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A skeletal muscle cell is also referred to as?
Each muscle fiber is formed during development by the fusion of number of _____________ , ___________ , cells known as ______________.
Location: Between the plasma membrane and surrounding basement membrane.
Function:Become active in response to strain or injury and undergo mitotic proliferation. Daughter cells divide into myoblasts which can fuse with or form new muscle fibers.
- Hormones involved: GH & Insulin etc
- Function: When there is much of a loss of muscle tissue.
Example: Working out lifting weights
The term muscle refers to....
a number of muscle fibers bound together by connective tissue
What has striated pattern?
Skeletal and Cardiac Muscles!
Thick and thin filaments are part of smaller, cylinder bundles called _____________
Most of the cytoplasm of a fiber is filled with ________
Myofibrils which are made up of ACtin & Myosin
One Z-Band to the next Z-Band is known as?
Held together by?
- Held together by proteins, Titin and nebulin
Where are I-Bands found?
Where there is no Myosin Filaments!
A-Band, what does it consists of?
Myosin, Start to finish = A-Band
Which muscles are multinucleated?
Skeletal Muscle are multinucleated
Each myofibril is wrapped by.......
Myosin heads have an actin binding site and an ATPase site that binds to ______
Actin structure consist of:
Binding sites are inhibited by ________
______ has a ______ molec. for every seven actin subunits.
2 Strands, in a double helix of actin molecules, each has a myosin-binding site.
Binding sites are inhibited by presence of tropomyosin
Slow-oxidative (Type 1) fibers Red
Have a low ______ _____ activity....
Has low ___-__ activity with high ___ capacity..
Has small _____ w/ many blood vessels.....
USED FOR......... and have _____ thus red
- Have a low GLYCOTIC ENZYME activity....
- Has low MYOSIN_ATPase activity with high OXIDATIVE capacity..
Has small DIAMETER
w/ many blood vessels.....
USED FOR... LONG ENDURANCE
.... HAVE MYOGLOBIN
______ has calcium binding sites
Fast Oxidative (Type IIa) FIbers - Red
Has high _______-___ activity
Has high _______ capacity
Intermediate _____ w/ many blood vessels
High in ________
Intermediate ________ enzyme cpacity
Intermediate GLycogen content
- Has high MYOSIN-ATPase activity
- Has high OXIDATIVE capacity
- Intermediate DIAMETER w/ many blood ves.
- High in MYOGLOBIN
- Intermediate GLYCOLYTIC enzyme capacity
- Intermediate GLycogen content
- Fast CONTRACTION
Fast Glycolytic (Type IIb) FIbers - WHITE
Low in _______ but high in ________
Fatigues very ___________
High _____-ATPase activity
High ______ activity
Produces the most ______ of the three.
- Diamter = LARGE FIBERS
- Low in MYOGLOBIN but high in GLYCOGEN
- Fatigues very QUICKLY
- High MYOSIN-ATPase activity
- High GLYCOLYTIC capacity
- Produces the most TENSION of the three.
What three things control for the strength of a muscle contraction?
- Number of stimuli/sec
- Diameter of fiber
- Length of fiber before contraction.
# of fibers (motor units) contracting depends on what 4 things?
- Number of fibers/motor unit
- KInd of fibers in motor unit
- # of action potentials
Causes of fatigue in muscle:
Depletion of cell nutrients...
- Change of ionic concentration in t-tubule :
- (K+) or lactic acid
- Depletion of cell nutrients... glycogen stores r depleted
Muscles need to be stimulated by....
Use of muscles causes.....
Endurance excercises causes more ____ fibers.
Power excercises (weights) cause more __ fiber
- Endurance excercises causes more oxidative fibers
- Power excercises (weights) cause more glycolytic fibers
WHat are myofibrils made up of?
Actin an d myosin
Myosin heads aka ______ have an _____ binding site and ____ site that binds to ATP
double helix of _____ molecules each has ___ binding site.
Binding sites are inhibited in pres. of ____ which has ______ for ever _ actin subunits.
2 strands in doubl helix of actin molecules each has myosin binding site.
What are sarcomeres of skeletal muscle held together by?