BY 124 1st Edition Lecture 21 Outline of Last Lecture Chapter 11 I II III IV V VI VII VIII IX X XI XII Cell communication Signaling Figure 11 6 G protein coupled receptor Amplification Phosphorylation Cascade Second Messenger Systems Phospholipase C Hormones Figure 11 18 Steroid Hormones Cell death Chapter 45 I II III IV Hormone signaling Water vs Lipid soluble Epinephrine Pituitary Gland Outline of Current Lecture I How creatures keep homeostasis II Types of regulation III Types of excretory systems IV Excretory organs a Kidneys Current Lecture Chapter 44 I II How creatures keep homeostasis a Homeostasis b Osmoregulation c Excretion Types of regulation These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III IV a Isotonic don t have to do anything animals are called osmoconformers b Hypertonic animals are called osmoregulators c Hypotonic animals are called osmoregulators Types of excretory systems a Flat worms Figure 44 11 i Flame cells protonephridia strictly rids body of water ii Ammonia is rid of the body through the skin of the creature b Earthworms Figure 44 12 i Metanephridium ii Waste leaves through external opening in a segment c Terrestrial insects Figure 44 13 i Malpighian tubule 1 Water and nitrogenous wastes moves in these tubules and the things that are unwanted in the open circulatory system body are excreted through the anus d Tardigrades Figure 44 5 i Can go through anhydrobiosis can live with severe lack of water e Aquatic vertebrates Figure 44 3 i Use gills to get oxygen into body ii Salt water fish are hypertonic and therefore lose water 1 Need to get water so drink it To fix this issue of drinking salt water and introducing more salt into body they use transport epithelium a single layer of cells that face external environment and connected by tight junctions to secrete salt ions a Kidneys do not have to really worry about salt concentrations in the body and so do not urinate much iii Sharks cartilaginous fishes 1 Keep large amounts of urea in body and therefore act like freshwater fish keep salt inside body hypotonic 2 Loses salt to water so have to keep taking in water iv Freshwater fishes see above v Mammals most amphibians freshwater fish 1 Excrete urea 2 Sea turtles can produce both urea and ammonia vi Many reptiles birds insects 1 Excrete uric acid a Decreases water loss Excretory organs Figure 44 14 a Kidneys i Nephron functional unit of kidney 1 Renal artery afferent arteriole efferent arteriole 2 Glomerulus capillary 3 Tubules capillary ii Function figure 44 10 1 Filtration of blood a Once inside nephron it is called filtrate 2 Reabsorption things go back in blood 3 Secretion things in interstitial fluid move into nephron 4 Excretion waste leaves body as urine iii Parts of a nephron figure 4 15 1 Bowmann s capsule cup like structure a Filtration occurs here b Very efficient c Contains little filters called podocytes d Little things that can be transported passively will be transported into out of nephron e Bigger things like blood cells can t pass passively i Nutrients are transported out of nephron want to get these back in body active transport ii Salt 1 Water moves passively because it ends up following the salt concentration f Study figure 2 Moves to Proximal tubule 3 Then to Loop of Henle countercurrent exchange a Descending loop only permeable to water i Water leaves here passively in outer medulla b Ascending loop only permeable to salt i Salt leaves here passively in inner medulla 1 Actively in outer medulla 4 Distal tubule is next a Most things leave tubule actively back to body because this allows for better control i If you need to reabsorb some things then you can but if not then you don t have to 5 Lastly is collecting duct that opens into renal duct a Final collection place b Some urea reenters body c Salt and urea create a solute concentration in outer medulla that allows the body kidney to reabsorb more water rather than excrete too much of it d Urea will eventually reach Bowmann s capsule again and will be reabsorbed to be excreted iv Kidney regulation Figure 44 16 1 ADH made by hypothalamus and excreted by posterior pituitary 2 Stimulus signals hypothalamus to create ADH due to increase in blood osmolarity maybe blood is too thick 3 Causes you to get thirsty which makes you drink water and thus thin out blood a little bit 4 Also the ADH increase leads to an increase in permeability in the distal tubule which prevents further osmolarity increase 5 Figure 44 20 v Figure 44 22 1 Juxtaglomerular apparatus a Release renin when there is a low blood volume or blood pressure b Renin activates Angiotensin I which is translated to Angiotensin II by ACE c Angiotensin II activates adrenal gland to produce aldosterone which increases Na and water reabsorption in distal tubules which increases blood volume 2 Atrial natriuretic protein opposite from above vi Threshold things move into nephron from blood to help regulate threshold vii Differences between other animal kidneys 1 Desert animals have long loops of Henle because they need to reabsorb as much water as possible 2 Whales and fish do not drink salt water so thus do not have to excrete as much water 3 Birds have nasal salt glands that release excess water and this is why they can drink salt water b Ureter connects kidneys to bladder c Bladder holds waste Urethra empties bladder