 100, is the cuff pressure
- Third sound, diastolic pressure
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MAP
Mean arterial pressure (drives blood into the circulatory system): diastolic + 1/3 pulse pressure
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Pulse pressure
(and relate this in the equation for MAP)
Pulse pressure:This is the pressure difference we're sensing when the arteries are engorged with blood during systolePulse pressure=Systolic-Diastolic =40 mmHg
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