UROGENITAL

• Urogenital System


  Also called as the genitourinary system. Organs or organ systems concerned with urinary excretion and reproduction
• Urogenital System consists of

  • Urinary/excretory System
  • Reproductive System
• Urinary System


  Responsible for water and solute balance in the Body
• Animals


  • Consist mostly of water with many dissolved salts and other solutes
  • Must keep the solute composition of the extracellular matrix within normal range to retain homeostasis
• Homeostasis


  Tendency towards relative stable equilibrium. In biology, defined as a stable state of an organism and its internal environment
• Osmoregulation


  Controlling the solute concentrations and balance water gain/loss
• Ways animals can maintain water balance


  • Osmoconformers
  • Osmoregulators
• Osmoconformers


  Isoosmotic with their surroundings and do not regulate their osmolarity
• Osmoregulators


  Expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment
• Aquatic invertebrates in temporary ponds

  • Lose almost all their body water and survive in a dormant state. This adaptation is called anhydrobiosis
• Tardigrades (water bears)


  • Can dehydrate from about 85% water to 2% water in the dehydrated, inactive state
• Ammonia


  A naturally occurring compound. At room temperature, NH3 is a colorless, highly irritating gas with a pungent and suffocating odor
• Most animals have organs that rid their body of waste ammonia and other unwanted solutes
• Conversion of Ammonia


  1. Ammonia, due to its toxicity, are converted into either urea or uric acid in order for it to be stored

  2. Urea - can be stored. However, requires water for disposal

  3. Uric Acid - are safer than ammonia and urea. Hence, can be disposed without needing a copious amount of water
• The kind of nitrogenous wastes excreted

  • Depends on an animal's evolutionary history and habitat, especially water availability
  • Another factor is the immediate environment of the animal egg
  • The amount of nitrogenous waste is coupled to the animal's energy budget
• Most excretory systems produce urine

  1. Filtration: Filtering of body fluids

  2. Reabsorption: Reclaiming valuable solutes

  3. Secretion: Adding nonessential solutes and wastes to the filtrate

  4. Excretion: Processed filtrate containing nitrogenous wastes is released from the body
• Nephridium


  Tubular organ of primitive invertebrates that takes up body fluid at one end and expels excess water and unwanted solutes at the other end
• Two Types of Nephridia

  • Protonephridium
  • Metanephridium
• Protonephridium


  • Main excretory system of primitive invertebrates such as Platyhelminthes (flatworms)
  • The smallest branches of the network are capped by a cellular unit called a flame bulb
  • These tubules excrete a dilute fluid and function in osmoregulation
• Metanephridium


  • Metanephridia consist of tubules that collect coelomic fluid and produce dilute urine for excretion
  • Metanephridia of earthworms function in excretion and osmoregulation
• Malpighian tubules


  In insects and other terrestrial arthropods, remove nitrogenous wastes from hemolymph and function in osmoregulation
• • Insects produce a relatively dry waste matter, mainly uric acid, an important adaptation to terrestrial life
  • This system is capable of conserving water very effectively
• Human Urinary System


  • Also called as the Renal System
  • The organ system that filters the blood of unwanted metabolic wastes
  • Filtration is done in the kidney
  • The one responsible for creating urine
  • Capable of eliminating 0.8-2.0mL of urine per day
• Parts of the Kidney

  • Renal Cortex
  • Renal Medulla
• Nephron


  • The most basic/functional unit of the kidney
  • Separates water, ions, and other small molecules from the blood
• Parts of the Nephron

  • Renal Corpuscle
  • Proximal Tubule
  • Loop of Henle
  • Distal Tubule
  • Collecting Tubule
• Renal Corpuscle


  • Also called as the Malpighian body
  • Filtration unit of the nephron
  • Consists of a knot of capillaries, called the Glomerulus, and a double-walled capsule, or the Bowman's Capsule, that drains into a tubule
• Proximal Tubule


  • Reabsorption of ions, water, and nutrients takes place
  • Molecules are transported actively and passively from the filtrate into the interstitial fluid and then capillaries
  • As the filtrate passes through, materials to be excreted become concentrated
  • Some toxic materials are actively secreted into the filtrate
• Parts of the Loop of Henle

  • Descending loop of Henle
  • Ascending loop of Henle
• Descending loop of Henle

  • Reabsorption of water continues through channels formed by aquaporin proteins
  • Movement is driven by the high osmolarity of the interstitial fluid, which is hyperosmotic to the filtrate
  • The filtrate becomes increasingly concentrated
• Ascending loop of Henle

  • In the ascending limb, salt but not water is able to diffuse from the tubule into the interstitial fluid
  • The filtrate becomes increasingly dilute
• Distal Tubule


  • Regulates the K+ and NaCl concentrations of body fluids
  • The controlled movement of ions (H+ and HCO3–) contributes to pH regulation
• Collecting Tubule


  • Carries filtrate through the medulla to the renal pelvis
  • One of the most important tasks is reabsorption of solutes and water
  • Urine is hyperosmotic to body fluids
• Countercurrent multiplier system


  Involving the loop of Henle maintains a high salt concentration in the kidney
• Urination


  1. Urine, collected in the Renal Pelvis, are transported through the ureter into the bladder where it is stored

  2. The bladder can hold the urine for up to 5 hours. However, as it fills with urine and becomes larger, the bladder will send nerve impulses to the brain and stimulates the need to urinate

  3. The urine will be expelled through the urethra
• Aldosterone


  Makes kidney tubules more permeable to sodium; encourages sodium reabsorption, leading to more water reabsorption and more concentrated urine
• Antidiuretics


  Pituitary hormone that encourages water reabsorption in the kidney, thus concentrating the urine
• Coffee is a famous example for diuretic substances
• Sexual reproduction


  The creation of an offspring by fusion of haploid gametes, male sperm and female eggs, to form a diploid zygote
• Asexual reproduction


  The creation of offspring without the fusion of egg and sperm