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