human anatomy chapter 10

Each myosin protein molecule in a thick filament consists of ______ strands. two four five three

2

When a muscle fiber contracts, which parts of the sarcomere maintain a constant length throughout contraction? H zone I band A band

A band

In a thin filament, individual G-actin molecules are strung together to form ______. H-actin troponin F-actin tropomyosin

F-actin

In each helical strand of F-actin, many small, spherical molecules are connected to form a long filament resembling a string of beads. Each spherical molecule is called ______. G-actin H-actin J-actin I-actin

G-actin

At maximal contraction of a muscle fiber, the thin filaments are pulled into the ______ zone which disappears. Z A I H

H

In a relaxed muscle fiber there are no thin filaments overlapping the thick filaments in the ______ zone. Z I A H

H

In a sarcomere, the ______ zone (or band) is the light, central region of the A band. Z M I H

H

The act of shivering is an example of skeletal muscle performing what function? Heat production Maintenance of posture Regulating elimination Protection and support

Heat production

The arrival of a nerve impulse at the synaptic knob of a motor neuron causes synaptic vesicles to release ______ into the synaptic cleft.

acetylcholine

The endomysium is composed of what type of connective tissue? dense elastic areolar dense collagenous adipose

areolar

The connective tissue layers in muscle provide protection, distribution sites for blood vessels and nerves, and a means of ______ to the skeleton. fusion detachment attachment

attachment

Match each function of skeletal muscle with its description.

body movement - muscles contract and pull on the tendons that attach the muscles to the bones posture - contraction of specific skeletal muscles stabilizes joints temperature regulation - heat is produced as a waste product of energy usage storage and movement of materials - voluntary sphincter muscles of the gastrointestinal and urinary tracts can be kept closed or opened

Functionally, troponin provides a binding site for ______ ions. sodium magnesium calcium chloride

calcium

A muscle fiber is what level of organization in the body? organ organ system molecular tissue cellular

cellular

The epimysium of a muscle is composed of ______ connective tissue. areolar dense regular dense irregular elastic

dense irregular

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

elasticity

In a muscle there are concentric layers of connective tissues. From deep to superficial these connective tissue layers are the ______, the ______, and the _______

endomysium perimysium epimysium

The three connective tissue layers surrounding the individual components of a muscle are the:_______,______ , and ______.

epimysium, perimysium, endomysium

In a transverse section of a muscle, you can see that each skeletal muscle is actually composed of many ________, which are bundles of muscle fibers.

fascicles

In a muscle, the perimysium surrounds ______ muscle cells. individual all fascicles of

fascicles of

A skeletal muscle cell is also called a muscle _______

fiber

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

into

Because muscle cells require a huge amount of ATP in order to contract, they have a large number of which organelle? ribosomes rough ER mitochondria lysosomes

mitochondria

Each muscle fiber is controlled by one ______ neuron. motor sensory interneuron association

motor

Neurons that stimulate muscle contraction are called ______ neurons. sensory association motor interneurons

motor

Skeletal muscle contraction is controlled by ________ neurons.

motor

Upon release from the synaptic knob, acetylcholine attaches to receptors on the ______. motor end plate synaptic vesicles synaptic knob sarcoplasmic reticulum

motor end plate

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

motor neuron

Match each muscle unit with the connective tissue layer that surrounds it.

muscle-epimysium fascicle-perimysium muscle cell-endomysium

The sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called ________ that extend the length of the cell.

myofibrils

Muscle fibers contain cylindrical structures called myofibrils, which are composed of ______. endomysium epimysium myofilaments sarcoplasmic reticulum

myofilaments

Myofibrils are made of ______. fascicles transverse tubules sarcoplasmic reticulum sarcolemma myofilaments

myofilaments

Myofibrils consist of bundles of short ______. fibroblasts myoglobins myofilaments transverse tubules

myofilaments

Myofibrils consist of bundles of short ______. transverse tubules myoglobins myofilaments fibroblasts

myofilaments

Muscle cells store oxygen bound to a ______ molecule?

myoglobin

Thick filaments are assembled from bundles of the protein called _______

myosin

Thick myofilaments are composed of bundles of ______ protein molecules.

myosin

Synaptic knob, motor end plate, and synaptic cleft are parts of a ______. muscle fiber neuromuscular junction motor neuron

neuromuscular junction

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

sarcomeres

Within a myofibril, Z discs separate the functional contractile units known as ______

sarcomeres

During the development of skeletal muscle cells, some myoblasts do not fuse and instead become ______ cells. chondrocyte Schwann satellite astrocyte

satellite

Attached to the skeleton and surrounding the openings of the urinary and gastrointestinal traces are locations of ______ muscle. cardiac smooth skeletal

skeletal

The _____ filament theory explains how muscle fibers shorten during contraction.

sliding

The attachment of ACh to the receptor on the motor end plate causes the receptor to open, allowing _______ ions to enter the muscle fiber.

sodium

The expanded tip of an axon is called a ______. neuromuscular junction sarcolemma synaptic knob

synaptic knob

A thick cordlike structure that attaches a muscle to a bone is called a(n) ______. tendon aponeurosis ligament

tendon

As a result of ACh stimulation, calcium ions are released from the ______ of the sarcoplasmic reticulum. mitochondria sarcoplasm terminal cisternae sarcolemma

terminal cisternae

The H band (or H zone) is more lightly shaded because only ______ thin filaments are present.

thick

in a sarcomere, the M line serves as an attachment site for the ______ filaments and keeps them aligned during contraction and relaxation. Z thin thick H

thick

in a sarcomere, the M line serves as an attachment site for the ______ filaments and keeps them aligned during contraction and relaxation. thick Z thin H

thick

In a muscle cell at rest, the myosin heads of a thick filament point ______ the sarcomere. toward the ends of toward the center of

toward the ends of

If the sarcoplasm of a muscle cell is flooded with calcium ions, to which protein will they bind? Multiple choice question. troponin myosin G actin tropomyosin

troponin

True or false: A single myofibril runs the length of the muscle fiber. True false question.TrueFalse

true

True or false: In the absence of calcium, troponin attaches to tropomyosin to hold it in place on the surface of the F actin strand. True False

true

Thick filaments are about ______ the diameter of thin filaments. four times equal two times three times

two times

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

Excitability

When viewed under a light microscope, the light bands, called ______ bands, contain only ______ filaments. I; thin A; thick A; thin I; thick

I; thin

The ______ line is a thin, transverse, protein meshwork structure in the center of the H zone of a sarcomere. M Z A I

M

Once started, a muscle impulse will travel along the sarcolemma and into the muscle fiber via the ______. sarcoplasmic reticulum sarcoplasm terminal cisternae T-tubules

T-tubules

The motor end plate has large numbers of ______ receptors. serotonin GABA acetylcholine

acetylcholine

Each myosin head in a thick filament can bind to the protein in a thin filament called ______

actin

Which of the following proteins are found in a thin filament? troponin actin elastin tropomyosin titin myosin

actin

The long tails of the myosin molecules in the thick filaments point toward the ______ of the filament. Multiple choice question. center start end head

center

Sarcoplasm is another term for skeletal muscle ______. cytoplasm organelles membranes

cytoplasm

Sarcoplasm is another term for skeletal muscle ______. organelles membranes cytoplasm

cytoplasm

In a muscle, the perimysium is composed of what type of connective tissue? adipose dense irregular dense regular areolar

dense irregular

Each myosin strand has a free ______ and an attached tail. titin midpiece neck head

head

What part of a myosin molecule does ATP bind to? tail middle neck head

head

In a motor unit, a single ______ neuron typically controls numerous muscle fibers in a muscle.

motor

While observing skeletal muscle tissue under the microscope you note that it appears striated. You tell your lab partner this is because ______. different organelles within muscle fibers take up stain differentially of alternating rough and smooth surfaces on the sarcolemma of the arrangement of myofilaments in each sarcomere

of the arrangement of myofilaments in each sarcomere

The connective tissue layer that surrounds each muscle fascicle is called ______. perimysium endomysium epimysium

perimysium

The endomysium contains ______ fibers to help bind together neighboring muscle fibers. elastic reticular hyaline osseous

reticular

An internal membrane complex in skeletal muscle cells that is similar to the smooth endoplasmic reticulum of other cells is called the sarcoplasmic _______

reticulum

The motor end plate is a specialized region of the ______. sarcolemma motor neuron sarcomere myofilament

sarcolemma

Match the name of the component of a muscle fiber with its description. Instructions

sarcolemma - plasma membrane of a muscle fiber muscle fiber - a muscle cell sarcoplasm - cytoplasm of a muscle fiber sarcoplasmic reticulum - smooth endoplasmic reticulum in a muscle fiber t-tubule - narrow tubular extensions of the sarcolemma into the sarcoplasm

Within a myofibril, each ______ shortens as the muscle fiber contracts. M line myofilament Z disc H zone sarcomere

sarcomere

If a skeletal muscle is injured, surrounding _______ cells may be stimulated to differentiate and assist in its repair and regeneration.

satellite

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

skeletal

A nerve impulse travels through an axon to its ______. axon hillock synaptic knob sarcoplasm dendritic zone

synaptic knob

A nerve impulse travels through an axon to its ______. sarcoplasm axon hillock dendritic zone synaptic knob

synaptic knob

The epimysium of a muscle surrounds ______. the individual muscle fibers each fascicle the entire skeletal muscle

the entire skeletal muscle