Advanced Biology - muscle tissue

• Muscle tissue


  Composed of cells that have the special ability to shorten or contract in order to produce movement of the body parts
• Characteristics of muscle tissue


  • Excitability - Ability to respond to stimuli
  • Contractility - Ability to contract
  • Extensibility - Ability to be stretched without tearing
  • Elasticity - Ability to return to normal shape
• Functions of muscle tissue


  • Movement (both voluntary and involuntary)
  • Maintaining posture
  • Supporting soft tissue within body cavities
  • Guarding entrance and exits of the body
  • Maintaining body temperature
• Types of muscle tissue


  • Skeletal muscle tissue
  • Cardiac muscle tissue
  • Smooth muscle tissue
• Characteristic features of skeletal muscle tissue


  • Fibers are multi-nucleated
  • Actin and myosin filaments form distinct cross striations pattern
  • Muscle is surrounded by connective tissue epimysium
  • Each muscle fiber surrounded by connective tissue endomysium
  • Voluntary muscle under conscious control
• Characteristic features of smooth muscle tissue


  • Found in hollow organs and in blood vessels
  • Fibers are fusiform in shape and contain single nuclei
  • Each cell is filled with specialized cytoplasm called the sarcoplasm, and is surrounded by a thin cell membrane known as sarcolemma
• Characteristic features of cardiac muscle tissue


  • Located in the walls and septa of the heart and in the walls of the large vessels attached to the heart
  • Exhibits striations as a result of arrangement of actin and myosin fibers
  • Exhibits only or two central nuclei
  • Shorter and branched
• Connective tissue


  Type of animal tissue that is made up of cells, fibers and a gel-like substance
• Connective tissue


  • Supports, protects, and gives structure to other tissues and organs in the body
  • Stores fat
  • Helps move nutrients and other substances between tissues and organs
  • Helps repair damaged tissue
• Connective tissue


  • Connects body parts
  • Found everywhere in the body
  • Most abundant and widely distributed of the tissue types
• Components of connective tissue


  • Cells
  • Protein fibers
  • Ground substance
• Wandering/migrant cells


  Cells found in connective tissue that are not fixed in place, usually referring to blood leukocytes
• Types of connective tissue


  • Loose connective tissue
  • Dense connective tissue
  • Specialized connective tissue
• Loose connective tissue


  Holds and binds organs together, characterized by loose, multidirectional weave of extracellular fibers and cells loosely separated in the rich extracellular matrix
• Loose connective tissue


  • Most common type in humans and other vertebrates
  • Holds or binds biological organs together
  • Binds epithelial tissue to adjacent tissues
  • Surrounds blood vessels and nerves
  • Site of fluid and gas exchange between blood and adjacent tissues
• Types of loose connective tissue


  • Areolar connective tissue
  • Reticular connective tissue
• Dense connective tissue


  Also called dense fibrous tissue, due to relative abundance of collagen fibers as the main matrix element, mainly composed of type I collagen
• Specialized connective tissue


  Encompasses a number of different tissues with specialized cells and unique ground substances, some solid and strong, others fluid and flexible
• Examples of specialized connective tissue


  • Adipose tissue
  • Cartilage
  • Bone
  • Blood
  • Lymph
• Adipose connective tissue


  Connective tissue consisting mainly of fat cells (adipocytes), specialized to synthesize and contain large globules of fat, within a structural network of fibers