Anatomy and Cell Biology 3309 Lecture Notes - Lecture 7: Intestinal Villus, Thoracic Duct, Hepatocyte

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sapphirebear815

15 May 2018

School

Western University

Department

Anatomy and Cell Biology

Course

Anatomy and Cell Biology 3309

Professor

Martin Sandig

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Lecture 7 – Liver

Transport of nutrients from intestine to the liver

- Outside the tubular portion of the GI tract

- Developed from the endoderm

- Food that comes from the stomach is called chyme

- After the stomach has churned food into chyme, it enters the small intestine

- Enterocytes will absorb the nutrients

- Most of proteins, amino acids, sugars and some fatty acids will enter capillary bed through

post-capillary venules and it is carried into the liver

o In the liver, they are processed → things are taken out and stored

- Most lipids are packaged into chylomicrons that travel through lymphatic system

o There are lacteals in the intestinal villus

o All fat does not pass through a filtering system initially – it is put into systemic

circulation at the thoracic duct and is then delivered throughout the body

o It eventually reaches the liver

- Liver is located in a strategic position

The liver

- Organization is mostly of cells that are called hepatocytes

- Hepatocytes are epithelial cells that form anastomosing plates and rows

o Amongst the cells, there are spaces that don’t stain

▪ Sometimes there is blood in there if there is blood in the liver

- Spaces are capillaries lined by endothelial cells

o They are highly leaky capillaries called hepatic sinusoids

- Majority of things seen are hepatocytes and sinusoids

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- Each hepatocyte has direct access to at least one sinusoid

- Some hepatocytes have an extremely large nucleus and other hepatocytes are binucleate

and have two nuclei

- This signifies that the DNA is being synthesized and makes the cell bigger

o Large nucleus = polyploidy cell and expresses the genes in abundance

o Vs. same thing with binucleate cell

- Cells can get large and they are factories doing many things

- This reflects the efficiency of the liver

Major functions of hepatocytes

- METABOLISM AND STORAGE:

o Detoxification of drugs and alcohol

o Hepatocytes absorb harmful substances and make them manageable in the body

o Steroid hormones are metabolized in the liver

o Smooth ER and cytosol are the organelles within hepatocytes involved with this

function

- SYNTHESIZES AND SECRETES PLASMA PROTEINS:

o Proteins of clotting cascade are produced in the liver

o Cholesterol is processed and produced

o Albumin: important serum protein

o Because they are secreted into the blood stream, there is protein machinery present

(smooth ER, rough ER, golgi)

- FORMATION OF BILE:

o Bile helps us digest fast

o Bile within small intestine emulsifies lipids into small particles so enterocytes can

take up and digest it

o Secretion of bile

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Venous portal system

- Want to send all of the different nutrients that we absorb in a capillary network in the small

intestine right to the liver before it is sent to the rest of the body

- Capillaries from the small intestine form veins that merge into larger vein (portal vein)

- Portal vein breaks up into secondary capillary network in the liver that allows hepatocytes

to have access to the components in the blood

- Portal system:

o VENOUS: capillary network forms a vein that forms a secondary capillary network

o OR artery forms capillary network and continues as an artery = arteriole portal

system

Blood and bile flow through the liver

- Hepatocytes are organized in hexagonal substructures (or called filtering cassettes)

o Many organizational sub structures are called classic hepatic lobules

- Hepatocytes form rows that are profused by blood coming from the small intestine through

the portal vein

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Document Summary

Transport of nutrients from intestine to the liver. Outside the tubular portion of the gi tract. Food that comes from the stomach is called chyme. After the stomach has churned food into chyme, it enters the small intestine. Most of proteins, amino acids, sugars and some fatty acids will enter capillary bed through post-capillary venules and it is carried into the liver. In the liver, they are processed things are taken out and stored: there are lacteals in the intestinal villus. Liver is located in a strategic position. Organization is mostly of cells that are called hepatocytes. Hepatocytes are epithelial cells that form anastomosing plates and rows: amongst the cells, there are spaces that don"t stain, sometimes there is blood in there if there is blood in the liver. Spaces are capillaries lined by endothelial cells: they are highly leaky capillaries called hepatic sinusoids. Majority of things seen are hepatocytes and sinusoids.

Related Questions

The digestion process begins at the mouth. Food enters and then accessory digestive organs like the tongue, teeth, and salivary glands break down the substance. It then travels through the pharynx and esophagus into the stomach, where the stomach acid further breaks down the food (UXL Complete Health Resource). After that, the food travels through the small and large intestines where a majority of its nutrients are absorbed. The waste then exits through the end of the large intestine which is made up of the rectum and anus. After the teeth assist in chewing, food rolls over the tongue and reaches stomach through the esophagus within 8 seconds. General Tsoâs Chicken and Rice consist of carbohydrates, fats and proteins. However, carbohydrates are digested easily than the fats and proteins. After broken down in the stomach, most of the nutrients are absorbed from the small intestine, and it takes 6 to 8 hours to pass through small intestine. The remaining unabsorbed material, âmoves very slowly through the large intestine where the final absorption of water and other nutrients take placeâ (UXL Complete Health Resource). The parasympathetic nervous system encourages the food to move through the digestive tract and motivates digestion process. The sympathetic nervous system works against the parasympathetic nervous system by decreasing the contraction and relaxation of the digestive tract (Taylor). Mouth produces saliva, which contains amylase. Amylase is key in digesting carbohydrates. The stomach produces hydrochloric acid, pepsinogen, intrinsic factor, and mucus (Taylor). Hydrochloric acid kills the bacteria and other organisms that enter the stomach, and then continues to activate pepsinogen. Pepsinogen then changes into pepsin, which digests protein peptides. The pancreas produces trypsin, chymotrypsin, carboxypeptidases, lipases, and phospholipases. Trypsin, chymotrypsin, and carboxypeptidases digest proteins, whereas lipases, phospholipases digest lipid molecules. Small intestine produces lactase, sucrase, maltase, lipases, and peptidases. Lactase, sucrase, and maltase digest carbohydrates (UXL Complete Health Resource). Saliva glands, pancreas, liver, and gallbladder are the accessory organs of the digestive process. Saliva glands produce mucus and amylase which digests starch into simple sugars and binds food particles together, while lubricating the palette when one swallows. The pancreas produces amylase, lipases, and proteinases etc. These digestive juices are responsible for breaking down carbohydrates, proteins, and fats. The liver is the largest gland in the body, âIt produces bile salts to emulsify lipids. It detoxifies metabolic end products to protect the bodyâ (UXL Complete Health Resource). Gallbladder stores bile juice. The chicken in the General Tsoâs contains proteins. Proteins cannot be digested in mouth. However, the mouth can physically digest chicken into smaller pieces. These partially digested chicken pieces travel to stomach, where it is digested by pepsin. The pancreas produces trypsin, chymotrypsin, carboxypeptidases, lipases, and phospholipases (UXL Complete Health Resource). The chicken is then digested by trypsin, chymotrypsin, and carboxypeptidases in the duodenum of the small intestine. After the complete digestion, the chickenâs proteins change into amino acids, which are then absorbed into blood. The rice of the General Tsoâs is a carbohydrate. Carbohydrates are partially digested inside the mouth by amylase. The rest of the rice travels to the stomach where it is digested by pancreatic juices and enzymes that are produced by small intestine. The digestion of the rice produces monosaccharides that absorb into the blood stream. The left over, and undigested parts of the chicken and rice that are useless to the body are excreted by large intestine through rectum.

1) Based on your finding in the Module 3 Report, begin the Module 4 Report by identifying which metabolites are being absorbed and specifically which vessels of the cardiovascular or lymphatic system are the initial vessel of transport from the digestive system. 2) From the point that the specific metabolites are absorbed from the GI tract, trace the path of the resulting metabolites to the following locations in the body for incorporation into the body structure: Metabolites of protein for use in the Gastrocnemius muscle for muscle maintenance. Metabolites of the carbohydrates for energy to contract the cardiac muscle cells. Metabolites of fat to incorporate into the myelin sheaths of the Schwann cells of the Trigeminal nerve that innervates the Masseter muscle. Water for incorporation into the synovial fluid of the hip joint. Iron for incorporation into red blood cells in the bone marrow of the sternum.

maroonguinea-pig686

Food that we consume is composed of very complex molecules. During the digestive process these compounds are broken down into smaller and smaller subunits in preparation for use by the body as building blocks needed for the many components of the human body. The digestion process begins at the mouth. Food enters and then accessory digestive organs like the tongue, teeth, and salivary glands break down the substance. It then travels through the pharynx and esophagus into the stomach, where the stomach acid further breaks down the food (UXL Complete Health Resource). After that, the food travels through the small and large intestines where a majority of its nutrients are absorbed. The waste then exits through the end of the large intestine which is made up of the rectum and anus. After the teeth assist in chewing, food rolls over the tongue and reaches stomach through the esophagus within 8 seconds. General Tsoâs Chicken and Rice consist of carbohydrates, fats and proteins. However, carbohydrates are digested easily than the fats and proteins. After broken down in the stomach, most of the nutrients are absorbed from the small intestine, and it takes 6 to 8 hours to pass through small intestine. The remaining unabsorbed material, âmoves very slowly through the large intestine where the final absorption of water and other nutrients take placeâ (UXL Complete Health Resource). The parasympathetic nervous system encourages the food to move through the digestive tract and motivates digestion process. The sympathetic nervous system works against the parasympathetic nervous system by decreasing the contraction and relaxation of the digestive tract (Taylor). Mouth produces saliva, which contains amylase. Amylase is key in digesting carbohydrates. The stomach produces hydrochloric acid, pepsinogen, intrinsic factor, and mucus (Taylor). Hydrochloric acid kills the bacteria and other organisms that enter the stomach, and then continues to activate pepsinogen. Pepsinogen then changes into pepsin, which digests protein peptides. The pancreas produces trypsin, chymotrypsin, carboxypeptidases, lipases, and phospholipases. Trypsin, chymotrypsin, and carboxypeptidases digest proteins, whereas lipases, phospholipases digest lipid molecules. Small intestine produces lactase, sucrase, maltase, lipases, and peptidases. Lactase, sucrase, and maltase digest carbohydrates (UXL Complete Health Resource). Saliva glands, pancreas, liver, and gallbladder are the accessory organs of the digestive process. Saliva glands produce mucus and amylase which digests starch into simple sugars and binds food particles together, while lubricating the palette when one swallows. The pancreas produces amylase, lipases, and proteinases etc. These digestive juices are responsible for breaking down carbohydrates, proteins, and fats. The liver is the largest gland in the body, âIt produces bile salts to emulsify lipids. It detoxifies metabolic end products to protect the bodyâ (UXL Complete Health Resource). Gallbladder stores bile juice. The chicken in the General Tsoâs contains proteins. Proteins cannot be digested in mouth. However, the mouth can physically digest chicken into smaller pieces. These partially digested chicken pieces travel to stomach, where it is digested by pepsin. The pancreas produces trypsin, chymotrypsin, carboxypeptidases, lipases, and phospholipases (UXL Complete Health Resource). The chicken is then digested by trypsin, chymotrypsin, and carboxypeptidases in the duodenum of the small intestine. After the complete digestion, the chickenâs proteins change into amino acids, which are then absorbed into blood. The rice of the General Tsoâs is a carbohydrate. Carbohydrates are partially digested inside the mouth by amylase. The rest of the rice travels to the stomach where it is digested by pancreatic juices and enzymes that are produced by small intestine. The digestion of the rice produces monosaccharides that absorb into the blood stream. The left over, and undigested parts of the chicken and rice that are useless to the body are excreted by large intestine through rectum. 1) Based on your finding in the Module 3 Report, begin the Module 4 Report by identifying which metabolites are being absorbed and specifically which vessels of the cardiovascular or lymphatic system are the initial vessel of transport from the digestive system. 2) From the point that the specific metabolites are absorbed from the GI tract, trace the path of the resulting metabolites to the following locations in the body for incorporation into the body structure: Metabolites of protein for use in the Gastrocnemius muscle for muscle maintenance. Metabolites of the carbohydrates for energy to contract the cardiac muscle cells. Metabolites of fat to incorporate into the myelin sheaths of the Schwann cells of the Trigeminal nerve that innervates the Masseter muscle. Water for incorporation into the synovial fluid of the hip joint. Iron for incorporation into red blood cells in the bone marrow of the sternum.

ivoryhorse368

1. Which organ is responsible for balancing the amount ofglucose floating around in the blood? (it stores excess glucosewhen there is too much and releases glucose into the bloodstreamwhen there isn't enough)

Select one:

a. liver

b. pancreas

c. spleen

d. stomach

2. The gastrointstinal tract has 4 basic layers. Which layer isthe one that comes in contact with the food that you eat?

Select one:

a. serosa

b. submucosa

c. muscularis

d. mucosa

3. Which digestive organ contains 3 layers of muscle tissue inthe muscularis?

Select one:

a. esophagus

b. large intestine

c. stomach

d. anus

The esophagus is the first organ in the digestive tract thatsecretes digestive enzymes to begin the chemical (molecular)breakdown of food.

Select one:

True

False

Gastric ulcers are often caused by bacterial infection.

Select one:

True

False

Lactose intolerance causes gas, bloating and stomach achesbecause undigested sugar molecules, called lactose, end up gettingdigested by bacteria in the intestines. When they digest it, theyproduce lots of gases.

Select one:

True

False

7. The lower esophageal sphincter prevents food in the stomachfrom backing up into the esophagus.

Since the esophagus is not equipped to handle the harsh acids inthe stomach, when food (mixed with stomach acids) does back up intothe esophagus, you get symptoms such as heart burn. This is calledgastroesophageal reflux (or "reflux").

When reflux is left untreated for many years, the person becomesa trisk for esophageal cancer. This is because the esophagus gets"burned" by the acids over and over again which can eventuallytrigger the development of cancerous cells.

Select one:

True

False

Peristalsis is defined as the rhythmic contractions of thedigestive system that pushes food along the digestive tract.

Select one:

True

False

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Anatomy and Cell Biology 3309 Lecture Notes - Lecture 7: Intestinal Villus, Thoracic Duct, Hepatocyte

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