Chapter 9 skeletal muscle Flashcards
(50 cards)
Describe skeletal muscle and its function
striated and voluntary
multi-nucleate
produces movement of the skeleton
describe smooth muscles and its function
unstriated and involuntary
one nucleus per long cell
constricts blood vessels and allows for organ mobility
describe cardiac muscle and its function
striated and involuntary; features branching and intercalated discs
serves as the pump for the circulatory system
list four functions of muscle tissue
excitability - ability to respond electrically to a stimulus
Contractibility – ability to shorten forcibly
Extensibility – ability to extend or stretch
Elasticity – ability to recoil after being stretched
skeletal muscles are also referred to as _____?
muscle fibers
describe what a prime mover is
a primary muscle group that does most of the work - agonist
describe what as synergist is
muscles that assist the prime mover
describe what an antagonist is
muscles that resist or work against the prime mover
describe how first class levers work
consists of fulcrum being at center
ex. elbow acts as fulcrum when lifting a weight. the weight is the resistance to the triceps acting as the force
describe how second class levers work
resistance is in the middle
ex. fulcrum at toes, resistence (body weight), force of calf muscles when jumping
describe how third class levers work
force is in the middle
ex: doing bicep curls. ulna acts as bar, elbow is fulcrum, force of bicep is pulling on ulna (so centered) weight is on end
what is constant and what is changing in isotonic contraction and does it produce movement?
Constant: tension
Changing: length
produces movement
think of picking up a weight
what is constant and what is changing in isometric contraction and does it produce movement?
constant: length
changing: tension
produces no movement
think of picking up an immovable weight such as heavy table
what is the difference between concentric and eccentric give an example of each?
concentric: muscles shorten
(picking up a weight, biceps contract)
eccentric: muscles lengthen
(dropping a weight down, bicep relaxes and stretches)
describe the differences between endomysium, perimysium, and epimysium
Endomysium – around individual cells
Perimysium – around fascicles (clusters of muscle cells)
Epimysium – around entire muscle
what is muscle fascia and what does it connect with?
connects with epimysium of muscles to help connect muscles together
what are two derivatives of fascia and give examples
tendons - cord-like connective tissue (such as within the shoulder and knee)
aponeuroses - sheet-like connective tissue (such as between abdominal muscles)
describe myofibrils, where they can be found and their function
myofibrils make up muscle fibers or myocytes
their primary function is to house the actin and myosin to facilitate movement within the muscle cell
define sarcomeres and where you find them
sarcomeres refer to the region of a myofibril between two z-discs
sarcoplasmic reticulum, what is it most similar to among other cells, where you will find them, and what is their function?
most similar to smooth endoplasmic reticulum of cells
they surround myofibrils like a loose knit sweater
their function is to release calcium to the thin filament
define sarcolemma, its location and function
most similar to cell plasma membrane
works to divide intracellular material and organelles from extracellular material
define T-tubules, where they are located, and what is their function
t-tubules are channels that lead within the myocyte in order to quickly transfer electrical signal to the sarcoplasmic reticulum in order for it to release calcium to the thin filament
where is the I-band located
where only z-disc line and thin filament are present
what is the z-line’s function
anchor site for actin (thin) filament and titin
