Turtle heart lab quiz questions
Why does the turtle heart not stop when it is removed from the turtles body a placed in ringers solution?
AV node is still firing
ANS on heart
Affected by the vagal nerve S= speeds up heart P= slows down heart
What happens when the atria are separated from the ventricle? Explain how this happens?
Atria beats regular, ventricle 1/2 as fast because AV node AV node takes over
What conditions in humans could cause AV blocks?
Myocardium infraction
What is the effect of atropine by itself? What is the effect of atropine following ACh?
No effect Speeds it up to normal heart rate
What effects does Epi have on the heart?
No effect Epi binds with beta 1 receptors activates adenylate cyclase which increases ATP production
Ectopic
Out of place
Focus(foci)
Point
Diastole
Relaxation
Vagal escape
Ventricles start beating again Occurs when the SA node fails from heart attack,ischemia, then AV node takes over
Compare the rates of beating of the seperated atria and ventricles?
Ventricles=beat slower because AV nodes take over SA=70-130 BPM AV= 40-60 BPM
Which parts of the heart contact first? Last?
atria then ventricles
Compensatory pause
2 cardiac cycles
Systole
Contraction
Know how to determine heart rate in BPM
Count pulse
AP's spread across the heart like a wave causing
Depolarization followed by repolarization causing contraction and relaxation
Premature ventricular contraction
Ectopic focus, PVC causes AP's so the atria fires, ventricles can't due to refractory period Drugs, MI(heart attack), ischemia(lack of oxygen in blood),genetics
When during the cardiac cycle is blood pressure highest? Lowest?
H= at peak of systole L=end of diastole
Would the human heart respond similarly to temperature changes? Does this ever happen?
Human heart responds similarly to turtle heart, during a heart transplant they put the heart in cold ringers solution so the ions and molecules move slower
What would the human heart do if removed from body?
Keep beating-> pacemaker(SA node)
What is the sinus venous?
SA node of the turtle heart(controls ventricles)
AP's in the human heart begin in the?
SA node->spreads through atria->AV node->ventricles
Vagal stimulation on the heart
Should slow heart down ACh binds with muscarinic receptors on SA node->opens K channels which lower SA node
How does cold ringer's solution affect the heart?Why? Mechanism?
Slow the heart down, slows down ions, AP's go slower
ACh
Slows heart rate Binds with muscrainic receptors
How does 42 degree ringer solution affect the heart? Why? Mechanism?
Speeds it up, speeds up ions, makes APs go faster
