Muscular System - Science Olympiad

Excitability

Ability to receive and respond to stimuli

Contractibility

ability to shorten and thicken

Extensibility

ability to stretch

Elasticity

ability to return to its original shape after contraction or extension

Skeletal muscle

Attached to bone

Skeletal muscle

Move the whole body

Skeletal muscle

Muscle type that contains Multiple peripheral nuclei

Skeletal muscle

Control is voluntary in this type

Skeletal, cardiac

Muscle types that Have striations

Skeletal muscle

Cylindrical cell shape

Smooth muscle

Exists on hollow organs, glands, and blood vessels

Smooth muscle

Function is the compression of tubes and ducts

Smooth muscle

Muscle type that contains single, central nuclei

Smooth, cardiac

Control is involuntary in these two types

Smooth muscle

Has no striations

Smooth muscle

Spindle-shaped cells

Cardiac muscle

Type of muscle in the heart

Cardiac muscle

Function of this muscle type is heart contraction to propel blood

Cardiac muscle

Muscle type with central and single nuclei

Cardiac muscle

Muscle type with branched-shaped cells

Skeletal

___________________ muscles are responsible for all locomotion

Smooth

___________________ muscle helps maintain blood pressure, and squeezes or propels substances (i.e., food, feces)

through organs

Cardiac

_______________muscle is responsible for coursing the blood through the body

Skeletal, smooth

___________ and ____________ muscle cells are elongated and are called muscle fibers

Cardiac

_______________muscle is responsible for coursing the blood through the body

Skeletal, smooth

________________ and _____________ muscle cells are elongated and are called muscle fibers

Actin, myosin

Muscle contraction depends on these two kinds of myofilaments

Sarcolemma

Muscle contraction depends on two kinds of myofilaments

Sarcoplasm

Cytoplasm of a muscle cell

Myo, mys, sarco

______, ________ and _______ are prefixes that all refer to muscle.

650

Number of muscles attached to the skeleton

Pairs

Muscles work in ___________: one muscle moves the bone in one direction and the other moves it back again.

Joints

Muscle movement bends the skeleton at moveable ___________.

Tendons

Muscles are anchored firmly to bone by ___________.

Tendons

made of dense fibrous connective tissue shaped like

heavy cords.

Origin

Attachment to the more stationary bone by tendon closest to the body or muscle head or proximal is the ______________.

Insertion

attachment to the more moveable bone by tendon at the distal end is the_______________.

Injured

Though very strong and secure to muscle, tendons may be _____________.

Pull of contraction

The force producing the bending is always a ______ ___ _____________.

Muscle contractions

can be short, single contractions or longer ones.

Contracts, stretches

As one group of muscles _______________, the other ___________ and then they reverse actions

Muscle contractions

_________ ___________can be short, single contractions or longer ones.

Joints, bone

Muscles span ______ and are attached to ________ in at least two places

Movable, immovable

When muscles contract the __________ bone, the muscle's insertion moves toward the _________ bone -

the muscle's origin

Directly

When muscles attach _________ the epimysium of the muscle is fused to the periosteum of a bone

Indirectly

When muscles attach __________ the CT wrappings extend beyond the muscle as a tendon or aponeurosis

Nerve, artery, veins

Each muscle is served by one _________, an ________, and one or more __________.

Contraction

Each skeletal muscle fiber is supplied with a nerve ending that controls ______________.

Nerve ending

Each skeletal muscle fiber is supplied with a _______ __________ that controls contraction.

Oxygen, nutrients

Contracting fibers require continuous delivery of ________ and ___________ via arteries.

Veins

Wastes must be removed via ________.

Wastes

_________ must be removed via veins

Origin, insertion

Each muscle has thousands of muscle fibers in a bundle running from _______ to _________ bound together by connective tissue through which run blood vessels and nerves.

Muscle fibers

Each muscle has thousands of ______ _________ in a bundle running from origin to insertion bound together by connective tissue through which run blood vessels and nerves.

Blood vessels, nerves

Each muscle has thousands of muscle fibers in a bundle running from origin to insertion bound together by connective tissue through which run ________ _________ and _______.

Nuclei

Each muscle fiber contains many ________.

Endoplasmic reticulum, sarcoplasmic reticulum

Each muscle fiber contains an extensive __________ ____________ or _________ _____________.

Myofibrils

Each muscle fiber contains many thick and thin ____________ running lengthwise the entire length of the fiber.

Mitochondria

Each muscle fiber contains many ______________ for energy.

Epimysium, perimysium, endomysium

The three connective tissue wrappings are:

Epimysium

an overcoat of dense regular CT that surrounds the entire muscle

Perimysium

fibrous CT that surrounds groups of muscle fibers called fascicles

Endomysium

fine sheath of CT composed of reticular fibers surrounding each muscle

Sarcomere

The basic functional unit of the muscle fiber is the

myosin, actin

The sarcomere consists of thick filaments with __________ (protein) molecules and thin filaments with _________ (protein) molecules plus smaller amounts of troponin and tropomysin.

A, I

When viewed under the microscope, sarcomeres appear as striations of dark ___ bands and light ___ bands.

A, H

The ___ bands are bisected by the ___ zone with the M line or band running through the center of this zone.

I, Z

___ bands are bisected by the ___ disk or line.

Sarcomere

A _______________ consists of the array of thick and thin filaments between two Z disks.

Myosin head

In the thick filaments, myosin molecules contain a globular subunit, the __________ _______.

Myosin head

Has binding sites for the actin molecules of thin filaments and ATP.

Actin

Activating the muscle fiber causes the myosin

heads to bind to _______ molecules pulling the short filament a short distance past the thick filaments.

ATP energy

The linkages break and reform using ______ _________ further along the thick filaments.

shortening, thickening, folding

The linkages break and reform (using ATP energy) further along the thick filaments. Thus the thin filaments are pulled past the thick filaments in a ratchet-like action. No _________, __________ or _______ of individual filaments occurs.

Contracts, decrease

As the muscle _________, the width of the I bands and H zones ________ causing the Z disks to come closer together, but there is no change in the width of the A band because the thick filaments do not move.

Separate, apart

As the muscle relaxes or stretches, the width of the I bands ________ as the thin filaments move _____ but the thick filaments still do not move.

Motor unit

A _____ _____ is a motor neuron and all the muscle fibers it supplies.

Muscle fibers

The number of ______ _______ per motor unit can vary from four to several hundred.

Small

Muscles that control fine movements (fingers, eyes) have _______ motor units.

Large

Large weight-bearing muscles (thighs, hips) have _______ motor units.

Muscle fibers

________ ________ from a motor unit are spread throughout the muscle; therefore, contraction of a

single motor unit causes weak contraction of the entire muscle.

Cross bridge attachment

myosin cross bridge attaches to actin filament.

Working (power) stroke

myosin head pivots and pulls actin filament toward M line.

Cross bridge detachment

ATP attaches to myosin head and the cross bridge detaches

Cocking of myosin head

energy from hydrolysis of ATP cocks the myosin head into the high energy state.

Nerve ending

In order to contract, a skeletal muscle must Be stimulated by a _______ ________.

Sarcolemma

In order to contract, a skeletal muscle must Propagate an electrical current, or action potential, along its _____________.

Intracellular

In order to contract, a skeletal muscle must Have a rise in __________ Ca2+ levels, the final trigger for contraction.

Excitation-contraction coupling

Linking the electrical signal to the contraction is ____________-____________ _________.

somatic nervous system

Skeletal muscles are stimulated by motor neurons of the ____________ _________ ___________.

Axons

_________ of neurons travel in nerves to muscle cells.

Motor neurons

Axons of _______ _________ branch profusely as they enter muscles.

Neuromuscular junction

Each axonal branch forms a _____________ ________ with a single muscle fiber.

Muscle fatigue

Term for when the muscle is in a state of physiological inability to contract.

Production, use

Muscle fatigue occurs when ATP __________ fails to keep pace with ATP _____.

ATP

Muscle fatigue occurs when there is a relative deficit of _____, causing contractures.

Lactic acid

Muscle fatigue occurs when ________ ______ accumulates in the muscle.

Ionic

Muscle fatigue occurs when _______ imbalances are present.

Chemistry

Vigorous exercise causes dramatic changes in muscle ___________.

Oxygen

For a muscle to return to a resting state, ________ reserves must be replenished