Chapter 9 quiz

• is found in hearts

• Makes up bulk of heart walls

• Striated

• Involuntary: cannot be controlled consciously

• Contracts at steady rate due to heart's own pacemaker, but nervous system can increase rate

is packaged into skeletal muscle: organs that are attached to bones and skin

are longest of all muscle and have striations (stripes)

Called voluntary muscle,  can be consciously controlled

• Contract rapidly; tire easily; powerful

found in walls of hollow organs

• Examples: stomach, urinary bladder, and airways

• Not striated

• Involuntary: cannot  be controlled consciously

are Muscle fibers

• ability to receive and respond to stimuli

ability to shorten forcibly when stimulated

ability to be stretched

• ability to recoil to resting length

Produce movement: responsible for all locomotion and manipulation

• Example: walking, digesting, pumping blood

2. Maintain posture and body position

3. Stabilize joints

4. Generate heat as they contract

• nerve and blood supply, connective tissue sheaths, and attachments

• Each muscle receives a nerve, artery, and veins

• Consciously controlled skeletal muscle has nerves supplying every fiber to control activity

• Contracting muscle fibers require huge amounts of oxygen and nutrients

• Also need waste products removed quickly

• Each skeletal muscle, as well as each ACh, is covered in connective tissue

• Support cells and reinforce whole muscle

• Dense irregular connective tissue surrounding entire muscle; may blend with fascia

• fibrous connective tissue surrounding fascicles (groups of muscle fibers)

• fine areolar connective tissue surrounding each muscle fiber

• attachment to movable bone

• attachment to immovable or less movable bone

• epimysium fused to periosteum of bone or perichondrium of cartilage

connective tissue wrappings extend beyond muscle as rope like tendon or sheetlike aponeurosis

are long, cylindrical cells that contain multiple nuclei

muscle fiber plasma membrane

• muscle fiber plasma

glycogen storage

• O2 storage

• Myofibrils

• Sarcoplasmic reticulum

• T tubules

• are densely packed, rodlike elements

• Single muscle fiber can contain 1000s

• Accounts for ~80% of muscle cell volume

• stripes formed from repeating series of dark and light bands along length of each myofibril

• dark regions

• lighter region in middle of dark A band

• Line protein (myomesin) that bisects H zone vertically

lighter regions

• coin-shaped sheet of proteins on midline of light I band

• Orderly arrangement of actin and myosin myofilaments within sarcomere

• thin filaments

• Extend across I band and part way in A band

• Anchored to Z discs

• composed of protein and myosin that contains two heavy and four light polypeptide chains