Formation of Urine PDF

Formation of Urine  What is Excretion? Getting rid of metabolic waste. For single celled organisms such as an amoeba, wastes are removed by simple diffusion  Unicellular → Multicellular Unicellular...

Formation of Urine  What is Excretion? Getting rid of metabolic waste. For single celled organisms such as an amoeba, wastes are removed by simple diffusion  Unicellular → Multicellular Unicellular Multicellular All cells in direct contact with Internal cells not in direct contact environment with environment All cells can easily get nutrients in Internal cells can’t get nutrients in & & waste out by diffusion waste out Need organ systems  An Example: Deamination Digesting protein makes a poison! nitrogen waste = ammonia = poison Amino acids make up protein They look like this: This part is the amino group. It is removed and converted into ammonia (NH33) in the liver. liver. Ammonia is toxic and cannot build up in the body, so it is combined with CO2 and converted to urea This part is converted to (only slightly toxic) carbohydrate.  Anatomy The excretory system is composed of the kidneys, ureter, urinary bladder, and urethra kidneys – main filtering organs other structures – used for the transport and storage of the waste products that are to be excreted What does it do? The excretory system takes blood and filters it. Waste products are removed (excretion) Fluids, e.g. water, are kept constant (osmoregulation)  The kidneys The kidney is a fist-sized organ found on the abdominal wall on either side of the spinal column. There are two kidneys – distinctive kidney bean shape At any given moment about 25% of the body’s blood supply can be found in the kidneys What gets removed? Ammonia/ Urea from the breakdown of excess protein Uric acid from the breakdown of nucleic acids like DNA/ RNA The filters Nephrons are the tiny parts inside the kidney that does the filtering. There are lots of nephrons in our kidneys! Nephrons Two main parts: The tube (nephron) Blood supply From the renal artery To the renal vein Quick Review: Parts of the Excretory System The renal vein carries deoxygenated The renal artery carries blood from the kidney oxygenated blood to the kidney The Ureters (2) carry urine from the kidney to the bladder The Urethra carries urine from the bladder and out of the body Self Check Which structure of the excretory system… 1....carries deoxygenated blood away from the kidney? 2....carries oxygenated blood to the kidney? 3....carries urine from the bladder out of the body? 4....carries urine from the kidney to the bladder? 5....is the specific location of blood filtration in the kidney? Our Focus Today: Nephrons Long tubules (and associated capillaries) where blood is filtered There are about 1 million nephrons per kidney Forming Urine Stage 1: Filtration ○ Fluids and solutes move into Bowman’s Capsule Stage 2: Reabsorption ○ Essential solutes and water are transferred from Nephron back into blood Stage 3: Secretion ○ Larger waste is transferred to the nephron (distal tubule) using active transport Watch the Video and….. Write in key concepts around the diagram on the next slide using textboxes Or Make yourself a handwritten sketch note  https://www.youtube.com/watch?v=8UVlXX-9x7Q Filtration Bowman’s capsule (catches everything that is pushed out of the blood) Efferent arteriole Things that get pushed (filtered blood) out of blood: H2O Glomerulus K+ (curled up mass of capillaries that push the NaCl blood at high pressure so it can be filtered) HCO3- creatinine Substances NOT urea transported across: Blood cells, platelets glucose and other large non Afferent arteriole amino acids dissolved particles will (unfiltered blood) not pass through 2. Reabsorption Glucose is needed for Movement of respiration substances OUT of Water and salt may be the tubules across needed to balance interstitial fluid into osmosis and ensure the blood of capillaries concentration of the plasma is correct. Reabsorption About 120ml is filtered through the nephrons every minute! If not reabsorbed you’d make this much urine each minute!!! Reabsorption requires both active and passive transport  Proximal Tubule reabsorption Capillaries (The blood supply that will take back the Things that come necessary things from the nephron. It might also put things into the nephron) back into the blood (mostly by active Proximal tubule transport): (the first curvy part of the nephron after the All glucose and Bowman’s capsule) amino acids most of the H2O, K+, NaCl, HCO3-  Loop of Henle - Reabsorption Descending Loop of Ascending Loop of Henle Henle Reabsorption NaCl is removed by active Water travels into transport blood by osmosis Causes a concentration NaCl becoming gradient to form concentrated in (H2O follows by osmosis) the loop Thin segment of the descending Loop of Thin segment of the Henle is impermeable to ascending Loop of Henle solutes, but permeable is impermeable to to water water, but permeable to solutes True or False? 1. Filtration occurs in the nephron 2. Glucose, amino acids, vitamins and hormones are reabsorbed in the distal convoluted tubule 3. NaCl is removed in the descending limb of the loop of Henle 4. NaCl becomes concentrated in the descending limb of the loop of Henle as water moves out 5. Blood is filtered by the glomerulus and only waste travels into the Bowman’s capsule  Distal Convoluted Tubule Reabsorption (body regains needed substances) NaCl and H2O (especially if body is dehydrated) Na+ and water permeability regulated by the hormones aldosterone, antidiuretic hormone The blood secretes the following directly into the nephron: Excess H+ ions Excess minerals such as K+ Drugs Toxins Cells full of mitochondria line the distal tubule to power active transport which works to fine-tune homeostasis Collecting duct reabsorption Some things are Collecting duct (things that remain in reabsorbed and goes the distal tubule ends up here) back into the blood: A little Urea A little NaCl Water Excreted material (goes to ureter then to bladder)  Collecting duct excretion These things stay in the nephron and leave the Collecting duct (things that remain in body: the distal tubule ends up here) water creatinine urea, NaCl Excreted material K+ (goes to ureter then to HCO3- bladder) Why is this whole process important? Removes about 25 grams of urea a day Maintains homeostasis by adjusting amount of water allowed to leave the body Whose kidneys are absorbing the most water? Who is likely the most thirsty?  The nephron osmoregulation - a little bit more about your pee! The urine released into the pelvis is more or less concentrated depending upon the blood concentration Excessive sweating and eating salty food will produce concentrated urine Drinking and cold weather will produce dilute urine Why won’t drinking ocean water save you from dehydration?  Drinking ocean water or having a high salt diet increases the [NaCl] inside your body Your body will get rid of the excess salt by removing it in the kidneys to the urine H2O diffuses into the nephron to dilute the urine (osmosis) and is lost. More water is lost as urine then absorbed by the body!  For Today practice slides Look at diagrams on page 450-452 and make sure you understand them and could explain them to a friend (practice talking through it) Add details from table 1 page 452 to your notes to fill in understanding Flow chart for lab (see outline) Optional: Read this and answer the questions Page 454 #3-6 (optional) Extra help videos if needed Watch the videos: Kidney Anatomy Handwritten Tutorial https://www.youtube.com/watch?v=7bpTiqe5R6c Nephron Anatomy Handwritten Tutorial https://www.youtube.com/watch?v=k5IF1j7b3fI Glomerular Histology Handwritten Tutorial https://www.youtube.com/watch?v=EZhYTnRiPaA Nephron Function Handwritten Tutorial https://www.youtube.com/watch?v=vNvZaGcLzEo