Geniohyoid Muscle

• Origin: Inferior genial tubercles of the mandible.
• Insertion: Anterior surface of the body of the hyoid bone.
• Nerve Supply: Branch of C1 through the hypoglossal nerve (CN XII).
• Arterial Supply: Sublingual branch of the lingual artery.
• Action: Elevates the hyoid bone and depresses the mandible.

The Auditory Tube

• This is a funnel-shaped tube connecting the nasopharynx to the tympanic cavity.

• Its wide end is towards the nasopharynx, where it opens posterior to the inferior meatus of the nasal cavity.
• The auditory tube is 3.5 to 4 cm long; its posterior 1/3 is bony and the other 2/3 is cartilaginous.
• It bony part lies in a groove on the inferior aspect of the base of the skull, between the petrous part of the temporal bone and the greater wing of the sphenoid bone.

• The function of the auditory tube is to equalise pressure of the middle ear with atmospheric pressure.

Sternum

o    Forms the medial part of the anterior chest wall
o    Manubrium (upper part)-clavicle and first rib articulate with the manubrium .
o    Body (middle blade)-second and tenth ribs articulate with the body via the costal cartilages
o    Xiphoid (blunt cartilaginous tip)

Ribs (12 pairs)

o    Each rib articulates with both the body and the transverse process of its corresponding
o    thoracic vertebra
o    The second to ninth ribs articulate with the body of the vertebra above'
o    Ribs curve outward, forward, and then downward
o    Anteriorly, each of the first seven ribs joins a costal cartilage that attaches to the sternum
o    Next three ribs (eighth to tenth) join the cartilage of the rib above
o    Eleventh and twelfth ribs do not attach to the sternum; are called "floating ribs"

Innervation of the Pharynx

• The motor and most of the sensory supply of the pharynx is derived from the pharyngeal plexus of nerves on the surface of the pharynx.
• The plexus is formed by pharyngeal branches of the vagus (CN X) and glossopharyngeal (CN IX) nerves, and by sympathetic branches for the superior cervical ganglion.

• The motor fibres in the pharyngeal plexus are derived from the cranial root of accessory nerve (CN XI), and are carried by the vagus nerve to all muscles of the pharynx and soft palate.
• The exceptions are stylopharyngeus (supplied by CN IX) and the tensor veli palatini (supplied by CN V3).

Classified on functional Basis

Secretion ,Protection and waterproofing, Absorbtion, Transport, Sensory

Secretion

Glandular epithelium’s 3 types:

- Exocrine - with ducts

- endocrine - without ducts

- mixed exo-endocrine

Exocrine glands: One cell

- goblet cells

- In lining epitheliums of respiratory tract and GIT

- Secretes musin (protein) Musin + water = mucus, Mucus is a lubricant

More than one cell

 Simple:  Has a single duct,

• Acinar - mucus glands of the penile urethra
• Tubular - cripts of Lieberkuhn
• Coiled tubular - sweat gland
• Spiral tubular - Gland of Moll
• Branched tubular - mucous glands of the pyloric region
• Branched acinar - sebaceous gland in the skin

Compound

• Consists of a branched duct with numerous secretory end organs
• Compound tubular - Brünners glands
• Compound alveolar - mammary, prostate, pancreas, parotid
• Compound tubuloalveolar - submandibular-, sublingual salivary glands

Endocrine glands

Secrete directly into the blood

One cell :  mast cells,  in soft CT,  near capillaries,

secrete - heparin - histamine

More than one cell

Cells can be arranged in the following ways:

• Cords - adrenal glands, parathyroid, anterior pituitary
• anastomosing cords with dilated blood capillaries in-between
• Isles - pancreas
• Follicles - thyroid
• cells line a follicle filled with non-cellular material

Internal Muscles of the Pharynx

• The internal, chiefly longitudinal muscular layer, consists of 3 muscles: stylopharyngeus, palatopharyngeus, and salpingopharyngeus.
• They all elevate the larynx and pharynx during swallowing and speaking.

The Stylopharyngeus Muscle

• This is a long, thin, conical muscles that descends inferiorly between the external and internal carotid arteries.
• It enters the wall of the pharynx between the superior and middle constrictor muscles.

• Origin: styloid process of temporal bone.
• Insertion: posterior and superior borders of thyroid cartilage with palatopharyngeus muscle.
• Innervation: glossopharyngeal nerve (CN IX).

• It elevates the pharynx and larynx and expands the sides of the pharynx, thereby aiding in pulling the pharyngeal wall over a bolus of food.

The Palatopharyngeus Muscle

• This is a thin muscle and the overlying mucosa form the palatopharyngeal arch.

The Salpingopharyngeus Muscle

• This is a slender muscle that descends in the lateral wall of the pharynx.
• The over lying mucous membrane forms the salpingopharyngeal fold.

• Origin: cartilaginous part of the auditory tube.
• Insertion: blends with palatopharyngeus muscle.
• Innervation: through the pharyngeal plexus.

• It elevates the pharynx and larynx and opens the pharyngeal orifice of the auditory tube during swallowing.