Cvs 2 - Part 2 Flashcards
The antidote to Digoxin is
Anti-Fab Antibodies
• What neurotransmitter is secreted by the post-ganglionic fibers of the sympathetic nerves that innervate the heart?
Norepinephrine
What neurotransmitter is secreted by the post-ganglionic fibers of the parasympathetic nerves (Vagus nerve) that innervate the heart?
Acetylcholine
What is the antidote of acetylcholine?
Atropine; deriving from the Atropa Belladonna plant
• Atropine is used in every case where the patient is
dying (in an attempt to revive the heart)
What is the alternate source (reservoir location) of Catecholamines (epinephrine and norepinephrine) in the human body?
Adrenal Medulla
• In emergency situations where there is a sympathetic response, what happens
adrenal medulla releases the catecholamines in the bloodstream
• Acetylcholine – effect on the body
decreases the heart rate, decreases the contraction of the heart muscles, and can lead to cardiac arrest
• The Conducting System: the pacemaker of the heart is?
How many impulses per minute
SA (Sinoatrial)Node (Pacemaker of the heart) generates impulses about 75 times per minute
• The wave of excitation develops at the
Describe its pathway
SA Node in the Right Atria and travels the Intermodal pathway to the AV Node; it stops at the AV Node for 0.1 seconds, allowing BOTH of the Atria to depolarize together and contract simultaneously.
• From the AV Node extends the AV Bundle from where the conducting system divides into 2 branches: the Right Bundle Branch and the Left Bundle Branch. Sprouting throughout from the Bundle Branches are the Purkinje Fibers that innervate individual ventricular muscle fibers.
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• ECG – begins with a P Wave, which measures the depolarization of the Atria prior to their contraction. After the P Wave there is a Q wave, which dives below to measure the depolarization to the cardiac apex. The complete Q, R, S complex measures the depolarization of the ventricles immediately prior to their contraction. Following this is the T Wave, which represents the repolarization of the ventricles.
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• Beginning of the P Wave –
Depolarization of the SA node (Pacemaker of the heart)
• P Wave –
Depolarization of the Atria just prior to their contraction.
• Beginning of the Q wave –
the wave of depolarization has effectively reached the cardiac apex.
• Q, R, S Complex –
Depolarization of the Ventricles just prior to their contraction.
• T Wave –
complete repolarization of the ventricles
What event creates heart sounds?
Closure of the valves of the heart
• S1 – first heart sound created by the
closure of the AV valves
• S2 – second heart sound created by the
closure of the Semilunar valves
• Systole –
contraction of the cardiac muscle;
• Diastole –
relaxation of the cardiac muscle;
blood pressure created because of Diastole is called
Diastolic Blood Pressure;
• As blood comes into the Right and Left Atrium, it naturally fills the ventricles. 70-80% of ventricular filling is directly due to .
gravity
• Atrial contraction only contributes 20-30% of ventricular filling
K
The volume of blood present in the ventricles at the end of Atrial contraction is
How much in ml?
termed “End Diastolic Volume or Preload”. It is approximately 135 ml.
• In heart failure, the primary objective is to reduce the load on the heart. By doing what?
Reducing the Preload by restricting the intake of fluids does this. If patient fails to respond by fluid restriction, diuretics are advised to increase the increase the urinary output.
• Concomitantly in Heart failure, an attempt is made to reduce
the Afterload (Diastolic blood pressure). Medications will be given to reduce the blood pressure (beta-blockers, etc.), to reduce the Afterload.
• What principle applies to the contraction of the cardiac muscle?
Frank Starling’s Principle
• Frank Starling’s Principle states that:
Within physiologic limits, the more the cardiac muscle is stretched, the more strongly it will contract.
First heart sound is heard during what phase
Isovolumetric contraction phase
• During Isovolumetric Contraction phase the heart is working against the
diastolic blood pressure present in the Aorta and the Pulmonary Artery.
• The “Diastolic blood pressure” is also called the
“Afterload”.
• Stroke volume is
70 ml
Stroke volume is the amount of blood
ejected out of the ventricles at the end of the Isovolumetric phase and happens during the “Ventricular Ejection Phase”.
• End Systolic Volume –
the amount of blood remaining in the ventricles after the ventricular ejection phase; it is 65 ml.
• EDV (135 ml) – SV (70 ml) = ESV (65 ml)
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Second heart sound is heard during what phase
Isovolumetric Relaxation Phase
• Cardiac output (CO) measures
the amount of blood that is pumped out of the heart every single minute
• Stroke Volume * Heart Rate =
Cardiac Output
• Thyroid storm –
Look it up
Chronotropy
Heart rate
• Positive Chronotrope will _______the heart rate;
Increase
Inotropy –
Contractility of the heart
Positive Inotropy _______ the strength of contractility;
increases
• Congestive Heart Failure –
congestion is seen throughout the rest of the body due to the hearts failure to collect the blood and pump it effectively.
• The most common congenital heart disease that effects 1 in 500 births?
Ventricular Septal defect
Digoxin
Medication extracted from the foxglove plant used for the treatment of heart conditions
blood pressure created because of Systole is called
Systolic Blood Pressure
Negative Chronotrope will ______ the heart rate
decrease
Negative ________ the strength of contractility
decreases
