Digestive system: Intestine.

The intestines are the parts of the digestive system responsible for the absorption of nutrients and water. Two anatomic regions exist, the small intestine and the large intestine. Both of these are further subdivided into anatomically discernible subdivisions. The small intestine has three parts: the duodenum, the jejunum, and the ileum; the large intestine is subdivided into the colon, cecum, rectum, and is continuous with the anus, the last portion of the alimentary canal  

This diagram lays out in schematic form some of the salient features of the two major subdivisions of the intestine, and highlights their similarities and differences. These are key things that will enable you to distinguish them from each other in the microscope. Overall the intestines have the normal form expected of tubular organs, including the four "tunics" discussed in Exercise 18, the tunica mucosa, tunica submucosa, tunica muscularis externa, and the tunica serosa.

Author. Dr. Thomas Caceci.
www.vetmed.vt.edu.

Oral cavity. "Tongue."

Tongue

• is almost purely made of muscle
• the ant 2/3 is called the oral part = originates from 1st pharyngeal arch
• post 1/3 = pharyngeal part, orginates from 3rd arch, behind terminal sulcus of tongue
• @ midline of terminal sulcus is foramen cecum, the remnant of thyroglossal duct
• root = from 4th arch
• Has midline sulcus on dosal surface = location of fusion of 1 lateral swellings of ant tongue over tuberculum impar.

Function: aid in speaking, allow for movement of food toward oropharynx and within oral cavity
Parts:
Body – most of the tongue
Apex – pointed ant part
root – part fixed to hyoid bone and mandible, is located behind palatoglossal fold, location of lingual tonsils.
Taste Buds: SEE HISTO
The inferior surface of tongue has a very thin mucus membrane, so can see many veins, and is attached to floor of mouth via another mucus membrane fold = lingual frenulum. – Basically keeps tongue in mouth while allowing apex to move about
Muscle of Tongue = all innervated by CN XII, except palatoglossus, which we already said is innervated by Pharyngeal plexus, via CN X
Intrinsic m - change the shape of tongue itself
Sup/Inf Longitudinal, Transverse, Vertical
Extrinsic m – change position of tongue

• Genioglossus – protrudes and depresses tongue
• Hyoglossus – depresses and retracts tongue
• Styloglossus – retracts and elevate tongue
• Palatoglossus – elevates tongue.

Reference: www.anatomytopics.wordpress.com/2008/12