Fats are broken down by lipases into di and monoglycerides in the duodenum of small intensine as
Fats\(\overset { Lipase }{ \longrightarrow } \) Diglycerides \(\longrightarrow \) Monoglycerides. 

The maximum absorption of digested food occurs in the small intestine of alimentary canal;.The absorbed form of different food materials are

The mucosa is folded into finger-like projections called villi. The cells lining the villi bear microvilli giving it a brush-bordered appearance. These two features increase the surface area of intestine for absorption. The villi are richly supplied with a network of blood capillaries and a large lymph vessel, lacteal, for easy absorption of nutrients.

Absorption of water in the small intestine occurs by osmosis.The water passes the lumen of the a small intestine through epithelial cells and then to blood capillaries in the villi.Water absorption in general is accompanied with the absorption of electrolytes and digested food in order to maintain an osmotic balance with the blood.

Each tooth is embedded in a socket jaw bone. This type of attachment is called thecodont.
Majority of mammals including human being forms two sets of teeth during their life, a set of temporary milk or deciduous teeth replaced by a set of permanent or adult teeth. This type of dentition is called diphyodont.

If goblet cells are non-functional for some reason, this will adversely affect smooth movement of food down the intestine due to the absence of much.
These glands secrete mucus which along with succus entericus which helps in digestion and movement of food material in the alimentary canal.

\(Dipeptides\underrightarrow { Dipeptidases } Amino\quad Acids\)
\(\\ Maltose\ \underrightarrow { Maltase } Glucose+ Glucose\)
\(\\ Lactose\ \underrightarrow { Lactase } Glucose +\ Galactose\)
\(\\ Sucrose \underrightarrow { Sucrase } \ Glucose\ +\ Fructose\)
\(\\ Nucleotides\ \underrightarrow { Nucleotidase } Nucleosides\ \underrightarrow { Nucleosidase } Sugars\ +\ Bases\)
\(\\ Di\ and\ monoglycerides\ \underrightarrow { Lipase } \ Fatty\ acids\ +\ Glycerol\)

The accessory digestive glands include the salivary glands, the liver and the pancreas.
(i) Human have three pairs of salivary glands, i.e., the parotids, submandibular's and sublingual's. They secrete major amount (about 1L) of the saliva, each day. The parotids are the largest glands in the cheek region near the ears. The submandibular glands are located towards the posterior end of the lower jaw. Sublingual glands are the smallest, present at the anterior part of the floor of the mouth.
(ii) The liver is the largest gland in the body. It weighs about 1.5 kg. It lies immediately under the diaphragm. The gall bladder is a small and elongated muscular sac situated below the liver.
(iii) The pancreas is an elongated gland, that is situated near the junction of the stomach and the duodenum. Both the liver and pancreas act as glands whereas, the gall bladder acts as storing organs

Constipation In this condition,the faces are retained within the rectum as the bowl movement occur irregularly.The causes of constipation are water defiency,lack of roughage in diet,etc.
Indigestion In this condition,the food is not properly digested leading to a feeling of fullness.The causes of indegestion are inadequate enzyme secretion,anxiety,food poisoning,over eating and spicy food

The buccal cavity performs the following major functions.
(i) The teeth and the tongue with the help of saliva masticate and mix up the food thoroughly.
(ii) Mucus in saliva helps in lubricating and adhering the masticated food particles into bolus.
(iii) The bolus is then passed into the pharynx and then into oesophagus for further digestion.

The activities of the gastrointestinal tract are under neural and hormonal control for proper coordination of different parts
The sight, smell and/or the presence of food in the oral cavity can stimulate the secretion of saliva
Similarly, gastric and intestinal secretions are also stimulated by neural signals.
The muscular activites of different parts of the alimentary canal can also be moderated by neural mechanisms (both local and through CNS).
Hormonal control of the secretion of digestive juices is carried out by local hormones produced by the gastric and intestinal mucosa.

Digestion of proteins in stomach
The proenzyme pepsinogen on exposure to HCl, gets converted into active enzyme pepsin.
Protein  \(\rightarrow\)Proteoses + Peptones
Pepsin always acts in acidic medium (pH 1.8). In infants, milk proteins are digested by rennin.
Digestion of protein in small intestine  Pancreatic juice contains proenzyme, i.e., trypsinogen that gets activated by an enterokinase, which is secreted by intestinal mucosa, into active trypsin. Trypsin acts in alkaline medium.
 \(Protein\underrightarrow { Trypsin\quad /\quad Chymotrypsin } Dipeptides\)
The dipeptides are changed into amino acids by the enzyme succus entericus (intestinal juice).
 \(Dipeptides\underrightarrow { Dipeptidases } Amino\quad acids\) 

Liver of the largest gland present in human body which is mainly responsible for the digestion of food
Role of liver in digestion of food
(i) Its hepatic cells secrete bile juice which passes through the hepatic duct into the gall bladder.
(ii) It has its major role in processing of proteins i.e., formation of urea.
(iii) Bile secreted by it is mainly responsible for digestion of fats for easy absorption in the body.
(iv) Also responsible for the removal of toxins from blood.