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Comparative Anatomy 2 Biology 2 Thursday, April 4, 2013 Comparative Anatomy • study of similarities and differences between organisms • circulatory systems - open vs closed, single loop vs double loop • respiratory systems - skin, gills, trachea, lungs Thursday, April 4, 2013 Excretory Systems • osmoregulation - salt and water balance • remove nitrogenous waste from protein breakdown • Protein metabolism produces ammonia • Fish and aquatic invertebrates excrete ammonia directly to water across skin or gills • Mammals, Adult amphibians and sharks convert ammonia to urea which is less toxic and requires less water for excretion. • Birds, reptiles and insects convert ammonia to uric acid which requires very little water for excretion Thursday, April 4, 2013 cell/organism water x ion or molecule Osmoregulation x x x x x x x x x x x x x x x x x x isotonic no net movement of water or salts Thursday, April 4, 2013 H2O x Fresh water body has more solutes than surroundings x x x H 2O x x x x x x x x x x x x x x x x x x x x x x x Salt water if body has less solutes than surroundings No excretory system • many marine invertebrates • release ammonia across surface • body is isotonic to seawater x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x Thursday, April 4, 2013 Protonephridia • found in flatworms • earliest excretory system in terms of evolution • there are numerous flame cells which are ciliated cells that draw water into the system. • a system of tubules carries the water to excretory pores in skin • mostly salt/water balance http://www.youtube.com/watch?v=Rb_3KIB4CmE Thursday, April 4, 2013 Malpighian Tubules • these are tubules that empty into gut in abdominal region •collect wastes from coelom •found in insects •see diagram on handout and in textbook Thursday, April 4, 2013 Green Gland • found in crustaceans at base of antennae •excretes excess salt •other waste diffuses across gills •see diagram on handout and in text Thursday, April 4, 2013 Metanephridia • found in annelids, pair in each segment •excrete excess salt • a funnel shaped nephridiostome collects fluid from coelom. •A convoluted tubule carries material to nepridiopore which is an opening in the body wall. The tubules cross the septa into the adjacent segment. •Salt and water are adjusted as fluid flows through tubule. •See diagram on handout and in text. Thursday, April 4, 2013 Urinary System • found in vertebrates • see diagram in text and handout • in mammals, it consists of • 2 kidneys • 2 ureters - carry urine from kidney to bladder • 1 urinary bladder - stores urine • 1 urethra - carries urine to surface Thursday, April 4, 2013 Kidneys • filter blood • composed of many nephrons and blood vessels • see diagram on handout and in textbook • in the nephron capsule, fluid and dissolved molecules leave blood and enter nephron • as fluid flows through nephron tubules, salt and water levels are adjusted, needed materials such as sugars are reabsorbed • waste materials flow into collecting tubules which merge to form ureters. Thursday, April 4, 2013 Salt Glands • Some marine birds and mammals have glands to secrete excess salt. Thursday, April 4, 2013 Cartilaginous Fish • Retain urea in tissue • Body is isotonic to seawater Na+ Na+ urea Na+ Na+ urea urea Na+ Na+ Thursday, April 4, 2013 Na+ Na+ Na+ Na+ Na+ Na+ Marine Bony Fish • Drink seawater to replace water lost to diffusion • Gills actively pump out salt. Na+ Na+ Na+ Na+ Na+ + Na Na+ Na+ Na+ Thursday, April 4, 2013 H2O Na+ Na+ Na+ Na+ Freshwater Bony Fish • Body fluids more concentrated than freshwater • Diffusion results in water gain, salt loss • Gills actively pump in salt. • Produce dilute urine to rid body of water. Na+ H2O Na+ + Na + Na Na+ Thursday, April 4, 2013 Lymphatic System • addition to circulatory system in vertebrates • produces cells that defend against disease • removes and cleanses excess tissue fluid • mammalian system includes lymphatic vessels, lymph nodes, thymus, spleen, tonsils and bone marrow. • note that it drains into vein near heart • see diagram in textbook • fish do not have vessel system, only birds and mammals have lymph nodes. Thursday, April 4, 2013 Defense Cells • found in lymphatic organs • also circulate in blood Lymphocytes “specific immunity” Thursday, April 4, 2013 Macrophages “engulf material” Lymph Vessels • lymph capillaries - pick up debris & excess fluid from tissues • merge into progressively larger lymph vessels • connect to vein near heart Thursday, April 4, 2013 Lymph Nodes • found along lymphatic vessels • concentrated in neck, armpit and groin • contain lymphocytes and macrophages to cleanse fluid • note that there are several vessels going in but one coming out so fluid spends time in node for cells to cleanse. • see diagram on handout and textbook Thursday, April 4, 2013 Antigen • Substance that triggers defense response Common Antigens: • viruses • bacteria • parasites • transplanted tissue Thursday, April 4, 2013 Non-specific defenses • Defenses that work against a wide variety of invaders • macrophages and other phagocytic cells • skin and mucus membranes (line gut, respiratory system) are physical and chemical barriers • some blood proteins attack invaders - interferon (viruses), complement (bacteria) Thursday, April 4, 2013 Specific Defense • Responses specific to a particular invader • aka Immune System Y Y Y Y Y B Lymphocytes •mature in bone marrow •produce and release antibodies against antigen (e.g. bacteria) •different B cells respond to different antigens Thursday, April 4, 2013 Y T Lymphocytes •mature in thymus •lymphocyte itself kills antigen (e.g. virus) containing cells •different T cells respond to different antigens