BIOL 112 1st Edition Lecture 15 Outline of Last Lecture I. The “Crown Group”II. Kingdom PlantaeIII. Plant EvolutionIV. “Cryptogams”V. Phylum BryophytaVI. Advances of Bryophytes from AlgaeVII. “Tracheophytes”VIII. Phylum PterophytaIX. Advances of Ferns over MossesX. Seed PlantsXI. GymnospermsXII. Phylum ConiferophytaXIII. Male Cone and PollenXIV. Female Cone and EggsXV. SeedXVI. Advances of Conifers over FernsXVII. AngiospermsXVIII. Phylum AnthophytaXIX. Flower AnatomyXX. The OvuleThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Outline of Current LectureXXI. Background of Form/FunctionXXII. The Digestive SystemXXIII. The Human Digestive System A. PharynxB. EsophagusC. StomachD. Small IntestineXXIV. AbsorptionCurrent LectureI. Background of Form/Function• Cells make up tissues•tissue: a group of cells with common structure/function, made upof the same differentiated type•Tissues make up organs•organs: specific collection or grouping of different tissues, the whole having some specific function (ex. skin)•organ system: collection of different organs with specific overall function to body•Different types of tissue:•Epithelial Tissue: make up digestive system, various types (strat-ified squamous, cuboidal, simple columnar, simple squamous, pseudo stratified columnar) apical surface is on the outside, basal faces another type of tissue on the inside.•Connective Tissue: Loose connective tissue, fibrous connective tissue, adipose tissue, cartilage; these tissues hold parts of the body together.•Muscle Tissue: Skeletal muscle (voluntary muscles), smooth mus-cle (organs), cardiac muscle (heart); how the animal moves aroundII. The Digestive System•Four Major Functions:•Processing food•Absorbs organic nutrients that are produced from processing the food•Absorption of electrolytes•Absorption of water•Processing•Digestion: Breaking of each of the macromolecule types into monomers (we cannot absorb polymers — they are too big)•Hydrolysis (Catabolic Reaction) -Polysaccharides —> simple sugars -Proteins —> amino acids -Lipids —> fatty acids and glycerol -Nucleic acids —> nucleotides•Primitive Animals vs. Advanced Animals•Digestion used to be mostly intracellular (Paramecium engulfs food and digests in lysosomes, digestion completed in cells•Now, digestion is exclusively extracellular; hydrolytic reactions must occur in lumens of digestive organs, then cells lining the lu-men absorb the new monomers.III. The Human Digestive System•Starts at mouth, ends at anus•If you were to take out your digestive system, it would be approxi-mately 5 times your height•Start with Food — Mouth•Chewing reflex, teeth•Saliva has 2 main functions: -it mixes the food with ptyalin (salivary amylase) -mucus binds the food together to make bolus of food, also lu-bricates A. Pharynx: “Throat” combined organ for digestive and respiratory sys-tem•swallow reflex•Epiglottis: acts as a “hatch” over the opening of the glottis, pre-vents food from being swallowed into lungs (or inhaled) B. Esophagus: tube leading to stomach•waves of peristaltic contractions push materials along to stom-ach, regardless of gravity’s pull on it (doesn’t matter if you’re standing or laying down)•the action of the contractions is called Peristalsis C. The Stomach•a big bag that can hold about a liter of material, sealed at both ends by sphincters (“valves”) -sphincters tend to remain closed unless a signal is sent to re-lax•Gastroesophageal sphincter: upper end of stomach, opened by peristaltic wave from esophagus•Pyloric Sphincter: lower end of stomach, permits food to enter in-testines after stomach is done processing food•extreme conditions in the stomach found no where else in the body, very acidic (pH 1-2, hydrochloric acid), enzyme —> pepsin (hydrolysis of peptide bonds)•food broken up from bolus into liquid mush: chyme•2 to 4 hours after a meal, the stomach has completed its proces-sion of the food from boluses into chyme and is now ready to send the contents along to small intestine -With each peristaltic wave, the pyloric sphincter opens and a small volume of chyme is squirted into the small intestine D. Small Intestine•About 3x your height — folded up in your abdomen•3 distinct sections: -Duodenum ~25 cm, “the smart part of the intestine”, closest to stomach, cells sense the opening of the pyloric sphincter and appearance of acid chyme, then secretes alkaline mucus into thelumen, pH shifts from 2 to about 7.8 -Jejenum ~1.8 m -Ileum ~2.7 m•Liver/Gall Bladder: Bile flows down bile duct to duodenum•Basically, liver secretes bile, bile stored in bag called gall bladder•Bile contains no enzymes. It is a “detergent” — emulsifies fats into tiny globule. This increases the surface area for attach by li-pase enzymes•Bile emulsification also helps absorption of digested fatty acids by “carrying” fatty acids to absorptive cells•Bile is also alkaline, to neutralize stomach acidIV. Absorption•In advanced animals, there is no phagocytosis in digestion; all ab-sorption then must be with monomers across the plasma membrane -passive diffusion, facilitated diffusion, active transport•Absorptive cells of small intestine can concentrate materials from chyme, then release these materials into the bloodstream; both steps occur by active transport•Total absorptive area of small intestine is about 300 m2 — about thesize of a tennis court!•How does it get so much area? Folding at several levels of structure:•Circular Folds in inner face of intestine•Villi on folds — villus is smaller finger-like projection of tissue•Microvilli of epithelial cells (also called “brush border”)•All these features increase surface area for