Physiology Exam 4 Notes

Physiology Exam 4 Notes - Physiology Exam 4 Notes:...

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Physiology Exam 4 Notes: Photosynthesis: Plants (6CO2+6H20 → Sunlight) CO2: Inorganic -Adult GI tract = 15 ft long (b/c living & contracted) - Contents of GI Tract are external to the body -Billions of Bacteria- we wouldn’t survive if it was internal - Stomach = PH of 2 4 Basic Processes: 1) Motility: Contraction of smooth muscle -Requires energy -Propulsive Movement (move contents along) & -Mixing Movements (diff speeds) -Smooth Muscle = GI Tract -Skeletal Muscle Accessory Organs: -Liver -Salivary Glands -Pancreas -Gall Bladder 2) Secretion: 3) Digestion: Absorb everything digestible -By enzymes -By Hydrolysis- Breaking down w/ water 4)Absorption: Designed to absorb anything digestible Starch: Storage form of plants Glucose: Storage form for humans *Most absorption takes place in the small Intestine *Nutrient Molecules→ Lymph (Fat) or Layers of the Digestive Tract: 1) Mucosa: Luminal Surface -Folds increase surface area for absorp -Mucous membrane- protective layer -Endo & Exocrine cells -Joined by tight junctions -Lymph- Protects from disease
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2) Submucosa: Thick layer of connective tissue -Elastin -Sub Mucosa Plexus 3) Muscularis Externa: Smooth muscle coat -Smooth muscle -Controls movements -Myenteric Nerve Plexus 4) Serosa: -Outer Layer -Secretes fluid for lube -Found throughout GI Tract connected to Body wall by mesentery 3 Receptor Types: 1) Chemoreceptors: Sensitive to chemicals in lumen 2) Osmoreceptors: Monitor osmolarity (conc. of solute mol) 3) Mechanoreceptors: Activated by phys. Deformation- stretch Saliva: Primarily Water -Enzyme = Salivary Amylase - Breaks Carbs to sugar -Digest. Of carbs begins in mouth -Anti-Bacterial component -Salivary Amylase → Stomach gets deactivated: ↓PH Stomach: -Most extendable -Esophagus→Stomach→Gastro Esophageal Sphincter 3 Main Parts of Stomach: 1) Fundus: (Above Sphincter) -Contains Gas 2) Body: (Largest Part) -Mostly Storage - Chyme: When food goes to stomach -Ruggae: Folds 3) Antrum: (Lower Part) -Major mixing area- 30 ml Chyme -Chyme mixed w/ Hydrochloric Acid & Enzymes -Thickest -Pyloric Sphincter separates Duodenum & Stomach
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Stomach: -Stores undigested Food -Empty @ Rate mostly controlled by small intest - Stomach : 50 ml- Expands to 1 Liter -Lots of Elastin -As stomach fills up, ruggae flatten -Smooth Muscle- Pacemaker Potential -Spontaneously Depolarize to threshold- Slow wave potential -Sweeps Fundus to Antrum about 3 times/min - BER: Basic Electrical Rhythm- rhythmic wave like Fluctuations in mem pot that bring mem closer or Farther from thresh -May or may not lead to contracting smooth muscle cells (Depends on how close to threshold cells are) Contraction: Peristaltic -What’s not pushed out of stomach is mixed around again -30ml Chyme in Antrum- Only a few gets pushed to Duod -Food absorbed from stomach -Stomach impermeable to water - Aspirin & Alcohol absorbed from stomach -Protein Digestion = Stomach Gastric Emptying: -Emptying of Chyme from stomach to duodenum
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Physiology Exam 4 Notes - Physiology Exam 4 Notes:...

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