How Animals Survive (Circulation and Gas Exchange)

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1 How Animals Survive (Circulation and Gas Exchange) by Flourence Octaviano on February 16, 2018 lesson duration of 30 minutes under Earth and Life Science generated on February 16, 2018 at 12:45 am Tags: Earth and Life Science

2 Generated: Feb 16, :45 AM How Animals Survive (Circulation and Gas Exchange) ( 1 hour and 30 mins ) Written By: Flourence Octaviano on February 13, 2017 Subjects: Earth and Life Science Tags: Earth and Life Science Resources (1) Reece JB, Urry LA, Cain ML Campbell Biology 10th. San Francisco(CA):Pearson Benjamin (2) Slide10.jpg Content Standard The learners demonstrate an understanding of the body in motion. Performance Standard The learners shall be able to make a presentation of some diseases that are associated with the various organ systems Learning Competencies The learners explain the different metabolic processes involved in the various organ systems describe the general and unique characteristics of the different organ systems in representative animals The learners explain the different metabolic processes involved in the various organ systems describe the general and unique characteristics of the different organ systems in representative animals Communicating Learning Objectives 5 mins Communicate Learning Objectives (Nutrition) 1. Introduce the learning objective by writing it on the board, then give the students 5 minutes to write down on a piece of paper what they already know or what they expect to learn under the specified topics: a. Know the structure function relationship in the various organ systems 1 / 6

3 b. Able to synthesize the various functions of the organ systems in the day-to-day activity of an individual c. Used their knowledge of physiological processes to understand the different diseases associated with the organ systems Patintero or Agawan Panyo 10 mins Through the game of mataya taya or it, patintero or agawan panyo the teacher can start the lesson. These activities will aid in increasing the metabolic rate, thus, has implication on the student s circulation and respiration. After the game, ask the student how they feel and what they can observe in terms of their heart rate, respiratory rate, pulse rate, perspiration, etc. Lesson Proper 40 mins Lesson Proper The products of digestion is important for the energy that an animal utilized for its day-to-day activity. This is aided by the circulatory system, for transport of the products of digestion throughout the body of the animal, while the respiratory system is responsible for the conversion of the product of digestion into usable energy. The Circulatory System There are different ways in which animals transport substances across their body. Animals with thin body rely on diffusion, which is the movement of substances from high concentration to low concentration, in the transport of substances. Together with a fluid medium, a thin structure allows diffusion to occur efficiently. Thus, organisms such as those with gastrovascular cavity like cnidarians, flatworms use diffusion in moving substances across and within their bodies. Compared to cnidarians, the gastrovascular cavity of flatworms have extensions in order to reach areas of the body far from the axis. Without these extensions of the gastrovascular cavity, diffusion might not be enough in the transport of substances. To overcome the problems with diffusion, animals with thicker tissues have devised a way in order to transport substances across and within their bodies. Animals have evolved structures which carry substances (circulatory fluid, e.g. blood), pipes (blood and lymph vessels) and a pumping organ (heart). Animals with these structures either have an open or closed circulatory system. In an open circulatory system, blood is not fully enclosed in a vessel and is pumped out of the system via an exit called an ostium to a space which surrounds tissues called a sinus. When the heart contracts, the circulatory fluid goes out of the system, if the heart relaxes the fluid returns. As the blood goes directly to the tissues, it mixes with the interstitial fluid which surrounds tissue and cells and is called a hemolymph. The interstitial fluid allows diffusion from the blood to a cell. In an open circulatory system, circulatory and respiratory systems are independent of each other. In animals with closed circulatory system, the circulatory fluid does not go out of the vessel. Exchange occurs through diffusion via thinner vessels called capillaries across the interstitial fluid. For both types of circulatory systems, the pumping organ (heart) allows substances to travel long distances with the aid of the vessels, which acts like a hi way for transport. With the ability of the circulatory fluid to carry a lot of substances, it allows efficient bulk transport of substances. Diffusion is still used, but only in exchange of substances not in its bulk transport. 2 / 6

4 THE CLOSED CIRCULATORY SYSTEM The thicker body conformation of animals, necessitate to counter the problem of transporting substances across distances. Not only diffusion, but also pressure and friction play a role in diminishing the efficiency of bulk transport in animals. Different animals, have adapted different mechanisms in transport such as in fishes where a single circulation is enough. Single circulation has implication on pressure created in pushing circulatory fluid, as it may lose the pressure to return to the heart. Once the circulatory fluid has passed through the capillaries, in order for diffusion to be efficient, speed of movement of the circulatory should decrease. As a result, the pressure decreases which might not be enough to push the blood back to the heart. But fishes have evolved an adaptation wherein their blood vessels are found between muscles, which squeezes the blood back to heart everytime the muscle contracts, whenever they are swimming. For those organisms which might have thicker bodies, thus, needing more pressure in pushing their circulatory fluid have adapted a double circulation. In double circulation, blood does not move in a single direction, as it goes back to the heart to restore pressure. Below is an illustration showing the different circulation. Amphibian double circulation differs from mammalian, crocodilian and avian as blood is mixed. The presence of one ventricle does not prevent the mixing of blood, unlike in the four-chambered heart of a mammal, crocodilian and an avian where the ventricle is divided into two. Mixing of blood does not have major implication on amphibians as 1) they have low metabolic rate, thus, less need for energy; 2) they have the ability to respire through their skin, thus not needing to fully oxygenate the blood through the lungs. STRUCTURES 1. Atrium- receives blood 2. Ventricle- pumps blood 3. Artery- transports blood away from the heart, muscular 4. Vein- transports blood back to the heart, has valves and thinner in structure 5. Capillary- exchange of substances, has very thin walls 6. Venule- small vein 7. Arteriole- small artery a. The pulse is the wavelike force which is a result of the pumping of blood through an artery with decreasing diameter. As the diameter of the artery decreases, the walls of the artery stretch to accommodate the blood that is passing through it. b. The heart has the ability to produce its own electrical signal to stimulate the contraction of the heart muscles. Thus, the heart is independent from the brain, the brain only affects the rate of heart contraction but not starts the contraction of the heart. The cardiac cycle is the complete cycle of contraction and relaxation, together with the intervening phase. c. Systole- is the contraction phase of the cardiac cycle d. Diastole is the relaxation phase of the cardiac cycle GAS EXCHANGE 3 / 6

5 Gas exchange is very important animals, as they require oxygen in the production of higher amount of energy compared to process of energy production without oxygen. Aerobic respiration is the term used when oxygen is present in the production of energy, while anaerobic respiration is the process energy production without oxygen. In order to acquire oxygen, different animals have evolved different adaptations in order to adapt to their environment. What is constant among these organisms are 1.) a thin respiratory structure, 2.) moist respiratory surface and 3.) respiratory structure with high surface area. As the organisms above live in an aquatic environment, they do not have a problem with keeping their respiratory surface moist. But they face a different problem, as water is heavier and has less O2 concentration than same volume of air. Thus, organisms need to ventilate their respiratory surfaces by increasing the contact between their respiratory surface and the respiratory medium. There are different ways to ventilate the respiratory medium, one method is the countercurrent exchange mechanism used by fish. Through the counter current exchange mechanism, the blood or the circulatory medium will always have a less concentration of oxygen compared to the respiratory medium. Thus, oxygen will always move from the water to the blood and waste gases will always move from the blood to the respiratory medium. AIR AS A RESPIRATORY MEDIUM As air is lighter and has more oxygen content compared to the same volume of water, ventilation is not much of a problem of terrestrial organisms. The problem with air as a respiratory medium is its dehydrating characteristic, thus, terrestrial organisms keep their respiratory surfaces moist by keeping it within their body. This has implication in the surface area of the respiratory structure, again, organisms were able to evolved adaptation to counter this problem. THE TRACHEAL SYSTEM OF INSECTS The tracheal system of insects has a branched network of tracheal tube which responds to the problem of decreased surface area in the respiratory structure. The tracheal system opens externally through the side of the insect through a structure called a spiracle. Air enters and exit through the spiracles. As the respiratory system of insects are independent from their circulatory system, gases is directly exchanged through tracheoles which have extensions that are directly connected to the cells. Air sacs act like aspirator which takes in and push out air out of the body of the insects. THE MAMMALIAN RESPIRATORY SYSTEM Compared to insects, mammals and other organisms have respiratory system that work together with their circulatory system. Gases are transported via the bloodstream and are exchanged via diffusion. Some organisms which have smaller lung capacity compensate gas exchange through thin epithelial lining of their anus or mouth like in turtles or through the skin like in frogs. Gas exchange occurs via the movement of air from the external environment and is exchanged via a deadend of clusters of thin epithelium of the walls of air sacs called alveoli. Compared to mammalian lungs, bird lungs do not have a problem with air not exhaled, as there is a unidirectional movement of the respiratory medium. This is possible because the lungs of birds do not terminate to a dead-end, rather there is a complete circuit of flow of air which pushes air complete out of the respiratory system. TERRESTRIAL VENTILATION Ventilation in lungs is called breathing, the alternating process of inhalation and exhalation. There are two mechanisms 4 / 6

6 of breathing, one is positive breathing and the other is negative breathing. In positive breathing air is pushed into the lungs, such as in frogs. Meanwhile, humans and other mammals use negative pressure breathing by sucking in air in to the lungs through the creation of a negative pressure. When chest muscles contract, they increase the volume of the chest cavity decreasing the pressure inside. As the pressure decreases inside the lungs, air is pulled into the lung cavity. The relaxation of the chest muscles squeezes out air through the process called exhalation. GAS EXCHANGE AND THE CIRCULATORY SYSTEM As the circulatory system functions in the delivery of the energy sources in the form of molecules processed by the digestive system, the respiratory system is important in the released of waste gases (CO2) and the delivery of oxygen for energy production. Sugars are broken down, and the resulting process results in the formation of ATP, which when broken down by cells produce energy which the cells can use for its metabolic activities. The process of glycolysis, is an anaerobic process which does not require oxygen but creates little amount of ATP. The electron transport chain (ETC), which uses oxygen produces the most ATP. Along the process, CO2 is produced as a by-product, which the circulatory system and respiratory system released via exhalation. Below is an summary of the whole process of cellular respiration, together with the ATP produced per mechanism. Debate on the advantage and disadvantage of GMOs 20 mins Play the game again, which was played before the lesson. But compared before, ask the students to records their initial heart rate, breathing rate and pulse rate. Start the game again, at the end of the game ask the students to record the final respiratory, heart and pulse rate. Ask them of a generalization then can make based on the activity on the relationship of the respiratory system and the circulatory system. Quiz 15 mins The teacher can make his/her own list of questions that will allow students to practice critical thinking skills. The quiz can be administered by pairs or individually. Paired or grouped quiz allows the student to further discussed the lesson and learn from their peers. The teacher can formulate open-ended questions or multiple-choice exam from the lesson. The following are guide questions which can help the teachers in formulating their questionnaires. 1. What are the different types of circulatory system? 2. What is the role of diffusion in organisms with thin body structure and thick body structure? How are substances transported in both organisms? 3. How does the circulatory system overcome the problem of diffusion in the transport of substances in organisms? 4. What is the difference between an open and closed circulatory system? Explain. 5. Why is there a need to have a double type of circulation? Explain. 6. Why is the respiratory system of arthropods separate from their circulatory system? Explain. 7. How do animals in aquatic environment adapt on the low concentration of oxygen in their environment? Explain. 8. What is the difference between positive pressure breathing and negative pressure breathing? Explain 5 / 6

7 Powered by by TCPDF ( CHED.GOV.PH 9. Sketch the flow of gases along the respiratory system. 10.How does the respiratory system of birds allow them to fly? Explain. End of the Topic Questions 0 mins 1. Which of the topics interest you the most? Why? 2. Which of the topics interest you the least? Why? 3. Did the activities help you understand the topic (Y/N)? Explain your answer. 4. Did you see the significance/ connection of the topic in your life? Download Teaching Guide Book 0 mins 6 / 6

Circulation and Gas Exchange Chapter 42

Circulation and Gas Exchange Chapter 42 Circulatory systems link exchange surfaces with cells throughout the body Diffusion is only efficient over small distances In small and/or thin animals, cells can