Tongue

1
Tongue

• The tongue is fleshy, movable, muscular
  organ, attached in most vertebrates to the floor
  of the mouth, that is the principal organ of
  taste, an aid in chewing and swallowing, and, in
  humans, an important organ of speech.

2
Regions of tongue

• Blade The blade is the region of the tongue
  anterior to the frenulum.
• Body The body extends from the circumvallate
  papillae to the frenulum, the anterior part of
  the genioglossus muscle. The body is the largest
  segment and it convenient to arbitrarily separate
  the body into an anterior and posterior part. The
  anterior body is beneath the hard palate, the
  posterior body lies beneath the soft palate.
• Base or root The base, or root, is that part
  of the tongue posterior to the sulcus terminalis,
  the line of circumvallate papillae taste
  receptors.

3

• Anatomically ,the tongue formed of two main
  regions
• Lingual mucosa.
• Lingual muscles.
• Lingual muscles divided into two main groups
• Extrinsic muscle The extrinsic muscles have one
  attachment to a bone (mandible, hyoid bone or
  styloid process) while the other end inserts
  within the tongue.
• Intrinsic muscles Intrinsic muscle originate
  and insert within the tongue and have no bony
  attachments.

4

• Orientation of tongue muscle
• One set runs parallel to the screen from upper
  left to lower righ.
• A second set runs at a right angle to these from
  lower left to upper right.
• The third group is cut in cross section, as it
  runs in and out of the plane of the screen it's
  therefore at right angles to both the other two.

5
Lingual papillae

• Filiform Papillae
• Are numerous . 
• Slender conical structures, project upwards
  forming a velvety covering on the tongue.
• its function is purely mechanical.
• In cattle ,they are extremely large and rough.
• The stiff papillae make effective bristles for
  removing debris.
• In large animals, such as cows, the filiform
  papillae reached up to perhaps 5.0 mm long.

6
Gustatory Papillae

• Fungiform papillae Are less common than the
  filiforms.
• Vallate (or circumvallate) The largest and most
  prominent,
• Foliate papillae which are most easily seen in
  the Order Lagomorpha (rabbits, hares, and conies).

7
Fungiform papillae

• Are mushroom shaped structures. 
• Rise above the general level of the filiform
  papillae, and have taste buds.
• Carry taste buds.
• Are less numerous than the filiform type, and
  scattered in among them.
• Are large enough to have a core of connective
  tissue.
• The papillae are flat-topped and have deep clefts
  between them.
• The clefts are lined with epithelium, and contain
  taste buds embedded in them.

8
Foliate papillae

• Is best seen in rabbits and is "leaflike" .
• Set in the sides of the tongue.
• Rise above the general level of the filiform
  papillae, and have taste buds.
• Carry taste buds.
• Are less numerous than the filiform type, and
  scattered in among them.
• Are large enough to have a core of connective
  tissue.
• The papillae are flat-topped and have deep clefts
  between them.
• The clefts are lined with epithelium, and contain
  taste buds embedded in them.

9
Vallate Papillae

• Is set into a deep pocket in the tongue's
  surface.
• It doesn't protrude above the general level of
  the surface.
• Are easily visible with the naked eye in most
  animals.
• They're paired and located near the back of the
  tongue.
• They're the least numerous type.
• This very large structure has a core of
  connective tissue (CT).
• Taste buds (TB) are present on the sides of the
  papilla.
• The small lingual salivary glands (SG) that empty
  into the moat keep the taste buds ready for
  re-use.
• There are two types of these lingual salivary
  glands serous and mucous in nature. The
  secretions of these glands are wash the
  chemoreceptor sites of the taste buds free of
  molecules, so that new sensations can be
  detected.