The digestive is used for breaking down of large/complex food molecules into simple form food into nutrients and then pass into circulatory system. To perform various function of the body, energy is required, which is absorbed by digestive system from food.
Digestive system is a 25 to 30 feet long tube. It includes organs that secret digestive juices.It is often divided into two processes based on mechanical and chemical digestion.
FUNCTIONS OF THE DIGESTIVE SYSTEM
- Ingestion: taking in food.
- Digestion: breaking down food molecules and covert into nutrients.
- Absorption: taking in nutrients by cells.
- Storage and elimination: indigestible food molecules.
- Egestion: removing any leftover wastes.
THE ALIMENTARY CANAL IS DIVIDED INTO 4 PARTS-
- Mouth and Buccopharyngeal cavity
- Small intestine- duodenum, jejunam, ileum.
- Large intestine- caecum, colon, rectum.
MOUTH AND BUCCOPHARYNGEAL CAVITY
The region where the crescentic masses of the endoderm and ectoderm directly contact with each other constitutes, which forms a septum between the primitive mouth and pharynx, is buccopharyngeal membrane.
It is divided in two part- buccal vestibule,
oral cavity-the oral cavity includes the lips, the iside lining of the lips and cheek, teeth, the gums, tongue, and the bony roof of the mouth
palate- the palate is the roof of the mouth in human body. It separates the oral cavity from the nasal cavity.
hard palate:- it is locted in the roof of mouth. the hard palate is a horizontal bony plate of the skull,
soft palate:- the soft palate is also known as the velum or muscular palate. The soft tissue constituting the back of the roof of the mouth.
Tongue:- the tongue is the muscular organ in the mouth. That is almost completely covered by a mucous membrane. It is the sensory organ responsible for tasting, and play a major rol in body language.
Location:- it is located in inferior of mouth and medial of the teeth.
Teeth:- 32 in number. Tooth is made of dentin, bone like substance. And covered by enamel layer. The enamel is the hardest substance in the human body. The soft rigion of teeth known as pulp, it have blood vessels and nerves. Location- anterior and lateral end of the mouth.
salivary glands:-it is important part of digestive system, it help in moisten food and also help in digestion of carbohydrates. It is lubricate food for pass through the mouth, pharynx and esophagus.
STOMACH- the stomach is a muscular beg forming th most dialated part of the digestive tube. The stomach is 25 cm long or 4-5 inch breath. It is located on the left side of the upper abdomen. It is secretes digestive enzymes and gastric acid. Stomach’s upper end is connect to lower end of oseophagus and its lower end is connected to first part of duodenum.
Sub division of the stomach
Funds- it is convex and dome shaped.
Body- it lies between funds & pyloric part. It contains all three
type of secretry cell.
- Mucous cell
- Chief, pectic or zymogenic cell
- Parital or oxyntic cell
Pylorus or antrum- it is sepreated from pyloric cenal by sulcus intermidents & form body by sulcus linitens. It is 7.5 cm long.
Duodenum:- shape– C shaped. Duodenum is the first and shortest part of the small intestine. this part is the most fixed part of small intestine. length- 20-25 cm. extends from the pylorus of stomach to duodenajujeno flexure
Jejunum- it is found between the duodenum and the ileum.most of the nutrients present in food they are absorbed by jejunum.
Ileum:- it opens into the large intestine via ileocecal valve. It is 3.5 meters long. In this part manly to absorb vitamin B12 and bile salt and nutrients that not absorbed in the jejunum.
The large intestine absorb water from indigestible food matter and after than transmit the waste material from the body.
The caecum receives feacal material from the small bowel. Caecum is proximal end of large intestine where the large intestine and small intestine meet. caecum means blind sac.
The colon is inverted U- shaped part and 5-6 ft. long. In this part reabsorb fluid and process waste products from the body. Colon consists of 4 parts.
Descending colon- it is store the remains of digested food
Rectum is a distal part of large intestine. It is place between sigmoid colon and anal canal. The rectum lies on the front or lower of sacrum and coccyx. Length- 2 cm. and diameter is 4 cm at upper part.
Rectum ampulla:- the lower part of rectum is dialeted to form rectum ampulla.
Anal cana:l- it is the terminal part of the large intestine. Situated below the level of pelvic diaphragm. Length is 4 cm long. Direction is downward and backward.
Anus:- anus is surface opening of the anal canal. Situated 4 cm below and infront of sacrum and coccyx. Surrounding skin is pigmented and thrown into radiatic folds.
DISORDERS OF DIGESTIVE SYSTEM
Inflammation- the inflammation of the intestinal tract is the most common ailment due to bacterial or viral infection. the inflammation also caused by the parasites of the intestine like round worm, tap worm, hook worm, pin worm.
Jaundice- in this case the liver is the mainly affected, skin and eye turn in yellow due to deposit of bile pigment.
Nausea & vomiting- the nausea and vomiting may be caused by food poisoning. the nausea and vomiting is not a diseases but they are symptoms of many conditions.
Diarrhea: in this condition having at least three loose or liquid bowel movements each day. It is caused by increased secretion of fluid into the intestine, reduced absorption of fluid in intestine.
Constipation: in this case the movement of bowel are infrequent or hard to pass, and the stool is often hard and dry.
Indigestion: indigestion can be pain or discomfort in your upper abdomen or burning pain.