chapter 10

Termination of the nerve impulse at an NMJ results in the passive sliding of ______ back to their original state.

myofilaments

After stimulation of ACh receptors, a muscle impulse spreads quickly along the _____ and into the muscle fiber along T-tubules.

sarcolemma

Approximately 40-50% of your body weight is _____ muscle.

skeletal

Maintenance of posture and production of heat are functions of ______ muscle.

skeletal

the ____ filament theory explains how muscle fibers shorten during contraction.

sliding

The force generated when a skeletal muscle is stimulated to contract is muscle

tension

As a result of ACh stimulation, calcium ions are released from the ______ of the sarcoplasmic reticulum.

terminal cisternae

Single unit muscle cells contract

together

As the troponin changes shape (due to binding calcium), it moves the ______ molecule to which it is attached, thus exposing the active sites on the G-actin molecules.

tropomyosin

A single motor neuron and the skeletal muscle fibers it controls is called a ______

motor unit

When smooth muscle is stretched, it responds by ______.

Contracting then relaxing

True or false: A muscle fiber that is partially shortened can produce a contraction stronger than the contraction it can produce when at its resting length.

F

five characteristics of skeletal muscle

excitability, conductivity, contractility, extensibility, elasticity

A motor unit is composed of a single ______ and all of the muscle fibers it controls.

motor neuron

Explain the five general functions of skeletal muscle

produce heat move the body maintain posture protect and support regulate elimination of materials

A single contraction and relaxation of a muscle fiber is referred to as a muscle

twitch

The connective tissue layer that surrounds an entire muscle is called

epimysium

The cytoplasm of a skeletal muscle cell has a specific name and is known as

Sarcoplasm

Upon release from the terminal cisternae, some calcium ions bind to ______ causing it to change shape.

Troponin

tendon

cordlike that attaches a muscle to a bone, dense regular

The amount of additional oxygen that must be inhaled in order to restore pre-exercise levels is called oxygen ___

debt

When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows ______ the synaptic knob.

into

In order to predict how much tension a muscle can produce when contracting, it is important to consider the ______ relationship of thick and thin filaments.

length-tension

Slow fibers have a relatively large number of ______. This permits slow muscle fibers to produce a greater amount of ______ than fast muscle fibers while contractions are underway.

mitochondria; ATP

After the age of 30, the number of ______ in existing muscle fibers decreases.

myofibrils

As you struggle to twist open a jar, more motor units are called into action until you finally generate enough force to open it. This is an example of ______.

recruitment

A "step-wise" increase in the force of contraction of a single muscle fiber or single motor unit due to repeated stimulation is called

summation

Slow-twitch and fast-twitch muscle fibers differ primarily in ______.

their ATPase which splits ATP

aponeurosis

thin, broad, flat tendon, dense irregular

Overall, as aging progresses, muscle strength and endurance are impaired, and the individual has a tendency to ____quickly

tire or fatgue

As you sit there reading this your muscles, even your relaxed ones are not completely relaxed and soft. This is because they have some background tension called resting muscle ______.

tone

True or false: Skeletal muscle is usually attached to the skeleton, but it is also found at the openings between the digestive tract and the external environment and the urinary tract and the opening to the external environment.

true

Smooth muscle contraction is under ___ control of the nervous system.

voluntary

If you strain to push on a wall that does not move, your muscles are in a type of _____ contraction

isometric

Athletes have more defined muscles than non-athletes even while at rest because they have ______ motor units contracting all the time.

more

At the end of muscle contraction, calcium ions are moved back into the ___ reticulum by ATP-driven ion pumps

sarcoplasmic

Cardiac muscle cells are ______ and thicker than skeletal muscle cells, and they have only ______ nuclei.

shorter 1-2

The epimysium of a muscle is composed of ______ connective tissue.

dense irregular

In an isometric contraction, the muscle ______ body movement.

doesnt produce

Muscle tissue demonstrates the property of _____ when it is done contracting and returns to its resting length.

elasticity

three connective tissue layers associated with a skeletal muscle

epimysium, perimysium, endomysium

A skeletal muscle cell is also called a muscle

fiber

Smooth muscle cells are ______ in shape.

fusiform

Smooth muscle is composed of short cells that have a ______ shape.

fusiform

The diameter of a muscle fiber will predict ______.

how much power it will produce

You make a New Year's resolution to work out more and by March notice your muscles are getting bigger. This is a result of muscle ______.

hypertrophy

Smooth muscle is found where in the respiratory system?

around the bronchioles

After breaking your arm, you have a cast on it for three months. When the cast is removed, your arm looks much smaller than it did before. The process called ______ caused this to happen.

atrophy

A muscle fiber is what level of organization in the body?

cellular

Which can cause muscle fatigue? Multiple select question. Na+ or K+ imbalances insufficient ATP insufficient Ca2+ insufficient acetylcholinesterase build up of intracellular Pi

Na+ or K+ imbalances insufficient Ca2+ build up of intracellular Pi

Slow and intermediate fibers require oxygen to produce ATP, so the metabolic reactions within these fibers are termed ______.

aerobic

In a muscle cell, the short-term energy is supplied by ______ respiration, whereas long-term energy is supplied by ______.

anaerobic; aerobic

A piano player uses her hands for brief quick movements. Which muscle fiber type would you therefore predict to be predominant in these muscles?

fast glycolytic

In a normally functioning muscle, the inability to contract and produce tension is called muscle

fatigue

Smooth muscle is found

in wall of the uterus in the wall of the small intestine around blood vessels

Multiunit smooth muscle cells are stimulated

individually

Multiunit smooth muscle cells are stimulated ______.

individually

Cardiac muscle cells form Y-shaped branches and join to adjacent muscle cells at junctions called ____ discs

intercalated

After you stop running, you notice that you keep breathing heavily for some time. This is because your body is in ______.

oxygen debt

As you hold a barbell and begin to flex your arm in a curl, your biceps brachii slowly lifts the weight by using more and more motor units. This phenomenon, which increases the strength of the contraction, is referred to as

recruitment

The plasma membrane of a skeletal muscle fiber is called the

sarcolemma

A contracting skeletal muscle fiber typically shortens as all of its ______ shorten in length.

sarcomeres

Muscle cells are said to have what characteristic because they can respond to stimulation from the nervous system?

Excitability