Chapter 41 - Organization of the Gastrointestinal System Flashcards Preview

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Flashcards in Chapter 41 - Organization of the Gastrointestinal System Deck (46)
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1
Q

Is a tube that is specialized along its length for the sequential processing of food.

A

Gastrointestinal tube

2
Q

The GI tract consists of both the series of ________ stretching from the mouth to the anus and the several __________ that add secretions to these hollow organs.

A

Hollow organs

Accessory glands and organs

3
Q

The _______ and _______ are responsible for:

  1. Chopping food into small pieces
  2. Lubricating it
  3. Initiating carbohydrate and fat digestion
  4. Propelling the food into the esophagus.
A

Mouth and oropharynx

4
Q

The ________ acts as a conduit to the stomach.

A

Esophagus

5
Q

The ______ temporarily stores food and also initiates digestion by churning and by secreting proteases and acid.

A

Stomach

6
Q

The _________ continues the work of digestion and is the primary site for the absorption of nutrients.

A

Small intestine

7
Q

The ___________ reabsorbs fluids and electrolytes and also stores the fecal matter before expulsion from the body.

A

Large intestine

8
Q

The accessory glands and organs include the:

A
  1. Salivary glands
  2. Pancreas
  3. Liver
9
Q

The __________ secretes digestive enzymes into the DUODENUM in addition to secreting HCO-3 to neutralize gastric acid.

A

Pancreas

10
Q

The liver secretes ______ which the gallbladder stores for future delivery to the duodenum during a meal.

A

Bile

11
Q

Bile contains ___________ which play a key role in the digestion of fats.

A

Bile acids

12
Q

The _______ consists of the EPITHELIAL LAYER, as well as an underlying layer of LOOSE CONNECTIVE TISSUE known as the __________ which contains CAPILLARIES, ENTERIC NEURONS and IMMUNE CELLS as well as a thin layer of SMOOTH MUSCLE known as ______________.

A

Mucosa

Lamina propria

Lamina muscularis mucosae (literally, the muscle layer of the mucosa).

13
Q

The layer of epithelial cells can be EVAGINATED to form ________ or INVAGINATED to form ________.

A

Villi

Crypts (or glands)

14
Q

Finally, on a larger scale the mucosa is organized into _________.

A

Large folds

15
Q

The __________ consists of LOOSE CONNECTIVE TISSUE and LARGE BLOOD VESSELS.

A

Submucosa

16
Q

The submucosa may also contain _______ that secrete material into the GI lumen.

A

Glands

17
Q

The muscle layer, the ___________ includes two layers of smooth muscle. _________ are present between these two muscle layers.

A

Muscularis externa

Enteric neurons

18
Q

The inner layer is ________.

A

Circular

19
Q

The outer layer is _________.

A

Longitudinal

20
Q

Assimilation of dietary food substances requires ________ as well as ________.

A

Digestion

Absorption

21
Q

The sedentary human body requires _____ body weight each day.

A

30 kcal/kg

Note: This nutrient requirement is normally acquired by the oral intake of multiple food substances that GI tract then assimilates.

22
Q

Absorb WATER and ELECTROLYTES.

A

Small and large intestine

23
Q

Absorbs lipids, carbohydrates and amino acids.

A

Small intestine

24
Q

Can provide sufficient calories to sustain adults and to support growth in premature infants.

A

Parenteral (i.e intravenous) alimentation

25
Q

Has been used successfully on a long-term basis in many clinical settings in which oral intake is impossible or undesirable.

A

Total parenteral nutrition

26
Q

Food substances are not necessarily - and often are - consumed in a __________ that the small intestine can directly absorb.

A

Chemical form

27
Q

To facilitate __________, the GI tract digests the food by both MECHANICAL and CHEMICAL PROCESSES.

A

Absorption

28
Q

_______ of ingested food begins in the mouth with CHEWING (MASTICATION).

A

Mechanical disruption

29
Q

The mechanical processes that alter food composition to facilitate absorption continue in the _______, both to initiate protein and lipid enzymatic digestion and to allow passage of gastric contents through the pylorus into the duodenum.

A

Stomach

30
Q

This change in the SIZE and CONSISTENCY of gastric contents is necessary because solids that are _______ in diameter do not pass through the pylorus.

A

> 2 mm

31
Q

Although most lipids are consumed in the form of triacylglycerols, it is ________ and _________, not triacylglycerols that are absorbed by the small intestine.

A

Fatty acids

Monoacylglycerols

32
Q

Thus, a complex series of _________ are required to convert dietary triacylglycerols to these smaller lipid forms.

A

Chemical reactions (lipid digestion)

33
Q

Similarly, amino acids are present in food as PROTEINS and LARGE PEPTIDES, but only amino acids and small peptides - primarly _________ and ________ are absorbed by the small intestine.

A

Dipeptides

Tripeptides

34
Q

Carbohydrates are present in the diet as:

A
  1. Starch
  2. Disaccharides
  3. Monosaccharides
35
Q

However, because the small intestine absorbs all carbohydrates as __________.

A

Monosaccharides

Note: Most dietary carbohydrates require chemical digestion before their absorption.

36
Q

Digestion requires enzymes secreted in the:

A

“SPMS”

  1. Stomach
  2. Pancreas
  3. Mouth
  4. Small intestine
37
Q

_________ involves the conversion of dietary food nutrients to a form that the small intestine can absorb.

A

Digestion

38
Q

For carbohydrates and lipids, these digestive processes are initiated in the mouth by salivary and lingual enzymes: ________ for carbohydrates and ________ for lipids.

A

Amylase
Lipase

*Carbohydrate digestion does not involve any secreted gastric enzymes.

39
Q

___________ is initiated in the stomach by GASTRIC PROTEASES (i.e., pepsins), whereas additional lipid digestion in the stomach occurs primarily as a result of the lingual lipase that is swallowed, although some gastric lipase is also secreted.

A

Protein digestion

40
Q

Digestion is completed in the ____________ by the action of both pancreatic enzymes and enzymes at the brush border of the small intestine.

A

small intestine

41
Q

Pancreatic enzymes, which include ________, ________ and ________ are critical for the digestion of lipids, protein and carbohydrates, respectively.

A

lipase, chymotrypsin and amylase

42
Q

The enzymes on the luminal surface of the small intestine (e.g., brush border disaccharidases and dipeptidases) complete the digestion of ___________ and ___________.

A

carbohydrates and proteins

43
Q

Digestion by these brush border enzymes is referred to as ____________.

A

membrane digestion

44
Q

The load to the small intestine is also significantly ________ than that of the ingested material.

A

greater

45
Q

Dietary fluid intake is 1.5 to 2.5 L/day whereas the fluid load presented to the small intestine is __________.

A

8 to 9 L/day

46
Q

The necessary control is achieved by neural and hormonal processes that are initiated by _____________; the result is a coordinated series of motor and secretory responses.

A

dietary food substances