Biology: March 21-25
Biology: March 21-25 Biology 1120-001
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This 3 page Class Notes was uploaded by Anzlee on Friday March 25, 2016. The Class Notes belongs to Biology 1120-001 at Middle Tennessee State University taught by Andrew Brower in Spring 2016. Since its upload, it has received 10 views. For similar materials see Biology in Biology at Middle Tennessee State University.
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Date Created: 03/25/16
Biology: March 21-25 Homeostasis • The body must maintain proper levels of heat, water, electrolytes, blood glucose, blood pressure, and pH. • Endothermy vs. Ectothermy • Homeothermy vs. Heterothermy • Overview: o sense stimulus o compare to level needed o respond • Negative feedback- responds to stimulus in opposite way to return levels to proper standing (ex. blood glucose levels- islets of Langerhans in pancreas monitor; insulin is produced when levels get too high) o Antagonistic effectors: increasing activity of one factor, lowers the activity of another • Positive feedback- drive conditions farther from needed levels respond in same direction of stimulus Body Temperature • Hypothalamus decreases temperature by sweating and dilation of blood vessels vs. Hypothalamus increases temperature by shivering and constricting blood vessels • Ectoderms: rely on envirornmental heat vs. Endoderms: maintain their own body temperature • Homeothermic: do not allow temperature to fluctuate vs. Heterothermic: allow temperature to fluctuate • Adaption: allows extremities to get cold while core body temperature is contained (ex. whale tongues and some bird feet) • Not all mammals must maintain a constant temperature: ex. dessert animals; hibernation Water and Electrolyte Balance • Regulate water and the concentration of: sodium, chloride, potassium, calcium, etc. • Solutes move by diffusion (high to low concentration) • Water moves by osmosis (high to low concentration) o Osmotic pressure of a solution: measure of its likelihood to take in water o Osmoconformers- osmolality of body fluid is isotonic/same with seawater (most marine invertebrates, hagfish, sharks) § Sharks: ATP pumps sodium chloride into gills and out of rectal glands o Most animals are not isotonic with their environment § Freshwater fish- hypertonic (water tends to enter body) § Marine bony fish- hypotonic (water tends to leave body) § Terrestrial animals- breathing and evaporation o How can salmon be both? § They alter their gill filament and are able to secrete and import electrolytes • Removal of water/salts is coupled with removal of metabolic waste (ex. ammonia) o Insects- Malpighian tubules o Crustaceans- antennal glands o Flatworms- flame cells o Earthworms- nephridia o Many terrestrial vertebrates: obtain water from consumption and lose it through urine o Mammals convert ammonia to urea § Allatonin converts uric acid to be more soluble o Birds, reptiles, insects convert it to uric acid Kidney • Top part: cortex • Bottom part: medulla • Receives blood from renal artery • Made of thousands of nephrons which all have a bent tube (mammals have millions) • Glomerulus is the filter on the top of each nephron • Water is passed through filter and pulled into tissues along tubes • Reabsorption of glucose and amino acids through active transport • Secretion of waste Digestion 1. Fragmentation 2. Chemical digestion 3. Absorption 4. Secretion Digestive Tract: • Mouth- jaws and teeth are modified for specific diets; tongues mix food with saliva • Esophagus- muscles contact and move food down esophagus • Stomach- endocrine glands contain parietal (secrete hydrochloric acid) and chief (secrete pepsinogen) cells • Small intestine- divided into duodenum, jejunum, and ileum; walls covered in villi and microvilli; massive surface area • Large intestine- small intestine empties into large intestine • Rectum • Anus • Salivary glands • Liver- secretes bile • Gallbladder- stores bile • Pancreas- secretes digestive enzymes; controls blood glucose • Digestive systems may differ between organisms, ex. ruminants- large, divided stomachs