What is the purpose of the stoma?

Answer 1

Note: Stoma is a term that is both common in medical as well as botanical fields.

This is the MEDICAL definition of Stoma. Please refer to the related questions for the botanical definition.

Answer to STOMA definition

A stoma is an artificial opening that a person is not born with. A doctor/surgeon can create/make a stoma surgically on a patient. An example of when this is done follows: If a person is suffering from colon cancer and a section of the colon has to be removed, the surgeon sometimes has to make a STOMA (artificial opening) on the abdomen of the patient so that the bowel movement has a place to leave the body while the colon is healing. Sometimes the use of a stoma is temporary like in the case of allowing the rest of the colon to rest until it is healed....however, sometimes the stoma is permanent because of the amount of involvement of cancer or whatever. In either case, it is an artificial opening.

Answer 2

The stoma (plural: stomata) is an opening on the underside of a leaf which takes in carbon dioxide from the air (used by the plant for photosynthesis) and releases oxygen and water (byproducts of photosynthesis) through the process of transpiration.

Stomata are concentrated on the undersides of the leaves out of direct sunlight and where there are not negatively affected by the cuticle layer of the plant.

Interestingly tissue culture plants (grown in a test tube) have stomata on both the upper and lower surfaces of the leaves as the plants have not developed a cuticle layer until they are removed from their tubes!
It's function is to exchange gases.

Answer 3

Edit : They control the exchange of gases. -Tyler Price [GradPoint/Novanet]Stoma (pl. stomata)

In botany, a pore (tiny hole) in the epidermis (outer layer of tissue) of a plant. There are lots of these holes, usually in the lower surface of the leaf. A leaf contains several layers of tissue. The outer layer is the epidermis and is only one cell thick. Stomata occur in the lower epidermis.

Each stoma is surrounded by a pair of guard cells that are crescent-shaped when the stoma is open but can collapse to an oval shape, thus closing off the opening between them. Stomata allow the exchange of carbon dioxide and oxygen (needed for photosynthesis and respiration) between the internal tissues of the plant and the outside atmosphere.

They are also the main route by which water is lost from the plant (water vapour), and they can be closed to conserve water, the movements being controlled by changes in turgidity of the guard cells.

At night the stomata may allow oxygen to diffuse in and carbon dioxide out because only respiration is taking place. However in many plants the stomata close at night, preventing this gas exchange.

Answer 4

Gaseous exchange is the primary function of a stoma.

Answer 5

The stoma is a small opening on the epidermis of a leaf. The function of the stoma is to allow for the exchange of gases such as carbon dioxide, water vapor and oxygen.

Answer 6

The stoma are tiny pores in the epidermis of a plant's leaf or stem. It allows the movement of gases in and out of the intercellular spaces.

Answer 7

a pore or hole in the leaf which allows air and water vapour in and out.

Answer 8

stomata is not a cell but the space between the guard cells. diffusion of carbon dioxide, oxygen and water occurs through the stomatal pores.