Excretion AP Biology Ms. Day

Waste disposal H OH H N –C– C–OH R CO2 + H2O | | | | Animals can’t store extra proteins What waste products? What do we breakdown? carbohydrates = CHO  CO2 + H2O (in CR) lipids = CHO  CO2 + H2O (in CR) proteins = CHON  CO2 + H2O + N nucleic acids = CHOPN  CO2 + H2O + P + N relatively small amount in cell Can you store sugars? YES Can you store lipids? YES Can you store proteins? NO Animals do not have a protein storage system =can store H OH H N | | | CO2 + H2O –C– C–OH | NH2 + H+= ammonia R 2005-2006

Types of Nitrogenous Wastes Nitrogenous wastes = wastes that contain nitrogen Toxic by-products of metabolism Result from breakdown of proteins & nucleic acids 3 Types of wastes Ammonia (NH3) Excreting it directly is very efficient  no energy expended Very toxic!!! Ex: Marine fish Urea and Uric Acid Requires energy to convert -NH2 to these forms Less toxic (uric acid is more toxic than urea b/c not soluble in water) Ex: Mammals (urea) and Birds (uric acid)

VERY TOXIC; very soluble in H2O produced in liver VERY TOXIC; very soluble in H2O LESS TOXIC; soluble in H2O TOXIC; Form ppt  NOT soluble in H20

Mammalian Kidneys Bean shaped organs Fist sized Filters water and solutes such as toxins (except NO proteins…TOO BIG) from blood Make urine Helps maintain salt/H2O balance

Mammalian Kidney Two regions Renal cortex – outer Renal medulla – inner Both regions have nephrons Nephron the functional unit of the kidney Single long tube Has ball of capillaries called glomerulus Cup shaped structure at beginning of tube called “Bowman’s capsule” Surrounds the glomerulus like a funnel

Nephron Structure

Renal means “kidney”

Human Excretory System Unfiltered blood enters the kidney by the renal artery Filtered (clean) blood leaves by the renal vein Urine exits the kidney through a tube called the ureter Ureters drain into the urinary bladder Urine exits the bladder through the urethra Think “a” for away

The kidneys, ureters, bladder, and urethra make up the urinary tract.

Excretory System in Kidney Built on a complex network of tubules (TUBES!!!) Provides a large surface area for the exchange of water and solutes Including nitrogenous bases (ex: urea)

4 Main Steps in Excretory System 1 4 Main Steps in Excretory System 2 3 4

4 Main Processes of Excretory Systems 1. Filtration Blood goes through filter made of selectively permeable membranes Keeps proteins and other large molecules Blood pressure in renal artery forces water/small solutes into kidney Salts, Sugars, Amino acids, Nitrogenous wastes are filtered into tube/nephron This makes a liquid called the FILTRATE

Occurs in tubes and capillaries 2. Reabsorption Active transport used Water and valuable solutes (ex: Ca+2) are moved from filtrate (tubes) back to blood Required because filtration is not extremely selective 3. Secretion Solutes are removed from animal’s body and added to the filtrate Excess salts & toxins (like urea, drugs) Urine is drained into the renal pelvis Renal pelvis collect URINE before ureters get it 4. Excretion the filtrate (urine) leaves the system Occurs in tubes and capillaries

1 2 3 4 2 1= filtrate collected here from blood  into nephron 2= Reabsorption into blood occurs (osmosis /active transport) 3= secretion occurs in filtrate 4= urine is collected and dumped into renal pelvis  ureter  excreted into bladder!

Animation #4 URINE FORMED!! https://www.youtube.com/watch?v=TzwPmz5V6Xg https://www.youtube.com/watch?v=es-t8lO1KpA

Summary Not filtered out (remain in blood) Blood cells and proteins Reabsorbed: active transport Na+, Cl-, Ca+2 (at times), glucose and amino acids Reabsorbed: diffusion Na+ and Cl- Reabsorbed: osmosis H2O Excreted Urea, H2O, any excess solutes, toxins/drugs

Maintaining Water Balance Monitor blood osmolarity amount of dissolved material in blood Acts on collecting duct!! Drugs and other poisons pass from the peritubular capillaries into the interstitial fluid and then across the epithelium to the nephron’s lumen. ADH = anti-diuretic hormone 2005-2006

Any Questions??

http://wps. aw. com/bc_martini_eap_4/40/10469/2680237 http://wps.aw.com/bc_martini_eap_4/40/10469/2680237.cw/content/inde x.html http://www.dnatube.com/video/2754/Nephron-Function http://www.dnatube.com/video/8472/The-Nephron-Functional-Unit-of- Kidney http://www.dnatube.com/video/8599/Kidney-and-Nephron