1. DIGESTIVE SYSTEM 2 Intestine
LIVER
PANCREAS

2. Small intestine Functions:
digestion – by enzimes from liver, pancreas, and enterocytes (Membrane and luminal digestion)
absorption – by enterocytes

3. Duodenum
Ileum
lacteal
Villus
serosa

4. plicae circularis: mucosa + submucosa intestinal villi:
Intestinal lining:
plicae circularis: mucosa + submucosa
intestinal villi:
epithelium, lamina propria, mm
crypts: invaginations of epithelium in the lamina propria (endocrine, Paneth cells and stem cells)
simple columnar epithelium: absorptive enterocytes, goblet cells
fenestrated capillaries and central lacteal

5. plicae circularis (folds): mucosa + submucosa
Intestinal lining:
plicae circularis (folds): mucosa + submucosa
intestinal villi: epithelium + lamina propria with muscularis mucosae
(increased surface)

6. Villus 1. Epithelium

7. 2. Goblet cells produce a protective mucus.
Epithelium: simple columnar . Cells:
1. Enterocytes -- Columnar absorptive cells --have microvilli = brush border for absorption of digested food.
2. Goblet cells produce a protective mucus.
Lamina propria: Connective tissue,
has fenestrated capillaries and central lacteal -- lymphatic capillary
Lymphocytes and plasma cells are very numerous.

8. Epithelium (villus) bb gc L

9. c Villus, lacteal v gc ivs lp l sm ivs GALT low
LOOK! The lamina propria (lp), blood-filled capillaries ©,
and lacteal (l),
smooth muscle cells (sm)
GALT - lymphocytes

10. Crypt p g a
== invaginations of epithelium in the lamina propria == intestinal glands

11. Epithelium of crypt
1.Goblet and 2.absorptive cells.
3. the granule-containing Paneth cells - produce Lysozyme (. at the bottom
4. enteroendocrine cells
5. undifferentiated stem cells

12. Crypt p g a

13. 3. Paneth cells, 4. enteroendocrine cells (CCK, secretin, GIP),
5. undifferentiated cells 4 5 3

14. Submucosa filled with Brunner’s mucous glands - alkaline mucus
Duodenum v
low m lp ig v mm v sm m me sm s bg
med
Submucosa filled with Brunner’s mucous glands - alkaline mucus

15. s low & med mag. Duodenum Bg c d mm
villi d
intestinal
glands mm mm Bg
low s
med
low & med mag.
Ducts (d) from Brunner’s glands (Bg) (s) pass through the muscularis mucosa (mm) to empty their alkaline mucus in or between the crypts (c).

16. Duodenum m s high med high
Brunner’s glands m
high s
med
crypts
submucosa
muscularis
externa
muscul.
mucosa
high
nerve supply - submucosal (s) and myenteric (m) nerve plexuses.

17. Jejunum v a ig g ig P The jejunum is like the duodenum & ileum
med
low
The jejunum is like the duodenum & ileum
but has no submucosal glands and Peyer’s patches.
Contains bigger amount of goblet cells

18. Ileum
cr. v
muscul.
mucosa v sm sm ln
med
low ln
The major distinguishing feature is the aggregated lymphatic nodules (ln) called Peyer’s patches in the mucosa or submucosa

19. Duodenum
Ileum
lacteal
Villus
COMPARE !

20. Large intestine (bowal) - general
Function = Reabsorbtion of water and electrolytes + Elimination of wastes
Inner lining - permanent internal folds of its mucosa + submucosa called plicae circulares and crypts.
Its mucosa lacks of villi.
muscularis externa: The inner circular layer is uniform but the outer longitudinal layer has 3 thicker bands, the taenia coli.
where the colon faces the abdominal cavity there is a serosa.

21. Taenia coli

22. Colon cr
muscularis
mucosa pc
med
submucosa
low
musc. ext.
Crypts (cr) composed mainly of 1. goblet cells – the most numerous .
2. Columnar absorptive cells
3. Enteroendocrine cells
4. Undifferentiated cells

23. High. Magn.

24. Large intestine COMPARE !
Appendix

25. Anal canal ss g L v ig v a v gc low mm high Anal columns
Brunched tubular glands (g)
Stratified sqaumous epithelium (ss)

26. Liver & Gall Bladder

27. Functions: Bile synthesis and secretion (emulsification)
Excretion of bilirubin
Protein synthesis
Gluconeogenesis
Storage
Detoxification
Protective
Hemopoietic organ
Endocrine

28. Liver has lobulated structure

29. Liver lobule is hexagonal in shape
① at its center - central vein ② hepatic plates（cords of cells – hepatocytes locate radially ③ hepatic sinusoids locate between plates

30. Liver lobule

31. cv sv pt Connective tissue poor develops
Central veins (cv) drain to a sublobular vein (sv).
.The portal triads (pt) locate at lobule coners.

32. The bile canaliculus wall is made
Hepatic plate (cord) is one or two cells thick
Between cells the bile canaliculi locate
Bile canaliculus
hepatocyte
sinusoid
Kupffer cell
The bile canaliculus wall is made
up of hepatocytes

33. Hepatocytes： !- Vascular and bile surfaces Organelles -
Polyhedral (6 surfaces)
!- Vascular and bile surfaces
Organelles -
a. RER
b. SER
c. Golgi complex
d. Mitochondria
Inclusions

34. The bile canaliculus form a network that eventually empty into bile duct at the periphery of the lobule. h h b

35. Hepatic sinusoid and Hepatic macrophages (Kupffer cell)
Lined by endothelium
and
Hepatic macrophages
(Kupffer cell)
Space of Disse
sinusoid
Kupffer cell

36. e d s
Space of Disse (d) between capillary and the hepatocytes

37. h
Look! s
RBC e h
Sinusoids (s) are lined by highly fenestrated endothelial cells (e). Between the endothelial cells and hepatocytes (h), is the space of Disse (arrow).

38. In the Disse space lie Adipose cells - storage vitamin A

39. Blood circulation of the liver
Hepatic artery interlobular artery
Portal vein interlobular vein
hepatic sinusoid
central vein cv
sublobular vein
hepatic vein s d cv v a

40. At the lobule coners the portal triads are found:

41. cv hs pt
Liver, injected
with red gelatin to demonstrate the abundant vasculature.
central vein (cv), the portal triad (pt)
hepatic sinusoids (hs).

42. Liver lobules – 3 types

43. Gall bladder

44. Pancreas -- mixed gland
Functions:
Exocrine
Trypsinogen, pepsinogen, peptidase
Amylase
Lipase
Deoxyribonuclease, ribonuclease
Endocrine

45. Pancreas – compound acinar serous gland
low
lobule
Exocrine – 98-99%
Endocrine – 1-2%
Anatomy:
Capsule
Septae (have Interlobular duct)
Lobules (Serous secretory units + ducts)
lobule id
med

46. Pancreas – compound acinar serous gland
Septa
Lobules
Interlobular duct
Serous secretory units

47. Pancreas. Exocrine secretory units
Zymogen granules
Intercalated duct is intercalated into the s. unit =
centroacinar cells

48. Exocrine part Structural features of the acinus: ① Purely serous.
② the presence of centroacinar cells in the center of the acinus
Intercalated duct
Serous cells
Centroacinar cells

49. Islets of Langerhans, - low & med. mag.
Pancreas. Endocrine
Islets of Langerhans, - low & med. mag.
Scattered among exocrine secretory units spherical collections of light-staining cords of endocrine cells .
low, H&E
med, trichrome

50. Pancreas. Endocrine islets of Langerhans: 1. B cell 2. A cell
3. D cell
4. minor cells:
PP, D1, EC,

51. Islets of Langerhans B - insulin blood glucose 70%
A – glucagon blood glucose
15-20%
D – somatostatin insulin
5-10% glucagon
PP – PP,
D1 – VIP,
EC – secretin, motilin

52. Control question Group, name
1. Compare Duodenum, Ileum and Colon Transversum
2. Liver: Blood supply. (What peculiar in the blood supply of the Liver?)