Vertebrate Muscle Anatomy. Muscles: convert the chemical energy of ATP into mechanical work. Three different kinds of muscles are found in vertebrate animals Skeletal Cardiac Smooth. involuntary, striated auto-rhythmic. voluntary, striated. heart. moves bone. multi-nuleated.
Vertebrate Muscle Anatomy
Muscles: convert the chemical
energy of ATPinto mechanical work.
digestive systemarteries, veins
Muscle attaches at the origin
At its other end, the insertion, the muscle tapers into a glistening white tendon
As the muscle contracts, the insertion is pulled toward the origin and the arm is straightened or extended at the elbow. Thus the triceps is an extensor.
skeletal muscle exerts force only when it contracts, a second muscle — a flexor — is needed to flex or bend the joint.
antagonistic pair of muscles work across other joints, provide for almost all the movement of the skeleton.
Skeletal Muscle: The striated appearance of the muscle fiber is created by a pattern of alternating dark A bands and light I bands.
Plasma membraneof muscle fiber
Ca2+ released from SR
bundle of myosin proteins:
globular heads aligned
Cardiac or heart muscle resembles skeletal muscle in some ways: it is striated and each cell contains sarcomeres with sliding filaments of actin and myosin.
Throughout our life, it contracts some 70 times per minute pumping about 5 liters of blood each minute.
Different electrical and membrane properties form skeletal
Cardiac cells have ion channels in their plasma membranes that cause rhythmic depolarization = triggering action potentials with no input form NS
myofibrils of each cell are branched.
The branches interlock with those of adjacent fibers by adherens junctions. These strong junctions enable the heart to contract forcefully without ripping the fibers apart.
Gap junction allows for coordinated behavior= contractions