Cardio Part II Flashcards
Pulse pressure is the difference between what two pressures?
Systolic-diastolic
Increased speed of ejection during SV does what to pulse pressure?
Increases it
Lowering arterial compliance affects pulse pressure in what way?
Increases it
What does arteriosclerosis refer to?
Stiffening of arteries with age
What is mean arterial pressure?
Cardiac output x Total Peripheral Resistance
Why is velocity so low through the capillaries?
Its highly branched and allows for diffusion
How much fluid a day does the lymphatic system pick up?
4L
Leaked fluid during capillary exchange is picked up by what system?
Lymphatic system
What do baroreceptors do?
Sense low blood pressure
How is Ca2+ permeability on the L type Ca2+ channel changed?
Phosphorylation
How is the rate of relaxation increased in sympathetic regulation?
Phosphorylation of troponin and the Ca2+ ATPase pumps
Which vessel is the site of gas exchange and diffusion?
Capillaries
Which vessel has high elasticity and low compliance?
Arteries
Which vessel has high compliance and low elasticity?
Veins
Blood pressure is a ratio between which two pressures?
Systolic/diastolic
Maximum pressure in the arteries
Systolic pressure
Minimal arterial pressure before ventricular ejection
Diastolic pressure
What is pulse pressure?
Pressure found at pulse sites
Increased stroke volume does what to pulse pressure?
Increases it
What do chromotropic effects act on?
The SA node
How does parasympathetic drive lower the heart rate?
Increased potassium permeability, hyperpolarizes the SA node
What type of receptor does acetylcholine act on?
Muscarinic receptors
Sympathetic drive increasing heart rate is an example of what effect?
Chronotropic effects
How does sympathetic drive increase heartrate?
Increases Naf permeability on SA node, exciting it
What are dromotropic effects?
Changes in speed of signal spread through atria and av node
Increase of signal spread through atria and av node
Sympathetic drive
Decrease of signal spread through atria and AV node
Parasympathetic
What factors affect stroke volume?
EDV, sympathetic drive input to ventricles and afterload changes
What are afterload changes?
Arterial pressures that blood faces as it leaves the ventricles
If EDV increases, what else increaases?
SV
What is the Frank Starling mechanism?
Law describing cardiac output, increased EDV = increased SV
What is venous return?
Blood coming back to the heart
What are effects on contractility referred to as?
Inotropic
What is cardiac contracility?
Strength of contraction at a given EDV
An increased rate of rise of force and peak force is associated with the phosphorylation of what two channels?
L-type Ca2+ channels and the RyR on SR membranes
What is the heart emptying phase called?
Systole
What is the heart filling phase?
Diastole
When is ventricular pressure at its lowest?
The mid-late ventricular filling phase
AVs are open and semilunars are closed during which phase of the cardiac cycle?
Mid-late ventricular filling
When is the pressure in the ventricles lowest during the cardiac cycle?
Mid-late ventricular filling phase
Which phase of the cardiac cycle is associated with the P wave?
Mid-late ventricular filling phase
What triggers the SA node to fire during the cardiac cycle?
When the ventricles are finished filling with blood
What happens right before the atria contract?
The SA node fires and depolarizes the atria
What is EDV?
End diastolic volume, happens at the end of the ventricular filling phase
What causes the ventricles to completely fill to EDV?
Atria contract
What is the first heart sound associated with?
Closing of the AV valves
What causes the AVs to close during the cardiac cycle?
Rising ventricular pressure during isovolumetric contraction
Why is it called isovolumetric contraction?
All heart valves are closed during the contraction, blood volume remains at EDV
True or false: isovolumetric contraction happens at EDV
True
QRS complex is at the beginning of what phase in the cardiac cycle?
Isovolumetric contraction
Which valves are open during ventricular ejection?
The semilunars
When is ventricular pressure at its highest during the cardiac cycle?
Ventricular ejection
What is ESV?
End systolic volume, remaining volume after ventricular ejection
When is ventricular pressure greater than atrial but lower than aortic?
During isovolumetric relaxation
When is the second heart sound heard?
During isovolumetric contraction
Which valves closing causes the second heart sound?
Semilunars
First heart sound - lub
AVs close
Second heart sound - dub
Semilunars close
Which phase of the cardiac cycle is happening during the ST segment of the ekg?
Ventricular ejection
The T wave finishes during which phase of the cardiac cycle?
Isovolumetric relaxation
During early ventricular filling, is ventricular pressure greater or lower than atrial pressure?
Lower
What is stroke volume? (SV)
Volume of blood pumped out of ventricles
What is the volume of blood in the ventricles after contraction called?
End systolic volime (ESV)
The percentage of blood pumped out is referred to as what?
Ejection fraction - SV/EDV
What is the average ejection fraction (EF)?
55-65%
What ejection fraction is indicative of hypertrophy?
75%
What ejection fraction is a sign of heart failure?
Under 40%
What is a measure of how much blood gets pumped out?
Carciac output
What is the equation for cardiac output?
heart rate x stroke volume
What is the average CO at rest?
5L/min
