The Muscular System

General Muscle Functions

• Muscular tissue enables the body and its parts to move or to move things

• Movement caused by the ability of muscle fibers to contract

• Muscle fibers are elastic – have memory

• Muscle cells shorten by converting chemical energy into mechanical energy, which causes movement

• Poor ability to repair itself

Types• Three Types of

Muscle Tissue• Classified according

to– Voluntary or

Involuntary– Striated or non-

striated– Appearance

• Continuous Cylinders• Branching• Smooth Sheets

• Skeletal• Cardiac• Smooth

A. Skeletal • Basic Movement• Threadlike /

Cylindrical• Striated

– Microscopic Stripes

• Voluntary – You Control Contractions

– Speed– Rate– Intensity

• 40% to 50% of body weight – Red Meat

B. Cardiac • Branching cylinders that reconnect

• Controls Heart Rate – Heart Pumping / Squeezing

• Involuntary– Controlled by Brain /

Hormones• Characterized by unique

dark bands called intercalated disks

– Interconnected nature of cardiac muscle cells allows heart to contract efficiently as a unit

C. Smooth or Visceral

• Smooth Sheet-like / Cells taper

• Found in walls of hollow organs (Visceral)

– Digestive Tract– Blood Vessels– Bladder

• Lacks cross stripes or striations when seen under a microscope

– Appears Smooth– Involuntary

• Moves substances through body

– Controlled by brain / hormones / nerves