Esophagus
Lu = lumen,
Mu = mucosa,
Su = submucosa,
ME = muscularis externa,
Ad = adventitia.
The muscularis externa consists of skeletal muscle in its upper third, smooth
and skeletal muscle in the middle third, and smooth muscle in the lower
third.
Chief (peptic) cell
These cells contain abundant, rough endoplasmic reticulum (ER), and secretory granules
(SG). The granules are released at the apical surface of the cell.
Parietal cell of the stomach
Note the large number of mitochondria and the intracellular canaliculi
filled with microvilli. Parietal cells are responsible for secreting HCl and
intrinsic factor, a glycoprotein responsible for the absorption of vitamin B12
from the small intestine.
Stomach, cross-sectioned pyloric gland
1.
2.
3.
4.
lumen of pyloric gland
nuclei of mucous cells
nuclei of enteroendocrine cells
lamina propria.
Intestinal villus from duodenum
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
intestinal lumen
nuclei of absorptive cells in surface epithelium
basal lamina
goblet cells
intercellular space
nuclei of absorptive cells
arteriole
capillary
post-capillary venule
lacteal
smooth muscle cells
unidentified connective tissue cells
lymphocytes en route through surface epithelium
14. endocrine cell.
Mucous goblet cell
Area similar to area in the rectangle in previous figure.
1. lumen
2. goblet cell
3. microvilli
4. nucleus of columnar absorptive cell.
Paneth cells, ileum
1. Ly = lysosomes,
2. U = undifferentiated crypt cell.
Paneth cells have prominent secretory granules in the apical side of the
cell; abundant rough endoplasmic in the basal portion of the cell is hard
to see.
Liver
1.
2.
3.
4.
H = hepatocyte,
S = sinusoid,
KC = Kupffer cell,
Arrows = bile canaliculi.
Note that bile canaliculi are formed by adjacent hepatocytes.
Liver sinusoid
Arrows = fenestrated endothelium. Note the space of Disse between the
endothelial cells and the hepatocytes
Scanning electron micrograph of Kupffer cell spanning the
diameter liver sinusoid
Note the fenestrations in the lining endothelial cells
Liver cell
1. lumen of hepatic
sinusoid
2. cytoplasm of
Kupffer cell
3. endothelial pores
4. space of Disse
5. microvilli
6. mitochondria
7. peroxisomes
8. Golgi zone
9. lipid droplets
10. lysosomes
11. bile canaliculus
12. junctional
complexes
13. glycogen particles
14. smooth
endoplasmic
reticulum
15. rough endoplasmic
reticulum
16. free ribosomes and polysomes
17. nucleus
18. vacuoles with very low density lipoproteins (VLDL)
19. micropinocytotic invagination.
Autophagic vacuoles
(A) peroxisome (left) and mitochondria (right) are enclosed within the
membrane.
(B) Two autophagic vacuoles containing endoplasmic reticulum.
Lysosomes will fuse with this vacuole, releasing into it enzymes that
digest its contents.
Peroxisomes (microbodies)
Two of these peroxisomes contain a dense nucleoid, which are crystals of
urate oxidase. The enzymes of peroxisomes have the ability to generate
hydrogen peroxide. Hydrogen peroxide, necessary in a number of cellular
reactions and capable of killing microorganisms also can damage cells.
Peroxisomes also contain catalase an enzyme that can convert hydrogen
peroxide to water.