Gastrointestinal Lab Flashcards

1
Q

What four types of vessel like structures would you expect to see running through the mesentery?

A

Arteries, veins, lymphatics and nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Peristalsis and segmentation

A

Peristalsis is responsible for the movement of food through the gastrointestinal tract, whereas segmentation is responsible for the mixing of the food with secretions and exposure of the digestive products to the absorptive surfaces. Segmentation is NOT a form of mechanical digestion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Components of the small intestine and the function of the small intestine

A

The small intestine is comprised of three segments: the duodenum, the jejunum and the ileum. The primary function of the small intestine is to complete the digestion of the food material and absorb the products of digestion as well as water and salts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which basic tissue type must be present in the gut tube to modulate digestive motility

A

Nervous tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does peristalsis help to move food through the small intestine?

A

Contraction of the smooth muscle behind the food bolus helps to propel/push food material along the GI tract at an appropriate rate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does segmentation assist with digestion and absorption of material in the small intestine?

A

By constantly turning over the chyme, it exposes the chyme to the enzymes allowing for digestion and then brings those products of digestion to the absorptive surface so that can be absorbed into the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is segmentation described as a “mixing” motility pattern, rather than a component of mechanical digestion?

A

Because mechanical digestion of the food has already occurred in the mouth and the stomach.
Segmentation allows for mixing of chyme with enzymes responsible for the final stages of digestion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Stomach regions and function

A

The stomach is divided into four regions, the cardia, fundus, body and pylorus (sometimes referred to as the antrum). The fundus is at the proximal end (adjacent to and above the opening of the esophagus), the body is the central region of the stomach and the pylorus is the distal region of the stomach (which connects to the small intestine).

The body and pylorus (antrum) have a significantly thicker layer of smooth muscle than the fundus, which aids in increasing contractility and therefore aiding in the mechanical digestion of food material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Two possible functions of rugae

A

Allows for the expansion of the stomach without increasing the pressure.
Increases the surface area of the mucosa and therefore increases the number of chief and parietal cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which region of the stomach displays a greater degree of movement- the fundus or pylorus (antrum)?

A

Pylorus (antrum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Motility pattern in the pylorus (antrum)

A

Mechanical and chemical digestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pyloric sphincter

A

Modulates the passage of chyme from the stomach into the initial part of the small intestine (the duodenum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The esophagus pierces the diaphragm, and runs for about 3-4 cm in the abdominal cavity before it enters the stomach. At the proximal end of the stomach, the lower esophageal sphincter or cardiac sphincter is present as a thickening of smooth muscle. What is the function of this sphincter?

A

Constricts the esophagus to prevent reflux/backflow of stomach contents.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Regions involved with mechanical digestion

A

Mouth and stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Regions involved with storage

A

Stomach, colon and rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Regions involved with movement

A

Throughout the whole tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Regions involved with mixing

A

Mouth, stomach, small and large intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Regions involved with exposure to absorptive surfaces

A

Small intestine (and to a lesser extent large intestine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Expulsion

A

Anal canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Exocrine components of the pancreas

A

In the exocrine component, the pancreas is arranged into an acinar structure (which means grape-like) and the secretions produced by each acinus are emptied into a small duct. These ducts then all join to form the main pancreatic duct, which empties into the duodenum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe how there structure of the chief cell is specialised for its function

A

Chief cells secrete enzymes (pepsinogen). Because of this they have abundant rough endoplasmic reticulum to produce proteins. They also have numerous apical zymogen granules to transport the enzymes to the apical membrane where they will be secreted into the lumen. The nucleus has a basal location.

22
Q

Describe how the structure of the parietal cell is specialised for its function

A

Parietal cells secrete acid. To do this the cell must pump H+ against its concentration gradient. This requires energy and so the parietal cells have abundant mitochondria. They are also highly folded when active to increase the surface area for secretion.

23
Q

Name the basic tissue that has been modified to form this secretory tissue of the pancreas

A

Epithelial tissue

24
Q

Peritoneum

A

When the peritoneum lines the walls of the abdominal cavity it is called parietal peritoneum; when it is deflected from the wall and lies on the surface of the organs it is called the visceral peritoneum. The visceral peritoneum is continuous with the parietal peritoneum and therefore holds the abdominal organs in place. Some organs lie against the abdominal wall and are termed retroperitoneal.

25
Q

The lesser and greater omentum

A

The lesser omentum, which attatches the lesser curvature of the stomach to the liver, and the greater omentum, which attaches the greater curvature of the stomach to the transverse colon. The greater omentum drapes down over the intestines like an apron and is important in preventing the spread of infections.

26
Q

How does the greater omentum prevent the spread of infection?

A

The greater omentum contains clusters of immune cells

27
Q

What normally anchors the small intestine to the abdominal wall?

A

The mesenteries

28
Q

If the appendix ruptured, which space would pus be released into?

A

Peritoneal cavity. This would cause inflammation of the peritoneum covering the cecum and adjacent small intestine.

29
Q

Mucus

A

Lubricates the gastrointestinal tract, limiting the amount of abrasion that will occur as the food passes through the tract and protects the stomach lining from corrosive acid. Secreted throughout the tract

30
Q

Enzymes

A

The enzymes carry out digestion of the food material. Secreted in the mouth, stomach and small intestine.

31
Q

Serous fluid

A

Dissolves the food material and also creates the optimum condutions for the function of the various digestive enzymes. Secreted in mouth and small intestine.

32
Q

Gastrin

A

Gastrin is formed by cells in the gastric mucosa and stimulates the secretion of gastric juice.

33
Q

Gastric inhibitory peptide

A

The presence of fats in the small intestine stimulates the production of Gastric Inhibitory peptide which inhibits gastric secretion and motility.

34
Q

Secretin and cholecystokinin

A

Secretin stimulates the secretion of pancreatic juice rich in bicarbonate whereas Cholecystokinin (CCK) stimulates the secretion of pancreatic juice rich in digestive enzymes.

35
Q

Main cation and anion of salivary glands

pH and volume per day

A

1.5L/day
pH=7.5
Cation = Na+
Anion = HCO3-

36
Q

Main cation and anion of stomach

pH and volume per day

A

3.0L/day
pH = 1
Cation = H+
Anion = Cl-

37
Q

Main cation and anion of pancreas

pH and volume per day

A

1.5L/day
pH=7.8
Cation = Na+
Anion = HCO3-

38
Q

Main cation and anion of liver

pH and volume per day

A

0.5L/day
pH=7.5
Cation = Na+
Anion = Cl-

39
Q

Main cation and anion of plasma

pH and volume per day

A

Not volume per day
pH = 7.4
Cation = Na+
Anion = Cl-

40
Q

Why doesn’t the hydrolysis of starch by amylase continue in the stomach?

A

No, the amylase is denatured by the acidic contents of the stomach

41
Q

What enzyme is secreted in the stomach?

A

Pepsinogen is secreted. It is then converted to the active enzyme pepsin by the acidic environment in the stomach.

42
Q

What effect would an acidic pH have on the rate of digestion of proteins in the stomach?

A

It would increase the rate as pepsin has an acidic optimum.

43
Q

Why does the pancreas secrete a large amount of bicarbonate?

A

To neutralise the acid delivered from the stomach into the duodenum, thus raising the luminal pH. This is necessary as the optimum pH for operation of the pancreatic and intestinal enzymes is alkaline.

44
Q

What are the three layers of the musculature in the muscularis externa, going from the innermost region (closest to the lumen) to the outermost region?

A

Oblique (innermost)
Circular (middle)
Longitudinal (outermost)

45
Q

What did the detergent do in the mechanical digestion of food in the GI tract experiment?

A

The detergent stabilises the emulsion droplets by coating them and preventing them from coercing again

The ‘detergent’ secreted into the GI tract to assist with the emulsification and digestion of fats is bile salts/ lecithin

46
Q

When the villi move there is localised mixing of gut contents. Which structures causes this movement?

A

Muscularis mucosae

47
Q

Why are there so many blood vessels in the lamina proprietary of the villus

A

To take away absorbed nutrients

48
Q

Functions of mucus in the small intestine

A

To protect the epithelium

49
Q

Which products of digestion are linked to the active absorption of sodium by transport proteins?

A

Amino acids and monosaccharides

50
Q

Which products of digestion are absorbed by simple diffusion through the epithelial cell membranes?

A

Monoglycerides and fats

51
Q

There are not many villi in the mucosa of the large intestine…what does this indicate about its function ?

A

Little nutrient absorption occurs so the villi aren’t necessary