9.1 - 9.3 Flashcards
The 3 basic types of muscle are ___ muscle, ___ muscle, and ___ muscle.
skeletal; smooth; cardiac
Recognize a light micrograph of a skeletal (striated) muscle
x
A single skeletal muscle cell is also called a muscle ___.
fiber
What term describes bundles of collagen fibers that attach bone to muscle?
tendons
Within each skeletal muscle fiber densely packed, striated subunits known as ___ extend in parallel rows from one end of the cell to the other leaving little room between for other organelles. The striations in these elongated structures are caused by the regular arrangement of thick and thin filaments into sarcomeres.
myofibrils
T/F: On the basis of structure, contractile properties, and control mechanisms, two types of muscle tissue can be identified: skeletal muscle and cardiac muscle.
F (there’s also smooth)
One end of each thin filament overlaps a portion of the thick filaments, whereas the other end is anchored to a network of interconnecting proteins known as the ___ ___.
Z line
The most striking feature seen when viewing skeletal muscle through a microscope is a distinct series of alternating light and dark. Because of these bands, skeletal muscle is also referred to as ___ muscle.
striated
In a muscle fiber, the ___ forms a series of sleeve-like segments around each myofibril.
sarcoplasmic reticulum
Which best describes the term “muscle fiber?”
a skeletal muscle cell
With reference to muscle physiology, which best defines the term “contraction?”
activation of cross-bridge cycling
What are myofibrils?
bundles of proteins in a muscle cell
The ___ define the limit of the sarcomere.
Z lines
The neurons whose axons innervate skeletal muscle fibers are known as ___ neurons.
alpha motor
Skeletal muscle fiber image- The web-like structure (in blue) is the ___ ___.
sarcoplasmic reticulum or SR
What is the function of troponin in skeletal muscle cell contractile regulation?
To hold tropomyosin in a position that blocks the cross-bridge binding sites on actin when the Ca2+ concentration is low
Recognize a single muscle fiber in the cartoon image of a skeletal muscle cell.
letter C on image
During cross-bridge cycling when Ca2+ remains present in the cytosol, which step of the cycle happens immediately after the energizing of the cross-bridge?
Attachment of the cross-bridge to the thin filament
In muscle physiology, the term contraction refers to activation of the force-generating sites within muscle fibers: these are called ___ ___.
cross bridges
In skeletal muscle, thin and thick filaments are arranged in cylindrical bundles called ___.
myofibrils
The force generated on an object when a skeletal muscle is stimulated to contract is called muscle ___.
tension
Which of the following is the name for neurons that originate with cell bodies in the brainstem or spinal cord and whose axons innervate skeletal muscle fibers?
motor neurons
A contraction known as a muscle ___ occurs when a muscle fiber is stimulated with a single action potential.
twitch
In skeletal muscle, the protein ___ regulates the position of tropomyosin on actin, thereby regulating cross-bridging binding.
troponin