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Terms in this set (16)

Types of fibers comprising muscles change during development. During some disease conditions and in some cases, following _________ training.
exercise
Jaw muscles in some animals contain a fiber type that is not found in other parts of the body and serves special functions..
masticatory myosin. It is evolutionarily very ancient.
Every muscle cell that we are born with has undergone a complete change and conversion to what we have now. Myosin isoforms at birth are called __________.
neonatal isoforms, we don't have those anymore.
Slow fibers, compared to fast fibers:
have ___________ NMJs
are __________ in diameter
contain different sarcomere protein ___________
contract more __________
are more __________ resistant
smaller
smaller
isoforms
slowly
fatigue. We use slow fibers for more long lasting events like standing up for a long period of time.
Why is it advantageous for slow fibers to be smaller?
slow fibers are more oxidative (mitochondria) than glycolytic, being smaller is more efficient to allow shorter distance from the capillary that is supplying oxygen to the center of the cell where mitochondria reside.
fast fibers rely more on ____________, while slow fibers rely more on _________ ______________.
glycolysis,
oxidative phosphorylation. Fast fibers do have a fair bit of mitochondria but need more ATP faster. Slow fibers do have some glycogen in them but have much higher mitochondrial volume.
Slow fibers are also called
type 1 fibers
There are at least 2 types of type II fibers:
type 2A and 2B.
Type 2A fibers tend to be ___________ than 2B
smaller
Type 2A fibers (fast) are larger and depend on more oxidative metabolism and are less _____________. They contract a little slower than type 2B which depends more on _____________.
fatigable
glycolysis
Type 2B, being faster, generate ____________ power but are less _______.
more
less
Type 1 (slow twitch) muscle fibers are the ________ efficient.
most
among skeletal fiber types.
muscles that are used for maintaining posture have a high proportion of type ____ fibers where as muscles that are utilized to perform tasks rapidly and with a lot of dexterity, contain primarily type ____ fibers.
type 1
type 2
There are no ________ in the heart.
NMJs. Except at the pacemakers. They communicate via gap junctions at intercalated disks which runs the full boundary of the cell.
Myosin heavy chain (MHC) beta is the same as type __.
type 1
MHC alpha is not normally expressed in skeletal muscle. A unique form of _____ is expressed in cardiac muscle.
TnI
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