Question

1. List parts or sub-groups of the following.  a. Oral cavity

2. b. Stomach
   c. Large Intestine d. Small Intestine

Answer 1

a. Oral cavity: The mouth or oral cavity is bound by muscles and bones .It has the following structures

Anteriorly it has - lips

Posteriorly - oropharynx

Laterally - muscles of cheeks

Superiorly - Bony hard palate and soft palate

Inferiorly - muscular tongue and soft palate

Oral cavity is lined throughout with mucous membrane.

b.Stomach :

It is a wide J- shaped and distensible bag like structure located in upper left portion of abdominal cavity. it is present below diaphragm

It has following sub- parts or structures

1. Cardiac portion - into which oesophagus opens

2.Fundic region - it is in middle

3.Pyloric portion - Which opens into small intestine through pyloric aperture , Which is guarded by pyloric sphincter.

C. Large intestine : It has following sub-parts/ structures

1. Caeceum : it is a small blind sac Which hosts some symbiotic microorganisms. A finger like tubular projection - vermiform appendix (abdominal tonsil) arise from caecum.

2.Colon : caecum opens into colon .

Colon is further divided into - an accending , a transverse , a descending parts and a sigmoid colon that continues behind into rectum.

Colon has external bulged out pouches called haustra

3. Rectum : it is a dilated sac opens into anal canal that opens through anu_s.

Anal canal is guarded by an internal anal sphincter and external anal sphincter.

d.Small intestine : It is longest part of alimentary canal. It has following sub-parts

It is distinguished serially into three regions

1. Proximal duodenum

2.middle long coiled jejunum

3.distal highly coiled ileum

Ileum opens into large intestine.