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80 Cards in this Set

  • Front
  • Back
muscle fibers
elongated cells that possess organelles and properties distinct from those of other cells
- long, slender cells
- capable of powerful contractions that shorten the cell along its lonitudinal axis
cardiac muscle tissue
found only in the heart
-involuntary
smooth muscle tissue
found in the walls of blood vessels, around hollow organs such as the urinary bladder, and in layers around the respiratory, ciculatory, digestive and reproductive tracts
- involuntary
skeletal muscle tissue
contains very large muscle cells
- voluntary
4 properties of muscle tissue
1) excitability - ability to respond to stimulation
2) contractility - ability to shorten actively
3) extensibility - ability to continue to contract over a range of resting lenths
4) elasticity - ability to rebound to original lenght after contraction
skeletal muscle functions
1) produce skeletal movement
2) maintain posture and body position
3) support soft tissue
4) regulate entering and exiting material
5) maintain body temperature
endomysium
delicate network of reticular fibers that surround each skeletal muscle fiber and binds it to its neighbor
perimysium
fibrous sheaths of connective tissue that divide muscle into a series of internal compartments called fascicles
- fibers = collagen & elastic fibers
- contains blood vessels and nerves
epimysium
dense irregular connective tissue layer that surround entire muscle
tendons
fibers of endoymysium, perimysium, and epimysium often converge to form a fibrous tendon that attaches the muscle to bone, skin, or another muscle
aponeurosis
tendon that forms a thick, flattened sheet
T-tubule
transverse, tubular extensions of the skeletal muscle cell membrane that extend deep into the cytoplasm to contact the sarcoplasmic reticulum
- helps stimulate and coordinate muscle contraction
sarcolemma
muscle cell membrane
sarcoplasm
muscle cell cytoplasm
myofibril
threadlike cylinders in the sarcoplasm of each muscle fiber that shorten during contraction
myofilaments
protein filaments within each myofibril
- actin and myosin
myosin
thick filaments
actin
thin filaments
sarcomere
reapeating units of myofilaments
sarcoplasmic reticulum
membrane complex that surrounds each myofibril
- similar to smooth ER of other cells
M line
thick dark protein band in center of H band that links thick filaments
Z line
thin but dark protein band to which thin filments ar attached
- sarcomere runs from Z line to Z line
zone of overlap
area of sarcomere where thin filaments pass between thick filaments
A band
are of sarcomere containing M line, H band, and zone of overlap
H band
area of sarcomere with thick filaments only
I band
area of sarcomere with thin filaments only
F-actin strand
twisted strand composed of 300-400 G-actin molecules
G-actin
each molecule of G-actin contains an active site than can bind to a thick filament
nebulin
slender strand of protein that hold F-actin strand together
tropomyosin
associated proteins that form a long chain that covers the active sites fo the thin filaments, preventing actin-myosin interaction
troponin
associated proteins that hold the tropomyosin strand in place
- changes position to move the tropomyosin to expose active sites for contraction
myosin
consist of a double myosin strand with an attached, elongated tail and a free globular head
- adjacent thick filaments are interconnected midway along their lenthy by proteins of M line
- oriented away from M line, heads projecting out
- myosin heads cross-bridges because connect thick and thin filaments during contraction
titin
core protein in thick filament that extends the length and continues ot an attachment at the Z line
- portion of titin exposed in I band is elastic and will recoil after stretching
acetylcholine (ACh)
chemical neurotransmitter released at the neuromuscular junction
acetylcholinesterase (AChE)
enzyme found at the synaptic cleft, bound to the post-synaptic membrane that breaks down ACh molecules
rigor mortis
muscles lock in contracted postion when death occurs
motor unit
all of the muscle cells controlled by a single motor neuron
muscle twitch
single momentary contraction
- response to a single stimulus
all or none principle
each muscle fiber contracts completely or it doesn't contract at all
muscle tone
resting tension in a skeletal muscle
muscle spindles
specialized muscle cells that are monitored by sensory nerves that control the muscle tone in the surrounding tissue
muscle hypertrophy
net enlargement of skeletal muscle
muscle atrophy
reduction in muscle size
fast fibers
(white fibers), large diameter, paler color, easily fatigued, powerful contractions
- anaerobic
slow fibers
(red fibers), smaller diameter, darker color from myoglobin, fatigue resistant, slower but extended contractions
- aerobic metabolism
intermediate fibers
properties intermediate between fast and slow fibers
parallel muscle
biceps brachii muscle
convergent muscle
pectoralis muscles
unipennate muscle
extensor digitorum muscle
- one side of tendon
bipennate muscle
rectus femoris muscle
- both sides of tendon
multipennate muscle
deltoid muscle
- multiple branches, tendons throughout
circular muscle
orbicularis oris muscle
- circle around opening
origin
where muscle begins
- structure on a bone of the skeleton that usually remains stationary
insertion
where muscle ends
- structure on a bone of the skeleton that usually moves
innervation
nerve supply to a particular structure or organ
- controls action
action
movement
gliding
two opposing surgaces slide past one another
abduction
movement away from the longitudinal axis of the body in the frontal plane
adduction
movement towards the longitudinal axis of the bpdy
flexion
movement in the anterior-posterior plane that decreases the angle between articulating elements
extension
movement in the anterior-posterior plane that increases the angle between articulating elements
hyperextension
any movement where a limb is extended beyond its normal limits, resulting in joint damage
circumduction
special type of angular motion that creates a complete circle
left and right rotaiton
in reference to head as in shaking no
- reference to subject, not observer
internal or medial rotation
anterior aspect of the limb rotates inward, toward the ventral surface of the body
external or lateral rotation
anterior aspect of the limb rotates outward, away from the ventral surface of the body
pronation
movement of wrist and hand to palm-facing down position
supination
movement of wrist and hand to palm-facing up position
eversion
twisting motion of the foot that turns the sole outward
inversion
twisitng motion of the foot that turns the sole inward
dorsiflexion
(ankle flexion) elevates the distal part of foot and toes, as when digging in heels (flex)
plantar flexion
(ankle extension) elevates the heel and proximal portion of foot, as when standing on tip toes (point)
lateral flexion
vertebral column bends to the side
protraction
moving a part of the body anteriorly in the horizontal plane
retraction
moving a part of the body posteriorly in the horizontal plane
aging and the skeletal muscle
1) skeletal muscle fibers become smaller in diameter
2) skeletal muscles become smaller in diameter and less elastic
3) tolerance for exercise decreases
4) ability to recover from muscular injuries decreases
axial musculature
- originates and inserts on the axial skeleton
- positions the head and vertebral colum
- moves the rib cage which assists in breathing
- 60% of the skeletal muscles in the body
appendicular musculature
- responsible for stabilizing the pectoral and pelvic girdles
- responsible for moving the upper and lower limbs
- 40% of muscles in body
intramuscular injections
into tissue rather than directly into circulation
- drug enters circulation gradually
- into mass of large skeletal muscle
- faster and less irritation
ideal injection sites
bulky muscles that contain few large vessels or nerves
- gluteus medius
- deltoid
- vastus lateralis