Cardiovascular Physiology Report

Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 The parasympathetic nervous system releases __________ to affect heart rate. You correctly answered: acetylcholine. 2 A cholinergic drug that worked the same as acetylcholine would You correctly answered: be an agonist and decrease heart rate. 3 Norepinephrine affects the heart rate by You correctly answered: increasing the rate of depolarization and increasing the frequency of action potentials. 4 The __________ receptor binds norepinephrine and epinephrine. You correctly answered: ß-1 adrenergic. Experiment Results Predict Questions 1 Predict Question 1: Pilocarpine is a cholinergic drug, an acetylcholine agonist. Predict the effect that pilocarpine will have on heart rate. Your answer: Pilocarpine will decrease heart rate. 2 Predict Question 2: Atropine is another cholinergic drug, an acetylcholine antagonist. Predict the effect that atropine will have on heart rate. Your answer: Atropine will increase heart rate. Stop & Think Questions 1 Which of the following is true of epinephrine? You correctly answered: It increases the heart rate and mimics the sympathetic nervous system. 2 The final chemical modifier we will look at is digitalis (also known as digoxin and digitoxin and derived from the foxglove plant). Individuals with weakened hearts need to allow maximum time for venous return and increased stroke volume and would therefore most likely benefit from You correctly answered: increased force of contraction and decreased heart rate. Experiment Data Solution Heart Rate (beats/min) ---- 61 Epinephrine 81 Pilocarpine 46 Atropine 71 Digitalis 42 ---- Epinephrine Pilocarpine Atropine Digitalis Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 Pilocarpine decreased the heart rate. Typical of cholinergic agonists, it You correctly answered: decreased the frequency of action potentials. 2 The effect of atropine was to You correctly answered: mimic the sympathetic nervous system. 3 The modifiers tested that decrease the heart rate were You correctly answered: digitalis and pilocarpine. 4 To increase the heart rate, the best choices would be You correctly answered: epinephrine and atropine. Review Sheet Results 1 Describe the effect that pilocarpine had on the heart and why it had this effect. How well did the results compare with your prediction? Your answer: Pilocarpine decreased the heart rate because it is a cholinergic agonist which mimics the effect of acetylcholine. The results compared well with my prediction since pilocarpine is a cholinergic agonist. 2 Atropine is an acetylcholine antagonist. Does atropine inhibit or enhance the effects of acetylcholine? Describe your results and how they correlate with how the drug works. How well did the results compare with your prediction? Your answer: Atropine inhibits the effects of acetylcholine and from the results in which it is a cholinergic antagonist, the effects of atropine cause the heart rate to increase. This means that the drug works to increase the heart rate by inhibiting acetylcholine of its ability to decrease the heart rate. The results compared well with my prediction since atropine is an acetylcholine antagonist. 3 Describe the benefits of administering digitalis. Your answer: The benefits of administering digitalis are that it decreases the heart rate and increases the force of contractions which helps people with weak hearts or heart failures. 4 Distinguish between cholinergic and adrenergic chemical modifiers. Include examples of each in your discussion. Your answer: Cholinergic chemical modifiers inhibit, enhance, or mimic the effects of acetylcholine while adrenergic chemical modifiers inhibit, enhance, or mimic the effects of epinephrine. Some examples of cholinergic chemical modifiers are pilocarpine and digitalis. An example of adrenergic chemical modifiers is atropine.