Osmoregulation and Excretion Chapter 44.1 to 44.4 Osmoregulation and Excretion

Selectively permeable membrane Fig. 44-2 Fill in the missing information. Selectively permeable membrane _________ Net water flow _________ Figure 44.2 Solute concentration and osmosis ______________ side __________________ side

Excretion of salt ions and small amounts of water in Fig. 44-4a Are saltwater fish losing or gaining water from its environment? Is there urine dilute or concentrated? Gain of water and salt ions from food Excretion of salt ions from gills Osmotic water loss through gills and other parts of body surface Figure 44.4a Osmoregulation in marine and freshwater bony fishes: a comparison Gain of water and salt ions from drinking seawater Excretion of salt ions and small amounts of water in scanty urine from kidneys (a) Osmoregulation in a saltwater fish

Uptake of salt ions by gills Fig. 44-4b Are freshwater fish losing or gaining water from its environment? Is there urine dilute or concentrated? Uptake of water and some ions in food Osmotic water gain through gills and other parts of body surface Uptake of salt ions by gills Figure 44.4b Osmoregulation in marine and freshwater bony fishes: a comparison Excretion of large amounts of water in dilute urine from kidneys (b) Osmoregulation in a freshwater fish

(a) Hydrated tardigrade (b) Dehydrated tardigrade Fig. 44-5 How have these organisms evolved to survive with little water? 100 µm 100 µm Figure 44.5 Anhydrobiosis (a) Hydrated tardigrade (b) Dehydrated tardigrade

Water balance in a kangaroo rat (2 mL/day) Water balance in a human Fig. 44-6a If both animals are mammals, why don’t they use the same method to obtain water? Water balance in a kangaroo rat (2 mL/day) Water balance in a human (2,500 mL/day) Ingested in food (0.2) Ingested in food (750) Ingested in liquid (1,500) Water gain (mL) Figure 44.6 Water balance in two terrestrial mammals Derived from metabolism (1.8) Derived from metabolism (250)

EXPERIMENT Nasal salt gland Nostril with salt secretions Ducts Fig. 44-7 How would the type of animal prey that a marine bird eats influence how much salt it needs to eliminate? EXPERIMENT Nasal salt gland Ducts Nostril with salt secretions Figure 44.7 How do seabirds eliminate excess salt from their bodies?

Proteins Nucleic acids Amino acids Nitrogenous bases Amino groups Fig. 44-9 Where does the amino group that is eliminated as waste product come from? How does the environment affect the form in which the amino group is eliminated? Proteins Nucleic acids Amino acids Nitrogenous bases Amino groups Most aquatic animals, including most bony fishes Mammals, most amphibians, sharks, some bony fishes Many reptiles (including birds), insects, land snails Figure 44.9 Nitrogenous wastes Ammonia Urea Uric acid

Filtration Capillary Excretory tubule Fig. 44-10 Match the statements with the functions in the diagram. Secretion: Toxins and excess ions are pulled from the blood to the filtrate. Filtration: Initial step of altering blood composition by moving water and solutes through Bowman’s capsule. Excretion: When the final filtrate called urine leaves exits. Reabsorption: The filtrate is adjusted by pulling out valuable substrates and returning them back into the body fluids. Filtration Capillary Filtrate Excretory tubule Figure 44.10 Key functions of excretory systems: an overview Urine

(a) Excretory organs and major associated blood vessels Fig. 44-14a What supplies blood to the kidneys? Drains blood away from the kidneys? vena cava Renal artery and vein Kidney Aorta Ureter Figure 44.14a The mammalian excretory system Urinary bladder Urethra (a) Excretory organs and major associated blood vessels

Renal medulla Renal cortex Renal pelvis Ureter Section of kidney Fig. 44-14b Where does fluid from the renal medulla initially collect? Where does all of that fluid collect? Renal medulla Renal cortex Renal pelvis Figure 44.14b The mammalian excretory system Ureter Section of kidney from a rat (b) Kidney structure 4 mm

10 µm Bowman’s capsule Glomerulus SEM Proximal tubule Distal tubule Fig. 44-14d What pattern can be seen in how the pathway of oxygenated and deoxygenated blood is laid out? 10 µm Glomerulus Bowman’s capsule SEM Proximal tubule Distal tubule Collecting duct Descending limb Figure 44.14d The mammalian excretory system Loop of Henle Ascending limb Vasa recta (d) Filtrate and blood flow

Proximal tubule Distal tubule Filtrate CORTEX Loop of Henle OUTER Fig. 44-15 Some cells lining tubules in the kidney synthesize organic solutes to maintain normal cell volume. Where in the kidney would you find these cells? Explain. Proximal tubule Distal tubule NaCl Nutrients H2O HCO3– H2O K+ NaCl HCO3– H+ NH3 K+ H+ Filtrate CORTEX Loop of Henle NaCl H2O OUTER MEDULLA NaCl NaCl Collecting duct Figure 44.15 The nephron and collecting duct: regional functions of the transport epithelium Key Urea Active transport NaCl H2O Passive transport INNER MEDULLA

Fig. 44-16-3 The drug furosemide blocks the contransporters for Na+ and Cl- in the ascending limb of the loop of Henle. What effect would you expect this drug to have on urine volume? Osmolarity of interstitial fluid (mOsm/L) 300 300 300 100 100 300 300 H2O NaCl H2O CORTEX 400 200 400 400 H2O NaCl H2O NaCl H2O NaCl H2O NaCl H2O NaCl H2O OUTER MEDULLA 600 400 600 600 Figure 44.16 How the human kidney concentrates urine: the two-solute model H2O NaCl H2O Urea H2O NaCl H2O 900 700 900 Key Urea H2O NaCl H2O Active transport INNER MEDULLA Urea 1,200 1,200 Passive transport 1,200

Fig. 44-17 What is the advantage of excreting waste as uric acid like this roadrunner does? Figure 44.17 The roadrunner (Geococcyx californianus), an animal well adapted for conserving water