A&P I LAB: MUSCULAR SYSTEM

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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


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