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Mini-FRQ Enzymes are a huge part of digestion

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Presentation on theme: "Mini-FRQ Enzymes are a huge part of digestion"— Presentation transcript:

1 Mini-FRQ Enzymes are a huge part of digestion
Describe structure and function of an enzyme How are enzymes tied to digestion?

2 Why do we breathe oxygen?

3 Gas Exchange Respiratory Systems alveoli elephant seals gills

4 Why do we need a respiratory system?
Need O2 in for aerobic cellular respiration make ATP Need CO2 out waste product from Krebs cycle food ATP O2 CO2

5 Gas exchange O2 & CO2 exchange between environment & cells
need moist membrane need high surface area

6 Optimizing gas exchange
Why high surface area? maximizing rate of gas exchange CO2 & O2 move across cell membrane by diffusion rate of diffusion proportional to surface area Why moist membranes? moisture maintains cell membrane structure gases diffuse only dissolved in water small intestines large intestines capillaries mitochondria High surface area? High surface area! Where have we heard that before?

7 Evolution of gas exchange structures
Aquatic organisms external systems with lots of surface area exposed to aquatic environment Terrestrial Constantly passing water across gills Crayfish & lobsters paddle-like appendages that drive a current of water over their gills Fish creates current by taking water in through mouth, passes it through slits in pharynx, flows over the gills & exits the body moist internal respiratory tissues with lots of surface area

8 Lungs Exchange tissue: spongy texture, honeycombed with moist epithelium Why is this exchange with the environment RISKY? Lungs, like digestive system, are an entry point into the body lungs are not in direct contact with other parts of the body circulatory system transports gases between lungs & rest of body

9 Mammalian respiratory systems
Larynx (upper part of respiratory tract) Vocal cords (sound production) Trachea (windpipe) Bronchi (tube to lungs) Bronchioles Alveoli (air sacs) Diaphragm (breathing muscle)

10 Alveoli Gas exchange across thin epithelium of millions of alveoli
total surface area in humans ~100 m2

11 Negative pressure breathing
Breathing due to changing pressures in lungs air flows from higher pressure to lower pressure pulling air instead of pushing it

12 Take out April calendar
Share plan with tablemates to get A or B on all April quizzes 2) Change Sat, April 21 to Sat, April 14th 3) Come up with a structure is ties to function example

13 Counter current exchange system
Water carrying gas flows in one direction, blood flows in opposite direction Living in water has both advantages & disadvantages as respiratory medium keep surface moist O2 concentrations in water are low, especially in warmer & saltier environments gills have to be very efficient ventilation counter current exchange Why does it work counter current? Adaptation! just keep swimming….

14 How counter current exchange works
front back 70% 40% 100% 15% water 60% 30% 90% counter-current 5% blood water blood 50% 70% 100% 50% 30% 5% concurrent Blood & water flow in opposite directions maintains diffusion gradient over whole length of gill capillary maximizing O2 transfer from water to blood

15 Gas Exchange on Land Advantages of terrestrial life Disadvantages
air has many advantages over water higher concentration of O2 O2 & CO2 diffuse much faster through air respiratory surfaces exposed to air do not have to be ventilated as thoroughly as gills air is much lighter than water & therefore much easier to pump expend less energy moving air in & out Disadvantages keeping large respiratory surface moist causes high water loss reduce water loss by keeping lungs internal Why don’t land animals use gills?

16 Terrestrial adaptations
Tracheae air tubes branching throughout body gas exchanged by diffusion across moist cells lining terminal ends, not through open circulatory system How is this adaptive? No longer tied to living in or near water. Can support the metabolic demand of flight Can grow to larger sizes.

17 Mechanics of breathing
Air enters nostrils filtered by hairs, warmed & humidified sampled for odors Pharynx  glottis  larynx (vocal cords)  trachea (windpipe)  bronchi  bronchioles  air sacs (alveoli) Epithelial lining covered by cilia & thin film of mucus mucus traps dust, pollen, particulates beating cilia move mucus upward to pharynx, where it is swallowed

18 Breathing and Homeostasis
ATP Homeostasis keeping the internal environment of the body balanced need to balance O2 in and CO2 out need to balance energy (ATP) production Exercise breathe faster need more ATP bring in more O2 & remove more CO2 Disease poor lung or heart function = breathe faster need to work harder to bring in O2 & remove CO2 CO2 O2

19 Hemoglobin Why use a carrier molecule? Reversibly binds O2
O2 not soluble enough in H2O for animal needs blood alone could not provide enough O2 to animal cells hemocyanin in insects = copper (bluish/greenish) hemoglobin in vertebrates = iron (reddish) Reversibly binds O2 loading O2 at lungs or gills & unloading at cells heme group The low solubility of oxygen in water is a fundamental problem for animals that rely on the circulatory systems for oxygen delivery. For example, a person exercising consumes almost 2 L of O2 per minute, but at normal body temperature and air pressure, only 4.5 mL of O2 can dissolve in a liter of blood in the lungs. If 80% of the dissolved O2 were delivered to the tissues (an unrealistically high percentage), the heart would need to pump 500 L of blood per minute — a ton every 2 minutes. cooperativity

20 Cooperativity in Hemoglobin
Binding O2 binding of O2 to 1st subunit causes shape change to other subunits conformational change increasing attraction to O2 Releasing O2 when 1st subunit releases O2, causes shape change to other subunits lowers attraction to O2

21 Transporting CO2 in blood
Dissolved in blood plasma as bicarbonate ion Tissue cells Plasma CO2 dissolves in plasma CO2 combines with Hb CO2 + H2O H2CO3 H+ + HCO3– HCO3– CO2 Carbonic anhydrase Cl– carbonic acid CO2 + H2O  H2CO3 bicarbonate H2CO3  H+ + HCO3– carbonic anhydrase

22 Releasing CO2 from blood at lungs
Lower CO2 pressure at lungs allows CO2 to diffuse out of blood into lungs Plasma Lungs: Alveoli CO2 dissolved in plasma HCO3–Cl– CO2 H2CO3 Hemoglobin + CO2 CO2 + H2O HCO3 – + H+

23 Chapter 42 ~ Circulation and Gas Exchange

24 Exchange of materials Animal cells exchange material across their cell membrane fuels for energy nutrients oxygen waste (urea, CO2) If you are a 1-cell organism that’s easy! diffusion If you are many-celled that’s harder

25 In circulation… What needs to be transported nutrients & fuels
from digestive system respiratory gases O2 & CO2 from & to gas exchange systems: lungs, gills intracellular waste waste products from cells water, salts, nitrogenous wastes (urea) protective agents immune defenses white blood cells & antibodies blood clotting agents regulatory molecules hormones

26 Circulatory systems All animals have: open closed
circulatory fluid = “blood” tubes = blood vessels muscular pump = heart open closed hemolymph blood

27 Open circulatory system
Taxonomy invertebrates insects, arthropods, mollusks Structure no separation between blood & interstitial fluid hemolymph The fact that open and closed circulatory systems are each widespread among animals suggests that both offer advantages. For example, the lower hydrostatic pressures associated with open circulatory systems make them less costly than closed systems in terms of energy expenditure. Furthermore, because they lack an extensive system of blood vessels, open systems require less energy to build and maintain. And in some invertebrates, open circulatory systems serve a variety of other functions. For example, in molluscs and freshly molted aquatic arthropods, the open circulatory system functions as a hydrostatic skeleton in supporting the body.

28 Closed circulatory system
closed system = higher pressures Taxonomy invertebrates earthworms, squid, octopuses vertebrates Structure blood confined to vessels & separate from interstitial fluid 1 or more hearts large vessels to smaller vessels material diffuses between blood vessels & interstitial fluid What advantages might be associated with closed circulatory systems? Closed systems, with their higher blood pressure, are more effective at transporting circulatory fluids to meet the high metabolic demands of the tissues and cells of larger and more active animals. For instance, among the molluscs, only the large and active squids and octopuses have closed circulatory systems. And although all arthropods have open circulatory systems, the larger crustaceans, such as the lobsters and crabs, have a more developed system of arteries and veins as well as an accessory pumping organ that helps maintain blood pressure. Closed circulatory systems are most highly developed in the vertebrates.

29 Vertebrate circulatory system
Adaptations in closed system number of heart chambers differs 2 3 4 high pressure & high O2 to body low pressure to body low O2 to body What’s the adaptive value of a 4 chamber heart? 4 chamber heart is double pump = separates oxygen-rich & oxygen-poor blood; maintains high pressure

30 Circulation system evolution
Fish: 2-chambered heart; single circuit of blood flow Amphibians: 3-chambered heart; 2 circuits of blood flow- pulmocutaneous (lungs and skin); systemic (some mixing) Mammals: 4-chambered heart; double circulation; complete separation between oxygen-rich and oxygen poor blood

31 Evolution of 4-chambered heart
Selective forces increase body size protection from predation bigger body = bigger stomach for herbivores endothermy can colonize more habitats flight decrease predation & increase prey capture Effect of higher metabolic rate greater need for energy, fuels, O2, waste removal endothermic animals need 10x energy need to deliver 10x fuel & O2 to cells convergent evolution

32 Vertebrate cardiovascular system
Chambered heart atrium = receive blood ventricle = pump blood out Blood vessels arteries = carry blood away from heart arterioles veins = return blood to heart venules capillaries = thin wall, exchange / diffusion capillary beds = networks of capillaries Arteries, veins, and capillaries are the three main kinds of blood vessels, which in the human body have a total length of about 100,000 km. Notice that arteries and veins are distinguished by the direction in which they carry blood, not by the characteristics of the blood they contain. All arteries carry blood from the heart toward capillaries, and veins return blood to the heart from capillaries. A significant exception is the hepatic portal vein that carries blood from capillary beds in the digestive system to capillary beds in the liver. Blood flowing from the liver passes into the hepatic vein, which conducts blood to the heart.

33 Blood vessels arteries arterioles capillaries venules veins veins
artery arterioles venules arterioles capillaries venules veins

34 Arteries: Built for high pressure pump
thicker walls provide strength for high pressure pumping of blood narrower diameter elasticity elastic recoil helps maintain blood pressure even when heart relaxes

35 Veins: Built for low pressure flow
thinner-walled wider diameter blood travels back to heart at low velocity & pressure lower pressure distant from heart blood must flow by skeletal muscle contractions when we move squeeze blood through veins valves in larger veins one-way valves allow blood to flow only toward heart Blood flows toward heart Open valve Closed valve

36 Capillaries: Built for exchange
very thin walls lack 2 outer wall layers only endothelium enhances exchange across capillary diffusion exchange between blood & cells

37 Controlling blood flow to tissues
Blood flow in capillaries controlled by pre-capillary sphincters supply varies as blood is needed after a meal, blood supply to digestive tract increases during strenuous exercise, blood is diverted from digestive tract to skeletal muscles capillaries in brain, heart, kidneys & liver usually filled to capacity sphincters open sphincters closed

38 Exchange across capillary walls
Lymphatic capillary Fluid & solutes flows out of capillaries to tissues due to blood pressure “bulk flow” Interstitial fluid flows back into capillaries due to osmosis plasma proteins  osmotic pressure in capillary BP > OP BP < OP Interstitial fluid What about edema? About 85% of the fluid that leaves the blood at the arterial end of a capillary bed reenters from the interstitial fluid at the venous end, and the remaining 15% is eventually returned to the blood by the vessels of the lymphatic system. Blood flow 85% fluid returns to capillaries Capillary 15% fluid returns via lymph Arteriole Venule

39 Blood Plasma: liquid matrix of blood in which cells are suspended (90% water) Erythrocytes (RBCs): transport O2 via hemoglobin Leukocytes (WBCs): defense and immunity Platelets: clotting Stem cells: pluripotent cells in the red marrow of bones Blood clotting: fibrinogen (inactive)/ fibrin (active); hemophilia; thrombus (clot)

40 Lymphatic system Parallel circulatory system
transports white blood cells defending against infection collects interstitial fluid & returns to blood maintains volume & protein concentration of blood drains into circulatory system near junction of vena cava & right atrium

41 Lymph system Production & transport of WBCs Traps foreign invaders
lymph vessels (intertwined amongst blood vessels) lymph node

42 Mammalian heart to neck & head & arms Coronary arteries

43 Mammalian circulation
systemic pulmonary systemic What do blue vs. red areas represent?

44 Coronary arteries bypass surgery

45 Valves tm

46 Heart valves 4 valves in the heart Atrioventricular (AV) valve
SL 4 valves in the heart flaps of connective tissue prevent backflow Atrioventricular (AV) valve between atrium & ventricle keeps blood from flowing back into atria when ventricles contract “lub” Semilunar valves between ventricle & arteries prevent backflow from arteries into ventricles while they are relaxing “dub” The heart sounds heard with a stethoscope are caused by the closing of the valves. (Even without a stethoscope, you can hear these sounds by pressing your ear tightly against the chest of a friend—a close friend.) The sound pattern is “lub–dup, lub–dup, lub–dup.” The first heart sound (“lub”) is created by the recoil of blood against the closed AV valves. The second sound (“dup”) is the recoil of blood against the semilunar valves.

47 Lub-dub, lub-dub Heart sounds Heart murmur closing of valves “Lub”
recoil of blood against closed AV valves “Dub” recoil of blood against semilunar valves Heart murmur defect in valves causes hissing sound when stream of blood squirts backward through valve SL AV AV

48 Cardiac cycle systolic ________ diastolic pump (peak pressure)
1 complete sequence of pumping heart contracts & pumps heart relaxes & chambers fill contraction phase systole ventricles pumps blood out relaxation phase diastole atria refill with blood systolic ________ diastolic pump (peak pressure) _________________ fill (minimum pressure) 110 70 ____

49 Measurement of blood pressure
High Blood Pressure (hypertension) if top number (systolic pumping) > 150 if bottom number (diastolic filling) > 90

50 Cardiovascular disease
Cardiovascular disease (>50% of all deaths) Heart attack- death of cardiac tissue due to coronary blockage Stroke- death of nervous tissue in brain due to arterial blockage Atherosclerosis: arterial plaques deposits Arteriosclerosis: plaque hardening by calcium deposits Hypertension: high blood pressure Hypercholesterolemia: LDL, HDL

51 Demonstrations Demonstrate the path of an O2 molecule from the air to a knee cell as it travels through the respiration system and the circulatory system (travelling on a red blood cell). Make sure to include arteries, capillaries and/or veins. Demonstrate the path of an CO2 molecule from a knee cell to the air as it travels through the respiration system and the circulatory system (travelling on a red blood cell). Make sure to include arteries, capillaries and/or veins.

52 All members verbally involved 8 or more different props Creativity
Scoring guide All members verbally involved 8 or more different props Creativity Accurate description Kinesthetic

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