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37 Cards in this Set

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Skeletal muscle cells
muscle cells must be stimulated by somatic motor nervous system neurons before they can contract.
Skeletal muscle structure
Connective tissue tendons connect the contreactile part of a muscle (body or belly) to bones.

A muscle contains many groupings of hundreds of cells, each group called a fascicle.

The connective tissue that surrounds each fascicle conbine to form the tendons.

Perimysium - surrounds each fascicle
Endomysium - surrounds each cell
Endomysia - are connected to the perimysia
Connective tissue
__________ _______ tendons connect the contreactile part of a muscle (body or belly) to bones.
fascicle
A muscle contains many groupings of hundreds of cells, each group called a _________.
tendons
The connective tissue that surrounds each fascicle conbine to form the _______.
Perimysium
surrounds each fascicle
Endomysia
are connected to the perimysia
Muscle fibers (cells)
Fibers
Fibrils
Filaments
Long cells that run the length of the muscle
Endomysium
covered w/ conn. tissue that is continuous w/fibers from the fascicles.
myofibrils
Cells are filled end to end w/rod-like structures called __________.
sarcoplasmic reticulum (S.R.)
Surrounding the myofibrils is the __________ _________ is connected to the cell's membrane by the T-tubules.
Sarcoplasmic reticulum
acts to store and release Ca++ into the cytosol.
Mitochondria
The S.R. surrounding the myofibrils, is also surrounded by ____________, which is available to produce energy.
Molecular structure
Contractile filaments (myofilaments) within the myofibrils are arranged in a exact pattern producing a banded appearance.

2 types of contractile filaments in each myofibril (thin and thick).

Filaments are arranged into repeating segments called sarcomeres (functional contractile units in a muscle cell).
Contractile filaments (myofilaments)
__________ __________ within the myofibrils are arranged in a exact pattern producing a banded appearance.
Thin filaments
Composed of 3 types of protein, g actin, tropomyosin and troponin.
Thin filaments
G actin has binding sites for parts of thick filament.
Thin filaments
Tropomysin acts to control the interaction of thick and thin filaments. It acts to block the G actin binding sites.
Thin filaments
Tropinin acts to move tropomyosin awayfrom the binding site when a muscle cell is stimulated.
Tropomysin
_________ acts to control the interaction of thick and thin filaments. It acts to block the G actin binding sites.
Tropinin
________ acts to move tropomyosin awayfrom the binding site when a muscle cell is stimulated.
Thin filaments
Ca++ binding to troponin moves the tropomysin.
Thick filaments
Composed of myosin proteins

At each end has a protruding portion called a head or crossbridge.

Head has 2 important "sites", an actin binding site & an ATPase site.

Found positioned in the center of each sarcomere.
Thick filaments
Composed of myosin proteins
Thick filaments
At each end has a protruding portion called a head or crossbridge.
Thick filaments
Head has 2 important "sites", an actin binding site & an ATPase site.
Thick filaments
Found positioned in the center of each sarcomere.
crossbridge
At each end has a protruding portion called a head or ___________.
Excitation-contraction coupling
The action of releasing a neurotransmitter at a muscle cell which INDIRECTLY leads to the contraction of that cell.
(calcium makes muscle contraction).
Interaction of thick & thin filaments
the actual shortening of sarcomeres occurs at the thin & thick filaments

When Ca++ combines with troponin, and move tropomysin in actin binding sites for myosin are now exposed.

Myosin heads can now interact w/ actin.
Muscle fiber contraction
Actin-myosin binding repeats to further move thin filaments towards the center of each sarcomere, shortening them.
Muscle fiber contraction
a repeating system

When stimuli to muscle cell are removed:

a. Ca++ is actively transported into S.R. by Ca-ATPase, decreasing Ca++ binding to troponin.

b. Tropomyosin moves back over actin binding sites stopping myosin-actin interaction & sarcomere shortening
sarcomeres
Each myofibril is composed of thin and thick filaments arranged in ___________.
myofibrils
As sarcomeres shorten, _________ shorten.
myofibrils
All __________ shorten in response to stimuli to the muscle cell. ( Takes use to the "All or none" law)
conn. tissue
Myofibrils shortening shortens the muscle cell which pulls on __________ _______ w/in the cell.
tendon
These conn. tissues exerts force on the _______ which pulls on the bone to be moved.