Ch 10 : Muscle Tissue

Muscle tissue is classified into three types: skeletal, cardiac, and smooth, each of which has unique functions and characteristics that are essential for movement and physiological processes.

• Primary function of muscle is to change chemical energy into mechanical energy to produce movement

• Three types of muscular tissue (Review Chapter 4)

  • Skeletal muscle tissue – striated, under voluntary control, and moves bones of skeleton

  • Cardiac muscle tissue – striated, under involuntary control, and pumps blood with auto rhythmicity in heart only

  • Smooth muscle tissue – non-striated, under involuntary control, and moves substances in hollow internal organs

Functions of Muscle Tissue

• Produces body movements (walking, running etc.)

  • Integrated function of skeletal muscles with bones and joints

• Stabilizes body positions (Standing up right, sitting etc.)

  • Skeletal muscle contractions without movement

• Moves substances within the body

  • All three kinds of muscles as part of different organ systems

• Generates heat

  • Involuntary shivering of skeletal muscle helps maintain temperature homeostasis

Special Properties of Muscle Tissue

• Electrical excitability 

  • Produce electrical action potentials (impulses) in response to certain stimuli

  • a property of both neurons and muscle cells

• Contractility

  • Ability to shorten forcefully when stimulated (by AP), generating tension (ex. Lifting a book off a table)

• Extensibility

  • Ability to stretch within limits without being damaged

  • Ex. (Stomach filling with food)

• Elasticity

  • Ability to return to original length after contraction or extension

Skeletal Muscle as an Organ

• Organ level of organization

  • Different types of tissues function together

• Skeletal muscle tissue

  • Individual cells are called muscle fibers

  • Each skeletal muscle organ composed of hundreds to thousands of muscle fibers

• Connective tissue

  • Surrounds and protects skeletal muscle tissue

• Nerve and blood supply

  • Organ is well supplied with nerves and blood vessels

    

Connective Tissue of Organ

• Hypodermis 

  • Areolar and adipose tissue

  • Separates muscle from skin, insulates and protects  

• Fascia

  • Dense connective tissue sheet

  • Unites muscles with similar functions, carries nerves and vessels, and fills spaces between muscles

• Three layers of connective tissue in organ (Epimysium, Perimysium, Endomysium)

  • Protect and strengthen skeletal muscle fibers

• Tendon or aponeurosis

  • Rope-like or broad flat extension of connective tissue beyond muscle fibers for attachment of muscle organ