Pulmonary And Cutaneous Respiration Lab Report
Title : Comparing the rates of pulmonary and cutaneous respiration in frogs
Introduction
Frogs are amphibians that live in moist environments to support one of their key mechanisms of respiration. Frogs have the ability to breathe many diverse ways, due to their unusual life cycle and aquatic and terrestrial environment. The Order Anura shows the extreme anatomical and physiological diversity. Many frogs use lungs to respire, bringing in air through their nares, mouth, into the trachea and then to the lungs for gas exchange and uptake of oxygen. The skin of many frogs is thin and extremely vascular to allow for gas exchange and thus can live in moist environments and secrete mucous from their skin to avoid desiccation. Cutaneous respiration …show more content…
also allows for the frog to remain almost completely submerged under water for long periods of time, while still oxygenating their blood (Jackson, 2015). When an organism is placed in an enclosed space and the CO2 is removed by an alkaline absorbent, the gas pressure within the space decreases as the Oxygen is used up. If the space is connected to a manometer, a low level in pressure will show the quantity of Oxygen consumed by the organism. Pulmonary respiration is thus studied. To study cutaneous respiration, the Oxygen in the water in which the frog is to be placed for a given length of time is attained before and after the experiment by Winkler’s method. The change in the values gives the quantity of Oxygen consumed through the skin (Rastogi,2005). Hoplobatrachus occipitalis, known as the crowned bull frog would be used for this experiment.
Main objective
• To determine and compare the rates of cutaneous respiration and pulmonary respiration in a frog
Specific objective
• To determine the rate of pulmonary respiration.
• To determine the rate of cutaneous respiration.
Materials: broad –mouth bottle with a two hole rubber stopper, 2 glass tubes one of which is bent; a manometer with the bent tube; rubber tubing and some reagent bottles, kerosene, live frog
Procedure
350 ml of fresh water would be put in a wide mouth bottle and a few drops of kerosene would be added to form a thin layer over the water surface to avoid evaporation.
The live frog would be placed inside the bottle and will amend itself in such a way that its nose remains above the kerosene layer. Concurrently, a reagent bottle would be filled with water and have a layer of kerosene on the surface. This will serve as the control. A vial containing NaOH together with filter paper saturated with alkali will be placed into the animal chamber. A bent tube would be is inserted through one of the holes to be connected to the manometer. Through the other hole, a sealed glass tube would be inserted to prevent any contact with the atmosphere. The set-up would be airtight and the position of the indicator in the nanometer would be checked every five minutes for an hour. The stopper of the bottle would be removed and the entire water would be siphoned into a reagent bottle. Winkler’s method would be used to find the Oxygen content of both the analyser and the control. The change in the values would give the amount of Oxygen consumed by the frog through the skin. The degree of Oxygen consumption can be found out by dividing the amount of Oxygen expended by the frog (Rastogi,
2005).
Analysis of data
• Calculating pulmonary respiration rate
Initial reading of manometer = x cm
Final reading of manometer = y cm
Total length of the indicator column during 1 hour = x-y cm
Calculate the capacity of the length of the indicator column (a cm), i.e. d x a = ml
Rate of pulmonary respiration calculated by ml (d x a) / total weight of frog., i.e. d x a / w = ml/ g weight/ hour
• Calculating cutaneous respiration rate
Oxygen content of control after an hour = x ml / hour
Oxygen content of analyzer after 1 hour = y ml/hour
Total Oxygen consumption for 1000 ml = x-y = a ml/hour
Calculate for 350 ml = a x 350/1000 = t ml/hour
Weight of frog = w g
Rate of Oxygen consumption through skin = t/w = ml/g weight/hour
Expected results
The expectation is that the rate of cutaneous respiration would be higher than the rate of the pulmonary respiration as the lungs’ of frogs are comparatively underdeveloped and are usually used when they are active or do not get enough Oxygen from cutaneous respiration.
References
Jackson, A. (2015). Frog -Animal Respiration. Retrieved on November 4, 2015 from http://animalrespriation.weebly.com/frog.html.
Rastogi, S.C., (2005). Experimental Physiology. New Age International, ISBN 8122415865, 9788122415865 page 81-83.
Introduction
Frogs are amphibians that live in moist environments to support one of their key mechanisms of respiration. Frogs have the ability to breathe many diverse ways, due to their unusual life cycle and aquatic and terrestrial environment. The Order Anura shows the extreme anatomical and physiological diversity. Many frogs use lungs to respire, bringing in air through their nares, mouth, into the trachea and then to the lungs for gas exchange and uptake of oxygen. The skin of many frogs is thin and extremely vascular to allow for gas exchange and thus can live in moist environments and secrete mucous from their skin to avoid desiccation. Cutaneous respiration …show more content…
also allows for the frog to remain almost completely submerged under water for long periods of time, while still oxygenating their blood (Jackson, 2015). When an organism is placed in an enclosed space and the CO2 is removed by an alkaline absorbent, the gas pressure within the space decreases as the Oxygen is used up. If the space is connected to a manometer, a low level in pressure will show the quantity of Oxygen consumed by the organism. Pulmonary respiration is thus studied. To study cutaneous respiration, the Oxygen in the water in which the frog is to be placed for a given length of time is attained before and after the experiment by Winkler’s method. The change in the values gives the quantity of Oxygen consumed through the skin (Rastogi,2005). Hoplobatrachus occipitalis, known as the crowned bull frog would be used for this experiment.
Main objective
• To determine and compare the rates of cutaneous respiration and pulmonary respiration in a frog
Specific objective
• To determine the rate of pulmonary respiration.
• To determine the rate of cutaneous respiration.
Materials: broad –mouth bottle with a two hole rubber stopper, 2 glass tubes one of which is bent; a manometer with the bent tube; rubber tubing and some reagent bottles, kerosene, live frog
Procedure
350 ml of fresh water would be put in a wide mouth bottle and a few drops of kerosene would be added to form a thin layer over the water surface to avoid evaporation.
The live frog would be placed inside the bottle and will amend itself in such a way that its nose remains above the kerosene layer. Concurrently, a reagent bottle would be filled with water and have a layer of kerosene on the surface. This will serve as the control. A vial containing NaOH together with filter paper saturated with alkali will be placed into the animal chamber. A bent tube would be is inserted through one of the holes to be connected to the manometer. Through the other hole, a sealed glass tube would be inserted to prevent any contact with the atmosphere. The set-up would be airtight and the position of the indicator in the nanometer would be checked every five minutes for an hour. The stopper of the bottle would be removed and the entire water would be siphoned into a reagent bottle. Winkler’s method would be used to find the Oxygen content of both the analyser and the control. The change in the values would give the amount of Oxygen consumed by the frog through the skin. The degree of Oxygen consumption can be found out by dividing the amount of Oxygen expended by the frog (Rastogi,
2005).
Analysis of data
• Calculating pulmonary respiration rate
Initial reading of manometer = x cm
Final reading of manometer = y cm
Total length of the indicator column during 1 hour = x-y cm
Calculate the capacity of the length of the indicator column (a cm), i.e. d x a = ml
Rate of pulmonary respiration calculated by ml (d x a) / total weight of frog., i.e. d x a / w = ml/ g weight/ hour
• Calculating cutaneous respiration rate
Oxygen content of control after an hour = x ml / hour
Oxygen content of analyzer after 1 hour = y ml/hour
Total Oxygen consumption for 1000 ml = x-y = a ml/hour
Calculate for 350 ml = a x 350/1000 = t ml/hour
Weight of frog = w g
Rate of Oxygen consumption through skin = t/w = ml/g weight/hour
Expected results
The expectation is that the rate of cutaneous respiration would be higher than the rate of the pulmonary respiration as the lungs’ of frogs are comparatively underdeveloped and are usually used when they are active or do not get enough Oxygen from cutaneous respiration.
References
Jackson, A. (2015). Frog -Animal Respiration. Retrieved on November 4, 2015 from http://animalrespriation.weebly.com/frog.html.
Rastogi, S.C., (2005). Experimental Physiology. New Age International, ISBN 8122415865, 9788122415865 page 81-83.