Exam 2 - A & P
motor end plate
The specialized sarcolemma that contains acetylcholine receptors is the
Epimysium
a layer of collagen fibers that surrounds an entire muscle is called
sodium ions
As a skeletal muscle contraction is initiated, acetylcholine binding alters the motor end plate membrane's permeability to
Perimysium
Muscle fascicles are separated by
have many nuclei
Muscle fibers differ from "typical cells" in that muscle fibers
(FIGURE 7-1) Actin and myosin
Structure I is composed of
(FIGURE 7-1) Myofibril
Structure J represents a
(FIGURE 7-1) Thin myofilament
Structure labeled H is
(FIGURE 7-1) Mitochondria
Structures labeled F are the
Axon terminal
The ____ contains vesicles filled with acetylcholine
calcium
The active sites on actin molecules are usually covered up by other molecules. What is the critical material required to uncover the active sites on the actin molecules that will bind to myosin heads?
sarcomere
The area between Z lines is the ___
I Band
The area of the sarcomere that is the light region between two successive A-bands is the
break down
The enzyme acetylcholinesterase causes acetylcholine to
A Band
The region of a sarcomere containing myosin, going from one end of the myosin molecules to the other end of the myosin molecules, is the ____
sarcoplasmic reticulum
The skeletal muscles store calcium ions in the terminal cisternae of the
ATP
The stiffness that occurs at death, when actin and myosin molecules stay linked to each other in a contracted state, is due to a lack of
Actin and Myosin arrangement
The striated appearance of skeletal muscle results from
Sarcoplasmic reticula
The terminal cisternae are structural features of the ___
(FIGURE 7-1) the cisterna of the sarcoplasmic reticulum along with the T tubules
The triad, seen as structure D, is composed of
Troponin molecules
Tropomyosin strands are held in position by ___
acetylcholine is released
Upon the nerve impulse arriving at the axon terminal,
to transmit electrical impulses to the cell's interior
What is the function of the transverse tubule?
incomplete tetenus
What term is defined as a tension production that rises to a peak with very brief periods of relaxation?
Acetylcholine is broken down by acetylcholinesterase
Which of the following is one of the steps that ends a contraction?
fiber
A muscle _____ contains a sarcolemma, sarcoplasm, myofilaments, and myofibrils
Perimysium
A sheath of connective tissue surrounding a bundle of striated muscle
synaptic cleft
Acetylcholinesterase is found within the
myofilaments are broken down
After death, rigor mortis lasts until
10,000
Each myofibril consists of approximately how many sarcomeres?
calcium ions
In response to action potentials arriving from the T tubules, the SR releases
(FIGURE 7-1) T-tubules
Label A is pointing to
motor neuron axon terminals
Neurotransmitters that cause skeletal muscle contraction are normally stored in
sarcoplasmic reticulum
Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tubule is tightly bound to
2, 4, 1, 3, 5 Nerve impulse arrives at synapse Acetylcholine is produced Action potential is generated along the sarcolemma Calcium is released into muscle cell cytoplasm Actin and myosin molecules continuously cross-link, with actin molecules being pulled inward
Steps of muscle contraction in the correct order
(FIGURE 7-1) Stores calcium
Structure B
(FIGURE 7-1) Sarcoplasmic reticulum
Structure C is the
(FIGURE 7-1) Sarcolemma
Structure E is the
(FIGURE 7-1) Myosin
Structure G is composed of