10/21 Class Lecture Chapter 9 Flashcards
how much muscle tissue makes up the body mass
half of bodys mass
prefixes for muscle
Myo, mys, and sarco
skeletal muscle characteristics
Organs attached to bones and skin Elongated cells called muscle fibers striated voluntary Contract rapidly; tire easily; powerful Require nervous system stimulation
special characteristics of muscle tissues
excitability
contractility
extensibility
elasticity
excitability
(responsiveness): ability to receive and respond to stimuli electricity, causes muscles to “jump”
contractility
ability to shorten forcibly when stimulated responds through contractility, shorts with force- why muscle is usefull
extensibility
ability to be stretched, expands but not forcibly (muscle pulls, it does not push)
elasticity
ability to recoil to resting length, flexible tissue
what are the reasons for the muscle characteristics
the muscle functions
Functions of muscles
Movement of bones or fluids (e.g., blood)
Maintaining posture and body position
stabilizing joints
heat generation
Protects organs, forms valves, controls pupil size, causes “goosebumps”
what is a skeletal muscle served by
one artery, one nerve, and one or more veins
how are skeletal muscles structured
connective tissue sheaths of skeletal muscle
epimysium
dense irregular connective tissue surrounding entire muscle; may blend with fascia (broad sheet of muscle)
perimysium
fibrous connective tissue surrounding fascicles (groups of muscle fibers)
endomysium
fine areolar connective tissue surrounding each muscle fiber, most microscopic
skeletal muscle attachments
insertion
origin
action
innervation
insertion
moveable bone
origin
immovable (less movable) bone
action
what is does (ex. Flexes forearm)
innervation
what nerve
direct skeletal muscle attachment
epimysium fused to periosteum of bone or perichondrium of cartilage
indirect skeletal attachment
connective tissue wrappings extend beyond muscle as ropelike tendon or sheetlike aponeurosis
sarcolemma
plasma membrane
sarcoplasm
cytoplasm