Download MUSCLES

CHAPTER 6A
acetylcholine
muscle fatigue
sarcoplasm
actin
muscle fibers
sarcoplasmic reticulu
action potential muscle tone
skeletal muscle
cardiac muscle
muscle twitch
smooth muscle
cross bridges
myosin
striated muscle
endomysium
neurotransmitter
synaptic cleft
isometric contractions oxygen debt
thick filaments
isotonic contractions sarcomeres
thin filaments
motor unit
Smooth muscle cells – light blue
Nucleus – red
Connective tissue – brown
Cells with striations – yellow
Intercalated discs – purple
Capillaries – blue
Sarcolemma – light green
Myofibrils - gray
Tendon – tan
Epimysium – orange
Muscle belly – peach/flesh
Perimysium/fascicle – yellow
Endomysium/muscle fiber – red
Myofibril – gray
I Band – pink
A Band – dark brown
H Band – brown
Sarcomere – dark green
Z line – green
Actin – light green
Myosin – aqua
Cross bridges – light blue
Skeletal muscle - ---------peach/flesh
Muscle cell – ---------------orange
Motor nerve - --------------dark brown
Axon – -----------------------brown
Axon branch – -------------aqua
Axon terminal – ------------yellow
Neuromuscular junction – red
Motor end plate - -----------blue
A. All muscles →____________ (essential function)
B. Makes up approx. ½ body’s mass
C. similarities:
1. contractions depend u/p 2 types of __________
2. muscle fibers
*elongated cells wh/ contract
*skeletal & smooth muscle cells
3. myo-, mys-, sarcoprefixes used when ______ is being referred to
ex: sarcoplasma – muscle cells’ cytoplasm
D. Muscle Functions
1. maintains __________
2. __________
3. helps maintain constant body __________
(contractions → ATP to break ↓ →
generates heat)
4. stabilizes _______ (tendons hold bones t/g)
E. Muscle Coverings
1. layered w/ __________ __________ __________
2. ____________
a. delicate conn. tiss. sheath surrounding
each individual muscle fiber
b. allows capillaries & nerves to reach
muscle fibers
3. ____________ – surrounds fascicles (bundles
of muscle fibers)
4. ____________
a. covers an entire muscle
b. separates muscles from ea. other
A. __________ Muscle
1. in walls of hollow organs
2. __________
3. cells:
a. __________
b. non-striated
c. spindle-shaped (tapered)\
4. very slow to contract
B. __________ Muscle
1. in heart walls
2. __________
3. cells:
a. __________
b. striated
c. branching chains of cells
4. cells interlock @ __________ __________
5. slow to contract
6. fibers completely relax b/t rhythmic
contractions → prevents __________
C. __________ Muscle
1. attach to skeleton (bones) by __________
2. _________ (only muscle type subject to
conscious control)
3. cells:
a. __________
b. striated
c. cylindrical (tubular)
4. variable speed of contractions (slow-fast)
5. fibers contract ____________
A. Muscle fiber components
1. sarcolemma – __________ __________
2. sarcoplasm – ____________
3. sarcoplasmic reticulum
a. specialized smooth __________ __________
b. stores ___ & releases it on demand when
muscle is stimulated to contract
4. ____________
a. encased in __________ __________
b. have striations
c. contractile portion of muscle fibers
5. ____________
a. chains of tiny contractile units of myofibrils
b. contractile unit b/t 2 Z-lines
c. aligned end-to-end
6. ____________
a. smaller structures of threadlike proteins w/i
sarcomeres
b. arrangement gives banding pattern
c. 2 types
1) ________ filaments
*contains bundles of protein
molecules → __________
*also contain enzyme to split ATP →
power for muscle contraction
2)________ filaments
*contains contractile protein→ _____
*only filament found in the light “I”
bands
B. bands
1. precise arrangement of myofilaments
→banding pattern/striations
2. __ Bands – dark bands, contain both
actin/thin & myosin/thick filaments
3. __ Bands – light bands, contain ONLY
actin/thin filaments
4. __ Zone – contains no actin/thin filaments
when @ rest
5. _____ Zone – disappears during a contraction
Note: page 183
Note: In order from smallest to largest
____________ →____________→ ____________→
____________ → ____________
A. contractions
1. sarcoplasmic reticulum (SR)
a. spec. smooth ER
b. stores Ca & releases on demand when
muscle fiber is stimulated to contract
2. muscle fibers are stimulated to contract by
_____ neurons (nerves); muscle fibers are
innervated
3. axon of a motor neuron has several branches &
can stimulate from a few to several muscle
fibers in a particular muscle (pg. 184)
4. __________ ________
1 motor neuron + all mus. fibers it
stimulates (pg. 184)
5. ____________ __________(pg. 185)
a. entire region where a neuron and
muscle fiber meet
b. synaptic cleft
gap b/t nerve endings and muscle
cells’ membranes
6. _______________
a. chemical released when nerve impulse
reaches the axon terminals (end of
nerve fiber branches)
b. ____________ is neurotransmitter that
diffuses a/c synaptic cleft
B. __________ __________ __________(pg. 187)
1. myosin/thick filaments attach to binding sites on
the thin/actin filaments (cross bridges)
2. during contraction the actin/thin filaments slide
past the myosin/thick filaments (thin filaments are
pulled t/w center of sarcomere)
3. causes sarcomere to shorten
4. Ca required for cross-bridges to occur
5. Ca triggers the binding of filaments wh/ initiates th
sliding; serves as signal for mus. contraction to b/g
6. when action potential ends, Ca is reabsorbed i/t SR
7. E is supplied by __________
C. E sources
Three ways ATP is acquired (ATP is ONLY E
source that can be used directly to power
muscle activity)
1. _________ ________(CP) interacting w/ADP
a. CP is a ↑ E cmpd. made when a muscle
is resting
b. when CP transfers a ↑E phosphate
group to ADP →regenerates ATP in
fraction of a sec.
2. ____________ ____________
a. supplies some 95% of ATP for mus. activity
b. uses O2
c. glucose is broken ↓to CO2 and H2O & some of
E released is captured in bonds of ATP
d. provides a rich supply of ATP
3. ____________ ____________
a. does not use O2
b. produces only 5% as much ATP as aerobic
resp., but is about 2.5x faster
c. produces lactic acid →promotes mus. fatigue &
soreness
D. how forcefully a muscle contracts depends
u/p how many of its cells are stimulated
E. ____________ __________
1. occurs when there is insufficient O2 to
generate ATP aerobically & anaerobic
respiration begins
2. insufficient ATP supply due to > consumption
3. when muscles lack O2 lactic acid b/g to
accumulate as well as ATP supply starts to run
low
4. causes muscles to contract less effectively,
finally stopping contractions alt/g (fatigue)
5. believed to result in muscle fatigue
F. muscle __________
1. may occur when muscles have been worked
strenuously for a long period of time
2. muscle is unable to contract even though it
is being stimulated
G. types of contractions
Muscles do not a/w shorten when they contract
1. ____________
a. means “same msmt.”
b. muscles do not shorten
c. mmt. does not occur
d. muscle tension keeps increasing, but
muscle is working a/g an object that is
immovable
e. ex: pushing a/g a door jamb
2. ____________
a. means “same tone”
b. muscle shortens; mmt. does occur
H. muscle ____________
1. single, brief, jerky contractions
2. usu. contractions are smooth and sustained
(tetanic contraction)
I. muscle ____________
1. state of continuous partial contractions
2. results in muscles remaining firm, healthy,
and constantly ready for action
3. even relaxed muscles have some fibers that
are contracting (not visible)
4. ex: curved fingers when arm is hanging relaxed
J. Exercise
1. increases muscle size, strength, &/
endurance
2. diff. exercises give diff. results
3. inactivity →muscle weakness &
wasting → ____________
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About.com – ALS video clip
Medclip.com – neuromuscular junction