Excretion The removal of cellular waste products. The metabolic activities of living organisms produce wastes. metabolic activity waste respiration dehydration synthesis protein* metabolism other metabolic activities CO 2, H 2 O H2OH2O nitrogenous wastes mineral salts *proteins contain nitrogen!

Proteins are composed of repeating units called _________________ amino acids Amino acids contain the element Nitrogen: O H H C C N OH R H When these amino acids are broken down (hydrolyzed), nitrogenous wastes are produced. This process is called _____________________ deamination Nitrogenous wastes vary from the extremely toxic to nontoxic as follows: extremely toxic less toxic nontoxic ammonia urea uric acid

Adaptations for Excretion 1. Protists (ameba, paramecium) CO 2 & H 2 O diffuse across the cell membrane excess H 2 O pumped out by contractile vacuole 2. Algae CO 2 from respiration is recycled/reused for photosynthesis

3. Plants recycle CO 2 & O 2 for photosynthesis and respiration toxic wastes are stored in vacuoles ( can be harmful to organisms that eat the plant)…go to excess gases leave stomates and lenticels See “Awesome Adaptations” sheet

Human Excretion excretionvs.egestion removal of metabolic wastes (CO 2, H 2 O, salts & nitrogenous wastes: ammonia, urea, uric acid) removal of undigested or indigestible material (fiber, corn, penny)

lungs 4. skin liver kidney

Organs of Excretion 1. Lungs- 2. Liver- ~aids in the emulsification of fat ~contains salts, cholesterol & urochrome “clearing house” of the body largest organ in the body breaks down dead and worn out RBCs hemoglobin found in RBC broken down to urochrome (yellow): the pigment in bile if bile isn’t eliminated properly, the skin becomes jaundice (yellow) ~eliminated with feces ~stored in gall bladderbile … CO 2 & H 2 O from aerobic respiration are removed when you exhale

The liver also disposes of nitrogenous wastes by makingurea : Proteins amino acids deamination bloodurea travels through sweat urine Deamination…breaks down an amino acid and removes the NH 2 group : O H H C C N OH R H The remaining C,H and O are available now to be reassembled into products that are useful to the body (very efficient!)

Ex).pyruvic acid- can enter the respiration pathway & produce energy glycogen- form of stored energy in animals fats- can be stored for energy The liver also detoxifies (makes harmless) substances such as alcohol

3.skin- contains sweat glands (coiled tubes in dermis) that have ducts leading to pores in the epidermis capillaries surround sweat glands: H 2 O, salts & urea diffuse from bloodgland to form sweat sweat regulates body T 0 /homeostasis when sweat evaporates and cools the skin

4. Urinary system A.consists of: 1. kidneys-filter waste from blood, produce urine 2. ureters-carry urine from kidney to bladder 3. urinary bladder-stores urine 4. urethra-carries urine from bladder out of body

B. Structure of the kidney 3. pelvis- 1. cortex- 2. medulla- outer region, blood is filtered, has nephrons middle, has collecting tubules & nephrons inner, connected to the ureter C. Nephron: the functional unit of the kidney 1. microscopic filtering units 3. located in the cortex and medulla 2. about 1 million/kidney (increased surface area for filtration)

cortex pelvis ureter urethra bladder ureter kidney adrenal gland renal vein renal artery medulla

D. Formation of Urine  occurs in the nephrons  consists of 2 stages: FILTRATION a. blood enters the glomerulus (bed of capillaries) b. substances under pressure move into the Bowman’s capsule c. this is called filtrate and contains: waterglucose saltsamino acids urea filtration filtration (of the blood) reabsorption reabsorption (when the blood reabsorbs the materials it needs)

Bowman’s capsule renal artery renal arteriole glomerulus renal vein capillary renal venule Loop of Henle collecting tubule good stuff waste reabsorbedcollected as urine

Note: blood cells and large molecules like proteins are too large to pass into Bowman’s capsule. If they detect blood or protein in your urine, there’s a problem! REABSORPTION a. Filtrate moves through the Loop of Henle d.Approx. 180 L filtrate/day produced but only 1 to 1.5L urine/day b/c ……. your kidneys reabsorb most of the filtrate to maintain water, salt and nutrient levels in your body. b.Most water, some salts & all glucose and amino acids are reabsorbed (returned to the blood) by the capillaries that surround the Loop of Henle. ~water diffuses ~other substances may require active transport

c. The fluid remaining in the tubule is called urine (water, salts, urea) e.Kidney threshold level ~most substances have a threshold level in the blood d. Urine passes to the collecting duct ureter bladder ~ if the blood concentration of a substance exceeds this level, the excess is NOT reabsorbed, but it is excreted Diuretic drugs- ex) sugar found in the urine of a diabetic Medications that decrease the amount of fluid/water in your body by INCREASING FILTRATION AND DECREASING REABSORPTION(of the fluid/water) An increase in fluid may be caused by (and a cause of) congestive heart failure, liver disease, kidney disease nephron clip \\Shsshared\SHSSHARED\Science Dept L\biomovies\nephron.mov \\Shsshared\SHSSHARED\Science Dept L\biomovies\nephron.mov

Disruption sheet

alveoli :: lungs villi :: small intestine :: kidney Functional unit analogy nephron

blood vessels /loop of Henle