Physiology of Digestive Systems
Fig 14.1 A digestive tract with one-way passage of food allows simultaneous operation of the sequential stages in the processing of food and reduces mixing of digested and undigested matter. The crop is a storage region found in some animals.
Fig 14.2 Structure and hydrolysis of common dietary carbohydrates (a) An example of hydrolysis.
Fig 14.2 Structure and hydrolysis of common dietary carbohydrates (b) Hydrogen bonding relationships for glucose units in cellulose and starch.
Fig 14.3 Comparison of mollusk and insect digestive tracts. (a) A bivalve mollusk tract.
Fig 14.3 Comparison of mollusk and insect digestive tracts. (b) Tract of a typical insect.
Fig 14.4 Vertebrate digestive tracts showing progressive anatomic specialization for digestion (stomach and accessory digestive glands such as pancreas and liver) and absorption surface area of small intestine.
Fig 14.4 Vertebrate digestive tracts showing progressive anatomic specialization for digestion (stomach and accessory digestive glands such as pancreas and liver) and absorption surface area of small intestine.
Fig 14.4 Vertebrate digestive tracts showing progressive anatomic specialization for digestion (stomach and accessory digestive glands such as pancreas and liver) and absorption surface area of small intestine.
Fig 14.4 Vertebrate digestive tracts showing progressive anatomic specialization for digestion (stomach and accessory digestive glands such as pancreas and liver) and absorption surface area of
Fig 14.4 Vertebrate digestive tracts showing progressive anatomic specialization for digestion (stomach and accessory digestive glands such as pancreas and liver) and absorption surface area of
Fig 14.4 Vertebrate digestive tracts showing progressive anatomic specialization for digestion (stomach and accessory digestive glands such as pancreas and liver) and absorption surface
Fig 14.5 The enteric nervous system of a rat s stomach.
Fig 14.6 Control of salivary secretion (mammal).
Fig 14.7 Oropharyngeal stage of swallowing in humans. (a) Position of the oropharyngeal structures at rest.
Fig 14.7 Oropharyngeal stage of swallowing in humans. (b) Changes that occur during the oropharyngeal stage of swallowing to prevent the bolus of food from entering the wrong passageways.
Fig 14.8 Anatomy of the stomach
Fig 14.9 (a) Gastric emptying as a result of antral peristaltic contractions (mammalian stomach).
Fig 14.9 (b) Gastric mixing as a result of antral peristaltic contractions (mammalian stomach).
表 14-2 脊椎動物胃蠕動與排空之調節因子 ( 胃內 ) 因子 調節模式 對胃蠕動與排空 之效力 胃內 食糜量 流動性 張力以及透過內神經叢 迷走神經 胃激素等作用對胃平滑肌有直接興奮性直接作用 ; 須為液體以被排出 量增加刺激蠕動 排空 增加流動性以便更迅速排空
表 14-2 脊椎動物胃蠕動與排空之調節因子 因子 調節模式 對胃蠕動與排空之效力 十二指腸內出現脂肪 酸 高張 張力 啟動腸胃反射或激發腸胃激素 ( 膽囊收縮素 胰泌素 胃抑制胜肽) 之釋放 於十二指腸內這些因子抑制胃之蠕動與排空直至十二指腸處理完 這些因子
表 14-2 脊椎動物胃蠕動與排空之調節因子 因子 調節模式 對胃蠕動與排空之效力 消化系統之外 情緒 改變自主神經平衡 激起或抑制蠕動與 排空 劇痛增加交感神經活動抑制蠕動與排空 下視丘利用葡萄糖減少 增加迷走神經活動 激起蠕動及伴隨飢餓劇痛
Table 14-3 The stomach mucosa and the gastric glands Exocrine cells Mucous cells Chief cells Parietal (wall) or oxyntic (sharp) cells Product secreted Alkaline mucus Stimuli for secretion Mechanical stimulation by contents Function(s) of secretory product Protect mucosa against mechanical, pepsin, and acid injury Pepsinogen Ach, gastrin When activated, begins protein digestion Hydrochloric acid Intrinsic factor Ach, gastrin, histamine Activates pepsinogen, breaks down connective tissue, denatures proteins, kills micro-organisms Facilitates absorption of B 12
Table 14-3 The stomach mucosa and the gastric glands Endocrine/paracrine cells Enterochromaffin-lik e (ECL) cells Product secreted Stimuli for secretion Histamine Ach, gastrin G cells Gastrin Protein products, Ach Function(s) of secretory product Stimulates parietal cells Stimulates parietal, chief, and ECL cells D cells Somatost atin Acid Inhibits parietal, G, and ECL cells
Fig 14.10 Mechanism of HCl secretion
Fig 14.11 Pepsinogen activation in the stomach lumen
Table 14-4 Stimulation of gastric secretion (mammal) Phase Stimuli Excitatory mechanism for enhancing gastric secretion Cephalic phase Stimuli in the head-seeing, smelling, tasting, chewing, swallowing Vagus (+) Intri nsic ner ves (+)
Table 14-4 Stimulation of gastric secretion (mammal) Phase Stimuli Excitatory mechanism for enhancing gastric secretion Gastric phase
Table 14-4 Stimulation of gastric secretion (mammal) Phase Stimuli Excitatory mechanism for enhancing gastric secretion Excitatory intestinal phase
Fig 14.12 Schematic representation of the exocrine and endocrine
Fig 14.13 Hormonal control of pancreatic exocrine secretion (mammal).
Fig 14.14 Schematic representation of liver blood flow (mammal).
Fig 14.16 Enterohepatic circulation of bile salts
Fig 14.17 Schematic structure function of bile salts.
Fig 14.17 Schematic structure function of bile
Fig 14.18 Schematic representation of a micelle.
Fig 14.19 Structure of the vertebrate digestive tract. (a)
Fig 14.19 Structure of the vertebrate digestive tract. (b)
Fig 14.19 Structure of the vertebrate digestive tract. (c)
Fig 14.19 Structure of the vertebrate digestive tract. (d)
Fig 14.21 Control of the ileocecal valve/sphincter (shown of
Fig 14.25 Biochemical balance among the stomach, pancreas, and
Fig 14.26 Anatomy of the large intestine (mammal, shown for a human)
Fig 14. 27 Comparison of rumen structure and function in a selective versus a nonselective feeder.
Fig 14. 27 Comparison of rumen structure and function in a selective versus a nonselective feeder.