PHS 3341 Lecture 12: Muscle Structure and Function Pt.1

• School: University of Ottawa
• Department: Physiology
• Course: PHS 3341
• Professor: Stephen Gee

Document Summary

Muscles are responsible for all of our movements - limb movements, trunk movements and even bowel movements. Muscle is the largest tissue in the body -- comprises 40-50% of body mass and there are 640 different muscles in the human body. Come in various shapes and sizes -- range in size from a few mm (extraocular muscles) to over 30cm in length. All muscles have the same primary function -- to convert chemical energy into mechanical energy to generate force and perform work. Postural muscles function continuously while a person is awake. Sphincters prevent outflow of organ contents (e. g. bladder) Smooth muscle contractions move food throughout the gi tract. Heat released by muscle used to maintain normal body temperature. Excitability - ability to receive and respond to stimuli. Extensibility - the ability to be stretched or extended and still contract. Elasticity - the ability to recoil and resume the original resting length. Comparison of skeletal, cardiac and smooth muscle cells.