DIGESTIVE SYSTEMDIGESTIVE SYSTEM

Associated Glands:Associated Glands:

1.1. Salivary glands.Salivary glands.

2.2. Liver.Liver.

3.3. Pancreas.Pancreas.

LIVERLIVER

CLASSIC HEPATIC CLASSIC HEPATIC LOBULE:LOBULE:Hexagonal.Hexagonal.Has Has portal areas portal areas at at the corners and a the corners and a central veincentral vein in the in the center.center.

LIVERLIVER

Portal areas contain:Portal areas contain:1.1. A A bile ductbile duct..

2.2. A branch of A branch of hepatic hepatic arteryartery..

3.3. A branch of A branch of portal veinportal vein..

4.4. Connective tissue.Connective tissue.

LIVERLIVERStructure of Lobules:Structure of Lobules: Plates of liver cells Plates of liver cells

((hepatocyteshepatocytes).). Between the plates of Between the plates of

hepatocytes there are hepatocytes there are blood sinusoidsblood sinusoids lined by lined by endothelial cells and endothelial cells and Kupffer cells Kupffer cells (macrophages).(macrophages).

PANCREASPANCREAS

Pancreas is a Pancreas is a mixedmixed gland:gland:– Exocrine part Exocrine part (acini & (acini &

ducts): produces ducts): produces digestive pancreatic digestive pancreatic enzymesenzymes..

– Endocrine part Endocrine part (islets (islets of Langerhans): of Langerhans): produces produces hormoneshormones..

PANCREASPANCREAS

Pancreatic acini:Pancreatic acini: Serous acini with Serous acini with

centroacinar cells (the centroacinar cells (the beginning of the ducts).beginning of the ducts).

Nuclei are basal.Nuclei are basal. Cytoplasm:Cytoplasm:

– Basal part basophilic (due Basal part basophilic (due to abundant rER).to abundant rER).

– Apical part acidophilic Apical part acidophilic (due to secretory (due to secretory granules).granules).

PANCREASPANCREAS

Islets of Langerhans:Islets of Langerhans: Pale spherical vascularized Pale spherical vascularized

collections of endocrine collections of endocrine cells.cells.

Formed of 5 types of cells:Formed of 5 types of cells:1.1. αα (A) cells: (A) cells: secrete glucagon.secrete glucagon.

2.2. ββ (B) cells: (B) cells: secrete insulin.secrete insulin.

3.3. δδ (D) cells: (D) cells: secrete secrete somatostatin.somatostatin.

4.4. G cells: G cells: secrete gastrin.secrete gastrin.

5.5. PP cells: PP cells: secrete pancreatic secrete pancreatic polypeptide.polypeptide.

PRACTICAL SLIDESPRACTICAL SLIDES

LiverLiver

PancreasPancreas