A&P I LAB: MUSCULAR SYSTEM
isometric contraction
A muscle that develops tension against some load but that does not shorten is undergoing _________________.
a T tubule and two terminal cisternae
A muscle triad consists of
False
A muscle triad consists of a sarcoplasmic reticulum, a T tubule, and a terminal cisternum.
axon
A myelinated _________is the structure coated with a whitish fatty layer, messages travel faster in it. What is the term used to describe the coated structure?
a motor unit
A single motor neuron and all the skeletal muscle fibers it innervates constitute a _______________.
True
A tendon is a structure that binds the fascia of a muscle to the periosteum of a bone.
Sarcomere
A________________ is the region of a myofibril that lies between two consecutive Z lines.
False
Actin is found only in the striated fibers of cardiac and skeletal muscle tissues.
False
Action potentials travel slower in a Myelinated axon. True or false?
True
An action potential in a muscle fiber is initiated by stimulation across the neuromuscular junction.
perineurium
Fasciculi are enclosed in a covering of_______________.
dendrites
Identify the part of the neuron that receive messages.
tropomyosin blocks attachment of myosin heads to actin
In a relaxed muscle,
False
Lifting a dumbbell is an example of isometric contraction.
Protein synthesis
Nissl bodies are compartmentalized rough endoplasmic reticulum which is unique to the nervous tissue. What is the function of nissl bodies?
False
Pathogens like clostridium tetani that causes tetanus travel in the axon by fast antrograde transport. True or false?
False
The energy provided by ATP molecules allows the myosin head to bind to the exposed binding site (form crossbridge) on the actin molecule.
acetylcholinesterase
The enzyme that breaks down or destroys acetylcholine is _____________________.
are believed to be attached to ATP molecules, which are used to recock the myosin heads
The globular heads on the myosin proteins of the myosin filament _________________________.
terminal cisternae
The source of Ca²
True
The strength of a muscle contraction is increased by recruiting more muscle fibers within a motor unit.
satellite cells
This type of glial cells are not found in the CNS.
True
To initiate muscle contraction, calcium ions bind to and change the shape of the troponin protein molecules, which then pull the tropomyosin proteins off the myosin binding sites of the actin helix.
lipofuscin
When the nerve gets old these inclusion golden-brown in color accumulate. Identify the inclusion described above.
Microglia
Which glial cell functions like macrophages (WBCs)?
True
During muscle contraction, the I bands get smaller and the Z lines get closer together, but the A bands do not change in size.
Axon
Messages, materials and pathogens travel up and down this structure in a neuron. Identify the structure.
Calcium ions bind to the troponin exposing the active site
Muscle contraction is initiated when
A bands
Muscle contraction is produced by shortening of all the following except _____________.
smooth
Muscle fibers characterized by a lack of striations, a single centrally located nucleus in each cell, and involuntary contractions are referred to as _____________ muscle fibers.
the sarcoplasmic reticulum actively removes calcium ions from the cytoplasm
Muscle relaxation occurs as
sarcoplasmic reticulum
The __________________ store calcium ions needed for muscle contraction.
T tubules
The channels that extend from the cell wall into the interior of a skeletal muscle cell form
