Presentation on theme: "Urinary System- Kidney Overall function – Osmoregulation (water, salt) – Nitrogenous waste in tetrapods – Ammonia in amphibians – Urea in mammals – Uric."— Presentation transcript:
Urinary System- Kidney Overall function – Osmoregulation (water, salt) – Nitrogenous waste in tetrapods – Ammonia in amphibians – Urea in mammals – Uric acid in birds and reptiles – Note: uric acid in birds is 3000x more concentrated than blood!
Kidney - Nephron The functional unit of the kidney Filters blood to make urine Glomerulus is a network of permeable blood capillaries – Afferent glomerular arteriole – Efferent glomerular arteriole
Kidney - Nephron Bowman’s capsule is a cup-shaped capsule around the glomerulus to catch filtrate Renal corpuscle – Glomerulus plus the Bowman’s capsule since they function as a unit
Kidney - Nephron Renal Tubules Increase in complexity with higher vertebrates Function to secrete substances directly from blood to tubule Function for reabsorption from tubules back to bloodstream based on need
Kidney - Nephron ADH = Antidiuretic hormone promotes water reabsorption from renal tubules Aldosterone – hormone that promotes sodium reabsorption from renal tubules and water passively follows Renal tubules are countercurrent for maximum efficiency
Key Points Define countercurrent. Look at the following picture and explain how countercurrent is advantageous.
Kidney Longitudinal kidney duct – Carries urine to cloaca in all but placental mammals – Various names for this duct depending on group
Kidney Types based on Embryology Pronephros Forms from intermediate mesoderm (mesomere) very far cranially Renal tubules are temporary pronephric tubules Pronephric duct carries urine to cloaca Pronephric duct persists in anamniotes but changes its name to Mesonephric duct
Kidney Types Mesonephros Middle region of intermediate mesoderm Longitudinal duct is Mesonephric duct (we called it archinephric duct in lab) Functional embryonic kidney in amniotes Adult kidney of anamniotes
Kidney Types Mesonephros – Mesonephric tubules invade testes and form the Vasa efferentia which carry sperm from testicle to mesonephric duct – Mesonephric duct carries sperm & urine in anamniotes – Mesonephric duct in amniotes will only carry sperm & is called the Spermatic Duct or Vas Deferens
Urinary Bladder The urinary bladder is formed from the embryonic membrane called the allantois (cloacal derivative) in placental mammals The remnant of the allantois is called the urachus which becomes an umbilical ligament