Question

Frog is in resting state, the mode of respiration it is expected to show is
A. Cutaneous and pulmonary
B. Buccal and cutaneous.
C. Only cutaneous
D. Only buccal

Answer 1

The frog's body has three respiratory surfaces that it employs to exchange gas with the environment: the skin, the lungs, and the mouth lining. The frog's entire respiration takes place through the skin while entirely immersed. The skin is made up of a thin layer of membranous tissue that is water permeable and has a dense network of blood vessels.

Complete answer:
For amphibians with moist, well-vascularized skin, gas exchange through the skin is typical and vital. Indeed, certain small salamanders lack lungs, and all gas exchange occurs through the skin surface, with the exception of a small contribution from the oral mucosa. Frogs also have a respiratory surface on the inside of their mouth that allows for easy gas exchange. At repose, this is the frog's primary mode of breathing, and he only fills his lungs on rare occasions. This is due to the fact that only adults have fully formed lungs. The relative importance of skin and lungs in frogs changes throughout the year. When oxygen uptake is low in the winter, the skin absorbs more oxygen than lungs.
When oxygen consumption is high in the summer, the absorption through the lungs increases by several orders of magnitude.

Hence the correct answer is option B. Buccal and cutaneous.

Because of the thin membranous membrane, breathing gases can easily diffuse along gradients between blood vessels and the surrounding environment. Mucus glands in the epidermis keep the frog moist when it is out of the water, which aids in the absorption of dissolved oxygen from the air.

A frog can also breathe in the same way that humans do, by inhaling through their nostrils and exhaling through their lungs. However, the method for taking air into the lungs differs slightly from that of humans. Frogs lack ribs and a diaphragm, which in humans help to expand the chest, lowering the pressure in the lungs and allowing outside air to flow in.

The frog lowers the floor of its mouth to draw air into it, which causes the throat to expand. The nostrils then open, enabling air into the enlarging mouth. When the nostrils close, the air in the mouth is driven into the lungs by the contraction of the mouth floor. The floor of the mouth glides down, sucking air out of the lungs and into the mouth, to expel carbon dioxide from the lungs. Finally, the nostrils are opened and the floor of the mouth is raised, allowing the air to escape through the nostrils.

Note:-
Frogs also have a respiratory surface on the inside of their mouth that allows for easy gas exchange. This is their primary mode of breathing when they are at rest, and it only fills the lungs on occasion. This is due to the fact that only adults have fully formed lungs.