chapter 9: muscles and tissues Flashcards
skeletal muscle tissue is found…
in organs that attach and cover the skeleton
characteristics of skeletal muscles
- have striations
- voluntary muscle
characteristics of cardiac muscles
- has striations
- involuntary muscle
characteristics of smooth muscle
- found in walls of hollow visceral organs
- non-striated
- involuntary muscle
what muscle is found in walls of hollow visceral organs
smooth muscle
characteristics of muscle tissue (4)
- excitability
- contractibility
- extensibility
- elasticity
muscle functions (4)
- produce movement
- maintain posture and position
- stabilize joints
- generate heat
skeletal muscle is made of … (4)
- muscle fibers
- nerves
- blood vessels
- connective tissues
what is epimysium
- outside the muscle
- dense irregular
what is perimysium
- dense irregular
- covers fascicles
- made of collagen and elastin
what is fascicle
grouped muscle fibers that resemble bundles of sticks
what is endomysium
- within the muscle
- wispy sheath of fine areolar connective tissue
- divides each muscle fiber
what is insertion
the moveable bone
what is origin
the less or immovable bone
2 types of muscle insertions
- direct/ fleshy
- indirect
function of tendon/ aponeurosis
anchors muscle to the connective tissue covering of skeletal element or to fascia of other muscle
what is the contractile unit of the muscle
sarcomere
plasma membrane of the muscle fiber
sarcolemma
cytoplasm of muscle cell
sarcoplasm
granules of stored glycogen that provide glucose during muscle cell activity for ATP production
glycosomes
red pigment that stores oxygen
myoglobin
myofibrils are
make up a single muscle fiber, rod shaped
myofibrils are made of…
sarcomeres
sarcomeres contain…
myofilaments
dark striation
A band
light striation
I band
lighter region of A band
H zone
describe sarcomere
smallest contractile unit of muscle fiber
2 types of myofilaments
- myosin
- actin
thick filaments contain …
myosin (red)
thin filaments contain …
actin (blue)
function of tropomyosin
rod shaped protein that spirals about the actin core and help stiffen and stabilize
function of troponin
globular protein, calcium-regulatory protein
what is dystrophin
links thin filaments to integral proteins of sarcolemma
events at neuromuscular junction (4)
- motor using fires action potential (AP) down axon
- Ach is release by neuron axon terminal into synaptic cleft
- ACh binds receptors on junctional folds of sarcolemma
- Ach binding causes depolarization called EEP
what happens in muscle fiber excitation
EEP triggers an AP
what happens in excitation-contraction coupling
- Ap in sarcolemma travels down T tubes
- SR releases Ca^2+
- Ca^2+ binds to troponin, myosin heads bind actin
what happens in cross bridge cycle
contraction occurs via cross bridge cycling
what is a myogram
recording of contractile activity consisting of one or more recorded lines called tracings
3 distinct phases of myogram
- latent period
- period of contraction
- period of relaxation
what is the latent period
first few milliseconds following stimulation when excitation-contraction coupling is occurring
what happens during wave summation
contractions become stronger due to stimulation before complete relaxation occurs
stimuli that produce no observable contractions are called
threshold stimulus
what do you call the strongest stimulus that increases contractile force
maximal stimulus
first observable contraction is called…
threshold stimulus
tetanus
smooth contraction due to rapid stimulation
isotonic vs isometric contraction
isotonic- muscle develops tension to lift the load, muscle shortens and remains constant
isometric- muscle reaches peak tension developing capability but does not shorten
2 types of isotonic contractions
concentric- muscle shortens and does work
eccentric- muscle generates force as it lengthens
differentiate aerobic and resistance exercise
aerobic- stamina, causes dramatic change in slow, oxidative fibers
resistance- strength
define muscle twitch
response of a muscle to a single stimulation
