-Discussion questions -What is your fitness level? -Do you agree with the findings?

1. -Discussion questions -What is your fitness level? -Do you agree with the findings? -Why or why not?

2. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • How animals regulate solute concentrations & • balance the gain & loss of water • What is excretion? • How animals get rid of nitrogenous waste of metabolism • What is the difference between an osmoregulator & an osmoconformer? • Osmoconformer – does not actively adjust its internal osmolarity • Isoosmotic to environment • Marine animals • Osmoregulator – actively controls osmolarity • NOT isoosmotic with environment

3. Osmotic water gain through gills and other parts of body surface Gain of water and salt ions from food and by drinking seawater Osmotic water loss through gills and other parts of body surface Uptake of water and some ions in food Uptake of salt ions by gills Excretion of large amounts of water in dilute urine from kidneys Excretion of salt ions and small amounts of water in scanty urine from kidneys Excretion of salt ions from gills (a) Osmoregulation in a saltwater fish (b) Osmoregulation in a freshwater fish Figure 44.3 Osmoregulation in marine and freshwater bony fishes • Hypoosmotic to ocean • loses LOTS of water at gills • “Drinks like a fish” • excretes salt & little urine • Hyperosmotic to lake • gain LOTS of water at gills • LOTS of dilute urine

4. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • Dehydration • Many adaptations to prevent this • What are the different nitrogenous waste products that animals excrete? • Ammonia • Urea • Uric acid

5. Nucleic acids Proteins Nitrogenous bases Amino acids –NH2 Amino groups Many reptiles (including birds), insects, land snails Most aquatic animals, including most bony fishes Mammals, most amphibians, sharks, some bony fishes O H C N C HN C O NH2 C C C O N N O NH3 NH2 H H Ammonia Urea Uric acid Figure 44.8 Nitrogenous wastes Ammonia – very soluble in water - VERY toxic - easily passes through membranes - 1 N at a time Urea - 100,000X less toxic than –NH3 - -NH3 + CO2 in liver - helps conserve water - 2 N at a time Uric acid- not very soluble in water - excreted in paste-like form - little water loss - stored in amniotic egg - 4 N at a time

6. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • Filtration • Reabsorption • Secretion • Excretion

7. Capillary 1 Filtration. The excretory tubule collects a filtrate from the blood. Water and solutes are forced by blood pressure across the selectively permeable membranes of a cluster of capillaries and into the excretory tubule. Excretory tubule Filtrate 2 Reabsorption. The transport epithelium reclaims valuable substances from the filtrate and returns them to the body fluids. 3 Secretion. Other substances, such as toxins and excess ions, are extracted from body fluids and added to the contents of the excretory tubule. 4 Urine Excretion. The filtrate leaves the system and the body. Figure 44.9 Key functions of excretory systems: an overview

8. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • How have excretory systems evolved? • Protonephridia – Planaria • Metanephridia – Earthworm • Malpighian tubules – insects • Kidney - us

9. Nucleus of cap cell Cilia Interstitial fluid filters through membrane where cap cell and tubule cell interdigitate (interlock) Tubule cell Flame bulb Protonephridia (tubules) Tubule Nephridiopore in body wall Figure 44.10 Protonephridia: the flame-bulb system of a planarian

10. Coelom Capillary network Bladder Collecting tubule Nephridio- pore Metanephridia Nephrostome Figure 44.11 Metanephridia of an earthworm

11. Digestive tract Rectum Hindgut Intestine Malpighian tubules Midgut (stomach) Feces and urine Salt, water, and nitrogenous wastes Anus Malpighian tubule Rectum Reabsorption of H2O, ions, and valuable organic molecules HEMOLYMPH Figure 44.12 Malpighian tubules of insects

12. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • How have excretory systems evolved? • What is the structure and function of the kidney?

13. Posterior vena cava Renal artery and vein Aorta Renal medulla Kidney Ureter Renal cortex Urinary bladder Urethra Renal pelvis (a) Excretory organs and major associated blood vessels Ureter Juxta- medullary nephron Section of kidney from a rat Cortical nephron (b) Kidney structure Afferent arteriole from renal artery Glomerulus Bowman’s capsule Renal cortex Proximal tubule Peritubular capillaries Collecting duct SEM 20 µm Efferent arteriole from glomerulus Distal tubule Renal medulla To renal pelvis Collecting duct Branch of renal vein Descending limb Loop of Henle (c) Nephron Ascending limb Vasa recta (d) Filtrate and blood flow Figure 44.13 The mammalian excretory system

14. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • How have excretory systems evolved? • What is the structure and function of the kidney? • What is the structure & function of the nephron?

15. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • How have excretory systems evolved? • What is the structure and function of the kidney? • What is the structure & function of the nephron? • Glomerulus – filtration due to BP • Proximal tubule – secretion & reabsorption • Loop of Henle • Descending – reabsorption • Ascending – reabsorption • Distal tubule – secretion & reabsorption • Collecting duct - reabsorption

16. Proximal tubule Distal tubule 1 4 NaCl Nutrients H2O HCO3 NaCl HCO3 H2O K+ H+ K+ H+ NH3 CORTEX Thick segment of ascending limb Descending limb of loop of Henle 3 2 Filtrate H2O Salts (NaCl and others) HCO3– H+ Urea Glucose; amino acids Some drugs NaCl H2O OUTER MEDULLA NaCl Thin segment of ascending limbs Collecting duct 3 5 Key Urea NaCl H2O Active transport Passive transport INNER MEDULLA Figure 44.14 The nephron and collecting duct: regional functions of the transport epithelium

17. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • How have excretory systems evolved? • What is the structure and function of the kidney? • What is the structure & function of the nephron? • What causes the movement of water out of the filtrate? • - Increasing salt concentration within the kidney

18. Osmolarity of interstitial fluid(mosm/L) 300 100 300 100 300 300 H2O CORTEX Activetransport 200 400 400 400 H2O Passivetransport H2O OUTERMEDULLA H2O 400 600 600 600 H2O 900 H2O 700 900 H2O INNERMEDULLA 1200 1200 1200 Figure 44.15 How the human kidney concentrates urine

19. Osmolarity of interstitial fluid(mosm/L) 300 100 300 100 300 300 Nacl H2O CORTEX Activetransport 200 400 400 400 Nacl H2O Passivetransport H2O Nacl OUTERMEDULLA Nacl H2O 400 600 600 600 H2O Nacl Nacl 900 H2O 700 900 Nacl H2O INNERMEDULLA 1200 1200 1200 Figure 44.15 How the human kidney concentrates urine

20. Osmolarity of interstitial fluid(mosm/L) 300 100 300 100 300 300 Nacl H2O H2O CORTEX Activetransport 200 400 400 400 Nacl H2O H2O Passivetransport H2O Nacl H2O OUTERMEDULLA Nacl H2O H2O 400 600 600 600 H2O Nacl H2O Urea Nacl 900 H2O H2O 700 900 Urea Nacl H2O H2O INNERMEDULLA 1200 Urea 1200 1200 Figure 44.15 How the human kidney concentrates urine

21. Chapter 44: Osmoregulation and Excretion • What is osmoregulation? • What is excretion? • What is the difference between an osmoregulator & an osmoconformer? • What is the biggest issue for land animals? • What are the different nitrogenous waste products that animals excrete? • What are the 4 main functions of excretory systems? • How have excretory systems evolved? • What is the structure and function of the kidney? • What is the structure & function of the nephron? • What causes the movement of water out of the filtrate? • How is blood osmolarity regulation? • - ADH • - RAAS

22. Homeostasis: Blood pressure, volume Osmoreceptors in hypothalamus Thirst Hypothalamus Increased Na+ and H2O reab- sorption in distal tubules Drinking reduces blood osmolarity to set point STIMULUS: The juxtaglomerular apparatus (JGA) responds to low blood volume or blood pressure (such as due to dehydration or loss of blood) ADH Increased permeability Pituitary gland Aldosterone Distal tubule Arteriole constriction Adrenal gland H2O reab- sorption helps prevent further osmolarity increase STIMULUS: The release of ADH is triggered when osmo- receptor cells in the hypothalamus detect an increase in the osmolarity of the blood Angiotensin II Distal tubule Collecting duct Angiotensinogen JGA Renin production Homeostasis: Blood osmolarity Renin (b) The renin-angiotensin-aldosterone system (RAAS) leads to an increase in blood volume and pressure. (a) Antidiuretic hormone (ADH) enhances fluid retention by making the kidneys reclaim more water. Figure 44.16 Hormonal control of the kidney by negative feedback circuits