BIOS 1710: Biological Sciences II, Week 6 Notes
BIOS 1710: Biological Sciences II, Week 6 Notes BIOS1710
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This 8 page Class Notes was uploaded by Sydney Jones on Monday October 3, 2016. The Class Notes belongs to BIOS1710 at Ohio University taught by Scott Moody in Fall 2017. Since its upload, it has received 49 views. For similar materials see Biological Sciences II: Ecology, Evolution, Animal Body Systems in Biology at Ohio University.
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Date Created: 10/03/16
Week 6 th September 26-30 CH 40 Sources of Energy 3 main molecules as sources of energy: 1. Carbohydrates 2. Fats 3. Proteins ATP- adenosine triphosphate, most common form of energy in animals Catabolic- reactions that break down food sources to fuel the energy needed for a cell Anabolic- reactions that result in net energy stored in cells and organism Carbohydrates - Uses anaerobic and aerobic metabolism - Can be partially broken down by glycolysis (anaerobic metabolism) Glycolysis- occurs in the cytosol of the cell, produces pyruvate and (2) molecules of ATP form each glucose molecule, rapid but short-term Pyruvate- if no oxygen is present it is converted into lactic acid by fermentation Aerobic Metabolism- cellular reparation, occurs in the mitochondria - if there is enough oxygen, pyruvate can be processed byt eh citric acid cyle - 1 molecule of glucose can produce 32 molecules of ATP in aerobic metabolism - 58% of energy is used for heat; 42% is used for energy Lipids - Also known as fats - Broken down to glycerol and free fatty acids - Use glycolysis or citric acid cycle to produce ATP - If not all used it is stored as adipose tissue Proteins - Needed for building and maintaining the body - Last type of molecule to be broken down from ATP Metabolism Metabolic Rate- an animal’s overall rate of energy, ml of oxygen consumed per hour Basal Metabolic Rate- rate ate which they consume oxygen at rest Activity -Exercise increased the need for ATP -Extended periods of exercise relies on glycolysis ▯ creating lactic acid and decrease in pH Metabolic Acidosis- fatigue by lactic acid - When exercise ends MR does not immediate return to resting level Recovery Metabolism- the continued recovery metabolism needed to reestablish the resting MR Oxygen Debt- difference between immediate energy needed at the beginning of exercise and energy supplied by aerobic metabolism Body Size - Larger animals have a higher MR - Basal MR increases with animal mass raised to the ¾ power; less in energy is used in larger animals Temperature - Temp affects the rate of chemical reactions Endotherms- produce most of their own head from metabolic reactions • Usually maintain a constant body temp (higher than the environment) • Mammals • Able to be active a broader rage of time • Active • Require more food to survive Ectoderms- get most their heat from the environment • Regulate body temp with behavior; moving in or out of the sun • Reptiles, fish, amphibians, and invertebrates • Activity level and MR increase with body temp • Cannot sustain prolonged activity - Endotherms have a higher MR Nutrition and Diet Energy Balance- maintained at a constant level, takes in same mount needed for energy Energy Intake- sources of energy Energy Use- energy expended - 70% of energy is sued for required for basic life processes - 36% of the US adult population is considered obese Nutrients - There are 20 different amino acids are typically found in proteins Essential Amino Acids- amino acids that cannot be synthesized by the body; 8 of the 20 - Most reliable source of essential amino acids is from meat Dietary Minerals- chemical elements (other then carbon, hydrogen, oxygen, and nitrogen) that are required for the body Vitamins- organic molecules only need very small amounts Feeding Suspension Filter Feeding- water with food suspended in it passes through a sieve- like structure • Only in aquatic environments • Worms and bivalve mollusks pump water over their gills • Mucus is produces to act as an adhesive Suction Feeding- rapid expansion of the fish’s mouth downs water and prey into the mouth • Food is broken up by pharyngeal jaws in the pharynx (fish) • Insects rely on suction to draw the blood - Jawed fish evolved form jawless ancestors Temporomandibular Joint- specialized joint; allows the top and bottom teeth fit perfectly together Incisors- in the front, for biting Canines- for piercing Molars/Premolars- found in the back; for crushing and shredding Digestion and Absorption Intracellular Digestion- in single cell protists, obtain food by phagocytosis, food is broken down in cells Extracellular Digestion- food is isolated and broken down outside of a cell - Food is moved in a single direction 3 parts of the gut: 1. Foregut- initial storage and digestive chamber; mouth, esophagus, and stomach (crop) 2. Midgut- remainder of digestion and most all nutrient absorption; organs secrete enzymes and chemicals that help brake down food; small intestine 3. Hindgut- water and minerals are reabsorbed; large intestine and rectum Mouth - Mechanical brake down of food is from the mouth (buccal cavity) Amylase- in salivary secretions that has and enzyme that brakes down carbs - Swallowing is controlled by the autonomic NS ▯ moved to the pharynx (connects nasal and mouth) and over the epiglottis (flap of tissue that protects food from entering trachea *Birds, alligators, crocodiles, and earthworms brake down food in the gizzard - The stomach mixes the food with digestive enzymes; main site of protein brake down Stomach - Stimuli from food (sight, smell, taste) stimulates appetite and secretion of hydrochloric acid (HCL) and digestive enzymes▯ brake proteins into amino acids Pepsin- primary digestive enzyme produced in the stomach; first released as pepsinogen (inactive); activated by a low pH in the stomach Gastrin- peptide hormone, when food enters the stomach it is released to increase the production of HCL - If the glands in the lining of the stomach that create mucus brakes down it can cause and ulcer ▯ most are caused by Heliobacter pyloi Peristalsis- muscular contraction of the stomach that moves the food to the base of the stomach Pyloric Sphincter- band of muscle that allows small amounts of digested food to the small intestine *about 4 hours to empty the stomach Small Intestine - Where fat digestion begins Made up of 3 parts: 1. Duodenum- first section, most of the remaining digestion happens here 2. Jejunum- nutrient absorption 3. Ileum- nutrient absorption - Have 2 accessory organs: liver and pancreas - The liver creates bile (made from bile salts & acids, and bicarbonate ions) that is used to brake down large clusters of fats to allow lipase (lipid enzyme) - The gallbladder stores the bile until fats enter the duodenum releasing cholecystokinin (CCK) causing the gallbladder to contract - The pancreases secrets hormones and substances into ducts connected to the duodenum Trypsin- digestive enzyme that brakes down proteins; trypsinogen (inactive) Secretin- stimulates bicarbonate ions (neutralizes the acid in the stomach); first hormone ever to be identified - The last two sections of the small intestine have villi (highly folded inner surfaces) and microvilli (highly folded surfaces of the villi cells) Tight Junctions- force the products of digestion to be absorbed across the microvilli Large Intestine - Also called the colon Rectum- where feces are stored, final segment of the LI Layers and parts of the large intestine: 1. Lumen- the central space 2. Mucosa- surrounds the lumen; secretory and absorptive functions 3. Submucosa- surrounds the mucosa; blood vessels, lymph vessels, and nerves 4. Circular Muscle- smooth muscle layer; contracts to reduce the size of lumen 5. Longitudinal Muscle- smooth muscle layers; contract to shorten small sections 6. Serosa- covers and protects the gut 7. Mesentery- membrane that supports the gut in the abdominal cavity Plant-eating Animals - Most herbivores lack cellulase ▯ they have specialized compartments that have bacteria that does produce it **Ruminants (cattle, sheep, and goats) have a four-chambered stomach 1. Rumen and Reticulum- first two chambers; large anaerobic bacteria that brake down cellulose ▯ regurgitated (rumination) helps this process 2. Omasum- where water is reabsorbed 3. Abomasum- where protein digestion begins - Other mammalian herbivores digest the plants by hindgut fermentation▯occurs in the cecum (chamber that branches off Large intestine) - Humans have a small cecum Appendix- extends from the cecum; a vestigial structure; may play a role in the immune system Vestigial Structure a structure that has lost its original function and is much reduced in size CH 41 Water and Electrolyte Balance Homeostasis- the maintenance of a staple internal environment Renal System- underlie water and electrolyte balance; waste elimination; kidneys Osmosis ** movement of water from higher water concentration to lower water concentration ▯ from lower solute concentration to higher solute concentration - Semipermeable allows water and smaller solutes to move through but not larger solutes like proteins Aquaporins- channels that allow water to move through by facilitated diffusion Osmotic Pressure- the tendency of water to move from one solution into another by osmosis * the higher the solute concentration the higher the osmotic pressure meaning there is a greater tendency for water to move into that solution Osmoregulation- the regulation of water and solute levels to control osmotic pressure; form of homeostasis - Cells control their osmotic pressure by movement of solutes (mostly electrolytes) - Usually animals gain water by drinking water that is less concentrated in solutes (hypotonic) than their body Osmoconformers- animals that match their osmotic pressure to the environment • This reduces the movement of water and solutes in or out of the body • Do not have to spend a lot of energy regulating osmotic pressure • Tend to live in environments with stable solute concentrations • Most marine invertebrates Urea- a waste product of protein metabolism animals excrete to keep levels low in the body Osmoregulators- animals that maintain an internal solute concentration that are different from the environment • Use a lot of energy on this; some fish spend 50% of their resting metabolic energy on this • Allows them to live in saltwater, freshwater, and land • The external surface (skin) prevents water/solutes from freely passing Chloride Cells- specialized cells in the gills of bony fish counter the ingestion and diffusion of excess electrolytes Excretion of Wastes - Ammonia is a by-product of the brake down of nucleic acids and proteins - Because ammonia has nitrogen and is toxic it is considered a nitrogenous waste ▯ can disturb pH balance and cause neuronal cell injury - Fish are able to excrete it through their gills because there is enough surrounding water to dilute it - Urea is less toxic than ammonia; produced in the liver and carried by the blood to kidneys (mammals) - Uric acid is the least toxic of the three Filtration, Reabsorption, and Secretion - Unicellular organisms’ wastes compounds are isolated in a contractile vacuole - Multicellular animals with a pressurized circulatory system use filtration; selectively permeable Excretory Tubules- filtered fluid (filtrate) containing waste, water, and other solutes drains here; connects to the outside Reabsorption- substances that are important are taken up by cells if the excretory tubule and returned to the blood; water is reabsorbed by osmosis Secretion- removal of toxic compounds and excess ions In other animals: • In flatworms excretion uses protonephridia with out filtering it first • In segmented worms (like earthworms) fluid is filtered through small capillaries into pairs of metanephridia (in each body segment) • In insects fluid moves into tubes called Malpighian tubules and empty into the hindgut Kidneys - Posterior to the abdominal cavity and bean-shaped - Receive blood from the hear by renal arteries that branch from the abdominal aorta Glomerulus- blood in filtered (vertebrates) through specialized capillaries that have opening (podocytes- loosely interlock to create slits) and form a tufted loop *There are thousands of glomeruli in each kidney How? 1. Filtrate is pushed into the glomeruli and then through renal tubules (further process the filtrate by reabsorption and secretion 2. Enters the collecting ducts (as urine) 3. From the collecting ducts it goes to a lager tube called the ureter bringing the urine to the bladder; called cloaca in amphibians, reptiles, and birds Nephron- the functional unit of the kidney; glomerulus, capsule, renal tubules and collecting ducts Cortex- outer layer of the kidney Medulla- layer of the kidney surrounded by the cortex - About 20% of the blood circulated thought eh body with each beat of the heart goes through the kidneys for filtration - Blood enters the glomerulus by afferent arteriole and leaving by efferent arteriole Bowman’s Capsule- encases the glomerulus Three parts of the renal tubule: 1. Proximal convoluted tubule- electrolytes and other nutrients that are required are absorbed in the blood; has thick walls with microvilli; permeable to water; 75% of the water has been reabsorbed 2. Loop of Henle • Descending limb: permeable to water • Thin ascending limb: permeable to Na and Cl • Thick ascending limb: actively pumps Na out (Cl follows passively) and water can not follow • Longer loop functions as a countercurrent exchanger and multiplier (relies on ATP) and creates a osmotic gradient form cortex to medulla; Vasa Recta- blood vessels; descending and ascending vessels in countercurrent organization allowing concentration gradient to be maintains; water from one arm is diffused almost directly into the other 3. Distal convoluted tubule- located in the cortex; hypotonic to the interstitial space (almost no electrolytes); urea is the principal solute - After the Distal convoluted tubule the dilute filtrate goes into the collecting ducts -The concentration gradient form cortex to medulla allows ducts to regulate water levels - Antidiuretic Hormone (ADH), aka vasopressin, controls water permeability of the collecting ducts by creating aquaporins; secreted by the pituitary gland ***Alcohol inhibits this hormone which is why you have to pee so much when drinking and become dehydrated making you hungover - Blood is filtered about 60 times per day Juxtaglomerular Apparatus- specialized cells of the efferent arteriole; respond to drop in PB and secret renin - When renin is released it stimulates the release of angiotensinogen from the lings to the blood into angiotensin II (active) causing the muscles of the arterioles to constrict increasing BP - Angiotensin II also releases aldosterone (produced by adrenal glands) to make the distal convoluted tubule and collecting ducts to take up more salt and water
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