More frog heart

See diagram in Silverthorn, page 500 for question 1. This will help explain effects on heart rate.


Use external resources for the caffeine question. I'm not going to be too strict on this part since it seems Dr. Rechs didn't cover this in lecture. Basically caffeine blocks adenosine receptors, thus enhancing the activity of NorEp. Use this as a starting point.

Frog heart question #2

For the dark purple heart, I'll give you some hints.

1. What specifically makes blood change color (any type of blood, not just frog blood).

2. What was happening to the heart at the time which would result in the blood color change? Remember that the oxygen consumption of the frog's body does not change during the experiment.

Frog heart question #1

Question number 1:


I want you to mention something about hyperpolarization/depolarization of the cell membrane and the ease of achieving an action potential. 


You also need to explain exactly what is happening in the muscle of the heart itself (why you get increased or decreased contractility, etc).

Skeletal Muscle graph

For your graph, use your data from page 60 of your lab manual.

Skeletal Muscle graph

Here is an example of what your graph could look like: 

(These numbers are completely made up, yours will look different!)

Other formats are acceptable as well. To make the one above, I used "XY Scatter" in Excel. Try playing around with Excel and if you can't figure it out, shoot me an email. Hand drawing a graph on graph paper is also acceptable.

Remember to label the X and Y axis and to put units!

RESPONSE TO COMMENT 3/6/2012

What you are trying to find on this graph is optimum length of the muscle, not threshold. Look at your stimulus voltage to see how many motor units are being recruited. 


If you still have questions, send me an email! I'll be on my computer all day...
-Chrisoula

Hello everyone, Just want to give you a heads up that this week's lab is VERY long. Please carefully read your lab book prior to class so things go as smoothly as possible. Otherwise, you may not be able to complete the lab in the time alloted. Thanks! See you tomorrow. Chrisoula