VM 704 (Physiology) Liver, Small/Large Intestine, Herbivore Digestive System

What are the 3 major functions of the liver?

1. Lymph production/phagocytosis

2. Carb, lipid, protein synthesis

3. Bile synthesis

What 3 pieces are involved in the portal triad of a hepatic lobule?

1. Bile duct

2. Portal vein

3. Hepatic artery

What is the name for the macrophages specifically found in the liver?

Kupffer cells

What is the Space of Disse?

The space between the endothelium and the hepatocytes.

What is the FUNCTION of the Space of Disse?

To collect lymph and bring it back into circulation.

What are the 3 main types of liver cells?

1. Hepatocytes

2. Stellate cells (in Space of Disse)

3. Kupffer cells (perform phagocytosis)

From which vessel does 75% of the blood supply to the liver come from?

The portal vein

From which vessel does the remaining 25% of the blood supply to the liver come from?

The hepatic artery

What happens if sinusoidal pressure increases in the liver?

Lymph production increases, excess lymph moves into abdominal cavity

What is one of the main causes of portal hypertension?

Right sided heart failure

Where do the hepatocytes initially secrete bile TO?

Into the caniculi

What happens when CCK and secretin are released?

1. CCK stimulates contractions to deliver bile to small intestine

2. Secretin stimulates secretion of bicarbonate and water to increase flow of bile

What are the 2 primary molecules (besides water and electrolytes) that are found in bile?

Bile acids and cholesterol

Which compound is responsible for the breakdown of heme?

Bilirubin

What do bile acids help emulsify?

Fat micelles (that cannot normally mix with water)

Where are the majority of bile acids reabsorbed?

The ileum

How is heme from bilirubin eliminated from the body system?

In feces

What is the main function of the small intestine?

Absorption of nutrients into the blood

What are the 4 main anatomical parts of the small intestine?

1. Duodenum (receives secretions)

2. Jejunum (most of absorption)

3. Ileum (empties into large intestine)

4. Mesentery

What are Peyer’s patches in the ileum of the small intestine?

Aggregated lymphoid tissue in the ileum

What kinds of cells are villi made of?

Epithelial cells

Which structure of the small intestine makes up the brush border?

Microvilli

What is the role of enteroendocrine cells in the lumen?

They sense the environment and secrete hormones

What is the role of goblet cells in the small intestine?

They release mucus into the lumen

What is the role of Paneth and Tuft cells in the small intestine?

Anti-bacterial defense

What is the role of stem cells in the small intestine?

Turnover of epithelial cells

What is the role of enterocytes in the small intestine?

Absorption of most of the nutrients

What are the 2 types of motility in the small intestine after eating?

1. Segmentation contractions

2. Peristalsis

What happens to osmolarity as chyme is digested in the small intestine?

It increases.

Where do chloride ions enter in the small intestine?

Crypt cells

Which enzyme breaks starch down into maltose?

Amylase

What is glucose cotransported with?

Sodium

What are the 2 ways fats are absorbed in the small intestine?

1. Emulsification

2. Enzymatic digestion

What are the 3 main functions of the large intestine?

1. Water absorption

2. Feces formation

3. Microbial fermentation

What are the 3 main segments of the large intestine?

1. Cecum

2. Colon

3. Rectum

In the large intestine, does the mucosa have villi?

No

Which hormone helps the large intestine pull in more salt?

Aldosterone

Which reflex is triggered when feces enter the rectum?

The defecation reflex

Which fermentation product from the large intestine acts as a fuel source?

Volatile fatty acids

What is the most readily available volatile fatty acid in ruminants?

Acetic acid

Which nerve controls input to rumen motility?

The vagus nerve

What is unique about ruminant neonates?

They are functional monogastrics (underdeveloped rumen)

What are the 3 compartments of the camelid GI tract?

1. Fermentation

2. Nutrient absorption

3. Glandular stomach