Chapter 44 Regulation of body fluids 11 12 2015 Homeostasis Excretory System Osmoregulation looking at the amount of solute and the water balance Excretion how we will get rid of nitrogen o Nitrogen comes from protein and nucleic acid Osmoconformers don t have to do anything o Salt water vertebrates Osmoregulators needed in hypo hyper tonic solutions o Fresh water animals because water comes in Tubules of protoenphridia Platyhelminthes o Concerned with taking care of the water that diffuses into the animal Along tubules are flame cells lined with cilia Contractile vacuole in paramecium fills with water and squirts it out so that the cell won t lyse Earthworms have Metanephridium FIG 44 12 o Internal opening bladder external opening capillary network Terrestrial arthropods have malpighian tubules FIG 44 13 o Salt water and nitrogenous waste moves into the gut feces and urine come out through the anus Tardigrada o Moves form 85 water in body to 2 Anhydrobiosis the ability to lose great amounts of water and still survive for long periods of time FIG 44 3 Osmoregulation in marine fish o Gain of water and salt ions from food and drinking water o Excretion of salt ions from gills o Excretion of salt ions and small amounts of water in scanty urine from kidneys o Osmostic water loss though gills and other parts of body surface Osmoregulation in cartilaginous fish sharks o Water and salt in through food o Uptake of salt ions through gills o Osmotic water though gills and other surfaces o Ions and water lost in urine o Salt excreted by rectal gland o More like a fresh water fish because of the presence of urea Osmosregulation in fresh water fish o Gain of water and some ions in food o Uptake of salt ions by gills o Osmotic water gain through gills and other parts of the body o Excretion of salts through dilute large amounts of urine FIG 44 8 What animals produce to get rid of nitrogenous waster Most aquatic animals including most bony fish ammonia o Stick water to amino group and ammonia will diffuse out Mammals most amphibians sharks and some bony fish urea Many reptiles birds insects or land snails uric acid o Takes a little more time to make As moving down the you are saving water but increasing energy costs Animals that lay eggs will most likely produce uric acid as nitrogenous waste Not always because some creatures can change what they make Baby in egg will make uric acid but will switch to urea as an adult Terrestrial turtles uric acid EXCRETORY ORGANS Kidneys o Can get confused during embryonic development have 1 or 3 kidneys o Going to take care of the salts and water to remain in a homeostatic state o Renal cortex outer part of the kidney o Renal medualla follows the cortex o Contains nephrons millions in each kidney FIG 44 14 First part Bowman s capsule connects to the proximal tubule loop of Henle travels from cortex all the way to the inner medulla and back up connects to the distal tubule collecting duct sends the urine from the cortex down to the inner medulla and out into the kidney afferent arteriole travels into glomerulus capillary tuff that hangs out in Bowman s capsule efferent arteriole comes out of the glomerulus into the GOES THROUGH TWO SETS OF CAPILLARIES FIG 44 10 what do nephrons do Filtration blood that moves into the nephron is first filtrated Once filtrate is in the nephron reabsorption occurs to pull out important stuff that we don t want to leave the body Secretion movement of things from the interstitial fluid into the nephron Lastly excretion occurs nephron dumps waste out FIGURE 44 15 KNOW EVERYTHING ABOUT IT Podocytes special filters in Bowman s capsule BP moves things out of the blood and into Bowman s capsule ions water small molecules will all be pushed into Bowman s capsule o Filter about 49 gallons per day of filtrate o Body wants to get rid of waste with the least amount of water o Most people produce 2 5 liters of urine a day o Transport epithelium helps to move molecules across membranes membranes have different permeability on either side o FIGURE 44 15 pathways of ions Glucose and some amino acids are forced out from the blood but we will take this back up in proximal tube by active transport because passive will only give 50 Normal insulin levels should leave no glucose in blood Sodium chloride want to take back as much as we can so moves back up through active transport Anytime you move salt water follows passively Take back bicarbonate and potassium ions passively Hydrogen ions move actively regulating pH going back into tubule to be gone Loop of Henle we see a counter current exchange mechanism maximizes diffusion descending is only permeable to water and the ascending is only permeable to sodium chloride sodium follows chlorine Distal tubule final check looking at what is in the filtrate and what is in the interstitial fluid what do I need to do to maintain homeostasis sodium chloride goes out actively and water follows salt can get ride of hydrogen and potassium ions by secretion from interstitial fluids don t have to do things here unless extremely necessary Once it gets into collected duct it is pretty much a goner except for water and urea that can get put back into interstitial fluid by passive transport o Regulation in Kidney FIG 44 19 Osmoregulators in hypothalamus trigger release of ADH increase in blood osmolarity ADH moves into collecting ducts to pull water back into the blood cAMP second messenger Posterior vena cava Renal artery and vein Aorta Ureter o Runs from the kidney to the bladder Urinary bladder o Stores urine Urethra o Empties urine out of the body 11 12 2015 11 12 2015