AP Board 10th Class Biology Notes Chapter 4 Excretion

Students can go through AP State Board 10th Class Biology Notes Chapter 4 Excretion to understand and remember the concept easily.

AP State Board Syllabus 10th Class Biology Notes Chapter 4 Excretion

→ Excretion is the term coined for all the biological processes involved in the separation and removal of wastes or non-useful products from the body.

→ The waste products include carbon dioxide, water, nitrogenous compounds like ammonia, urea, uric acid, bile pigments, excess salts, etc.

→ A human excretory system consisting of a pair of kidneys, a pair of ureters, urinary bladder, and urethra.

→ The kidney is bean-shaped from the inner side of each kidney, has fissure or hilus.

→ Through the hilus renal artery enters and the renal vein and ureter exit.

→ Each kidney is composed of a large number of uriniferous tubules or nephrons, which are structural and functional units of the kidney.

→ A nephron comprises Glomerulus, Bowman’s capsule, Proximal Convoluted Tubule (PCT), Distal Convoluted Tubule (DCT), and collecting tubule.

→ Urine formation occurs in four stages: They are

  1. Glomerular filtration,
  2. Tubular reabsorption,
  3. Tubular secretion and
  4. The concentration of urine.

→ Glomerulus filtrate is also called primary urine.

→ Primary urine is almost equal to blood in chemical composition except for the presence of blood cells.

→ Useful substances in primary urine are reabsorbed into the peritubular network.

→ In tubular secretion, some other wastes like extra salts, ions of K+, Na+, Cl and H+ secretes from peritubular capillaries into the distal convoluted tubules.

→ 75% of the water content of the nephric filtrate is reabsorbed in the region of the proximal convoluted tubule.

→ Kidneys remove nitrogenous waste from the body, maintains water balance (osmoregulation), salt content, pH, and blood pressure in the human body.

→ The concentration of urine takes place in the area of collecting tubes in the presence of a hormone called vasopressin.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ The absence of vasopressin hormone produces dilute urine.

→ The movement of urine in the ureter is through peristalsis.

→ The urinary bladder opens into the urethra which is 4 cm long in females and about 20 cm long in males.

→ The urethra’s opening is separate in females but is in common with the reproductive tract in males (urinogenital duct).

→ The discharge of urine from the body is called micturition.

→ Urine has amber color due to the presence of urochrome.

→ Urine contains 96% of water, 2.5% of organic substances, and 1.5% of inorganic solutes.

→ Complete and irreversible kidney failure is called ‘End-Stage Renal Disease’ (ESRD).

→ Uremia is the condition in which kidneys stop working completely and it results in a body being filled with extra water and waste products.

→ The dialysis machine is used to filter the blood of a person whose kidneys are damaged. The process is called ‘hemodialysis.’

→ Kidney transplantation is a permanent solution for renal failure patients.

→ The process of transplantation of organs from brain-dead patients to another is called ‘cadaver transplantation.’

→ The first kidney transplantation was performed by Dr. Charles Hufnagel in Washington, the USA in 1954.

→ In India, the first kidney transplantation was done on 1st December 1971 at the Christian Medical College, Vellore, Tamilnadu.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ Lungs, skin, liver have their own specific functions but carry out excretion as a secondary function.

→ Different animals have different excretory organs.

  • Eg. amoeba and paramoecium – contractile vacuole.
  • Phylum Excretory organs and systems.
  • Platyhelminthes: Flame cells
  • Annelids: Nephridia
  • Arthropoda: Green glands, Malpighian tubules
  • Mollusca: Meta nephridia
  • Echinodermata: Water vascular system
  • Reptiles, Birds, and Mammals: Kidneys
  • Porifera, coelenterates: Water bathes almost all their cells
  • Protozoa: Simple diffusion from the body surface into the surrounding water.

→ In plants, there are no specific organs to excrete wastes.

→ Plants can get rid of excess water by a process like transpiration and guttation.

→ In plants, waste products may be stored in leaves, bark, and fruits.

→ Waste gets stored in the fruits in the form of solid bodies called Raphides.

→ The biochemical substances produced in plants are of two types, primary metabolites, and secondary metabolites.

→ Carbohydrates, fats, and proteins are primary metabolites.

→ Alkaloids, Tannins, Resins, Gums, and Latex, etc., are called secondary metabolites which do not require normal growth and development.

→ Alkaloids are nitrogenous by-products and poisonous.

→ Tannins are carbon compounds used in the leather industry and medicines.
Eg.: Cassia, Acacia.

→ Resin occurs mostly in Gymnosperms in specialized resin passages. They are used in varnishes.

→ Gum is a sticky substance that comes out when branches are cut in plants like Neem, Acacia.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ Latex is a sticky, milky white substance secreted by plants.

→ From the latex of Heaven, Braziliensis rubber is prepared and from the latex of jatropha, bio-diesel is prepared.

→ Excretion is the removal of material from a living being, whereas secretion is the movement of materials from one point to another points.

→ Creatine: Nitrogenous organic acid occurs naturally in vertebrates, helps to supply energy to all cells in the body primarily muscles. This is achieved by increasing the formation of AiR

→ Tubular fluid: The filtered out fluid from the glomerulus contains waste molecules, nutrient molecules, and water. From the glomerulus, this fluid enters the tubular portion of the nephron.

→ Perftubular: Around the tubes, the renal tubule of nephrons ¡s surrounded by peritubular capillaries formed from an efferent arteriole.

→ Podocyte: These are single-layered squamous epithelial cells lining the glomerulus. The fine pores present between podocyte cells allows the passage of materials filtered out of the glomerulus.

→ Hyper – osmotIc: It ¡s more concentrated with solutes and has a higher osmotic pressure than blood plasma. This solution bathes and surrounds Interstitial fluids the cells of multicellular animals.

→ Glomerulus: It is a bunch of fine blood capillaries developed from an afferent arteriole. The blood ¡s filtered through the capillaries of the glomerulus into Bowman’s capsule.

→ PCT (Proximal Convoluted Tubule): It is the first part of the renal tubule of Nephron that starts from Bowman’s capsule. Useful substances in primary urine are reabsorbed into the peritubular network.

→ DCI’ (Distal Convoluted Tubule): It s the last part of the renal tubule of Nephron. In DCT some other wastes like extra salts, ions of K+, Na+, Cl and H+ are secreted from peritubular capillaries into DCT.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ Afferent Arteriole: It forms a capillary network called glomerulus inside the Bowman’s capsule. It brings the pressured blood to the glomerulus and the pressure produces the flow of plasma fluids into the tubule.

→ Efferent ArterIole: ft is formed from Afferent arteriole. They play an important role in maintaining the glomerular filtration rate.

→ Calyces: Renal calyces are parts of the kidney that collect urine before it passes further into the urinary tract. These are the parts of the renal pelvis.

→ Micturition: It is the discharge of urine.

→ Urochrome: It is a pigment that causes the yellow color in urine. It is a breakdown product of the blood’s hemoglobin and is removed by the kidneys.

→ Henle’s loop: It is the portion of the nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. It is named after its discoverer a German Anatomist Friedrich Gustav, Jakob Henle. Its main function is to create a concentration gradian in the medulla of the kidney.

→ Dialyzer: A medical instrument for separating substances in solution by unequal diffusion through a semi-permeable membrane.

→ Hemodialysis: It is the process of filtering the blood of a person by using a dialysis machine.

→ Anticoagulant: It does not allow the blood to clot. Eg. Heparin.

→ Alkaloid: Alkaloids are nitrogenous by-products and poisonous which are stored in different parts of the plant.

→ Biodiesel: The fuel which is obtained from biological materials of plants and animals.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ Excretion: It is a biological process involved in the separation and removal of wastes or non-useful products from the body.

→ Michigan body: It ¡s the first part of Nephron. It consists of a blind cup-shaped broader end of the nephron called Bowman’s capsule and glomerulus.

→ Specimen: An individual animal, a plant, piece of mineral, etc., used as an example of its species or type for scientific study or display.

→ Hilus: The inner side opening of the kidney through which renal artery enters and exits of renal vein and the ureter.

→ Ureters: A pair of whitish, narrow stretch and expandable muscular tubes of 30 cm length arise from the hilus of the kidneys.

→ Cortex: Dark-colored outer zone of the kidney.

→ Medulla: Pale-colored inner zone of the kidney.

→ Nephron: It is also called a uriniferous tubule. It is the basic structural and functional unit of the kidney. It filters the blood, reabsorbs and what is needed, and excretes what is not needed as urine.

→ Bowman’s capsule: It is the cup-shaped broader end of the nephron.

→ PelvIs: It is a funnel-like dilated proximal part of the ureter in the kidney. It is the point of convergence of two or three major calyces.

→ Distensible: Able to stretch and expand.

→ Peristalsis: The involuntary wave-like muscular movement in the alimentary canal or ureter.

→ Sphincter: A ring of muscle that contracts to close an opening.

→ Urethra: It is a tube that takes urine from the urinary bladder to the outside.

→ Amber color: It is a pure chroma color, located on the color wheel midway between yellow and orange.

→ Dialysis: The chemical bath used in dialysis to draw toxins out of the bloodstream and supply electrolytes and other chemicals to the bloodstream.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ Transplantation: An operation moving an organ from one organism to another.

→ Immune system: It ¡s a network of cells, tissues, and organs that work together to defend the body against attack by foreign invaders.

→ Braindead: It is the irreversible end of brain activity. Patients classified as brain dead can have their organs surgically removed for organ donation.

→ Contradilve vacuoles: It is a subcellular structure involved in osmoregulation. It’s are found predominantly in protists and in unicellular algae.

→ Guttation: The secretion of droplets of water from the pores of plants.

→ Yam: The edible starchy tuber of a climbing plant widely distributed in tropical and subtropical countries. (Pendulum in Telugu)

→ Chicle: It Is a natural gum traditionally used in making chewing gum and other products. It is collected from several species of Meso-American trees.

→ Alkaloid: These are nitrogenous by-products and poisonous. These are stored in different parts of the plants.

AP Board Solutions AP Board 10th Class Biology Notes Chapter 4 Excretion

→ Osmoregulation: The process of regulating water contents and ion concentration in the body is called osmoregulation.
AP Board 10th Class Biology Notes Chapter 4 Excretion 1
→ William John Kolff (1911 – 2009):

  • William John Kolif invented the first practical artificial kidney in 1947.
  • He was a pioneer of Haemodialysis as well as in the field of artificial organs.
  • He constructed a dialysis machine with which filtered the blood artificially.
  • The machine works on simple principles of diffusion and filtration across a semipermeable membrane.