Homeostasis Wk7 pt2

winniesmith1's version from 2017-05-05 12:57

Section 1

Question Answer
what is the function of teethmechanical processing
what is the structure of an adult tooth Crown (covered in enamel) Neck and Root, root canal
What do incisors doclipping/cutting
What do cuspids (canines) dotearing/slashing
What do bicuspids (premolars) docrush, mash, grind
What do molars do crushing/grinding
Describe primary dentition (deciduous teeth)total=20. Incisors 8, Cuspid 4, Molars 8.
Describe secondary (permanent) dentitiontotal=32 Incisors 8, cuspid 4, molars 20

Section 2

Question Answer
Describe the pharynxthroat- A common passageway for solid food, liquids, and air. Food passes through the oropharynx and laryngopharynx to the oesophagus. Nasopharynx, oropharynx, laryngopharynx
Oesophagus structure- location and function-Hollow muscular tube about 25 cm long and 2 cm wide. -Conveys solid food and liquids to the stomach. -Enters abdominopelvic cavity through the oesophageal hiatus. -Innervated by fibres from the oesophageal plexus.
Oesophagus structure- resting muscle toneIn the circular muscle layer in the superior 3 cm of oesophagus prevents air from entering
Describe the oesophageal mucosal layer extremely thick epithelial portion
What are the 4 steps of the swallowing process 1) Buccal phase 2) pharyngeal phase 3) oesophageal phase 4) Bolus enters stomach

Section 3

Question Answer
*look at pg26 for stomach structure (such as pylorus)* What are the major functions of the stomach 1. Storage of ingested food 2. Mechanical breakdown 3. Chemical breakdown by acid and enzymes 4. Production of intrinsic factor
Describe the stomach lining: layers Simple columnar epithelium, mucosa, muscularis externa, serosa
Stomach lining: simple columnar epithelium lines stomach - produces mucus
Stomach lining: mucosaGastric pits connect gastric glands onto the gastric surface. Cells at the base divide, replacing superficial cells
Stomach lining: smooth muscle (muscularis mucosae and muscularis externa). -Oblique layer in addition to circular and longitudinal layers
Stomach lining: Gastric glands In fundus and body of stomach. Has parietal cells, chief cells and G cells
What do parietal cells do secrete intrinsic factor and HCI
What do chief cells do secrete pepsinogen, converted to pepsin by HCI
What do G cells do secrete gastrin
What do pyloric glands do in pylorus, Produce mucous. G cells secrete gastrin. D cells release somatostatin (inhibits gastrin release).

Section 4

Question Answer
secretion of hydrochloric acid: step 1 Carbonic anhydrase converts CO2 and H2O to carbonic acid (H2CO3), which dissociates to form hydrogen ions (H).
secretion of hydrochloric acid: step 2Countertransport mechanism ejects the bicarbonate ions and imports chloride ions.
secretion of hydrochloric acid: step 3Chloride ions diffuse across the cell and exit through open chloride channels into the lumen of the gastric gland.
secretion of hydrochloric acid:Hydrogen ions are actively transported into the lumen of the gastric gland.
ppt- GI tract 1- use pics pgs 31-34. Regulation of gastric activity stages Cephalic phase, Gastric phase, Intestinal phase
Outline digestion in the stomach preliminary digestion of proteins by pepsin. - some digestion of carbohydrates (by salivary amylase). Lipids (by lingual lipase). NO ABSORPTION.
Stomach contents become more fluid, pH approaches 2.0, pepsin activity increases, protein disassembly begins.

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