Chapter 7 Muscular System (connect)

Endomysium

Blood capillaries and nerve fibers reach each muscle fiber by way of the ___

skeletal muscle characteristics

Has multinucleated fibers, voluntary, striated, support the body, help stabilize joints, make the body parts move, help maintain a constant body temperature

Mitochondria

If oxygen is avaliable, the ___ in a muscle cell can use glucose and fatty acids to produce ATP

atrophy

The condition that occurs when muscle fibers are gradually replaced by fat and fibrous tissue is known as

ATP, actin

The myosin head contains two binding sites for:

motor units

The strength of muscle contraction depends on the recruitment of ____

circular muscle

The term orbicularis means

physical exercise enhances immunity, moves lymph

What homeostatic effect does the muscular system have on our lymphatic system and immunity?

muscle contraction provides heat and moves the skin of the face

What homeostatic effect does the muscular system have on the integument?

muscle contraction causes bones to move

What homeostatic effect does the muscular system have on the skeleton?

creatine phosphate

What is the name of a high energy phosphate molecule that is stored in cells and can be used to re-synthesize ATP immediately?

stores oxygen for the muscles

What is the role of myoglobin during skeletal muscle contraction?

Origin; insertion

When a muscle contracts at a joint, one bone remains fairly stationary, and the other one moves. The ____ of a muscle is on the stationary bone, and the ____ of a muscle is on the bone that moves.

oxygen debt

When a muscle fiber depletes its stores of creatine phosphate and has a high level of lactic acid, it incurs a(an)

fatigue

When a muscle relaxes even though stimulation continues, this is known as

synergist

When flexing the elbow, the brachialis acts as the prime mover. The biceps brachii act as a ___ to the brachialis

myosin molecules form temporary links with actin, myosin filaments break down ATP to use for contraction, actin filaments slide over myosin filaments

Which of the following events describes the sliding filament theory of muscle contraction?

epimysium

collagen fibers of the ___ continue as a strong, fibrous tendon that attaches the muscle to a bone

perimysium

connective tissue layer that covers a group of muscle fibers (fascicles)

endomysium

connective tissue layer that covers individual muscle fibers

epimysium

connective tissue layer that covers the muscle itself

H zone

containes only myosin

I band

contains only actin

acetylcholine

during muscle contraction, the neurotransmitter _____ is released from the synaptic vesicles into the synaptic cleft

motor neurons

effectors such as skeletal muscles are stimulated to contract by what type of neuron?

cardiac muscle characteristics

forms the heart wall, has striations, has rhythmical contraction

vastus

huge

1 axon per 23 muscle fibers

in the eye, the innervation ratio of motor axon to muscle fibers is

synaptic vesicles

acetylcholine is stored in ____, found in the axon terminals of motor neurons

Intermediate twitch fibers

aerobic cellular respiration

slow twitch fibers

aerobic cellular respiration

T tubule

after the muscle is activated by a motor neuron, the signal travels down a ___ __

fast twitch

anaerobic cellular respiration

muscle fiber

another name for a muscle cell is a ____

maximus

largest

longus

long

cell; respiration; fermentation

muscle cells can make new ATP by creatine phosphate breakdown, ___ , ___ , and ___

relaxation and contraction

muscle cells use ATP for

oxygen

myoglobin has the ability to temporarily store ___ to be used in cellular respiration

axon terminals

part of a motor neuron that connects to a muscle fiber forming a neuromuscular junction

Sarcolemma

plasma membrane

sarcomeres

repeating units within myofibrils that act as the functional units of muscle contraction and are responsible for striations, (provides skeletal muscle with its striations and is the region between two seccessive Z lines)

teres

round

minimus

small

dense bodies

smooth muscle fibers contain protein molecules called ___ ___ scattered throughout the sarcoplasm that helps the thin filaments produce a shortening of the cell

actin

the binding site for myosin is found

fiber

the contractile cell of muscle is elongated and is a muscle ___

Sarcoplasm

the cytoplasm

myoglobin

the molecule in the sarcoplasm that binds oxygen is ___

actin (thin); myosin (thick)

the muscle fiber contracts as a result of linkages formed between the ___ and ___ filaments, which allos them to slide past each other

synergist

the muscle of a group that assists

prime mover

the muscle of a group that does most of the work

actin, ATP

the mysosin head contains two binding sites for__

Sarcoplasmic reticulum

the network of membranous channels that surrounds each myofibril and is a storage site for calcium ions

axon; sarcolemma

the neuromuscular junction is a connection between the ____ of a motor neuron and the ___ of a muscle fiber

myofilaments

thick and thin filaments whose structure and functions account for muscle striations and contractions

sarcomere

this structure provides skeletal muscle with its striations and is the region between two successive Z lines.

threshold

As long as a stimulus is above its, a muscle fiber will contract with the same amount of force each time. This is known as the all-or-none law.

myoglobin

The reddish-brown pigment that combines loosely with oxygen within muscle cells is called

fatigue

A build up of lactic acid and lowered levels of ATP and acetylcholine can cause muscle:

a nerve fiber and all the muscle fibers in innervates

A motor unit is made up of:

creatine phosphate breakdown, fermentation, cellular respiration

ATP, required for muscle contraction, is generated by...

fermentation

An anaerobic process by which glucose is broken down to lactate (lactic acid) is called

recruitment

As the intensity of nervous stimulation increases, more and more motor units are activated. This is known as:

intercalated disks

Branching cardiac muscle fibers are connected by ___, which contain gap junctions and adhesion junctions

ATP

Creatine phosphate cannot participate directly in muscle contraction but it can regenerate ___ by transferring its phosphate to ADP.

muscle tone

Even when a muscle appears to be at rest, some of the muscle fibers are always contracting. This is known as:

sarcoplasm, does not

Fermentation occurs in the _____, and _____ require oxygen.

summation

In _____, a muscle is given repeated stimuli that allows the force of the contraction to increase.

dense bodies

In smooth muscle fibers, the thick filaments do not attach to the thin filaments to produce shortening of the fiber. Instead, the thin filaments are anchored directly to the sarcolemma or to protein molecules called:

actin, myosin

In the sliding filament theory of muscle contraction, ____ filaments slide over _____ filaments.

smooth muscle characteristics

Located in the wall of hollow organs, does not fatigue easily, located in blood vessels, has a single nucleus in each muscle fiber

cellular respiration

Most of the ATP needed for muscle contraction is produced during

slow

Muscle fibers that are dark in color, are slow to develop maximum tension, and are resistant to fatigue are ___ twitch fibers

intermediate

Muscle fibers that have an abundant blood supply, many myoglobin molecules and mitochondria, and are adapted for exercises like walking, jogging and biking, are known as ___ twitch fibers

posture

Muscle tone is important in the ability to maintain _____.

lactic acid; creatine phosphate

Oxygen debt refers to a high level of ______, and low levels of ______.

Heat

Skeletal muscle contraction causes ATP to break down, releasing ____ that is distributed about the body

maintenance of blood pressure, movement of lymph in lymphatic vessels, absorption of nutrients, the movement of food through the digestive tract, the act of breathing

The muscular system works with other systems of the body to maintain homeostasis. Which of the following relates to how the muscular system is used to help maintain homeostasis?

insertion

The attachment of a muscle onto the bone that is being moved is called the

antagonist

The action of the biceps brachii is to flex the elbow, and the action of the triceps brachii is to extend the elbow. Therefore, the triceps are considered ___ to the biceps

all-or-nothing law

The law that states a muscle fiber contracts completely or not at all, with the same amount of force regardless of the strength of the stimulus, as long as the threshold is reached, is the

smaller (1 axon per 20 muscle fibers)

The more precise control that is needed to perform a motor movement requires a _____ motor unit.

Neuron; muscle fiber

The neuromuscular junction is composed of the junction between a ____ and a ____

motor units

When picking up an unknown object, it may be difficult at first since you don't know how heavy it is. Eventually you can lift it up, due to a process called recruitment, during which more and more ___ ___ are activated resulting in stronger and stronger muscle contractions

pull; push

When skeletal muscles contract they can only ___, they cannot ____

abundance of myoglobin, abundance of mitochondria, resistant to fatigue

Which of the following characterize slow-twitch fibers?

levator scapulae

Which of the following muscles is named according to its action?

active transport of Ca ++ back into sarcoplasmic reticulum, break the link between actin and myosin, energize myosin

Which of the following roles does ATP have in muscle contraction and relaxation?

active transport of Ca ++ back into the sarcoplasmic reticulum, break the link between actin and myosin, energize myosin

Which of the following roles does ATP have in muscle contraction and relaxation?

the mechanical force of a whole muscle contraction

a myogram measures

motor unit

a nerve fiber and all the muscle fibers it innervates is called a ___

mitochondria; decreases

With age, degenerative changes take place in the muscle fiber ____, and endurance ____.

cellular respiration

___ ___ completed in a mitochondrion provides most of the muscle's ATP

creatine phosphate

___ ___ is an organic compound that transfers a high energy phosphate for the production of ATP

sarcoplasmic reticulum

calcium for muscle contraction is stored in the ___

tetanic

summation can occur until a miximum sustained contraction occurs, called a ___ contraction

origin

the ___ of a muscle is on the stationary bone, or its immovable end

Myofibril

the part of the muscle fiber that contracts consists of a bundle of myofilaments

sarcolemma

the plasma membrane of a muscle fiber

transverse (T) tubule

the sarcolemma penetrates deep into the muscle fiber by forming a ___

the myosin head

the structure that contains binding sites for ATP and actin

cross bridge

the temporary connection between actin and the myosin head is called a ___

myosin, tropomyosin, troponin, actin

the thick and thin myofilaments are made up of the proteins

myosin

the thick myofilament is made up of the protein___ (shaped like a golf club)

deltoid

triangle

troponin

when Ca 2+ is released from the sarcoplasmic reticulum and binds to ___ , it exposes the myosin binding sites on actin molecules

tropomyosin

when a muscle is relaxed, the protein that winds around actin filaments and covers up the binding site for myosin

power stroke

when the myosin head binds to actin, it releases ADP and P and the myosin head bends toward the middle of the sarcomere. This action is called the ___ ___ and it pulls the filaments towards the middle of the sarcomere

A band

which area of a sarcomere contains both actin and myosin

latissimus

wide