Histology Notes

Epithelial Tissue

  • Simple squamous epithelium:

    • Location: Alveoli of lungs, walls of capillaries

    • Function: Allows passage of materials in non-protective areas

  • Stratified squamous epithelium (Keratinized):

    • Location: Dermis of skin, Hair, nails

    • Function: Protection of underlying tissues subjected to abrasion

  • Stratified squamous epithelium (non-keratinized):

    • Location: Lining of mouth, vagina, and esophagus

    • Function: Protection of underlying tissues subjected to abrasion

  • Pseudostratified ciliated columnar epithelium:

    • Location: Lining of nasal cavities and respiratory tree (ciliated), Male carrying ducts (nonciliated)

    • Function: Secretion of mucus, propulsion of mucus by ciliated form

  • Simple columnar epithelium:

    • Location: Lining of digestive tract, gall bladder

    • Function: Absorption, secretion of mucus, enzymes; ciliated type propels mucus

  • Simple cuboidal epithelium:

    • Location: Kidney tubules

    • Function: Secretion and absorption

  • Transitional epithelium:

    • Location: Lining of urinary bladder and ureters

    • Function: Stretches readily and permits distension of urinary organ containing urine.

Connective Tissue

  • Hyaline cartilage:

    • Location: Articular cartilage, apex of nose, costal cartilage, larynx and bronchi

    • Function: Supports and reinforces and resists compressive stress

  • Elastic cartilage:

    • Location: Skeleton of ear and epiglottis

    • Function: Allows recoil of tissue following stretching, maintains arterial pulsation, recoil following inspiration

  • Fibrocartilage:

    • Location: Invertebral disc and pubic symphysis

    • Function: Absorbs compressive shock

  • Bone:

    • Location: Skeleton

    • Function: Support, storage of minerals and blood production

  • Blood:

    • Location: Throughout the body

    • Function: Distributes nutrients and gasses throughout the body and returns wastes to points

  • Areolar connective tissue:

    • Location: Hypodermis, wrap organs and blood vessels

    • Function: Wraps and cushions organs, contains macrophages that consume bacteria in inflammation, holds and conveys tissue fluid

  • Reticular connective tissue:

    • Location: Lymph nodes, spleen, and red bone marrow

    • Function: Fibers form a soft skeletal structure that holds macrophages, mast cells, and blood cells

  • Adipose connective tissue:

    • Location: Hypodermis, surround organs

    • Function: Provides energy reserve (fat), insulates and protects organs

  • Dense regular collagenous connective tissue:

    • Location: Tendons and ligaments

    • Function: Attach muscle to bone (tendons) and bone to bone (ligaments)

  • Dense irregular collagenous connective tissue:

    • Location: Dermis, periosteum, and form capsules around certain organs

    • Function: Provides structural strength in areas where tension pulls in many directions

Muscle Tissue

  • Skeletal Muscle:

    • Location: Attached to bone and tendons

    • Function: Movement of the body

  • Cardiac muscle:

    • Location: Heart

    • Function: Pump blood throughout the body

  • Smooth muscle:

    • Location: Makes up walls of most organs

    • Function: Moves materials through the body slowly as in digestion

Nerve Tissue

  • Nerve tissue:

    • Location: Brain, spinal and peripheral nerves

    • Function: Transmit electrical signals to the brain from all areas and returns signal