Major muscles 1

Muscular System

There are four characteristics associated with muscle tissue:

Excitability - Tissue can receive & respond to stimulation

Contractility - Tissue can shorten & thicken

Extensibility - Tissue can lengthen

Elasticity - After contracting or lengthening, tissue always wants to return to its resting state

Functions

The characteristics of muscle tissue enable it to perform some important functions, including:

Movement – both voluntary & involuntary

Maintaining posture

Supporting soft tissues within body cavities

Maintaining body temperature

Functions

The Muscular System

Muscles are responsible for all types of body movement – they contract or shorten and are the machine of the body

Three basic muscle types are found in the body, what are they?

3 Types of Muscle

The human body is comprised of 324 muscles Muscle makes up 30-35% (in women) and 42-

47% (in men) of body mass

Cardiac

Smooth

Skeletal

Characteristics of Muscles

Muscle cells are elongated (muscle cell = muscle fiber)

Contraction of muscles is due to the movement of microfilaments

All muscles share some terminology· Prefix myo refers to muscle

· Prefix mys refers to muscle

· Prefix sarco refers to flesh

Anatomy of skeletal muscles

Skeletal muscle fiber (cell)

Muscle Fascicle

Surrounded by perimysium

Surrounded by endomysium

endomysium

perimysium

Skeletal muscle

Surrounded by epimysium

epimysium

tendon

Muscle Fascicle

Muscle fibre

Myofibril

Actin

Myosin

Major Muscles (anterior)





Rectus Femoris Actions: flex hip, extend knee (two joint muscle)

Vastus Lateralis Vastus Intermedius Action: extend knee (single joint muscle)Vastus Medialis

Rectus Femoris Origin – inferior pelvis Vastus Lateralis Vastus IntermediusVastus Medialis Origin – proximal femur



Pubic symphysis




Major Muscles (posterior)


Olecranon process



Medial Hamstrings

Lateral Hamstrings


Two Joint Muscle


One Joint Muscle


Education

Major muscles 1