Gastrointestinal Anatomy: Basic Structure of GI Structure Flashcards

1
Q

What are the 4 main functions of the GI system?

A

Motility (transport food and water through the body + waste management)

Absorption (bringing nutrients/water from lumen into the internal environment)

Secretion (synthesisse and reelase enzymes, mucus, and serous fluid into the lumen)

Digestion (break nutrients into smaller pieces)

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2
Q

These are structures that close off ends and separate sections of tube.

A

Sphincters

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3
Q

What is the type of epithelia found in the mouth/oral cavity and the esophagus? Why?

A

Stratified squamous epithelium, to protect from abrasion

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4
Q

What is the type of epithelia found in the stomach, small intestine and large intestine? Why?

A

Simple columnar, because columnar epithelia is much better in secretion and absorption

  • has a larger surface area to absorb and secrete material
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5
Q

What is the type of epithelia found in the anus?

A

Stratified squamous epithelium (to protect from abrasion of the POOP)

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6
Q

Unicellular glands usually contain lots of these cells.

A

Goblet cells

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7
Q

These cells are columnar, they have apical mucus granules and a basal nucleus

A

Goblet cells

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8
Q

What are the 2 types of glands?

A

Simple and compound

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9
Q

What’s the difference between a simple gland and a compound gland?

A

A simple gland has a single duct (like the stomach and small intestine)

A compound gland has 2 or more ducts (like the salivary glands) - it also has an increased SA to perform more secretions

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10
Q

What are the 4 layers of the gut tube?

A

Mucosa, submucosa, muscularis (externa/proper), adventitia

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11
Q

This consists of the epithelium, basement membrane and a lamina propria. May contain glands, and has a layer of smooth muscle (muscularis mucosae) that moves mucus and produces tiny localised movements.

A

Mucosa

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12
Q

This consists of predominantly FCT, glands and blood vessels. It can perform many secretions, of which is regulated by the submucosal nerve plexus.

A

Submucosa

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13
Q

This layer consists of smooth muscle. It contains the myenteric plexus which is located between layers and regulates motility (transport of food and water and other things in the gut)

A

Muscularis

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14
Q

What are the 2 layers of the muscularis?

A

Circular muscle layer (inner) and longitudinal muscle layer (outer)

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15
Q

This is the outermost layer of the gut tube and consists of FCT; this provides support to organ and may also help it to anchor to neighbouring cells.

A

Adventitia

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16
Q

Why are there two layers of smooth muscle with different orientations? (in the muscularis)

A

Because there are different motility patterns in the gut tube. Different orientations of muscle will result in different contractions of the gut tube.

17
Q

Digestion begins where?

A

In the mouth (oral cavity)

18
Q

What are the 3 salivary glands? What do they each secrete?

A

Parotid (serous fluid with amylase)

Sublingual glands (mucus only)

Submandibular glands (mixed serous and mucus)

19
Q

Which salivary glands are activated in anticipation for food?

A

Submandibular glands

20
Q

These are compound secretory glands that secrete serous fluid, mucus, and enzymes like amylase.

A

Salivary glands

21
Q

These cells in the salivary glands are responsible for secreting bicarbonate.

A

Duct cells

22
Q

These cells in the salivary glands can secrete serous fluid, enzymes and mucus.

A

Acinar cells

23
Q

This is the terminology for cells in clusters.

A

Acinus

24
Q

What is the function of duct cells?

A

To secrete bicarbonate for pH buffering in the gut. (especially when you eat acidic food)

Also serous and mucus secretions ultimately pass through the ducts.

25
Q

This is a long tube (~25cm) located posterior to the trachea that extends from the pharynx to the stomach.

A

Esophagus

26
Q

This ensures the food enters the esophagus and not the trachea.

A

Epiglottis

27
Q

What are the layers of the muscularis externa of the esophagus? Why is it laid out this way?

A

First 1/3: skeletal muscle (because swallowing and chewing is voluntary movement)

Middle 1/3: mixture of smooth and skeletal muscle

Last 1/3: smooth muscle (because involuntary movement)

28
Q

Why is the mucosa and submucosa in the esophagus highly folded?

A

To have the capacity to expand for passage of bolus and for the glands as well

29
Q

The esophagus has goblet cells, true or false?

A

False. Esophagus has glands with ducts to surface epithelium.

30
Q

Where is mucus made in the esophagus?

A

In the mucus secreting glands (in mucosa and submucosa), it gets to surface epithelium through the ducts

31
Q

What is responsible for regulating motility in the muscularis externa?

A

Myenteric plexus

32
Q

Secretion in the submucosa is regulated by the?

A

Submucosal nerve plexus