Basics of Excretion | Excretory Products & their Elimination (Part 1) | Class 11

Basics of Excretion | Excretory Products & their Elimination (Part 1) | Class 11


the topic of this presentation is human excretory system part 1 in this presentation we will discuss some basics related to excretory system first of all we will discuss about this term Metabolism because this term will be used in our discussion ahead metabolism means that all the chemical processes – chemical reactions that occur within a living organism in order to maintain life all those are collectively called metabolic processes or metabolism for example cellular respiration glucose is oxidized during cellular respiration in the presence of oxygen and ATP is formed ATP is our desired product but along with the desired products some by-products are also formed which are some time toxic and harmful and these are called waste products for example carbon dioxide is formed here, so it a waste product water is also formed water is also formed along with ATP and this water is also called metabolic water we have just seen that by-products are formed during metabolic reactions and some of these are harmful and known as metabolic waste now we will learn some example of metabolic waste CO2 and water are metabolic wastes of carbohydrates and fat during metabolism of proteins – as these are made of amino acids and amino acids contain nitrogen metabolic wastes of these are nitrogenous and contain nitrogen Ammonia, urea and uric acid are metabolic wastes formed during metabolism of proteins. in the same way, you know about hemoglobin it is oxygen carrying component in the blood carries oxygen a component of it is heme Bilirubin and Biliverdin are metabolic wastes of heme their excretion occurs through bile the pigments present in bile – Bilirubin and Biliverdin these are the metabolic wastes of heme so, these are some of the example of Metabolic wastes now we will discuss this term ‘excretion’ we have already discussed about metabolic wastes removing these metabolic wastes out of the body this process is called excretion now we will learn about the excretory organs found in our body what are the organs which help in excretion kidneys are the main excretory organs Kidneys mainly remove nitrogenous wastes like ammonia and urea there are other organs also along with kidneys – like lungs we know that lungs play very important role in respiration but they remove large amounts of CO2 during exhalation, that’s why we consider them excretory organs also in the same way liver also helps in excretion as we know that bile is formed in liver and we have just discussed that waste products of heme are bilirubin and biliverdin these are excreted through bile that’s why liver is also considered as excretory organ in the same way, sweat glands Sweat Glands secrete sweat contains traces of urea that’s why sweat is also a kind of excretory secretion here we must remind you that the main function of sweat glands is to facilitate a cooling effect on the body surface still, as traces of urea are excreted through sweat, that’s why sweat glands are also considered as excretory organs we want to tell one more term to our students – osmoregulation Regulation of water content and salt concentration in the body is called osmoregulation main function of kidneys is definitely excretion but along with excretion it also plays very important role in osmoregulation we will discuss this point in detail in our further presentations that how kidney plays very important role in osmoregulation also we want to tell one more term to our students – defecation prefix ‘de’ before any scientific term means ‘removal’ removal of something Removal of feces is called defecation undigested wastes present in rectum this is a part of large intestine Removal of undigested wastes through anus is called defecation. when these small terms are clear to us we develop clear understanding about the topic and concepts then learning becomes very easy now we will discuss three terms – ammonotelism, ureotelism amd uroctelism let’s start with ammonotelism the organisms which Excrete metabolic wastes in the form of ammonia is called ammonotelic organisms and this phenomenon is called ammonotelism Most of the aquatic forms like protozoans, sponges, cnidarians, flatworms, nematodes, echinoderms the most important examples are bony fish, aquatic amphibians (tadpole), aquatic insects etc bony fishes are ammonotelic whereas cartilagenous fishes are ureotelic this point is very important if you are preparing for some competition tadpoles are aquatic forms whereas adults are terrestrial adults – frogs and toads – are ureotelic whereas tadpoles are ammonotelic such examples are very important if you are preparing for some competition so, these are some of the examples of ammonotelic organisms Ammonia is the most toxic form of metabolic wastes because it is readily soluble in water it is readily soluble in water, it requires a large amount of water to excrete it out if the body that’s why only aquatic forms can afford to be ammonotelic ammonotelism can be seen only and only in the aquatic forms as very large amount of water is required to excrete ammonia Ammonia, as it is readily soluble it is excreted by diffusion across body surface of the aquatic forms bony fishes have scale on their body surface ammonia can be excreted through scales but ammonia is excreted through gill surface as ammonium ions now the question arises that what is function of kidneys in these bony fishes as ammonia is excreted through their gill surface kidneys play important role in osmoregulation these play very important role in osmoregulation definitely some little amount of ammonia is also excreted through kidneys in the form of urine but the main function of kidneys in bony fishes is osmoregulation these are some important points we have discussed related to ammonotelism we will discuss some important points related to ureotelism you must have known the meaning of ureolism Excretion of urea as nitrogenous waste is called ureotelism and such organisms are known as ureotelic organisms urea is less toxic than ammonia as it less soluble in water in comparison to ammonia due to less solubility in water it is less toxic and requirement of water to excrete it out of the body is also less that’s why terrestrial organisms are mostly ureotelic here I must tell my students that during metabolism of proteins, the first metabolic waste formed is ammonia this ammonia is transported to liver liver converts this ammonia to urea now this urea is transported to kidneys through blood circulation and will be excreted out of the body through kidneys this is excretion of urea occurs in our body let’s discuss some examples mammals are ureotelic aquatic reptiles like turtles are ureotelic let me cite some important examples terrestrial amphibians like frogs and toads are ureotelic marine fishes are also marine fishes now we will discuss some important points related to Uricotelism Excretion of uric acid as nitrogenous waste is called uricotelism and such organism are called uricotelic organisms uric acid is least soluble in water if we compare solubility of these three components – ammonia, urea and uric acid then uric acid is least soluble in water that’s why Uric acid is least toxic and is removed with a minimum loss of water that’s why the organisms which are found in scarcity of water – dry conditions such organisms are uricotelic like Reptiles, birds, terrestrial snails and insects they live in the environment of water scarcity live in dry environment therefore these organisms are uricotelic

Randy Schultz

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10 thoughts on “Basics of Excretion | Excretory Products & their Elimination (Part 1) | Class 11

  1. Shivam Kumar says:

    12 ka bhi uploaded kariye plzz mam

  2. Ni3 Y says:

    Nice video mam….plz plant anatomy PR bhi jaldi ek video bna dijiye

  3. long time says:

    thank u so mach maam….. please har week video upload kar dho

  4. Armaan Raza says:

    Mam plant kingdom ka lecture kab ayaega

  5. Madhukar Jarange says:

    mam please upload videos of principle of inheritance and variation

  6. Sarvesh maurya says:

    thank u mam

  7. Shaurya Singh says:

    Seriously soo simple and awesome way of… Teaching… I am dam lucky to b your Student…. This is a soo amazing way of learning ….

  8. Manju sakhuniya says:

    Wel-come back mam… 😍
    Aap khaa chale gaye the.. 🙈🙋

  9. Swati Kumari says:

    Mind blowing mam plz make more videos

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