succus entericus

Question 1

Front

Answer 1

Back

Question 2

What is succus entericus?

Answer 2

The alkaline secretion of the glands in the small intestine, primarily the crypts of Lieberkühn.

Question 3

What is the average daily volume of succus entericus secreted?

Answer 3

Approximately 1-2 liters per day.

Question 4

What is the pH of succus entericus and why is it important?

Answer 4

It is slightly alkaline (pH ~7.5-8.0). This neutralizes acidic chyme from the stomach, providing the optimal pH for pancreatic enzyme activity.

Question 5

What are the two main types of enzymes in succus entericus?

Answer 5

1. Brush border enzymes (embedded in enterocyte membrane)<br></br>2. Secreted enzymes (released into the lumen)

Question 6

Name the key brush border enzymes and their actions.

Answer 6

• <b>Enteropeptidase</b>: Activates trypsinogen to trypsin.<br></br>• <b>Disaccharidases</b>: Maltase, Sucrase, Lactase (digest disaccharides).<br></br>• <b>Peptidases</b>: Aminopeptidases (digest oligopeptides).

Question 7

What are the secreted enzymes in succus entericus?

Answer 7

They are minimal. The major digestive enzymes in the lumen come from the pancreas, not intestinal secretion.

Question 8

What is the primary function of succus entericus?

Answer 8

To provide a liquid medium for absorption and to supply brush border enzymes for the final stages of digestion.

Question 9

How is the secretion of succus entericus regulated?

Answer 9

Primarily by local neural and hormonal reflexes triggered by:<br></br>1. <b>Local tactile stimulation</b> (e.g., by chyme)<br></br>2. <b>Secretin and CCK</b> (potent stimulators)

Question 10

What is the role of mucus in succus entericus?

Answer 10

Protects the intestinal mucosa from mechanical and chemical damage and provides lubrication.

Question 11

Clinical correlate: What causes lactose intolerance?

Answer 11

A deficiency of the brush border enzyme <b>lactase</b>, leading to an inability to digest lactose, causing osmotic diarrhea and gas production.

Question 12

Differentiate between succus entericus and pancreatic juice.

Answer 12

<b>Succus Entericus</b>: From intestinal glands, alkaline, contains brush border enzymes.<br></br><b>Pancreatic Juice</b>: From pancreas, highly enzymatic (amylase, lipase, proteases), also alkaline.