1. See Website for Details
22 October 2012
This Week in Physiology:
Lab: Frog Muscle
Bring your textbook.
Lectures: Ch. 9 Muscle Physiology
Next Week in Physiology:
Abstracts due Monday
See Website for Details

2. 1QQ # 18 for 10:30 Convert to a correct statement or if true, write true.
Rods have a higher threshold to light than cones.
The trichromatic theory of color vision states that humans can see only blue, green, and red light.
Hair cells in the vestibular organs and cochlea have mechanically-gated Na+ channels in their cilia.
The convergence ratio of photoreceptors to retinal ganglion cells is 105:1 in the fovea.
Rapidly adapting receptors are well suited for signaling the onset and offset of a stimulus.

3. 1QQ # 18 for 11:30 Convert to a correct statement or if true, write true.
Rods have a higher threshold to light than cones.
The trichromatic theory of color vision states that humans can see only blue, green, and red light.
Gradual changes in the width and thickness of the basilar membrane of the cochlea are responsible for tonotopy.
The utricle and saccule allow us to detect acceleration.
Slowly adapting receptors are well suited for signaling the onset and offset of a stimulus.

4. dArk band = aligned myosin filaments
Fig
S 6
dArk band = aligned myosin filaments
lIght band = absence of myosin filaments
09.02.jpg
Myofilaments

5. Terms: Myofiber, myofibril, myofilament
Fig b
Terms: Myofiber, myofibril, myofilament
09.11b.jpg
Thick myofilament = myosin Thin myofilament = actin

6. S 4
YouTube Videos Role of ATP in muscle Creepy Muscle demo Sarcomere contraction Powerstoke in muscle I
09.09.jpg

7. Energy for powerstroke & Necessary for detaching myosin from actin
Fig
S 5
2 roles of ATP:
Energy for powerstroke &
Necessary for detaching myosin from actin
Crossbridge cycling continues as long as ATP and Ca++ present.
09.08.jpg

8. Fig
S 8
09.03.jpg

9. Classes of Myofibers based on Twitch Duration
Each muscle fiber express only one of two different myosins isozymes:
Fast twitch = rapid hydrolysis of ATP means crossbridges cycle faster
Slow twitch = slower hydrolysis, isozyme catalyzes the reaction slower
Isozymes not modified by athletic training!
Contraction velocity also affected by load!