Más contenido relacionado


Rubina kidney 123-2.pptx

  1. content  Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 3  Anatomy and the structure - - - - - - - - - - - - - 4  Development of kidneys - - - - - - - - - - - - - - - 5 - 6  Types of kidneys - - - - - - - - - - - - - - - - - - - - - - 7 -11  Evolution of Kidneys - - - - - - - - - - - - - - - - - - - 12
  2. • The kidneys are two reddish-brown bean- shaped organs found in vertebrates. • They are located on the left and right side in the retroperitoneal space, and in adult humans they are about 12 centimeters in length. • The kidneys excrete a variety of waste products produced by metabolism into the urine. Introduction External view Internal view Kidney Anatomy
  4. Intermediate Mesoderm Nephrogenic Cord Pronephros Mesonephros Metanephros
  5. Pronephros Pronephric kidney is a transient embryonic organ that serves as a kidney. It gives rise to mesonephric kidney. A mesonephric kidney is an embryonic organ that disappear is all mammals when the permanent kidney is functional. A metanephric kidney is a highly complex organ that filters waste products from circulation. It forms a permanent kidney.
  6. Archinephros: the Ancestral Kidney Aorta Glomerulus Archinephric Duct Cloaca • Excretory organ of ancestral vertebrates. • Also called holonephros or complete kidney as it extends the entire length of the coelom. • Composed of a pair of archinephric ducts. • Each duct has a pair of tubules to a segment. • Each tubule is opened by a nephrostome into the coelom. • All tubules are drained into a common archinephric duct, which opens into the cloaca. HAGFISH
  7. • The first kidney tubules to appear in the embryos of all vertebrates called Pronephros. • Tubules are segmented, one pair at each segment. • Pronephric tubules: simple, become long, and coiled. • Glomerulus: Malpighian tuft (capillary blood vessels) removes urine and toxins from the blood. • No. of pronephric tubules : 3 in the larval frog, 7 in human embryos, and 12 in chicks. • Functional only in the embryonic or larval stage of amphibians and fishes. Pronephros : The Larval Kidney Nephrostomes Pronephric Duct Pronephric Tubule Pronephric Chamber Glomus Pronephric Kidney Pronephros Mesonephros Metanephros
  8. Mesonephros: Kidney of Anamniotes • Mesonephros – “ middle kidney ”. • Main excretory organ of aquatic vertebrates ( anamniotes ). • Temporary kidney in higher vertebrates • When the pronephros degenerates the persistent pronephric duct is called mesonephric duct or the Wolffian duct. • In fishes and amphibians, mesonephros is functional both in embryos as well as the adult. • In amniotes ( reptiles, birds, and mammals ) mesonephros is functional only in the embryos replaced by metanephros in the adults. • In Sharks and Caecilians, mesonephric tubules extend posteriorly throughout the length of coelom - Opisthonephros Pronephros Nephric duct Nephrogenic cord Degenerating Pronephros Mesonephros Nephrogenic cord Cloaca Degenerating mesonephros Metanephric mesenchyme Uretric bud Nephric duct Mesonephros
  9. Metanephros: Kidney of Amniotes • Kidney of amniotes. • Most posterior and last to develop in both ontogeny and phylogeny. • Permanent kidney (reptiles, birds, and mammals) develop in embryos from the lower part of the Wolffian duct and replacing the embryonic mesonephros. • When metanephric tubules develop, all the mesonephric tubules disappear except those associated with the testis in male and forming vasa efferentia. • Consists of compact paired organ containing many nephrons; a ureter separate from the Wolffian duct leads from the metanephros to the bladder Gonad Mesonephros Metanephrogenic mesenchyme Uretric bud Nephric bud
  10. Examples of vertebrates
  11. Characters FISH Dogfish (Scoliodon) AMPHIBIA Frog (Rana) REPTILIA Lizard (Uromastix) AVES Pigeon (Columba) MAMMALIA Rabbit (Oryctolagus) 1. Excretory organs A pair of kidneys, urinary ducts, and a urinogenital sinus. No bladder. A pair of kidneys, ureters a urinary bladder and cloaca. A pair of kidneys, a urinary bladder and cloaca. No bladder. A pair of kidneys, a pair of ureters and cloaca. Include a pair of kidneys, paired ureters, a bladder and urethra 2. Kidneys Adult kidneys greatly elongated, ribbon-like flat. Each kidney has 2 distinct parts Anterior narrow part. Posterior broader part is functional kidney and called opisthonephros. Adult kidneys are elongated, oval, flat. Not differentiated into parts and are mesonephric. Adult kidneys are small, irregular. Each kidney is bilobed. Kidneys are metanephric. Adult kidneys are small, flat, dorsally. Each kidney is trilobed. Kidneys are metanephric. Adult kidneys are small, bean shaped. Kidneys are metanephric and not divided into lobes. 3. Histology of kidneys Covered ventrally by peritoneum, not differentiated into cortex and medulla and made of a compact mass of coiled uriniferous tubules. Same as in fishes Same as in fishes and amphibians. Kidney covered ventrally by peritoneum, differentiated into cortex and medulla and contains a very large number of uriniferous tubules. Each kidney covered ventrally by peritoneum, differentiated into an outer cortex and inner medulla, and made of much convoluted uriniferous tubules 4. Uriniferous tubules Have a special urea absorbing segment. Loop of Henle absent. Lack a urea-absorbing segment and loop of Henle. Lack urea-absorbing segment and loop of Henle. Lack urea absorbing segment, but water absorbing loop of Henle present Absorb urea through glomerular filteration and tubular reabosrption and also have water absorbing loop of Henle. Comparative Account Of The Excretory System Of Vertebrates
  12. Characters FISH Dogfish (Scoliodon) AMPHIBIA Frog (Rana) REPTILIA Lizard (Uromastix) AVES Pigeon (Columba) MAMMALIA Rabbit (Oryctolagus) 5. Peritoneal funnel Nephrostomes present. Nephrostomes present. Nephrostomes absent. Nephrostomes absent. Nephrostomes absent. 6. Ureters Mesonephric ureters of both sides run over ventral surface of kidney and open into a urinogenital sinus, which leads into cloaca. Ureters open separately in male but by a common aperture on a urinary papilla in female. Mesonephric ureters arise and run along outer side of kidneys and open behind by separate apertures directly into cloaca. A urinogenital sinus is absent. Metanephric kidney ducts or ureters run ventrally over kidneys and open dorsally and separately into middle chamber of cloaca, called urodaeum. Urinogenital sinus absent. As in reptiles, ureters are metanephric. They run ventrally over kidneys and open behind separately into urodaeum through its roof. Without pelvis. Ureters begin from a wide funnel-like cavity in kidney, called pelvis. Cloaca absent. 7.Urinary bladder Absent A large thin-walled membranous elastic bilobed urinary bladder opens ventrally into cloaca by a sphinctered aperture. Small, thin-walled, inelastic, undivided sac opening ventrally into coprodaeum of cloaca. Absent Large, median, pearshaped, muscular sac. Its neck, called urethra, opens at the tip of penis in male and into vestibule of female which opens to outside through vulva. 8. Nature of excretion Predominantly ammonotelic because excrete more ammonia than anything else. Ureotelic, excreting predominantly urea along with water. Urecotelic, excreting semisolid uric acid and urates which are not much soluble in water Like reptiles, brids are also urecotelic excreting mainly uric acid and urates in a semi-solid state. Urecotelic since chief excretory product in urine is urea dissolved in water.