Muscle Tissue

Introduction

Properties

Types

Unique Term of component of muscle cells

  • Consist of : Elongated cells call muscle fibers that can use ATP to generate force
  • Arrangement: Parallel array - work together effectively
  • Function: Body movements, posture maintenance, generates heat & for changes in size and shape of its internal organs
  • Characterized by aggregates of specialized cells whose primary role is contraction

Extensibility

  • Ability of muscle to stretch w/o being damaged

Elasticity

  • Ability of muscle to return to its original length and shape after contraction and extension

Contractibility

  • Ability of muscle to contract forcefully when stimulated

Electrical excitability

  • Ability to respond to certain stimuli (action potential)

Striated Muscles

Non-striated Muscle/Smooth Muscle

Muscle cells aka muscle fibers

Sarcoplasm= cytoplasm

Sarcoplasmic reticulum = SER

Sarcolemma = Cell membrane

Sarcosomes = Mitochondria

Alternative of light and dark cross-bands

Skeletal Muscle

Cardiac Muscle

Intercalated discs

Histology

  • Present only in the heart
  • Involuntary & striated
  • Shape: branched cylinders with one central nuclei
  • Attached to and communicate with each other by intercalated discs and desmosomes

Transverse portion

  • Bind cardiac cell together

Lateral portion

  • Ionic continuity between cells
  • Highly specialized end-to-end junctions
  • Junctional complexes at the interface between adjacent cardiac muscle cells

Myogenesis of skeletal muscle

Connective tissue surrounding skeletal muscle

Organization of muscle fibers

Functions

Histology

  • Voluntary/ conscious control and striated (visible light and dark banding)
  • Shape: Long cylinders with multinucleated peripheral nuclei
  • Skeletal movement
  • Posture and body position
  • Support of soft tissue
  • Guarding of entrances and exits
  • Maintenance of body temperature

Myoblast
(precursor/pendahulu)

Myotubes
(long multinucleated cells)

Myofibrils
(cytoplasmic & contractile elements)

Myofilaments
(protein responsible for contraction)

Histology

  • Location: Walls of hollow organs(blood vessels, GI tract, bladder)
  • Lack striations and involuntary (regulated by hormones, ANS &local)
  • Shape: Spindle with a single central nuclei, fusiform features
  • T tubules-absent
  • Bundles of myofilaments crisscross obliquely through the cell

Regeneration of muscle tissue