Welcome to Zoology World

balindrakumar033@gmail.com   25/11/2017,Saturday

WELCOME TO ZOOLOGY WORLD

The science or study of animal life. Together with botany, the study of plant life, it forms the science of biology. Zoology is such a vast subject that most zoologists specialize or focus on the study of particular organisms or taxonomic groups. tion of animals.

Teeth is a living structure

What are the organs of the digestive system

The various types of digestive glands present in mammals are salivary glands,gastric glands, intestinal glands,pancreas and liver.The digestive glands secrete digestive juices.Parasympathetic nervous system increases the secretion of digestive juice whereas sympathetic nervous system decreases it.

Salivary gland:

Parotid,Sub-mandibular and Sub-lingual are found in mouth

The three pairs of salivary glands present in humans are as follows-

1.Parotid:

One-pair ,largest salivary gland present below pinna.A stenson's duct arises from each gland ,opening in vestibule between the 2nd molar teeth of upper jaw and cheeks.Parotid glands secrete enzymes. Viral infection of parotid glands causes"Mumps"(by paramyxo virus).

2.Sub-mandibular/ sub-maxillary:

One-pair,present at the junction of upper and lower jaw in cheek region. A wharton's duct arises from each gland and opens on lower jaw. These are seromucous glands.

3.Sub-lingual:

One-pair,present in the floor of buccopharyngeal cavity. These are mucous glands 6-8 ducts,called ducts of rivinus or Bartholin's duct arises from these glands and opens below tongue on the floor of buccopharyngeal cavity.

Saliva/ Salivary juice:

The secretion of salivary glands is called saliva or salivary juice.Some of the characteristics are as follows-

  1. Amount:1.0-1.5litre/day.
  2. Chemical nature:Slightly acidic.
  3. pH:6.3-6.8
  4. Control of secretion:
  5. Autonomic reflex(parasympathetic nervous system increases salivation while sympathetic nervous system inhibit secretion.)

  6. Chemical composition:
  7. Water(99.5%), mucous(acts as lubricant), salts(NaCl,NaHCO3 etc.) ,enzymes (ptyalin,lysozyme)etc.

what is the function of the digestive system

Makes the medium slightly acidic for the action of its enzyme.</li>
<li>Help in taste detection,deglutition,
speaking etc.

Salivary juice and its enzymes-

  1. Makes the medium slightly acidic for the action of its enzyme.
  2. Help in taste detection,deglutition, speaking etc.