Class Notes (834,585)
Canada (508,623)
Physiology (903)
PHGY 209 (410)
Ann Wechsler (172)

PHGY 209 Muscle physiology.doc

7 Pages
Unlock Document

PHGY 209
Ann Wechsler

Muscle3 types of muscleSkeletal muscle is used for posture and locomotionThis is the muscle that enables our arms and legs to contract under our conscious controlCardiac muscle is responsible for the rhythmic contractions of the heartSmooth muscle causes involuntary contraction in blood vessels gut bronchi and the uterusThin cells constituting muscles are called muscle fibers can be 1 ftlongMuscle is attached at each end to tendons which in turn attach to bone on both sides of a jointContraction of skeletal muscle pulls on the tendons resulting in flexion of the joints Muscle fibers are generated during development by the fusion of a large number of small precursor cells called myoblastsEach myobast has a single nucleus whereas the fiber is a multinucleated cellThe striations within each myofibril are caused by alternating light Ibands and dark AbandsIn the center of each light band is a dark line called the Zline These structures delineate the sarcomere the contractile unit of skeletal muscleEach sarcomere consists of two sets of parallel and partially overlapping protein filamentsthick filaments extending thin filamentsfrom one end of the A band to the other andattached to the Z lines and extending across the I band and part way into the A bandThin filaments are physically attached to Z linesThin filaments consist of actinEach actin filament is formed from two chains of globular actin subunits twisted into a helix The myofibril is a lattice of thick and thin filaments
More Less

Related notes for PHGY 209

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.