MUSCULAR SYSTEM

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Contractility

Contractility

Unique function of muscle wherein it has the ability to move which is an essential activity of the living human body.

Responsible for all body movement

Muscles

Attached to the bones of the skeleton

Skeletal muscles

__________ is an skeletal muscle because under a microscope they show crossbandings of alternating light and dark bands running perpendicular to the length of the muscle

Striped or striated

name given to a band of connective tissue that envelops, separates, or binds muscles or groups of muscle

Fascia

A sheath of dense, irregular connective tissue wrapping each muscle. Allows a muscle to contract and move powerfully while maintaining its structural integrity

Epimysium

A middle layer of connective tissue covering each fascicles (muscle fibers organized into bundles)

Perimysium

A thin connective tissue layer of collagen and reticular fibers covering each muscle fiber

Endomysium

Plays a role in transferring force produced by the muscle fibers to the tendons

Endomysium

allows for production of the large amounts of proteins and enzymes needed for maintaining its normal function

Multiple nuclei

specialized smooth endoplasmic reticulum stores, releases, and retrieves calcium ions

sarcoplasmic reticulum

The plasma membrane of muscle fibers

Sarcolemma

Proteins that run the length of the cell and contain sarcomeres connected in series

Myofibrils

The smallest functional unit of a skeletal muscle fiber

Sarcomere

Defined as the region of a myofibril contained between two cytoskeleton structures called

Z-doscs

Composed of the myosin, which span the center of the sarcomere extending toward the Z-discs

A band

Where the thick filaments are anchored at the middle of the sarcomere

M-line

Light region contain thin actin filaments anchored at the Z-discs

I band

In the middle of the A band is a little lighter, because the thin filaments do not extend into this region.

Hone

Composed of two filamentous actin chains wherein its associated with the regulatory proteins, troponin and tropomyosin

Thin filaments

Contains a myosin binding site

Globular actin monomer

Thick myofilaments

Composed of myosin protein complexes. Its globular head contains an actin-binding site and a binding site for the high energy molecule ATP

Titin

A large protein anchored at the M-line; helps align the thick filament and adds an elastic element to the sarcomere

The moveable end of the muscle that attaches to the bone being pulled

Insertion

The end of the muscle attached to a fixed (stabilized) bone

Origin

The principal muscle involved among a number of muscles involved in an action

Prime mover

A muscle with the opposite action of the prime mover

Antagonist

helps steady movement or stabilize joint activity; muscle that assists the prime mover

Synergists

Also called visceral muscle; cells are small and spindle shaped, there is only one nucleus, located at the center of the cell

smooth muscles

Found only in the heart

Cardiac muscles

The membranes of adjacent cells are fused at places called

Intercalated discs

Special circular muscles in the openings between the esophagus and stomach, and the stomach and small intestine

Sphincter muscles or dilator muscles

Attached to the skeleton and also located in the wall of the pharynx and esophagus

Location of skeletal muscle

Have long, cylindrical, and multinucleated, and contains alternating light and dark striations. Nuclei located at edge of fiber

Structure of skeletal muscle

Contractions occur voluntarily and may be rapid and forceful. Contractions stabilize the joints

Function of skeletal muscle

Located in the walls of tubular structures and hollow organs such as in the digestive tract, urinary bladder, and blood vessels

Location of Smooth muscle

Long and spindle shaped, with no striations

Structure of Smooth muscle

Contractions occur involuntarily and are rhythmic and slow

Function of smooth muscle

Located in the heart

Location of cardiac muscle

Short, branching fibers with a centrally located nucleus; striations not distinct

Structure of cardiac muscle

Contractions occur involuntarily and are rhythmic and automatic

Function of cardiac muscle

Which is the ability of the cells to shorten and generate force

Contractility

Can change their electrical states and send an action potential along the entire length of the plasma membrane

Excitability or irritability

Ability to stretch and extend beyond the resting length of the cells

Extensibility

Allows muscle to recoil back to its original length

Elasticity

Name basis of Frontalis

Location (forehead)

Name basis of gluteus maximus

Size (largest muscle in buttock)

Name basis of External abdominal oblique

Direction of fibers (edge of the lower rib cage)

Name basis of Biceps

Number of origins (two-headed muscles in humerus)

Name basis of Sternocleidomastoid

Location of origin and insertion (origin in sternum and clavicle; insertion is the mastoid process of the temporal bone)

Name basis of Flexor carpi ulnaris

Action flexor (flexes the wrist)

Name basis of Extensor carpi ulnaris

Extensor (extends the wrist)

Name basis of Depressor anguli oris

Depressor

To; toward

Ad

Away from

Ab

Under

Sub

Something that moves

Ductor

Against

Anti

On top of

Epi

To the side of

Apo

Longest

Longissimus

Long

Longus

Short

Brevis

Large

Maximus

Medium

Medius

Tiny, little

Minimus

Straight

Rectus

One

Uni

Two

Bi/di

Three

Tri

Four

Quad

Outside

Externus

Inside

Internus

largest

Maximus/magnus

Smallest

Minimus

Intermediate in size

Medius

Larger

Major

Smaller

Minor

Shortest

Brevis

Longest

Longus

Great or huge

Vastus

Shaped like a deltoid

Trapezius

Refers to triangular shaped muscle that sits on top of the shoulder

Deltoid

root word is “serrare,” which means saw

Serratus