Accessory digestive glands

ACCESSORY DIGESTIVE GLANDS

LIVER, GALLBLADDER, AND PANCREAS


 TO IDENTIFY THE EXOCRINE AND ENDOCRINE FUNCTIONS OF THE LIVER AND PANCREAS  TO EXAMINE THE HISTOLOGICAL STRUCTURE OF THE LIVER, GALLBLADDER, AND PANCREAS  TO CORRELATE STRUCTURE AND FUNCTION OF THESE ACCESSORY DIGESTIVE GLANDS ACCESSORY DIGESTIVE GLANDS

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
2) ENDOCRINE PORTION

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
2) ENDOCRINE PORTION
- synthesizes and secretes enzymes via a system of ducts that are essential for digestion in the intestine
- synthesizes and secretes hormones into the bloodstream to regulate glucose, lipid, and protein metabolism



ACCESSORY DIGESTIVE GLANDS
 PANCREAS 1) EXOCRINE PORTION
- COMPOUND ACINOUS GLAND
- EACH ACINI CONSIST OF 5-8 PYRAMIDAL CELLS THAT SIT ON A BASAL LAMINA AND SURROUND A CENTRAL LUMEN
ACINAR CELLS
- BASALLY LOCATED NUCLEI & RER
- SUPRANUCLEAR GOLGI ZONE
- ZYMOGENIC GRANULES CONTAINING DIGESTIVE ENZYMES IN APICAL REGION
CENTROACINAR CELLS
- LINE LUMEN OF ACINUS
- SECRETE LARGE AMOUNTS OF BICARBONATE

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
INTERCALATED DUCTS
INTRALOBULAR DUCTS
INTERLOBULAR DUCTS
MAIN DUCTS
PANCREAS H&E

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
INTERCALATED DUCTS
- lined with simple squamous epithelium
INTRALOBULAR DUCTS
- lined with simple cuboidal epithelium
- size on the order of magnitude of acini
INTERLOBULAR DUCTS
- lined with simple columnar epithelium
- found in fibroconnective tissue septa

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
ACINAR CELLS
- BASALLY LOCATED NUCLEI & RER
- SUPRANUCLEAR GOLGI ZONE
- ZYMOGENIC GRANULES CONTAINING DIGESTIVE ENZYMES IN APICAL REGION
CENTROACINAR CELLS
- LINE LUMEN OF ACINUS
- SECRETE LARGE AMOUNTS OF BICARBONATE
trypsinogen, amylase, lipase

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
INTERCALATED DUCTS
PANCREAS H&E

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 1) EXOCRINE PORTION
PANCREAS H&E
EXO-
ENDO-
2) ENDOCRINE PORTION

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 2) ENDOCRINE PORTION
- PRINCIPLE FUNCTION IS TO SECRETE HORMONES THAT REGULATE BLOOD GLUCOSE LEVELS
ISLETS OF LANGERHANS
- MASSES OF RICHLY VASCULARIZED ENDOCRINE CELLS SCATTERED THROUGHOUT THE PANCREAS
- SEPARATED FROM SURROUNDING ACINAR CELLS BY THIN CAPSULE OF RETICULAR FIBERS
- 3 CELL TYPES IN ISLET DISTINGUISHED ONLY VIA SPECIAL STAINS

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 2) ENDOCRINE PORTION

ACCESSORY DIGESTIVE GLANDS

 PANCREAS 2) ENDOCRINE PORTION
CELL TYPES:
1) ALPHA CELLS (20%)
2) BETA CELLS (75%)
3) DELTA CELLS (5%)
- SECRETE GLUCAGON; RAISES BLOOD GLUCOSE LEVELS
- SECRETE INSULIN; LOWERS BLOOD GLUCOSE LEVELS
- SECRETE SOMATOSTATIN; INHIBITS GLUCAGON AND INSULIN SECRETION

ACCESSORY DIGESTIVE GLANDS

 LIVER 1) EXOCRINE PORTION
2) ENDOCRINE PORTION
- synthesizes and secretes bile via a system of ducts that is essential for digestion in the intestine
- synthesizes and secretes numerous plasma proteins into the bloodstream: (albumin, fibrinogen, prothrombin, lipoproteins, etc.)

ACCESSORY DIGESTIVE GLANDS

 LIVER PORTA HEPATIS
PORTAL TRIAD

ACCESSORY DIGESTIVE GLANDS

 LIVER Classical Liver Lobule
- basic functional unit of liver

ACCESSORY DIGESTIVE GLANDS

 LIVER CLASSIC LOBULE
PORTAL LOBULE
LIVER ACINUS
- central vein at center
- hexagonal in shape
- portal triad at corners
- portal triad at center
- triangular in shape
- central vein at corners
- short axis: branches of portal triad between 2 classic lobules
- long axis: between 2 central veins

ACCESSORY DIGESTIVE GLANDS

ACCESSORY DIGESTIVE GLANDS

ACCESSORY DIGESTIVE GLANDS

 LIVER 1 HEPATOCYTES 2 SINUSOIDS 3 SPACE OF DISSE 4 BILE CANALICULI

ACCESSORY DIGESTIVE GLANDS

 LIVER 1 HEPATOCYTES 2 SINUSOIDS 3 SPACE OF DISSE 4 BILE CANALICULI - perisinusoidal space between basal surfaces of the endothelial cells and the surfaces of the hepatocytes
- small canal beginning the biliary tree formed by apposed grooves in adjacent hepatocytes

LIVER

ACCESSORY DIGESTIVE GLANDS
 LIVER

LIVER H&E

PV
HA
BD

ACCESSORY DIGESTIVE GLANDS

 LIVER BILE DUCTS
- lined with simple cuboidal epithelium

ACCESSORY DIGESTIVE GLANDS

 LIVER LIVER H&E
1 HEPATOCYTES 2 SINUSOIDS

ACCESSORY DIGESTIVE GLANDS

 LIVER LIVER
RETICULAR FIBER MESHWORK

ACCESSORY DIGESTIVE GLANDS

 LIVER RETICULAR FIBER MESHWORK
KUPFFER CELLS
- phagocytic cell, liver macrophage



ACCESSORY DIGESTIVE GLANDS
 LIVER KUPFFER CELLS
CV
LIVER H&E

ACCESSORY DIGESTIVE GLANDS

 LIVER KUPFFER CELLS
LIVER H&E

ACCESSORY DIGESTIVE GLANDS

 LIVER 3-D APPRECIATION FOR HISTOLOGICAL STRUCTURE OBSERVED IN 2-D

ACCESSORY DIGESTIVE GLANDS

 LIVER 3-D LOOK AT THE BILIARY SYSTEM

ACCESSORY DIGESTIVE GLANDS

 LIVER LIVER H&E
SITE OF HEMOPOEISIS DURING EARLY GESTATION

ACCESSORY DIGESTIVE GLANDS

 LIVER LIVER H&E
SITE OF HEMOPOEISIS DURING EARLY GESTATION

ACCESSORY DIGESTIVE GLANDS

 GALLBLADDER ROUTE OF BILE
HEPATOCYTE
BILE CANALICULI
RT & LT HEPATIC DUCTS
COMMON BILE DUCT
FILLING OF GALLBLADDER
- LOCATION FOR CONCENTRATION AND STORAGE OF BILE

ACCESSORY DIGESTIVE GLANDS

 GALLBLADDER THREE LAYERS:
1) MUCOSA
- lined with tall columnar epithelium and underlying basal lamina & lamina propria
- mucosa highly folded and irregular
2) MUSCULARIS EXTERNA
- layers of smooth muscle with irregular orientation
3) ADVENTITIA or SEROSA
- NO MUSCULARIS MUCOSA OR SUBMUCOSA -

ACCESSORY DIGESTIVE GLANDS

 GALLBLADDER EPITHELIUM:
- tall columnar epithelium and underlying basal lamina & lamina propria
- basally located nuclei
- fine microvilli border