 Well, we have finished the chapter which is the Temperature and Body Fluid Regulation. So now we will explain its summary in two modules which we have read in this chapter. So thermal regulation, just say there is the temperature regulation. So it is a complex and important, there is a physiological process for maintaining homeostasis that is despite environmental changes. So in this, we have read the regulation of temperature. This is said to be the thermal regulation. And in fact, it is the part of homeostasis. Homeostasis is a condition which has to be maintained by every living body as well as by cell and outside environment. Now in this, there are two types of ectotherms and then the endotherm animals. So ectotherm generally obtain heat from the environment. And in general, there are thermoconformers. And the outside temperature automatically becomes the same body temperature. And the endotherms generate body temperature by the metabolism, like we call cellular metabolism. So under this process, there is ATP and ATP that is used for the maintenance of temperature of the body. Because it is very important to maintain the body temperature. Because the enzymes that work in the body are active on a special temperature. So the homeotherms generally have a relatively constant core body temperature while the heterotherms have a variable body temperature. So within the heterotherms, the body temperature can vary. It may be for a short period of time, it may be for a long period of time. The high constant body temperature of birds, mammals and that all depends on insulation. Because like we read in the mammals in the birds, how they maintain the body temperature. In winter and in summer. And in this, there is insulation, which especially in birds, there are feathers that they are very important structures to maintain the body temperature. In winter. And then there is the penting, which is like a lot of other animals. They bark. Like there are birds, which bark in very severe summer. Or dogs bark like this. Then there is sweating. Sweating is usually done in mammals. And the cooling effect is done. And they maintain the body temperature like this. Then specific behaviors. Behavior means that there are insects and many other animals. In winter, they expose themselves to the sun. So that they can conserve heat. Then there is the vasoconstriction. When vasoconstriction happens, then obviously blood flows less. Because of which, it is in winter. So that the heat can be at least radiated. Then there is the vasodilation. Vasodilation happens in summer. So that the blood circulates more and more from the skin. And the heat radiates from the skin. And it can maintain the body temperature. Then there is Mirabil. That is Reti Mirabil. This is a network of blood capillaries. Which is in different parts of the body. And the purpose of this is that the heat can be generated. Or the heat can be conserved. Well, thermogenesis that involves mainly shivering. If in winter, to generate heat, shivering. And these mammals also shiver when there is intense winter. What is the purpose? What is its mechanism? It is obvious that when muscles will work, relax and contract. During this time, it is obvious. Work is happening. Work is always generated during heat. And in this way, this body temperature is one of the maintenance. You understand that there is one effort. Then the hypothalamus. Hypothalamus is the temperature regulating center. That functions as a thermostat. With a fixed set point. Like in birds, in mammals. There is a special temperature of the body. And why is this left? This is due to the hypothalamus. And in hypothalamus, there is a center. Which is the maintenance of the body. And this is the center. When it is disturbed, then the temperature can increase. This is called fever. Now this set point can either rise or fall during hibernation or torpor. And hibernation is a process which is called winter sleep. Many animals undergo this process, hibernation. Or torpor has... During the day, during the day, for a short period of time, their temperature can rise or fall. But their temperature does not set. But it can change. Like in a hummingbird. This was all about the temperature regulation. After that, in invertebrates, there is an osmoreculation. The maintenance of water in the body is very important. Because this is again the part of homeostasis. So in all these animals, from invertebrates to mammals, there are different mechanisms. One mechanism is contractile vacuole. Contractile vacuole is usually in invertebrates. And it is also frequently found in produce ones. Like amoeba, paramecium, and many other relatives. Then these flame cells. These are called flat worms. In these, the extra water from the body are very specialized cells. There is space and contractile vacuoles. So the water from the body comes out of these. After that, there are internal glands, which are called green glands, which are in arcobots. Then there are maxillary glands, then coxial glands, and nephridia. These are the structures that are very important to maintain osmoregulation. There are multiple groups of animals. Then there are malpaginitibules. These malpaginitibules are usually present in the arthropods or insects. Well, the osmoregulatory system of vertebrates governs the concentration of water and ions. The excretory system eliminates metabolic waste. Water, ions from the body, which we have read very clearly and each aspect of osmoregulation is in the vertebrates in terms of kidney. Then the freshwater animals, they tend to lose ions and take in water, just like fishes. To avoid hydration, freshwater fishes rarely drink water. They have impermeable, that is, body surfaces. They have mucus on the body, which causes a lot of water. They don't drink it. Water comes from the surface and it can come through copias or gills, or ions. And these fishes, especially dilute freshwater fishes, eliminate water and maintain osmoregulation. By secreting, there is a dilute urine, and besides that, there are also salts. That's why they adjust. Freshwater fishes, they have to conserve these ions, but when they become excess, they are also eliminated through urine. This is the first part of the summary of this current chapter, which is the chapter of osmoregulation, thermoregulation, or excretion. This is the first part of this chapter. So this is all about this one.