Respiratory System 1w2g6d

I. OBJECTIVES

The lesson aims to: •

Make the learners be able to describe and compare the structure and function of the respiratory systems and breathing mechanisms of human and frog

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Teach the learners how to identify the parts of a frog’s respiratory system and its functions

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Have the learners internalize the understanding of the exchange and transportation of gases and know its importance

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Show the learners the path of air in the respiratory system a frog

III. SUBJECT MATTER Topic: Respiratory Systems of Human and Frog Concepts:  Parts of a Frog’s respiratory system and their functions.  The processes executed by the Frog’s respiratory system  Air pathway from the environment to the frog’s lungs  Comparison of frog and human respiratory system and processes Materials:  Visual aid for the frog’s respiratory system with labels and functions as well as for human.  A simple prototype of the respiratory system showing how inhalation and exhalation occurs  Representation of a frog with a pathway of air to be traced

References: "Do Frogs breathe through their Lungs?" by Lisa Miller http://animals.pawnation.com/frogs-breathe-through-lungs-2161.html "Frog Respiration" http://www.brown.edu/Departments/Engineering/Courses/En123/MuscleExp/Frog%20Re spiration.htm

"Frog's Body Parts and Functions" by Kristin Faith http://www.slideshare.net/kristinfaith858/frog-body-parts-and-functions "Frog's Internal Systems" http://www.tutorvista.com/content/biology/biology-iii/animal-morphology/respiratoryexcretory-nervous-reproductive-system-frog.php "Peripheral Gas Exchange" http://www.ptdirect.com/training-design/anatomy-and-physiology/respiratorysystem/peripheral-gas-exchange-internal-respiration "Pulmonary Ventilation" http://www.ptdirect.com/training-design/anatomy-and-physiology/respiratorysystem/pulmonary-ventilation-breathing?searchterm=pulmonary "Respiratory Gas Transport" http://www.ptdirect.com/training-design/anatomy-and-physiology/respiratorysystem/respiratory-gas-transport "Respiratory System" by Andaya, Amelito Manuel, et al. www.slideshare.net/guiarabacca/bio-22-lab-mheg3

"Respiratory System of Frog" http://standardnote.blogspot.com/2012/12/respiratory-system-of-frog.html "Respiratory System of Frogs" http://www.2classnotes.com/digital_notes.asp?p=Respiratory_System_of_Frogs

"The Differences between the Respiratory Systems of Frogs and Humans" by Rob Hainer, Demand Media http://animals.pawnation.com/differences-respiratory-systems-frogs-humans-2684.html

"The Human Respiration Process" http://www.oxygen-review.com/respiration.html "Three Ways that Respiration occurs in the Frogs". by Lisa Miller http://animals.pawnation.com/three-ways-respiration-occurs-frog-2555.html "What is it called when Frogs breathe through their Skin?" by Rob Hainer, Demand Media http://animals.pawnation.com/called-frogs-breathe-through-skin-2870.html

III. PROCEDURE

Motivation: To get the learners ready for the lesson, a short game will be played. A set of three volunteers for the first challenge and another three for the second challenge will be needed for the game. The first challenge is to inhale and just hold their breath as long as they can. The student who consumes the longest time will be the winner. For the second challenge, the three students should exhale and hold their breath for as long as they can bear. Again, the student who consumes the longest time will be the winner. Prizes will be given afterwards.

Lesson Proper: Respiration is the process of exchanging gases between an organism and its environment. Respiration happens through the process of breathing wherein there is taking in of air and expelling it out of the lungs. This process takes place in the respiratory system. The respiratory system plays a vital role in the inhalation and exhalation of respiratory gases in the human body. External respiration is the exchange of gases between the lungs of the organism and the external environment. Internal respiration, on the other hand, is the exchange of gases between the blood vessels and the tissue cells in the alveoli. The respiratory system allows the inhalation of gases such as oxygen in the air which will then be transported by the blood around the body to supply tissues and cells, and the exhalation of waste gases such as carbon dioxide into the air. PARTS OF FROG’S RESPIRATORY SYSTEM AND THEIR FUNCTIONS

FROG’S RESPIRATORY PROCESSES In adult frogs, respiration can occur in 3 different ways either independently or in tandem. Adult frogs breathe through their lungs and exchange gases through their skin and the lining of their mouths. Although frogs have lungs, they perform much of their respiration through their skin, bying their lungs completely. Their moist skin is specially designed with tiny blood vessels near the surface to help diffuse oxygen in and carbon dioxide out, even when the frogs are hibernating or underwater. I. Cutaneous Respiration When a frog breathes through its skin, it's called cutaneous gas exchange. This means that it’s exchanging oxygen for carbon dioxide, similar to the way human lungs exchange the gases. The gases through the skin by diffusion. A frog's skin can absorb oxygen, which is captured by capillaries lying just beneath the skin's surface. These capillaries transport the oxygen throughout the frog's circulatory system, carried by the blood. Blood cells not carrying oxygen pick up carbon dioxide and carry it back through the circulatory system to the skin, where it diffuses out of the frog. When frogs hibernate in cold weather, they breathe through their skin almost exclusively. A frog's skin must stay moist for the cutaneous gas exchange to work properly, which is why you see frogs in damp areas, near water and at night most often. The hot sun can dry their skin out quickly, so they tend to only come out during the day if they can dive into some water when necessary or dig under damp soil. Frogs give off carbon dioxide two and a half times faster through their skin than their lungs, which makes keeping their skin moist essential to their survival.

II. Pulmonary Respiration Cutaneous gas exchange suffices for most of a frog's breathing needs, but it still has lungs to supplement his oxygen needs. Most frogs breathe through their noses with their mouths closed. Frogs' lungs have relatively thin walls that can act like balloons. When a frog fills his lungs with air, he can hold the air there to help him remain buoyant while swimming. Lungs in frogs are not efficient respiratory organs because only mixed air enters into them and mainly function as hydrostatic organs. Lungs are pair of thin walled, translucent with inner surface divided into alveoli by septa. Pulmonary respiration has a maximum frequency of 20/minute. It occurs when more energy is required. Mouth and gullet are kept closed during pulmonary respiration.

III. Buccopharyngeal Respiration Frogs have an additional surface for respiration other than their skin -- the moist lining of the mouth. When the frog's mouth is not submerged completely in water, this respiratory lining is in constant use, bringing oxygen into the bloodstream from the surrounding air and diffusing excess carbon dioxide back into the environment. In order to draw air into its mouth the frog lowers the floor of its mouth, which causes the throat to expand. Then the nostrils open allowing air to enter the enlarged mouth. The nostrils then close and the air in the mouth is forced into the lungs by contraction of the floor of the mouth. To eliminate the carbon dioxide in the lungs the floor of the mouth moves down, drawing the air out of the lungs and into the mouth. Finally the nostrils are opened and the floor of the mouth moved up pushing the air out of the nostrils.

Respiratory movements in pulmonary respiration are because of buccopharyngeal cavity which acts as a force pump. These movements are carried out by set of paired muscles sternohyal and pterohyal muscles. Sternohyal muscles are attached with hyoid and coracoid, clavicles of the pectoral girdle and on contraction depresses the buccal floor enlarging the buccopharyngeal cavity. Pterohyals are attached in between hyoid and pro-otics of the skull and on contraction lifts the floor of buccal cavity. With the depression of buccal floor, air enters buccal cavity through the nares. External nares are then closed by pushing tuberculum prelinguale and the movable premaxillae. It is followed by raising of the buccal floor by pterohyal muscles which reduses the volume and air is pushed into the lungs where exchange of gases takes places. Buccal floor is again lowered enlarging its volume which draws air into the buccal cavity. External nares are opened followed by raising the buccal floor, pushing the air out through external nares.

PATHWAY OF AIR FROM THE ENVIRONMENT TO THE FROG’S LUNGS In order to draw air into its mouth the frog lowers the floor of its mouth, which causes the throat to expand. Then the nostrils open allowing air to enter the enlarged mouth. The nostrils then close and the air in the mouth is forced into the lungs by contraction of the floor of the mouth. To eliminate the carbon dioxide in the lungs the floor of the mouth moves down, drawing the air out of the lungs and into the mouth. Finally the nostrils are opened and the floor of the mouth moved up pushing the air out of the nostrils.

COMPARISON OF FROG AND HUMAN RESPIRATORY SYSTEM I. Anatomical Differences Frogs and humans need to breathe for the same reason: to bring oxygen into the body and to expel carbon dioxide. We both have lungs for these tasks, but that's where most of the similarities end. Frogs live in a different environment than humans, and differences in their respiratory systems reflect that. A. Lungs Humans breathe exclusively through their lungs, but frogs use their lungs for only part of their respiration. Frog lungs have thinner walls and are almost like balloons. They often fill their lungs to help them stay buoyant when swimming. Both species have bronchial tubes leading to the lungs, but human systems are more complicated, with many branching bronchiole. The lungs of frogs and humans have alveoli, tiny vessels that make the actual gas exchange. But the alveoli in humans are more densely packed because we breathe only through our lungs. B. Diaphragm As humans, we use our diaphragm muscle to push up on our lungs and help us breathe out. Contracting the diaphragm pushes air out. Releasing the diaphragm lets the lungs stretch back out, making room for air you're breathing in. Frogs don't have a diaphragm. Instead, they use muscles in their throat sacs to help draw in air and push it back into the lungs.

C. Skin Frogs have another organ they use to breathe: their skin. Frogs can exchange oxygen for carbon dioxide through their skin, but it needs to be moist for the process to work correctly. That's why you typically see frogs near water or burrowed in damp soil. Frogs' skin is an efficient breathing machine, exchanging carbon dioxide 2 1/2 times faster than their lungs can. In comparison, humans eliminate less than 1 percent of the necessary carbon dioxide through the skin D. Mouths If you've never seen a frog yawn, it's because they don't. They don't breathe through their mouths, only through their noses. We, on the other hand, have a choice of breathing through our noses or our mouths, or both. Frogs use muscles beneath their jaws to help move air, but their mouths stay closed while they breathe. II. Differences in Respiration A. Frogs at their early stage breathe through their gills. All frogs start life as aquatic tadpoles, breathing underwater through internal gills and their skin. Then later most develop into land animals with lungs for breathing air. But in all stages, breathing is controlled by pulsing the throat. Most frogs lose their gills when they undergo metamorphosis. B. Frogs can breathe with mouths closed. Frogs breath with their mouths closed. Their throat movements pull air through the nostrils to the lungs then breathe out with body contractions. Compared with many other amphibians, frogs have relatively well-developed and complex lungs, which are subdivided and contain many alveoli—tiny sacs that are responsible for gas exchange within the lungs. Unlike mammals that control their breathing with the diaphragm, frogs use their mouths and nostrils in tandem to bring air into their lungs. When a frog breathes in, it lowers the floor of its mouth and relaxes its throat. Then it opens its nostrils to allow air to enter into the newly expanded mouth and throat, at which point the frog contracts its mouth floor and forces air into the lungs.

C. Frogs can breathe through their skin. An adult frog's thin and permeable skin allows it to take in oxygen, even when completely submerged. Oxygen readily es through this thin membrane-like skin, providing the frog with the oxygen it needs to stay alive underwater without the need for gills. Because of the permeability of a frog's skin, moisture is lost easily and most frogs must remain in a moist or humid environment in order to retain their water levels. D. Frogs can breathe with the lining of their mouth Buccopharyngeal Respiration. Frogs have an additional surface for respiration other than their skin -- the moist lining of the mouth. When the frog's mouth is not submerged completely in water, this respiratory lining is in constant use, bringing oxygen into the bloodstream from the surrounding air and diffusing excess carbon dioxide back into the environment.

A. Organs for breathing and gas exchange FROG

HUMAN

May occur through lungs

Gas exchange is exclusively through the lungs

May occur through gills (larval stage)

Gills are absent

May occur through the skin (cutaneous)

Cannot breathe cuteneously/through the skin

Bronchi tubes leading to the lungs

Bronchial tubes and many bronchioles

The moist tip of the buccopharygeal cavity

May take in air by opening the mouth

B. Organs for pumping air in and out of the lungs FROG

HUMAN

Muscles in the frog’s throat sacs are Diaphragm for contraction and relaxation of responsible for drawing air in and out of the the lungs causing inhalation and exhalation lungs.

II. Certain respiratory processes that frogs can that human cannot and vice versa

A. Frogs at their early stage breathe through their gills. All frogs start life as aquatic tadpoles, breathing underwater through internal gills and their skin. Then later most develop into land animals with lungs for breathing air. But in all stages, breathing is controlled by pulsing the throat. Most frogs lose their gills when they undergo metamorphosis. B. Frogs cannot breathe through the oral cavity. Frogs breath with their mouths closed. Their throat movements pull air through the nostrils to the lungs then breathe out with body contractions. Compared with many other amphibians, frogs have relatively well-developed and complex lungs, which are subdivided and contain many alveoli—tiny sacs that are responsible for gas exchange within the lungs. Unlike mammals that control their breathing with the diaphragm, frogs use their mouths and nostrils in tandem to bring air into their lungs. When a frog breathes in, it lowers the floor of its mouth and relaxes its throat. Then it opens its nostrils to allow air to enter into the newly expanded mouth and throat, at which point the frog contracts its mouth floor and forces air into the lungs. C. Frogs can breathe through their skin. A frog's skin must stay moist for the cutaneous gas exchange (breathing through the skin) to work properly, which is why you see frogs in damp areas, near water and at night most often. The hot sun can dry their skin out quickly, so they tend to only come out during the day if they can dive into some water when necessary or dig under damp soil. Frogs give off carbon dioxide two and a half times faster through their skin than their lungs, which makes keeping their skin moist essential to their survival.

IV. GENERALIZATION

Below is a list of the summary of the key concepts learned from the lesson.

 The process of gaseous exchange (O2 and CO2) and utilization of oxygen to breakdown food to release energy is called respiration.

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In frog, respiration takes place through moist skin, lining of bucco-pharyngeal cavity and lungs.

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The respiration through skin is called cutaneous respiration.

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The coetaneous respiration occurs in hibernation and aestivation and in water.

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The skin is always becomes moist by mucous secreted from the mucous glands.

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Due to moist skin, the oxygen from the environment diffuses into the blood through skin and the carbon dioxide diffuses out from the blood into the environment.

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The respiration through the buccopharyngeal cavity is called buccopharyngeal respiration.

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The buccal cavity consists of moist mucous membrane and richly supplied with blood vessels.

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The air enters into the cavity through nares and gaseous exchange takes place through the lining of buccal cavity between blood and air present in the cavity.

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The respiration through the lungs is called pulmonary respiration.

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This respiration occurs only when the need of oxygen is more during swimming and jumping.

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There is a pair of lungs. The lungs are thin walled elastic sacs. They are present within thoracic cavity on either side of heart.

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Numerous small air sacs are present in the lungs called alveoli.

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The alveoli are very thin walled and supplied by blood vessels. The air enters into the alveoli of the lungs through the external nares, internal nares, buccopharyngel cavity, glottis, laryngotrachial camber, and bronchi.

V. APPLICATION Respiration is the process of exchanging gases between an organism and its environment. Respiration happens through the process of breathing wherein there is taking in of air and

expelling it out of the lungs. This process takes place in the respiratory system. The respiratory system plays a vital role in the inhalation and exhalation of respiratory gases in the human body. The respiratory system allows the inhalation of gases such as oxygen in the air which will be transported by the blood around the body to supply tissues and cells, and the exhalation of waste gases such as carbon dioxide. Three types of respiration in frogs: cutaneous, buccopharyngeal and pulmonary. Cutaneous respiration is respiration through moist skin is called as cutaneous respiration. Skin is richly supplied with alone vessels and is permeable to gases. Oxygen get dissolved in moist surface of skin them exchange of gases takes place by diffusion. It goes on all the time whether frog is in water or on land. It is only mode of respiration during hibernation or aestivation or when frog is under water. Buccopharyngeal respiration takes place on land during mouth and glottis remains closed while nostrils remain open. The floor of buccal cavity is alternately raised and lowered so that air is drawn into and expelled out of buccal cavity through. Nostrils. The epithelial lining of buccal cavity is moist and highly supplied with alone capillaries and exchange of gases takes place through it. Pulmonary respiration is respiration through the use of lungs. Each lungs is ovoid, thin walled and highly elastic. Externally, they remain covered by peritoneum. Internally, each lung is divided by a network of folds or septa forming a number of small air scar or alveoli with a large central cavity. The alveoli are linked with thin epithelum highly pursued with capillaries. Exchange of gases takes place through these alveoli. Pulmonary respiration takes place between buccal respiration and during it buccal cavity acts a force pump. The up and down movements of the floor of buccal cavity is brought by the action of two muscles, sternohyal muscles and petrohyal muscles. The sternohyal are attached at the lower and to sternum and at the upper end to under surface of hyod bone in the floor of buccal cavity. The petrohyal muscles are attached below to the upper surface of hyoid bone and above to squamosal bone of skull.