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34 Cards in this Set

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______ describes how actin and myosin interact to shorten a muscle and generate force.
Sliding filament theory
What muscle tissues are exciteable?
They all are.
______ is a myofilament about 15 nm in diameter composed of bundled myosin molecules.
thick filament
_____ is a myofilament about 7 nm in diameter composed of actin, troponin, and tropomyosin.
thin filament
_____ is a regulatory protein associated with tropomyosin that acts as a calcium receptor (safety on gun)
troponin
The myosin head must have a ___ molecule bound to it to initiate the contraction process.
ATP
When you run hard and get cramps, you are running out of ___
ATP
____ signal for calcium entry
channels
_______ stores calcium
sarcoplasm reticulum
Rigor mortis is the hardening of the muscles after death b/c they cannot relax b/c ____ is no longer produced after death.
ATP
_____ is a light band of only thin filaments
I band
_____ has a dark appearance formed by parallel thick filaments that partly overlap the thin filaments
A band
____ is a protein to which thin filaments and elastic filaments are anchored at each end of a sarcomere.
Z disc
appearance of _______ is a narrow dark line in the middle of the I band
Z disc
_____ is the smooth ER of a muscle fiber which is a calcium reservoir
sarcoplasmic reticulum
_____ is the plasma membrane of a muscle fiber (sock)
sarcolemma
_____ is the cytoplasm of a muscle fiber
sarcoplasm
_____ is a bundle of protein myofilaments
myofibril
_____ is an extension of the sarcolemma extending from 1 side of the muscle fiber to the other and it conveys electrical signals from the cell surface to its interior
T tubule
______ is the dilated ends of sarcoplasmic reticulum adjacent to a T tubule
terminal cisternae
_____ makes ATP which you need for contraction
mitochondria
What happens to vertebral discs as more force is generated?
They get closer together.
A single myosin _____ has a tail that is fixed and a head that flexes.
filament
Many myosin filaments fit together to make ________.
thick filaments.
Myosin heads bind actin filaments, only if _______ does not cover actin.
troponin
_____ is a globular subunit of F actin with an active site for binding a myosin head
G actin
Many actins bind with many myosin heads on the thick filaments during a _____.
contraction
_____ consist of all the actin and myosin found between 2 Z-lines.
sarcomeres
What happens to sarcomeres during a contraction?
They shorten.
______ are oranized groups of actin/myosin filaments inside a myofiber.
myofibrils
During contraction the opposing Z-lines are drawn closer together by the ______ of the myosin heads along the actin filaments.
ratcheting action
Ratcheting of myosin heads across actin _____ the myofiber.
shortens
As the sarcomeres shorten, the z-lines (discs) get closer, eventually crunching into _____.
myosin
The crunch prevents further shortening and limits the _________.
maximum contraction (muscle shortening)