Homework #2

EEMB 160 : The Neural Basis of Behavior, "Neurobehavior"

NAME:   Due: May 5 (Friday) in lecture!! Covers approximately lectures 4/17 through 5/1 & all associated readings. Covers discussion sections from 3rd, 4th & 5th week Covers web modules 3 25 points total You can complete this assignment through the web site and then print it to turn it in. (Try clicking on the buttons to choose your answer on the multiple choice questions and type your short answers or single word answers in the text boxes provided below the question.) IF YOU DO DECIDE TO PRINT YOUR ANSWERS VIA THE BROWSER, PLEASE BE SURE TO PROOFREAD THE ASSIGNMENT BEFORE TURNING IT IN TO MAKE SURE ALL YOUR ANSWERS APPEAR, ESPECIALLY THE MULTIPLE CHOICE ANSWERS! Also, links (underlined, blue text) within the questions or answers are NOT indicating the answer, but take you to a part of a module that might help you with the question. Address: http://lifesci.ucsb.edu/~mcdougal/neurobehavior/modules_homework/2000hw2.html A note about doing your assignment on-line, WATCH OUT FOR NETSCAPE OR INTERNET EXPLORER CRASHING IN THE MIDDLE OF YOU TYPING IN YOUR ANSWERS (YOU'LL LOSE ALL YOU'VE TYPED)!! It might be a good idea to have some answers written out or have them pasted into a program that is saveable (like Word or a text editor). Also, after you print your assignment, look through it to make sure all your answers printed. Also, make sure the right margin is not cut off, truncated your answers. Printing Instructions: If you use Internet Explorer you should just be able to print away (might want to make sure that "fit to page" is checked under Print Preview mode. If you have Netscape, all bets are off--I'll try to make the page skinny enough to fit on one page. Then go to print. WRITE (OR TYPE) YOUR ANSWERS ON THIS SHEET!!

1. [1 pt] Why does the crayfish have a neuron specialized to inhibit or "turn off" its stretch receptor neurons that sense the stretch level of its abdominal segment muscles?   2. [2 pts] List the following steps in the order they occur during excitation-contraction coupling in vertebrate muscles. (1) End-plate potential travels outside of end-plate region (2) Ca+2 comes out of the sarcoplasmic reticulum (aka lateral cisterna) (3) Neuronal AP (4) Depolarization of end-plate region (5) Voltage-gated channels open (6) AP travels down t-tubules into muscle fiber (7) Ligand-gated channels open (8) Voltage-gated channels on sarcoplasmic reticulum open (9) muscle AP (10) Actin & myosin slide along each other to produce a contraction (11) ACh release   3. [2 pts] Arthropods use very few neurons to run their muscles. What organization makes this possible AND distinguishes them from the organization of vertebrate muscles and their innervating motor axons? List two reasons.   4. [2 pts] Contrast how a vertebrate achieves graded whole muscle contractions with how an arthropod achieves the same task.   5. [1 pt] What is the term to describe when similar organs or mechanisms evolve independently of each other in very distantly related organisms due to the same selection pressure? How did Darwin use this as an explanation for the evolution of the various groups of electrical fish?   6. [2 pts] What is the difference between the purpose of the strong pulses that the strongly electric fish give off vs. the weak pulses that the weakly electric fish give off?   7. [1 pt] Which of these sensory receptors are involved in passive electroreception? mechanoreceptors marginal bodies electrocytes ampullary receptors tuberous receptors   8. [2 pts] How do several small, modified muscle cells produce electrical discharges of up to 500 V in strongly electric fish?   9. [1 pt] How is the depolarization of the axon terminal linked to synaptic transmission?   10. [1 pt] Which of the following characterize(s) inner hair cells (more than one may be correct)? Function to dampen sensitivity of the ear Tansduce sound waves Possess stereocilia Possess stretch-sensitive channels Function to contract the tectorial membrane   11. [1 pt] Hair cells have no axons, but can still release neurotransmitter onto other neurons. True False   12. [2 pts] Name three sensory systems that we’ve learned about in this course that permit "visualization" of the environment without eyes, and for each one, give an example of an organism that evolved the sensory ability.   13. [2 pts] A compound eye is composed of many or discrete individual "mini-eyes". Each one has it’s own or focusing element. One unit of the compound eye is composed of many cells. The cells that form the light-sensitive region of the eye or the rhabdom are called . There are typically 8-12 of these cells per unit. is the visual pigment in compound eyes. Compound eyes are found in which group of organisms (not a subgroup)? .   14. [3 pts] Limulus visual system is an excellent example of input processing or filtering that occurs before the signal reaches the central nervous system. Lateral inhibition in the Limulus eye is a classic example of this pre-CNS filtering. What is lateral inhibition and what is its purpose?   15. [2 pts] How does the compound eye of Limulus differ from a compound eye in a true fly?     Return to Modules & Homework Page Return to Home Page