Basic tissue

• Four types of tissue:

  • Epithelium: covers body surfaces, forms glands, protects and supports the body and organs
  • Connective Tissue: transmission of nerve impulses
  • Nervous Tissue: movement
  • Muscle
• Functions of Epithelium:

  • Absorption of nutrients and ions (e.g. intestine)
  • Protection from mechanical abrasion, chemical injury, bacterial invasion (e.g. skin)
  • Sensory reception
  • Filtration
  • Secretion of enzymes, hormones, or mucous (e.g. gland)
• Epithelium is structurally and functionally divided into 2 types:

  1. Covering & Lining epithelium

  2. Glandular epithelium
• Classification of Covering Epithelium:

  • Number of cell layers: Simple, Stratified, Pseudostratified
  • Shape of cell: Squamous, Cuboidal, Columnar
  • Surface specialization: Cilia, Microvilli, Stereocilia
• Types of Covering Epithelium:

  • Simple: Squamous, Cuboidal, Columnar, Pseudostratified columnar ciliated epithelium
  • Stratified: Squamous, Cuboidal, Columnar, Transitional
  • Keratinized, Non-keratinized, Ciliated, Non-ciliated
• Cell Junctions:

  • Epithelial cells adhere strongly to neighboring cells and basal laminae
• Glandular Epithelium:

  • Epithelial cells are a major component of all glands
  • Classification based on number of cells, type of secretion, mode of secretion, duct/ductless, and shape
• Components of Connective Tissue:

  • Cells: Wandering and Fixed cells
  • Extracellular Matrix: Fibres (Collagen, Elastic, Reticular) and Ground substance (Proteoglycan, Glycosaminoglycans, Glycoproteins)
• Classification of Connective Tissue:

  • Embryonic CT, CT Proper, Specialized CT
  • Types include Mesenchymal CT, Mucous CT, Loose CT, Dense regular CT, Dense irregular CT, Adipose tissue, Reticular tissue, Cartilage, Bone, Blood
• Types of Muscle:

  • Smooth Muscle: nonstriated, involuntary
  • Skeletal Muscle: striated, voluntary
  • Cardiac Muscle: striated, involuntary
• Nervous Tissue:

  • Properties: Irritability, Conductivity
  • Constituents: Nerve cells/neurones, Nerve fibres, Neuroglial cells, Nerve endings
• Neurons:

  • Classified based on structure, length of fiber, type of neurotransmitter, function, and clinical aspect
  • Types include Myelinated, Non-myelinated, Unipolar, Bipolar, Multipolar, Type I, Type II
• Neuroglial Cells:

  • Astrocytes, Oligodendrocytes, Microglia, Ependymal cells
• Nerve Endings:

  • Sensory endings: receptors for general and special senses
  • Motor endings: terminal end plates on the surface of muscle fibres