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Questions and Answers
Name 2 comparisons between frog and human hearts.
Name 2 comparisons between frog and human hearts.
- Frog heart has 3 chambers instead of 4 with 2 atria and 1 ventricle. 2. Pacemaker cells are located in the Sinus Venosus (SV) node instead of SA and AV.
Where does the mixing of oxygenated and deoxygenated blood occur in the frog?
Where does the mixing of oxygenated and deoxygenated blood occur in the frog?
Ventricle
What are two frog heart structures that try to prevent mixing?
What are two frog heart structures that try to prevent mixing?
- Trabeculae: site of attachment for papillary muscles which reduce suction against heart wall to prevent mixing. 2. Spiral folds: help guide blood flow from atria to the systemic and pulmonary arteries while maintaining separation.
What are the simplified steps of blood circulation in the frog model?
What are the simplified steps of blood circulation in the frog model?
Where does oxygenated blood flow to after leaving the frog heart?
Where does oxygenated blood flow to after leaving the frog heart?
Where does deoxygenated blood flow to after leaving the frog heart?
Where does deoxygenated blood flow to after leaving the frog heart?
Where is the ground electrode placed on the frog?
Where is the ground electrode placed on the frog?
Where is the positive electrode placed on the frog?
Where is the positive electrode placed on the frog?
Where should you hook the negative electrode in?
Where should you hook the negative electrode in?
What are the 5 factors that affect cardiac function?
What are the 5 factors that affect cardiac function?
What is the effect of temperature on cardiac function?
What is the effect of temperature on cardiac function?
What is Q10?
What is Q10?
What is the effect of ionic concentration (Potassium specifically) on cardiac function?
What is the effect of ionic concentration (Potassium specifically) on cardiac function?
What is the effect of ionic concentration (Calcium specifically) on cardiac function?
What is the effect of ionic concentration (Calcium specifically) on cardiac function?
What is the effect of parasympathetic and sympathetic innervation on cardiac function?
What is the effect of parasympathetic and sympathetic innervation on cardiac function?
What is atropine?
What is atropine?
What is Isoproterenol?
What is Isoproterenol?
What is Frank-Starling Law?
What is Frank-Starling Law?
What is the effect of the refractory period?
What is the effect of the refractory period?
What is truncus arteriosus?
What is truncus arteriosus?
In the frog, there is only one electrical connection between the atria and ventricles via?
In the frog, there is only one electrical connection between the atria and ventricles via?
What does the vagus nerve inhibit?
What does the vagus nerve inhibit?
What does the Frank-Starling Mechanism involve?
What does the Frank-Starling Mechanism involve?
Cholinergic drugs have ____ effects.
Cholinergic drugs have ____ effects.
Why is there a delay between the peak of the QRS complex and ventricular contraction?
Why is there a delay between the peak of the QRS complex and ventricular contraction?
How do you think increased extracellular K+ will affect cardiac function (rate/contractile strength)?
How do you think increased extracellular K+ will affect cardiac function (rate/contractile strength)?
How do you think increased extracellular Ca2+ will affect cardiac function (rate/contractile strength)?
How do you think increased extracellular Ca2+ will affect cardiac function (rate/contractile strength)?
Name two structures that are dramatically different between mammalian and frog hearts.
Name two structures that are dramatically different between mammalian and frog hearts.
Indicate what peaks 1 and 2 represent in the trace depicting mechanical activity of the frog heart.
Indicate what peaks 1 and 2 represent in the trace depicting mechanical activity of the frog heart.
Describe the mechanism for how cold Ringer's decreased heart rate.
Describe the mechanism for how cold Ringer's decreased heart rate.
Which frog Ringer's treatment should show the largest force of contraction?
Which frog Ringer's treatment should show the largest force of contraction?
What effects do Isoprel (Isoproterenol) and Acetylcholine (ACh) have on heart rate?
What effects do Isoprel (Isoproterenol) and Acetylcholine (ACh) have on heart rate?
What receptor does atropine block to increase heart rate?
What receptor does atropine block to increase heart rate?
Flashcards
Frog heart chambers
Frog heart chambers
A frog heart has 3 chambers: 2 atria and 1 ventricle.
Sinus Venosus (SV) node
Sinus Venosus (SV) node
The frog's pacemaker, controlling heart rate.
Blood mixing in ventricle
Blood mixing in ventricle
Oxygenated and deoxygenated blood mix in the frog's ventricle.
Right Atrium blood entry
Right Atrium blood entry
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Left Atrium blood entry
Left Atrium blood entry
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Single artery for pumping
Single artery for pumping
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Trabeculae function
Trabeculae function
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Spiral folds function
Spiral folds function
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Q10
Q10
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High extracellular Potassium
High extracellular Potassium
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L-type Ca channels
L-type Ca channels
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Parasympathetic effect
Parasympathetic effect
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Sympathetic effect
Sympathetic effect
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Vagus nerve
Vagus nerve
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Frank-Starling law
Frank-Starling law
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Refractory period
Refractory period
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Truncus arteriosus
Truncus arteriosus
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Atrioventricular (AV) node
Atrioventricular (AV) node
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Cold Ringer's effect
Cold Ringer's effect
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High calcium Ringer's effect
High calcium Ringer's effect
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High potassium Ringer's effect
High potassium Ringer's effect
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Isoproterenol (Isuprel)
Isoproterenol (Isuprel)
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Acetylcholine's effect
Acetylcholine's effect
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Atropine function
Atropine function
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QRS complex delay
QRS complex delay
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Increased extracellular Ca2+
Increased extracellular Ca2+
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Study Notes
Frog Heart Anatomy and Function
- Frog heart consists of 3 chambers: 2 atria and 1 ventricle, unlike the 4 chambers of a human heart.
- Pacemaker cells in frogs are found in the Sinus Venosus (SV) node rather than the SA and AV nodes in humans.
- Mixing of oxygenated and deoxygenated blood occurs in the ventricle.
Blood Flow Mechanics
- Blood from the right atrium enters via the Sinus Venosus, while oxygenated blood from the lungs enters the left atrium through pulmonary veins.
- Blood remains separated until it reaches the ventricle which then pumps through a single artery.
Structures Preventing Blood Mixing
- Trabeculae provide structural support and reduce suction against the heart wall, helping to minimize blood mixing.
- Spiral folds guide blood flow from the atria to both systemic and pulmocutaneous arteries, facilitating some separation of blood types.
Cardiac Function Influencers
- Five key factors affecting cardiac function include temperature, ionic concentration, innervation (both parasympathetic and sympathetic), mechanical stretch, and the refractory period.
Effects of Temperature and Ionic Concentration
- Q10 quantifies the increase of biological process rates with a 10-degree temperature change; common values are between 2 and 3.
- Increased extracellular potassium lowers concentration gradients, causes depolarization, and can, at high doses, prevent contraction by reversing equilibrium potential.
- Calcium influx through L-type Ca channels causes calcium-induced calcium release, critical for cardiac contraction.
Nervous System Influence
- Parasympathetic innervation releases ACh, slowing heart rates. Sympathetic innervation releases NE, increasing heart rates.
- The vagus nerve inhibits SA nodes, leading to a slower resting heart rate; overstimulation may cause "vagal escape."
Contraction Mechanisms
- Frank-Starling law connects ventricular muscle stretch (length) to contraction strength (tension); influenced by epinephrine.
- The refractory period, due to plateau potentials, delays Na channel repolarization, impacting contraction and relaxation timings.
Unique Frog Heart Features
- The truncus arteriosus is the single vessel through which the frog's heart pumps blood.
- The AV node is the sole electrical connection between the atria and ventricles, facilitating sequential contractions.
Ringer's Solutions and Their Effects
- Cold Ringer's decreases heart rate due to fewer open L-type calcium channels, impacting contraction.
- Ringer's with high calcium enhances contraction strength, while high potassium prevents contractions due to significant repolarization.
Pharmacological Effects
- Isoproterenol (Isuprel) stimulates beta receptors, enhancing heart rate and contractions via sympathetic activation.
- Acetylcholine activates potassium channels, leading to increased repolarization and reduced heart rate.
Clinical Relevance of Atropine
- Atropine blocks mAChRs, allowing increased heart rate by inhibiting parasympathetic activity; useful in cases of bradycardia or asystole during emergencies.
Electrophysiology Insights
- The delay between the QRS complex and ventricular contraction allows for complete atrial depolarization before ventricular activation.
- Increased extracellular Ca2+ leads to stronger contractions by enhancing the influx of calcium into cardiac cells.
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Description
Test your knowledge on the anatomical and functional differences between frog and human hearts with this quiz. Explore concepts such as heart chambers, blood mixing, and the specific structures that prevent blood mixing in frogs. Perfect for students studying comparative anatomy!