Digestion and Absorption flash cards

1. 1.What are the two main components of the human digestive system?

   The alimentary canal and the associated (accessory) digestive glands.

   Hint: Tube + glands

2. 2.Name the parts of the alimentary canal in order.

   Mouth → buccal cavity → pharynx → oesophagus → stomach → small intestine → large intestine → rectum → anus.

   Hint: Mouth to anus

3. 3.Where does the alimentary canal begin and end?

   It begins at the mouth (oral aperture) and opens out through the anus.

   Hint: Both openings

4. 4.What is the vestibule of the buccal cavity?

   The space between the jaws (with teeth) and the cheeks/lips.

   Hint: Between teeth and cheeks

5. 5.How are teeth attached to the jaw bones in humans?

   Each tooth is embedded in a socket of the jaw bone — this is called thecodont attachment.

   Hint: Socketed

6. 6.What does 'diphyodont' dentition mean?

   Two sets of teeth develop in a lifetime — a temporary set of milk (deciduous) teeth replaced by permanent (adult) teeth.

   Hint: Two sets

7. 7.What does 'heterodont' dentition mean?

   The teeth are of different types (incisors, canines, premolars, molars).

   Hint: Different kinds

8. 8.Name the four types of teeth in humans.

   Incisors (I), canines (C), premolars (PM) and molars (M).

   Hint: I, C, PM, M

9. 9.What is the dental formula of an adult human?

   $2123/2123$ — per half jaw: 2 incisors, 1 canine, 2 premolars, 3 molars.

   Hint: Half jaw × 4

10. 10.How many teeth does an adult human have?

    32 teeth (dental formula 2123/2123, counted for both halves of upper and lower jaws).

    Hint: Full permanent set

11. 11.What hard substance covers the crown of a tooth?

    Enamel — the hardest substance in the body.

    Hint: Hardest in body

12. 12.What is the tongue attached to the floor of the buccal cavity by?

    The frenulum (a fold of tissue).

    Hint: Anchoring fold

13. 13.Where are taste buds located?

    On small papillae (projections) on the upper surface of the tongue.

    Hint: On papillae

14. 14.What is the pharynx and its role?

    A common passage for food and air; it connects the buccal cavity to the oesophagus.

    Hint: Food + air crossroad

15. 15.What prevents food from entering the glottis during swallowing?

    A cartilaginous flap called the epiglottis covers the glottis.

    Hint: Covers windpipe

16. 16.What is the oesophagus and where does it open?

    A thin, long tube that passes through the neck, thorax and diaphragm and opens into the stomach.

    Hint: Food pipe to stomach

17. 17.What is the gastro-oesophageal sphincter?

    A muscular sphincter that regulates the opening of the oesophagus into the stomach.

    Hint: Oesophagus–stomach valve

18. 18.Name the three major regions of the stomach.

    Cardiac (where oesophagus opens), fundic, and pyloric (opens into the duodenum).

    Hint: Cardiac, fundic, pyloric

19. 19.What are the three parts of the small intestine?

    Duodenum (C-shaped), jejunum (long coiled middle) and ileum (highly coiled).

    Hint: D, J, I

20. 20.What is the shape of the duodenum?

    C-shaped; the hepatopancreatic duct opens into it.

    Hint: Letter C

21. 21.What are the three parts of the large intestine?

    Caecum, colon and rectum.

    Hint: C, C, R

22. 22.What is the caecum and what does it bear?

    A small blind sac that hosts symbiotic microorganisms; it bears a vermiform appendix.

    Hint: Blind sac + appendix

23. 23.What is the vermiform appendix?

    A narrow finger-like tubular projection of the caecum that is a vestigial organ.

    Hint: Vestigial off caecum

24. 24.Name the three parts of the colon.

    Ascending, transverse and descending colon (opening into the rectum).

    Hint: Up, across, down

25. 25.Name the four layers of the wall of the alimentary canal (serosa to lumen).

    Serosa, muscularis, sub-mucosa and mucosa.

    Hint: Outer to inner

26. 26.What is the serosa made of?

    A thin mesothelium (epithelium of visceral organs) with some connective tissue.

    Hint: Outermost, mesothelium

27. 27.How are the muscle layers of the muscularis arranged?

    Usually an inner circular and an outer longitudinal layer (an oblique layer is also present in the stomach).

    Hint: Circular + longitudinal

28. 28.What features does the mucosa form in the stomach and intestine?

    Irregular folds (rugae) in the stomach and small finger-like villi in the small intestine.

    Hint: Rugae and villi

29. 29.What are villi and microvilli, and why are they important?

    Villi are folds of intestinal mucosa; their epithelial cells bear microvilli, forming a brush border. Together they greatly increase the surface area for absorption.

    Hint: Increase surface area

30. 30.Name the three major (extramural) digestive glands.

    The salivary glands, the liver and the pancreas.

    Hint: Saliva, bile, pancreatic juice

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