Batrachospermum Occurrence:- (1) Batrachospermum is fresh water alga. (2) It is found in clear, cool, and running streams. (3) Deepwater plants are dark violet or reddish in color. But the shallow-water species are olive green. (4) The intensity of light changes the color of pigments. (5) The thallus is attached to the substratum. Vegetative structure (1) The thallus of an adult plant is soft, thick, filamentous. (2) It is freely branched and gelatinous. (3) The central axis is made up of a single row of large cells. Whorls of branches of limited growth are developed on this axis. (4) These branches are filamentous and dichotomously arranged. (5) The main axis is corticated. It consists of a row of elongated cylindrical cells. (6) It is differentiated into nodes and internodes. (7) There are two types of branches that arise from the nodes: Branches of limited growth Branches of unlimited growth Batra
Frog-Respiration
Types of Respiration:-
Cutaneous respiration
Buccopharyngeal respiration
Pulmonary respiration
Cutaneous Respiration:-
The skin of the frog is used as a respiratory organ. It is thin, moist, vascular, and permeable to gases. The O2 from outside diffuses into the blood and the Co2 from the blood diffuses out through the skin.
Buccopharyngeal Respiration:-
The buccal cavity and pharynx are lined with a thin mucous membrane that is moist, permeable, and vascular to gases and richly supplied with blood. The buccopharyngeal cavity is connected to the exterior by a pair of External nares, buccal cavity, and Internal nares.
Inspiration:-
When the throat is lowered the buccopharyngeal cavity becomes enlarged.
This reduces the pressure of air in the buccopharyngeal cavity. Hence fresh air from outside pushes into the buccopharyngeal cavity, Now the exchange of gases takes place between the blood of the mucous membrane and the air.
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| Larval Stages in Frog |
Expiration:-
In expiration, the throat is raised. This increases the pressure of air. Hence the foul air goes out from the buccopharyngeal cavity through the respiratory tract.
Pulmonary respiration:-
In this type of respiration, lungs are used. Lungs are connected with atmospheric air through the respiratory tract that includes: external nares, nasal chamber, internal nares, buccopharyngeal cavity, and glottis. Lungs are thin-walled, oval, elastic, and highly vascular. Their lining is produced into a number of ridges called Septa. The septa enclosed a cavity called Alveoli.
Aspiration:-
During aspiration, the mouth is closed and nares open. The throat is lowered and buccopharyngeal enlarged, so air from outside enters the buccopharyngeal.
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| Pulmonary respiration |
Inspiration:-
During, inspiration nares closed throat is raised. The buccopharyngeal cavity is decreased. So the air is forced through the glottis into the lungs. Exchange of O2 and Co2 between air and the blood of alveoli.
Expiration:-
During expiration, the throat is lowered. The volume of the buccopharyngeal cavity raised. Air from the lungs enters the buccopharyngeal cavity through the glottis. Now the throat is raised, external nares open and foul air is expelled out.
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