SEHS UNIT 1.2 - The Muscular System

General characteristics common to muscle tissue

contractility

extensibility

elasticity

atrophy

hypertrophy

controlled by nerve stimuli

fed by capillaries

Contractibility

Ability of a muscle to contract when stimulated by a neuron

Extensibility

Ability of muscle to be stretched beyond its resting length

Elasticity

Ability of muscle to return to its normal resting length after being stretched (Similar to a rubber band or spring)

Atrophy

Muscle mass loss due to inactivity

Hypertrophy

Muscle mass gain due to increased activity

Nerve control

Movement occurs based upon stimulation for the central nervous system

Fed by capillaries

Network of blood vessels delivering blood carrying nutrients, O2 and glucose to the muscles, and remove CO2.

Skeletal Muscle

Voluntary

Striated and

Multinucleated (Bicep brachii)

Cardiac Muscle

Involuntary,

Striated,

Branched, and

Uninucleated (Heart)

Smooth Muscle

Involuntary

nonstriated

tapered and

Uninucleated (Blood vessels)

Muscle Fiber

A single strand of muscle cell

Fascicle

A bundle of muscle fibers

Myofibril

Made of many sarcomere sub-units and is a strand which runs the length of a muscle fiber

Sarcomere

The smallest part of the muscle. Is the contractile unit which is made primarily of actin and myosin filaments

Actin

Thin Filaments that get pulled to the M line during contractions

Myosin

Thick filaments that are stationary during sarcomere contractions

Tendons

Connective tissue that connects muscles to bones

Endomysium

Inside the muscle. The layer surrounding a muscle fiber.

Perimysium

The layer surrounding a muscle fascicle

Epimysium

The outside layer on top of a muscle body

Origin

Where muscle attaches to a stationary bone, which does not move during contractions

Insertion

Where muscle attaches to a moving bone during contraction

Pectoralis Major

Pectoralis Minor

Biceps Brachii

Deltoid

Erector Spinae

Rectus Abdominis

External Obliques

Trapezius

Latissimus Dorsi

Hamstrings

Biceps femoris, semitendinosus, semimembranosus

Tibialis Anterior

Gastrocnemius

Soleus

Triceps Brachii

Gluteus Maximus

Sartious

Longest muscle in the body

Iliopsoas

Quadriceps

rectus femoris, vastus lateralis, vastus medialis, vastus intermedius