Question

Ptyalin is secreted by
(a) Stomach
(b) Salivary gland
(c) Pancreas
(d) Bile

Answer 1

Ptyalin is an enzyme that acts on starch (carbohydrates) and breaks it into maltose. It is secreted by a serous gland which is situated in front of the ear and either side of the mouth.

Complete Step by Step Answer: Ptyalin is secreted by the Salivary gland. In humans, there are 3 pairs of major salivary glands- They are the parotid glands which are the largest of the salivary glands, sublingual glands, and submandibular glands.
- Parotid salivary gland is the largest salivary gland that secretes purely serous saliva through the Stenson’s duct which opens near the second maxillary molar tooth. - Salivary amylase is also known as Ptyalin. It hydrolyses the starch into sugars and is present in the saliva. Out of 3 salivary glands, it is secreted by the Parotid gland.

Additional Information:
There are four surfaces in the Parotid gland: shallow or lateral, upper, anteromedial, and posteromedial. The three borders of the glands are — anterior, medial, and posterior. The parotid gland has two ends – the upper end in the shape of a narrow upper surface and the lower end (apex).
- Submandibular glands also known as the Submaxillary gland secretes both mucous and serous saliva through Wharton’s duct.
- Sublingual Gland secretes pure mucous saliva through numerous small ducts which open in the floor of the mouth and are collectively known as Duct of Rivinus. The largest, the major duct is known as the Duct of Bartholin.
The process of digestion starts from the ptyalin acting upon the complex carbohydrates. The pH of saliva ranges from 6.2 to 7.6 with the average being 6.7 which is slightly acidic.
- Saliva contains ptyalin, which starts digesting the starch. Thus, digestion of starch begins in the mouth.
- The stomach is highly acidic and those conditions are not favorable for ptyalin, which prefers a higher pH or low acidity to neutral for activity.
- Overall, the ptyalin only degrades a small portion of the total starch in the diet. The rest is digested by the pancreatic amylase in the intestine.
So, the answer is ‘Salivary gland’.

Note:
- Parotid glands are enclosed in sheaths that restrict the degree of their swelling when they are inflamed, as in mumps.
- When something touches the gums, the lips, or any part of the lining of the mouth, or when chewing happens, the amount of saliva secreted increases. Stimulating material does not need to be food — dry sand in the mouth or even moving the jaws and tongue while the mouth is empty increases the salivary flow. This combination of direct stimulation of the oral mucosa with increased salivation is known as an unconditioned salivary reflex. When a person discovers that a specific sight, sound, smell, or other stimulus is frequently associated with food, that stimulus alone may be sufficient to induce increased salivary flow. This reaction is known as the conditioned salivary reflex.