Homework #3 is due now. Bonus #3 is due F 4/27.

Nervous System Signaling Stimulus Integration Transduction Transmission Response

Muscles allow movement

An earthworm: without something to push against, muscles are not much use. CB 49.25

The skeleton, made of bones, gives support CB 49.26

Bones are alive

Connections between bones and muscles

Muscles can only contract Muscles can only contract. Therefore, two muscles are needed for each range of motion. CB 49.27

2 nerve signals for every movement: excitatory and inhibitory CB 49.27

How do muscles contract?

Muscle cells are comprised of series of sarcomeres. CB 49.28

Muscle cells are comprised of series of sarcomeres CB 49.32

Each sarcomere is a repeating unit of actin and myosin proteins CB 49.28

As each sarcomere contracts, the muscle contracts CB 49.28

Neuro-transmitters released at nerve/ muscle junction cause calcium to be released in muscle CB 49.32

A third protein, tropomyosin controls when the muscle contracts CB 49.31

ATP provides the energy for myosin movement along the actin CB 49.30

CB 49.32

How do muscles contract? http://health.howstuffworks.com/adam-200006.htm (if you have a strong stomach, this video shows muscle contraction using a naked man and a cadaver) http://youtube.com/watch?v=nqGyilzp1FQ