chap 13

Select all correct descriptions of slow-twitch muscle fibers.

Reserve of fats Have many mitochondria Function in endurance

Select all of the following that are components of a muscle fiber.

Sarcolemma T tubule Sarcoplasm

During muscle contraction, what changes occur in a sarcomere?

Sarcomere takes a square shape as it shortens.

Which of the following stores calcium within a muscle fiber?

Sarcoplasmic reticulum

Select all of the ways by which muscles help maintain body temperature.

Shivering Constricting blood vessels

Small, fluid-filled sacs between tendons and bones are called

bursa

When muscle relaxation begins, ions are moved back into the sarcoplasmic reticulum.

calcium

Within a myofibril, myosin binding sites are exposed on actin when ions bind to troponin.

calcium

The most efficient method of obtaining ATP for the activity of muscle cells is Blank_

cellular respiration

The most efficient method of obtaining ATP for the activity of muscle cells is Blank______.

cellular respiration

A painful, involuntary muscle spasm is called a

cramp

Strong painful muscle spasms that usually occur in the legs or feet are called

cramps

The function of myoglobin in muscle cells is to Blank_

deliver oxygen directly to mitochondria

A nerve fiber with all of the muscle fibers it innervates is called a unit.

motor

The medical term for aching muscles is

myalgia

The cells that make up muscle tissue are called

myocyte

The cells of all muscle tissues are called

myocytes

The long, cylindrical, contractile portions of a muscle fiber, which are composed of even smaller myofilaments, are called

myofibrils

Within each muscle fiber are hundreds or thousands of cylindrical structures that runs the entire length of the muscle fiber. These are called Blank______.

myofibrils

The striated appearance of skeletal muscle is due to the arrangement of Blank______.

myofilaments

Inside a skeletal muscle cell, a set of small cylinders called Blank______ are assembled into larger cylinders called Blank______.

myofilaments; myofibrils

The protein located in muscle cells that delivers oxygen directly to the mitochondria is Blank_

myoglobin

The protein located in muscle cells that delivers oxygen directly to the mitochondria is Blank______.

myoglobin

The main protein that is found in the thick filaments in the myofibrils is called .

myosin

What protein makes up a thick myofilament?

myosin

The region where the end of an axon from a neuron comes into close contact with a muscle fiber is called a junction.

neuromuscular

Muscle fibers that function for endurance and are highly resistant to fatigue are -twitch fibers.

slow

Which type of muscle tissue is located in the walls of blood vessels and hollow internal organs?

smooth

When a person is cold they may develop "goose bumps" due to contraction of the arrector pili muscles, which are Blank

smooth muscles that attach to hair follicles

The small gap between the membrane of an axon terminal and the sarcolemma of a muscle fiber is called a cleft.

synaptic

Fascia is a type of connective tissue that surrounds the muscle. What is it called when it extends beyond the muscle?

tendon

The neurotransmitter that is released at a neuromuscular junction is called

Acetylcholine

elect all of the following are proteins that are part of the thin filaments found in skeletal muscle myofibrils.

Actin Troponin Tropomyosin

The synaptic cleft of a neuromuscular junction is the space between which two structures?

Axon terminal Sarcolemma

What permits rapid passing of a contraction between cardiac muscle fibers?

Intercalated discs

What happens when calcium is released to permit muscle contraction?

A calcium-troponin complex allows tropomyosin to shift.

What is the definition of a motor unit?

A nerve fiber with all of the muscle fibers it innervates

Select all of the molecules involved in moving or stabilizing cross-bridges between actin and myosin during skeletal muscle contraction.

Calcium ATP

Select all correct descriptions of the thin filaments in a skeletal muscle fiber.

Contain tropomyosin and troponin Contain actin

What is the principle purpose of the muscular system?

Create movement

What is lacking in the muscles in a case of Duchenne muscular dystrophy?

Dystrophin

The sarcoplasmic reticulum of a muscle fiber is the Blank

Endoplasmic reticulum

What is the name for the bundles of skeletal muscle fibers in a whole muscle?

Fascicles

Select the three biochemical pathways that muscle cells can use to generate ATP.

Fermentation Cellular respiration Creatine phosphate pathway

What are bursae?

Fluid-filled sacs between tendon and bone

Select all of the following that occur during muscle contraction.

H band disappears I band shortens

What is the part of a sarcomere that contains only thin filaments?

I band

How does Duchenne muscular dystrophy affect muscle fibers?

Leaking of calcium causes fibers to dissolve.

Muscle cells are most likely to obtain their ATP by cellular respiration during what type of exercise?

Long, low intensity exertion

Select all of the functions of skeletal muscle.

Maintenance of constant body temperature Support Movement

Select all correct descriptions of fast-twitch muscle fibers.

Many fibers in motor units Usually anaerobic Helpful in sprinting or swinging a golf club

What is muscle tetanus?

Maximal sustained contraction of a muscle

What does the all-or-none law of muscle contraction state?

Muscle fibers will contract completely or not at all.

Which of these is an autoimmune disease that affects muscle contraction?

Myasthenia gravis

According to the sliding filament model, which of these events occur during muscle contraction?

Myosin filaments form cross bridges that pull on actin. Actin filaments are pulled toward the center of the sarcomere. Myosin filaments break down ATP.

The medical term for inflamed muscles is

Myositis

Select the three types of human muscle tissue.

Skeletal Cardiac Smooth

Select all the components of a neuromuscular junction.

Synaptic cleft Sarcolemma Axon terminal

In a skeletal muscle fiber, the sarcolemma forms tubules that penetrate into the cell and contact the sarcoplasmic reticulum.

T

What is a muscle fiber structure formed from the sarcolemma that penetrates into the cells?

T (transverse) tubules

Inflammation of a tendon caused by a sprain is called

Tendinitis

Which of these conditions is most likely to lead to bursitis?

Tendinitis

If a muscle is provided with a rapid series of threshold stimuli, the process of summation can lead to maximal sustained contraction called

Tetanus

What does the sliding filament model describe during muscle contraction?

The actin slides past the myosin.

Select all correct descriptions of Duchenne muscular dystrophy.

The most common type of muscular dystrophy Activates an enzyme that destroys muscle fibers Caused by a lack of dystrophin protein

Select the two types of myofilaments that make up the myofibrils of a skeletal muscle fiber.

Thin Thick

In a skeletal muscle fiber, what is the protein associated with an actin filament to which calcium ions bind?

Troponin

Select all of the body parts that contain smooth muscle.

Walls of hollow organs Blood vessels

Myasthenia gravis is an autoimmune disease that affects the muscles due to the production of antibodies that attack the

acetylcholine receptors

There are two types of myofilaments. Thin filaments primarily consist of two intertwining strands of a protein called

actin

What is the major protein in the myofilament that is composed of two intertwined strands?

actin

A muscle fiber will contract completely or not at all. This is known as the or principle.

all nothing

The muscular system is made up of Blank______.

all the muscles

Muscle fibers that fatigue quickly, are light in color, and contain little or no myoglobin are -twitch fibers.

fast

During muscle contraction, ATP can be generated by the creatine phosphate pathway, by cellular respiration, and by

fermentation

During muscle contraction, ATP can be generated by the creatine phosphate pathway, by cellular respiration, and by .

fermentation

Gap junctions between cardiac muscle cells that allow contractions to rapidly spread through the heart are called discs.

intercalated

The most common cause of myalgia, or aching muscles, is Blank

overuse or overstretching of the muscles

The sarcolemma of a muscle fiber is the Blank_

plasma membrane

The plasma membrane of a muscle fiber is called the Blank

sarcolemma

The plasma membrane of a muscle fiber is called the Blank______.

sarcolemma

Within a myofibril, the distance from one Z line to the next is called a(n) Blank__

sarcomere

A spasm of the muscle of the face is called a facial Blank

tic

During skeletal muscle contraction, what is the protein that moves to expose the binding sites on an actin filament?

tropomyosin

A muscle Blank______ is a single contraction of a motor unit.

twitch

A single contraction of a motor unit is called a muscle

twitch