Biology: Human Digestive

  1. _____________ digestion occurs within the cell, usually in membrane-bound vesicles.
    Intracellular digestion
  2. ______________ digestion refers to the digestive process that occurs outside the cell, within a lumen or tract.
    Extracellular digestion
  3. Mammals have a one-way digestive tract known as the ________________.
    Alimentary canal
  4. Path of human digestive tract
    • 1. oral cavity
    • 2. pharynx
    • 3. esophagus
    • 4. stomach
    • 5. small intestine
    • 6. large intestine
    • 7. anus

    *OP ESSLA**
  5. The ________________ is where mechanical and chemical digestion of food begins.
    oral cavity
  6. _____________ digestion is the breakdown of large food particles into smaller particles through the biting and chewing action (mastication).
    mechanical digestion
  7. While _____________ digestion does not lead to changes in the molecular composition of food, the total surface area of the food is increased, allowing for faster and more efficient enzymatic action
    mechanical digestion
  8. _____________ digestion refers to the enzymatic breakdown of macromolecules into smaller molecules, and begins in the mouth when the salivary glands secrete saliva.
  9. _________ lubricates food to facilitate swallowing, and provides a solvent for food particles.
  10. ___________ is secreted in response to a nervous reflex triggered by the presence of food in the oral cavity.
  11. Saliva contains the enzyme ________________ (ptyalin) which hydrolyzes starch into simple sugars.
    salivary amylase
  12. The tongue manipulates the food during chewing, rolling it into a ball called a ___________, and pushes it into the pharynx.
  13. Chemical rxn of salivary amylase:
    • salivary amylase
    • starch + H2O --------------------> maltose
  14. The digestive and respiratory passages come together in the _____________.
  15. Food is moved down the esophagus by rhythmic waves of involuntary muscular contractions called _________________.
  16. When a wave of peristalsis spreads down the esophagus, a specialized ring of muscle in the lower esophagus opens, allowing food to enter the stomach. Following the peristaltic wave, this muscle, called the lower ________________, returns to its normal closed state, thus preventing the regurgitation of stomach contents into the esophagus.
    lower esophageal sphincter or cardiac sphincter
  17. The walls of the stomach are lined with a thick gastric mucosa containing 2 glands: _________________, _______________.
    • Gastric glands
    • Pyloric glands
  18. The _____________ glands of the stomach are stimulated by nervous impulses from the brain, which responds to the sight, taste, and/or smell of food.
    Gastric glands
  19. The _____________ glands are composed of 3 types of secretory cells: mucous cells, chief cells, and parietal cells.
    Gastric glands
  20. ____________ cells secrete mucus, which protects the stomach lining from the harshly acidic juices present in the stomach.
    Mucous cells
  21. ______________ is composed of the secretions of the chief cells and the parietal cells.
    Gastric juice
  22. ___________ cells secrete pepsinogen, the zymogen of the protein-hydrolyzing enzyme, pepsin.
  23. __________ is the zymogen of the protein-hydrolyzing enzyme, pepsin.
  24. Parietal cells secrete _____________.
  25. ______________ facilitates the conversion of pepsinogen to pepsin.
  26. In the stomach, _________ hydrolyzes specific peptide bonds to yield polypeptide fragments.
  27. The ___________ glands secrete the hormone gastrin in response to the presence of certain substances in food.
    Pyloric glands
  28. In the stomach, __________ stimulates gastric glands to secrete more HCl, and also stimulates muscular contractions of the stomach, which in turn churn food.
  29. The low pH of the stomach stops the activity of _______________, which functions optimally at a near neutral pH of saliva.
    salivary amylase
  30. In the stomach, ___________ is a hydrolytic enzyme that acts on protein to produce peptides.

    protein +H2O --------------> peptides
  31. In the stomach, the churning produces an acidic, semi-fluid mixture of partially digested food known as _____________.
  32. At the junction of the stomach and the small intestine is the muscular ________________.
    pyloric sphincter
  33. The _________________ regulates the passage of chyme from the stomach into the small intestine via alternating contractions and relaxations.
    pyloric sphincter
  34. Although nutrient absorption occurs in the small intestine, alcohol and certain drugs (ex: aspirin) can be directly absorbed into the systemic circulation through capillaries in the stomach wall.
    A. True
    B. False
  35. The small intestine is divided into 3 sections in the following order:
    duodenum, jejunum, and ileum.
  36. Most digestion in the small intestine occurs in the ________________, where the secretions of the intestinal glands, pancreas, liver, and gall bladder mix together with the acidic chyme entering from the stomach.
  37. The presence of chyme triggers hormonal release, which in turn stimulates and regulates the secretions of the small intestine and its accessory organs.
    A. True
    B. False
  38. The majority of nutrient absorption occurs across the walls of the _____________.
    Jejunum and the ileum.
  39. The ___________ is a vestigial structure containing lymphoid tissue that is often surgically removed if it becomes infected.
  40. Protein digestion begins in the ____________.
  41. Lipid digestion begins in the _______________.
    Small intestine
  42. What is the main function of the large intestine?
    reabsorption of water form solid feces/wastes.
  43. In addition to hormonal regulation, the digestive processes are also stimulated by the _______________, and inhibited by the ________________.
    • stimulated by the parasympathetic nervous system
    • inhibited by the sympathetic nervous system
Card Set
Biology: Human Digestive
Biology: Human Digestive