Anatomy and Cell Biology 3309 Lecture Notes - Lecture 37: Lobules Of Liver, Portal Vein, Hepatic Veins
2 May 2018
School
Department
Professor
Histology Lecture 8 – Semester 2
Liver
- Outside the tubular portion of the GI tract, but developmentally, they develop from the endoderm
(invagination from the vegetal pole of the embryo)
QUESTIONS
The mucosa of the small intestine contains:
A. Gastric Glands
B. Surface mucous cells
C. Goblet cells
D. Chief cells
E. Rugae
- EVERYTING ELSE IS IN THE STOMACH
The production of the hydrochloric acid in the stomach involves
A. Cells with abundant zymogen granules
B. Intracellular canaliculi
C. Goblet cells
D. Secretion of gastrin by parietal cells
E. Membrane bound enterokinases
Learning Objectives
- Explain the main functions of the liver
- Summarize the blood supply of the liver
- Describe the features of the classic liver lobule
- Describe two other ways how liver lobules are organized
- Describe the course of hepatic blood vessels and bile ducts
- List the structures found in the portal area
- Explain the structure and function of the Space of Disse
- Outline the location and function of Kupffer cells
- Explain the structure and function of the bile canaliculus.
Liver
- Largest gland in the body
- Interposed between blood vessels of intestinal tract and general circulation
o Receive venous blood from intestine via portal vein
o Receive arterial blood via hepatic vein
- Liver receives (In the portal blood) the material absorbed from the intestine
- Functions:
o 1. Absorbed products of digestion are metabolized or transformed & returned to the blood
o 2. Toxic substances in the blood are degraded or detoxified
o 3. Bile is produced for release into the intestine where it plays a role in digestion of lipids
o 4. Protein components of blood plasma is produced
o 5. Carbohydrates are stored as glycogen & released as glucose - maintains blood glucose
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Transport of nutrients from the intestine to the liver
- After the stomach has turned the food into chyme
- The food that comes from the stomach = chyme
o It enters the small intestine
- Enterocytes will absorb the nutrients
- Most of our proteins, amino acids, sugars, some fatty acids will enter the capillary beds through post
capillary venules and carried into the liver
o It is being processed in the liver – things will be taken out and stored
- Most of our lipids are packaged into chylomicrons, that travel through the lymphatic system
o Representation of the lymphatic system in the intestinal villus = lacteal
- All of the fat does not pass through a – system, it gets dumped into the systemic circulation at the
thoracic duct, and is being delivered throughout the body
o It eventually reaches the liver
The Liver
- Plates (rows) of epithelial cells (hepatocytes), and blood-filled spaces (sinusoids)
o Hepatocytes form plates radially surrounding terminal branches of the hepatic veins (central
veins)
o Plates of cells are exposed to blood flowing in parallel vascular channels (hepatic sinusoids)
- Organization is mostly hepatocytes
o Epithelial cells!!
o Forming anastomosing plates in rows
o Amongst those cells, there are spaces that do not stain (might find blood there if there is
blood in the liver)
▪ These spaces are lined by endothelial cells – there are highly leaky capillaries
(hepatic sinusoids)
- Each hepatocyte has direct access to at least one sinusoid
- Some of the hepatocyte have an extremely large nucleus and some hepatocytes are binucleated
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o This signals that the DNA is being synthesized and makes the cell bigger (large nucleus is a
polypoid cell) expresses the genes in abundance the same way with a binucleated cells
- Reflection of being efficient in the liver
- Hepatocyte:
o RER, SER, many mitochondria
o Golgi complex adjacent to canaliculi
o Glycogen and lipid deposits
Major functions of Hepatocytes
- Metabolism and storage:
o Lipids soluble drugs
o Steroids
▪ Steroid hormones are metabolized
o Storage of carbohydrates as glycogen
o Detoxification of drugs, alcohol, etc.
▪ Hepatocytes absorb harmful substances and make them manageable in the body
o INVOLVED WITH THESE FUNCTIONS = SER, Cytosol
- Bile formation and secretion:
o Synthesis and recycling of bile acids to and from intestine
o Bile is an important substance that helps us digest fat
▪ In the small intestine, bile emulsifies lipids into small droplets that the enterocytes
can take up and digest
▪ Bile secretion is important feature of hepatocytes
o INVOLVED WITH THESE FUNCTIONS = SER
- Synthesis and secretion of:
o Proteins (albumin, prothrombin, fibrinogen)
▪ Liver synthesizes and secretes a lot of plasma proteins ** important
• A lot of the proteins of the clotting cascade are produced in the liver
▪ Albumin – serum protein
o Cholesterol
▪ Processed and produced
o Lipoproteins
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Outside the tubular portion of the gi tract, but developmentally, they develop from the endoderm (invagination from the vegetal pole of the embryo) The mucosa of the small intestine contains: gastric glands, surface mucous cells, goblet cells, chief cells, rugae. The production of the hydrochloric acid in the stomach involves: cells with abundant zymogen granules, intracellular canaliculi, goblet cells, secretion of gastrin by parietal cells, membrane bound enterokinases. Describe the features of the classic liver lobule. Describe two other ways how liver lobules are organized. Describe the course of hepatic blood vessels and bile ducts. Outline the location and function of kupffer cells. List the structures found in the portal area. Explain the structure and function of the space of disse. Explain the structure and function of the bile canaliculus. Interposed between blood vessels of intestinal tract and general circulation: receive venous blood from intestine via portal vein, receive arterial blood via hepatic vein.
