3BIG IDEA 2: Biological systems utilize energy and molecular building blocks to grow, to reproduce, and to maintain homeostasis.BIG IDEA 3: Living systems store, retrieve, transmit, and respond to information essential to life processes.BIG IDEA 4: Biological systems interact, and these interactions possess complex properties.
4We will cover….. Feedback control AGAIN! Evolutionary development of animal organ systems to control homeostasis with the environmentCellular signalingSpecific systems: endocrine, nervous, immunePlants – homeostatic`mechanisms and how they respond
5Organism Organization CellsTissuesOrgansOrgan Systems (not technically in plants)OrganismThe structure of a component of an organism underlies its function.
6Homeostasis occurs in ALL organisms Involves all levels (except unicellular organisms): cells, organs, organismsReflects continuity and changeShaped by evolutionAffected by disruptionsDefenses evolved to maintain
7Remember….Body systems coordinate their activities to maintain homeostasis.
21Other thermoregulatory mechanisms InsulationEvaporative heat lossBehavioral responsesRegulation of metabolic heat- endotherms use metabolic heat tomaintain their body temp- ectotherm gain heat mostly fromenvironment
22Raising temp metabolically Mammals and birds regulate rate of metabolic heat production through activity and shivering.Some mammals generate heat through nonshivering thermogenesis, rise in metabolic rate produces heat instead of ATP.Some mammals have brown fat for rapid heat production.
23Negative feedback: control of sugar in the blood
29Homeostatic mechanisms and organ systems are shaped by evolution. Excretory systems deal with osmoregulation (water balance) and excretion of nitrogenous wastes
30osmoregulationProkaryotes respond via altered gene expression to changes in the osmotic environment Protists: Many have contractile vacuoles
31Freshwater: Water will diffuse into the fish, so it excretes a very hypotonic (dilute) urine to expel all the excess water. Gills uptake lost salt.A marine fish has an internal osmotic concentration lower than that of the surrounding seawater, so it tends to lose water and gain salt. It actively excretes salt out from the gills.
33dealing with nitrogenous wastes The excretory system in vertebrates:- maintains water, salt, and pH balance- removes nitrogenous wastes (from breakdown of protein and nucleic acids) by filtering the blood- nitrogenous waste type depends on environment
38The kidney works closely with the circulatory system in that the salt content, pH, and water balance of the blood is controlled by the kidneys.
39Within the kidney, fluid and dissolved substances are filtered from the blood and pass through nephrons where some of the water and dissolved substances (nutrients) are reabsorbed. The remaining liquid (including toxins) and wastes form urine.
40What homeostatic mechanisms work here? Concentrated blood (too much salt, too little water) signal receptors in the hypothalamus to stimulate release of ADH (AntiDiuretic Hormone) by the pituitary gland which influences kidney to reabsorbs water, making blood more dilute.
41Alcohol inhibits the release of ADH, causing the kidneys to produce dilute urine.
42If, on the other hand, a person drinks an excess of water, the sodium in the blood becomes more dilute and the release of ADH is inhibited.The lack of ADH causes the nephrons to become practically impermeable to water, and little or no water is reabsorbed from them back into the blood.Consequently, the kidneys excrete more watery urine until the water concentration of the body fluids returns to normal.
45The Respiratory System - delivers oxygen to and removes CO2 from the circulatory system and eventually the tissues- in humans, this occurs in the alveoli of the lungs which are covered in capillariesThe respiratory system works closely with the circulatory system.
50How does structure correlate with the function of the parts?
51What homeostatic mechanisms are at work here? Breathing is controlled by the medulla of the brainstem. It repeatedly triggers contraction of the diaphragm initiating inspiration.The rate of breathing changes with activity level in response to carbon dioxide levels, and to a lesser extent, oxygen levels, in the blood. Carbon dioxide lowers the pH of the blood (water and CO2 make carbonic acid H2CO3).Hemoglobin carries oxygen and also can carry bicarbonate ions (form of CO2)..
52There are chemosensors in the carotid artery and the arch of the aorta There are chemosensors in the carotid artery and the arch of the aorta . The sensors of the aortal are sensitive to the level of oxygen in the blood. Sensors near the medulla are sensitive to the level of carbon dioxide in the blood.If oxygen level falls or carbon dioxide levels vary too greatly from the set point, a negative feedback mechanism increases respiratory rate.
58Structures vary for types of animals: Fish – one ventricle, one atrium, gill capillaries, single loopAmphibian – one v, 2 a, lung and skin capillaries, double circulation (one to body, one to lungs)Reptiles – partially divided v, 2 a, other same as amphibsMammal, Birds – 2 v, 2 a, lung capillaries, double circulation
64Beating of the heart controlled when cardiac muscles transfers an electrical signal via the SA (sinoatrial) node or “pacemaker” (in top right atrium) to the AV (atrioventricular) node between the right a and v.
65Blood PressureForce of blood against an artery. Measured as Systolic (Super Top Most….when ventricles are contracting) over Diastolic (down, minimum, when ventricles fill with blood); normal 120/80
72PathwayOral Cavity – only carbs broken down here! Mechanical digestion - teethEsophagus – just a muscular tube, peristalsis pushed food downStomach – only protein broken down here! (low pH due to secretion of gastric juice), lots of churning in another muscular organ
73The Big Boys…..small intestines and accessory glands Carbs, proteins, and lipids broken down here.Most digestion and absorption here!Pancreatic enzymes and bile (for fat) from the liver via the gallbladder released in this area.Microvilli extend the surface area.
75Finishing up…Large intestine (colon)- no digestion, just reabsorbs water and creates feces
76Can you live without your…How? Stomach?Small Intestine?Large intestine?
77How does the homeostatic evolution of these systems reflect: ContinuityDivergence
78Case StudyThe story of Darlene Etienne and her miraculous homeostatic mechanisms!
79"We cannot really explain this because that's just (against) biological facts," Lambert told a news conference. "We are very surprised by the fact that she's alive. ... She's saying that she has been under the ground since the very beginning on the 12th of January so it may have really happened — but we cannot explain that."Authorities say it is rare for anyone to survive more than 72 hours without water, let alone 15 days. But Etienne may have had some access to water from a bathroom of the wrecked house, and rescuers said she mumbled something about having a little Coca-Cola with her in the rubble.Fuilla said Etienne did not suffer a broken leg, as first reported, but that both legs were trapped under debris. "Both legs are very sore," he said.
80Earthquake survival stories Rescuers said the 16-year-old, who was severely dehydrated and covered in dust, possibly survived by drinking bathwater but could not have lasted much longer.Earthquake survival stories