• U-shaped bone
• Body
• Greater horn
• Lesser horn

• Suspended by ligaments from the styloid process

The Nasal Mucosa

• Mucosa lines the entire nasal cavities except for the vestibule of the nose.
• The nasal mucosa is firmly bound to the periosteum and perichondrium of the supporting structures of the nose.
• It is continuous with the adjoining cavities to which the nasal cavity communicates (e.g., the nasopharynx and paranasal sinuses).

• The inferior 2/3 of the nasal mucosa is called the respiratory area and air passing over this is warmed and moistened before it passes into the lungs.
• The superior 1/3 is called the olfactory area.

The Olfactory Area of Nasal Mucosa

• This area contains the peripheral organ of smell.
• Sniffing draws air into this area
• Olfactory receptor cells (from the olfactory nerve, CN I, are located in the mucosa of this area in the nose.

Nerves to the Respiratory Area of Nasal Mucosa

• The inferior 2/3 of the nasal mucosa are supplied chiefly by the trigeminal nerve (CN V).

• The mucous membrane of the nasal septum is supplied chiefly by the nasopalatine nerve, a branch of the maxillary nerve (CN V²).
• Its anterior portion is supplied by the anterior ethmoidal nerve (a branch of the nasociliary nerve) which is derived from the ophthalmic nerve (CN V¹).

• The lateral walls of the nasal cavity are supplied by branches of the maxillary nerve (CN V²); the greater palatine nerve, and the anterior ethmoidal nerve.

Arteries of the Nasal Mucosa

• The blood supply of the mucosa of the nasal septum is derived mainly from the maxillary artery.

• The sphenopalatine artery, a branch of the maxillary, supplies most of the blood of the nasal mucosa.
• It enters by the sphenopalatine foramen and sends branches to the posterior regions of the lateral wall and to the nasal septum.

• The greater palatine artery, also a branch of the maxillary, passes through the incisive foramen to supply the nasal septum.

• The anterior and posterior ethmoidal arteries, branches of the ophthalmic artery, supply the anterosuperior part of the mucosa of the lateral wall of the nasal cavity and nasal septum.

• Three branches of the facial artery (superior labial, ascending palatine, and lateral nasal) also supply the anterior parts of the nasal mucosa.

Veins of the Nasal Mucosa

• The veins of the nasal mucosa form a venous network of plexus in the connective tissue of the nasal mucosa.
• Some of the veins open into the sphenopalatine vein and drain to the pterygoid plexus.
• Others join the facial and infraorbital veins.
• Some empty into the ophthalmic veins and drain into the cavernous sinus.

• Ossification

• Intramembranous-found in the flat bones of the face
  • Mesenchymal cells cluster and form strands
  • Strands are cemented in a uniform network. Which is known as osteoid
  • Calcium salts are deposited; osteoid is converted to bone
  • Trabeculae are formed and make cancellous bone with open spaces known as marrow cavities
  • Periosteum forms on the inner and outer surfaces of the ossification centers
  • Surface bone becomes compact bone
• Endochondral-primary type of ossification In the human

• The palate has a rich blood supply from branches of the maxillary artery.

Gross anatomy-study of structures that can be identified with the naked eye; usually involves the use of cadavers

• Microscopic anatomy (histology)-study of cells that compose tissues and organs; involves the use of a microscope to study the details of the species
• Developmental anatomy (embryology)-study of an individual from beginning as a single cell to birth
• Comparative anatomy -comparative study of the animal structure in regard to similar organs or regions

EPITHELIUMS

Epithelial Tissue Epithelial tissue covers surfaces, usually has a basement membrane, has little extracellular material, and has no blood vessels. A basement membrane attaches the epithelial cells to underlying tissues. Most epithelia have a free surface, which is not in contact with other cells. Epithelia are classified according to the number of cell layers and the shape of the cells.

• Epitheliums contain no blood vessels.  There is normally an underlying layer of connective tissue
• Almost all epitheliums lie on a basement membrane.The basement membrane consists of  a basal lamina and  reticular lamina. The reticular lamina is connected to the basal lamina by anchoring fibrils. The reticular lamina may be absent in which case the basement membrane consist only of a basal lamina. The basal lamina consists of a   - lamina densa in the middle (physical barrier) with a lamina lucida on both sides (+charge barrier),The basement membrane is absent in ependymal cells.The basement membrane is not continuous in sinusoidal capillaries.

• Epitheliums always line or cover something
• Epithelial cells lie close together with little intercellular space
• Epithelial cells are strongly connected to one another especially those epitheliums that are subjected to mechanical forces.  

Functions of Epithelium:

→ Simple epithelium involved with diffusion, filtration, secretion, or absorption

→ Stratified epithelium protects from abrasion

→ Squamous cells function in diffusion or filtration