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