Guangyuan Pan Period 2 Muscular System

Major function of muscular system

3 types of muscle & function

Skeletal muscles

Sarcomere

Neuromuscular junction

Sliding filament theory of muscle contraction

Action potential in a muscle fiber

Muscle Covering

Smooth

Cardiac

Skeletal

Movement of bones at joints, maintenance of posture

Movement of viscera, peristalsis

Pumping action of the heart

Skeletal muscle

Voluntary

Many nuclei

Well-developed transverse tubule system

lack of transverse tubules

Single nucleus

Wall of hollow viscera, blood vessels

Involuntary

Wall of the heart

single nucleus

Well-developed transverse tubule system; intercalated disc separating adjacent cells.

Incoluntary

Pectoralis major

Deltoid

Extensor digitorum

Biceps brachii

Sternocleidomastoid

External oblique

Large Size

Located in the chest

Shaped like a triangle

named for action

Extends digits

Has 2 origins/heads

found in the arm

attaches to sternum , clavicle, and mastoid process

Fingers, toes

I bands (light bands) aremade up of actin filaments, which are anchored to the Z lines

A bands (dark bands) are made up of overlapping thick and thin filaments

a sarcomereextends from one Z line to the next

in the center of the A band is the H zone, which consists of myosin filaments only

made up of many units called sarcomeres, joined end-to-end

the M line, in the center of the H zone, consists of proteins that hold the myosin filaments in place

located near outside of body

fibers run at a slant

Cell membrane of a muscle fiber is the sarcolemma

Cytoplasm of a muscle cell is the sarcoplasm; it contains many mitochondria and nuclei

Fibers respond to stimulation by contracting

Sarcoplasm contains parallel myofibrils, which are active in
muscle contraction

Each muscle fiber is a single, long, cylindrical muscle cell

Thick filaments in myofibrils consist of the protein myosin

Thin filaments in myofibrils are mainly composed of the protein
actin, but also contain troponinand tropomyosin

the neuron communicates with the muscle fiber by way of chemicals called neurotransmitters, which are released at the synapse

a synapse between a motor neuron and a muscle fiber that it regulates

contract only when stimulated by a motor neuron

myosin heads bind to actin, forming cross-bridges, connecting myosin to acting

the ADP and it releases from myosin and cross-bridge pulls the thin filament

from there the exposed binding sites on actin allow the muscle contraction cycle to start

the new ATP binds to myosin, breaking the connection to actin

muscle contraction releases calcium from the sarcoplasmic reticulum and it exposes binding sites on thin filaments

the ATP splits, which provides power the myosin heads and store energy for the next power stroke.

Prime mover

Pumping action of the heart

Synergist

Movement of viscera, peristalsis, vasoconstriction

Antagonist

Movement of bones at joints, maintenance of posture

the antagonist is the villain to the prime mover, they oppose all the actions from the prime mover

the synergist helps the prime movers and actually supports the prime mover

the prime mover is the function that does most of the work

Fascia

aponeuroses

epimysium

Fascicles

Endomysium

muscles are connected to each other by broad sheets of connective tissue

Layers of dense connective tissue that surround and separate each muscle

the layer of connective tissue around each skeletal muscle

it surrounds bundles of skeletal muscle fibers

Each muscle cell (fiber) is covered by a connective tissue layer