Glands of Digestion Flashcards
Gallbladder
A small organ inferior to the liver; the bulk of this organ is the body; a CYSTIC DUCT connects to the narrow neck
Functions of the gallbladder
- store bile - can hold about 70ml
- concentrate bile
Hepatic Bile
PRIMARY bile from the liver
Cystic Bile
CONCENTRATED bile from the gallbladder
Bile release
Controlled by CCK and the VAGUS NERVE
Mucosa - surface epithelium of gallbladder
- simple columnar*
- Cells:
1) Clear Cells
2) Brush Cells
Clear Cells
aka, CHOLANGIOCYTES
- many have microvilli
- function = concentrate bile by absorbing water
Brush Cells
- few in number
- function = produce MUCINOGEN (lubricating function)
Mucosa - lamina propria of gallbladder
- loose and very vascular CT
- Neck often possesses small mucous glands
- function = to lubricate the narrow neck lumen
*Muscularis mucosa ABSENT
Submucosa of gallbladder
- **ABSENT (very unusual)
- why development of gallstones is significant
Muscularis externa of gallbladder
NOT normal pattern
-thin smooth muscle layer with a DISORGANIZED muscle arrangement
Serosa/adventitia of gallbladder
mostly SEROSA, but some adventitia where it attaches to the liver
Pancreas
surrounded by a thin CT capsule; septa dive into the organ creating lobules
Endocrine pancreas
Islets of Langerhans producing hormones (PANCREATIC ISLETS)
Exocrine pancreas
Serous acini producing digestive enzymes
-LARGEST portion
Serous (pancreatic) Acini
secretion is controlled by CCK and from parasympathetic nerves
Pancreatic ducts (exocrine pancreas)
Secretion (of h2o and hco3) controlled by SECRETIN and acetylcholine from parasympathetic nerves
Characteristics of Pancreatic Ducts
- Centroacinar cells (located next to acinar cells)
- Centroacinar cells along with the cuboid cells in intercalated pancreatic ducts produce an ALKALINE FLUID with large quantities of HCO3 ions
- Collagen-rice CT wraps pancreatic ducts (function = to provise extra protection from the possible leaking of digestive enzymes)
Liver
Largest gland in the body with endocrine AND exocrine functions
General functions of the liver
- metabolism of lipids, carbs, and proteins
- production of blood proteins, factors, and non-essential vitamins
- detoxify blood
- produce hepatic (primary) bile: an exocrine function
- store certain vitamins: ie, vit A, vit B12
Classic liver lobule
hexagonal-shaped lobules are difficult to distinguish in humans due to the lack of CT between the lobules
Hepatocytes
- microvilliated cuboidal cells possessing lateral bile canaliculi between adjacent hepatocytes
- BILE CANALICULI collect bile
- bile moves from the HEPATOCYTES towards the BILE DUCT BRONCHI in the portal triad
- arrangement = in rows btwn hepatic sinusoids like spokes of a wheel
Kupffer Cells
aka, stellate macrophages
- resident macrophages; develop from monocytes
- function = phagocytosis of debris and ages RBCs; act as an APC
Ito Cells
aka, hepatic stellate cells
-functions = store lipids for immediate use; store vit A; produce COLLAGEN I, III, and IV and growth factors
**NOT collagen II!
Pit Cells
NK cells
Hepatic Progenitor Cells
likely present and responsible for regenerative capabilities
Portal Triads
Include branches of:
1) Hepatic artery (smallest)
2) Portal vein (largest)
3) Bile duct (dark stain)
Hepatic Sinusoids
dilated, fenestrated thin walled vessels found between the rows of hepatocytes; carry a MIXTURE of venous (75%) and arterial (25%) blood
*nutrient rich, O2 poor
Central Vein
fenestrated thin walled vessel that collects blood from the hepatic sinusoids
*Blood flows from the PORTAL TRIAD towards the CENTRAL VEIN
Space of Disse
aka, perisinusoidal space
- space between the hepatocytes and the fenestrated hepatic sinusoids where blood can DIRECTLY CONTACT the microvilliated surfaces of the hepatocytes
- flow slows enough so the cells can interact with the blood and its contents
- this is why the liver can take over functioning for the spleen in ~24-48 hours
Glisson’s Capsule
dense irregular CT covered with serosa
-other CT is limited in the human liver
