URINARY SYSTEM/ EXCRETORY SYSTEM ■ The excretory system is the system of an organism's body that performs the function of excretion, the bodily process of discharging wastes. The Excretory system is responsible for the elimination of wastes produced by homeostasis. EXCRETORY SYSTEM ■ FUNCTION : IT ELIMINATES NITROGENOUS WASTES FROM THE BODY AND MAINTAIN WATER BALANCE ■ INVERTEBRATE ORGANS: EXCRETORY PORE, NEPHRIDIA AND MALPIGHIAN TUBULES ■ VERTEBRATES: SKIN, KIDNEYS, URETERS, URINARY BLADDER, URETHRA INVERTEBRATES EXCRETORY SYSTEM FOR INVERTEBRATES: FUNCTION ■ COLLECT WATER AND FILTER BODY FLUIDS ■ REMOVE AND CONCENTRATE WASTE PRODUCTS FROM THE BODY FLUIDS AND RETURN OTHER SUBSTANCES TO BODY FLUIDS AS NECESSARY FOR HOMEOSTATIS ■ ELIMINATE EXCRETORY PRODUCTS FROM THE BODY ORGANS ■ NEPHRIDIUM ■ Flatworms uses as their excretory organ ■ MALPHIGIAN TUBULES ■ Body fluids are drawn into the malphigian tubules by osmosis use to large concentrations of potassium inside the tubule ■ PROTONEPHRIDIA ■ Protonephridia are generally found in basal organisms such as in case of flatworms. Protonephridia is likely a defense mechanism which tend to cope with a hypotonic environment by removing excess water from the organism. AQUATIC INVERTEBRATE EXCRETION ■ Some aquatic invertebrates simply diffuse ammonia out of their bodies into the surrounding water ■ Example ; sponges, cnidarians and some round worms ■ Other aquatic invertebrates swell up with water, dilute the wastes and excrete the wastes through tiny pores in their skin TERRESTRIAL INVERTEBRATE EXCRETION ■ Many terrestrial invertebrates convert ammonia into urea. ■ Urea is a simpler nitrogenous compound that is much less toxic than ammonia. ■ This urea is eliminated from the body in the urine Porifera ■ All members of the Porifera phylum lack a distinct excretory system ■ Waste products such as ammonia diffuse into cells as water follows through its body Cnidarians ■ This phylum does not have a distinct excretory system ■ In some coelenterates the waste material diffuse into the surrounding through epidermal cells ■ Animals like sea anemones have a single opening Platyhelminthes ■ Excretory system consists of a network of fine protonephridia tubules embedded within the mesoderm ■ This excretory system main function is to remove excess water from the body of the organism ■ Organisms like flatworm possess defined excretory structures called protonephridia, which help in waste disposal Echinodermata ■ Echinoderms have a primary organs for excretion but instead release the nitrogenous waste in the form of ammonia through their respiratory system. ■ The anus though is located most echinoderms and used for jettison waste. Mollusca ■ The mollusks undigested food becomes a solid waste that is eliminated through the anus as feces. ■ The mollusks use a simple tubed shaped organ called the nephridia to eliminate the ammonia from the blood stream and to the outside. Arthropoda ■ Arthropoda have what is considered a complete excretory system which means they have a mouth, anus and digestive system ■ Lobsters excrete their waste through their antennae. This acts a method to retain water as it does not have to expend energy to pass waste ANNELIDA ■ Nephridia are organs of excretion in annelids. ■ The nephridia are coiled tubules with an expanded funnel-shaped nephrostome. ■ Filtration of the blood across the tubule wall can occur because of the close association between capillaries and the nephridium. VERTEBRATES VERTEBRATE EXCRETION ■ Aquatic vertebrates kidneys and rely on gill slits to release excretory wastes into surrounding water for dilution ■ Terrestrial vertebrates rely on the kidney’s to filter out the ammonia and change it into urea and send it to be released in urine EXCRETION REGULATION OF BLOOD AND VOLUME PRESSURE FUNCTIONS (HUMAN BODY) REGULATION OF THE CONCENTRATION OF SOLUTES IN THE BLOOD REGULATION OF EXTRACELLULAR FLUID PH REGULATION OF RED BLOOD CELL SYNTHESIS REGULATION OF VITAMIN D SYNTHESIS HUMAN BODY (URINARY SYSTEM) ■ KIDNEY ■ URETER ■ URINARY BLADDER ■ URETHRA KIDNEY ■ The kidney in mammals are bean-shaped organs that lie in the abdominal cavity attached to the dorsal wall on either side of the spine ■ A cavity within the kidney called pelvis collects the urine and carries it to the ureter, which connects with the bladder where the urine is stored temporarily ■ Rings of the muscle (sphincters) control the release and the urine leaves the body through urethra. URETER ■ the duct by which urine passes from the kidney to the bladder URINARY BLADDER ■ The urinary bladder is a muscular sac in the pelvis, just above and behind the pubic bone. When empty, the bladder is about the size and shape of a pear. URETHRA ■ a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body. THE NEPHRON ■ Consists of a cup shaped capsule containing capillaries and the glomerulus and a long renal tube. ■ Functional unit of kidney ■ Function: ■ Glomerular filtration of water and solutes from the blood ■ Tubular reabsorption of water and conserved molecules back into the blood ■ Tubular secretion of ions and other waste products from surrounding capillaries into the distal tubule URINE PRODUCTION ■ FILTRATION ■ TUBULAR REABSORPTION ■ TUBULAR SECRETION Fish ■ Fish utilize kidneys to filter out the wastes from their blood and then use their skin and gills to excrete nitrogenous wastes, ammonia and excess water (they rely a lot on diffusion) ■ Do not have a Loop of Henle Amphibians ■ In amphibians, nephrons in the kidneys filter out the nitrogenous wastes and excess water that get transported away along the ureter. ■ When they are in water, they absorb specific salts through their skin and the kidney then produces very dilute urine ■ When amphibians are on land they conserve water by reabsorbing water across the epithelium of the urinary bladder Reptiles ■ Reptiles have a very small kidney and in diapsids ■ Reptiles do not have the ability to produce liquid urine that is more concentrated than their own body fluid because they lack loop of Henle Birds ■ Birds require everything to be much lighter to assist them in flying more easily. Therefore they do not have a bladder, as it is too heavy ■ Instead the excretory system joins the digestive system by connecting the cloaca and the ureter, which results in a liquid excrement ( urine and feces are mixed) ■ Birds possess a loop of Henle; which assist in more efficient usage of water by reabsorbing some of it back into the blood
