Muscular tissue practice exam

Which of the following properties of muscle tissue is its ability to generate tension to do work? A. extensibility B. elasticity C. contractility D. excitability

C

Muscles generate heat, stabilize the body positions and: A. line organs that open to the outside B. coordinate homeostatic functions for the body C. protect the body from invading organisms D. produce body movements

D

If ACh is not released at the neuromuscular junction then:

Muscle contraction will not happen

Identify the struture

Myofibril

The term aponeurosis refers to a

broad, flat, sheetlike tendon

Cardiac muscle fibers are attached to one another at

intercalated discs

Muscle contraction is triggered by impulses carried over

motor neurons

A motor neuron and all the muscle fibers it stimulates form a

motor unit

In tetanus

muscles undergo sustained contractions

A muscle fascicle is surrounded by

perimysium

An increase in the number of active motor units in a muscle is called

recruitment

Excitability refers to the ability of a cell to

respond to a stimulus by producing an electrical signal

Elasticity refers to the ability of a muscle fiber to

return to original shape after contracting or stretching

Creatine phosphate supplies energy for

synthesis of ATP

When ATP attaches to the myosin head

the head detaches from actin

In an isometric contraction

the muscle contracts but does not shorten

When calcium ion concentration in the sarcoplasm is low, the

troponin-tropomyosin complex slides back over the myosin binding sites

The following is a list of events in random order that occur in the contraction of skeletal muscle. Identify which of the subsequent letters represents the correct chronological order of these events. 1. Ca2+ binding to troponin 2. release of Ach at the neuromuscular junction 3. coming together of Z discs 4. depolarization of sarcolemma 5. myosin head attaches to myosin binding site on actin 6. depolarization of T-tubules

2, 4, 6, 1, 5, 3

For the initiation of an action potential that starts contraction in skeletal muscle fiber: A. Ach must bind to receptors on the motor end plate B. Ach must bind to the neurolemma of the somatic neuron C. acetylcholinesterase must break down Ach at the synapse D. K+ must flow into the neurolemma

A

The _______ is responsible for the striation of striated muscle.

Alternating of A bands and I bands

The sarcoplasmic reticulum A. is the cell membrane around each muscle fiber. B. stores Ca2+ when the fiber is at rest. C. opens to the outside through the sarcolemma. D. produces ATP for muscle contraction.

B

Which of the following does NOT have T-tubules? A. Skeletal B. Smooth C. Striated D. Cardiac

B

What links thin filaments to the sarcolemma?

Dystrophin

When examined under a microscope, in which type of muscle tissue are myofibrils not apparent?

Smooth muscle

Which type of muscle tissue is involuntary, slow in contracting, and able to regenerate considerably better than other types of muscle?

Smooth muscle

The binding of Ca2+ to ____________ starts the contraction cycle

Troponin

The enzyme acetylcholinesterase causes

acetylcholine to break down

Myofibrils are composed primarily of

actin and myosin

Calcium ions move from the cytoplasm (sarcoplasm) into the sarcoplasmic reticulum because of the action of

active transport pumps in the sarcoplasmic reticulum membrane

The outermost layer of connective tissue surrounding a skeletal muscle is the

epimysium

The elevated use of oxygen after exercise is called

excess post-exercise oxygen consumption

A sustained muscle contraction without partial relaxation stimuli is called

fused (complete) tetanus

Smooth muscle differs from skeletal because smooth muscle

has dense bodies instead of Z discs

The motor end plate is part of a

skeletal muscle at the synapse

Calmodulin is involved in the contraction of:

smooth muscle

When smooth muscles are stretched they contract, but within a short time the tension decreases. This is called

stress-relaxation response