1.2.3 Basic Organization of Cell Tissues of GI Tract Flashcards Preview

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Flashcards in 1.2.3 Basic Organization of Cell Tissues of GI Tract Deck (26)
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1
Q

What is this an image of?

A

Enteroendocrine cell

  • enteroendocrine: endo = part of epithelium, endocrine = release hormone into blood (in contrast to exocrine which release their products outside the body, e.g., the gut lumen)
  • some enteroendocrine cells project to the gut lumen where they have receptors that can sense nutrients and respond by releasing their hormone
2
Q

What are some methods of stimulation of intestinal secretion?

A

Mast cells secreting histamine and binding to the cells

or

Submucosal neuron that releases acetylcholine

3
Q

cAMP does what to the CFTR channel?

A

Increases Cl- secretion through it

4
Q

What is this an image of? What are each of the lines pointing to?

A

Esophagus

5
Q

What is this an image of and what are the lines pointing at?

A

Small intestine crypt

6
Q

What is this an image of?

A

Large intestine on TEM

Colonocytes

Presence of large intercellular spaces is characteristic of a fluid absorbing epithelium.

Has the capacity to secrete fluid as well

7
Q

cAMP inhibits what in the intestines?

A

THe Na/H exchangers which can cause diarrhea

8
Q

Goblet cells do what?

A

Secrete mucins

9
Q

What is this an image of?

A

Small intestine with simple columnar epithelium

  • villus epithelium is generally considered absorptive
  • crypt epithelium is generally considered secretory

M = mucosa

SB = submucosa

ME = muscularis externa

S = serosa

10
Q

cAMP inhibits what in the intestine?

A

Na Reabsorption

11
Q

What channel secretes NaCl in the intestines?

A

CFTR - activated by cAMP

12
Q

What are the layers of the GI tract?

A
13
Q

What is this an image of?

A

Migration of the epithelial cells - how fast it occurs

14
Q

What is the role of each of the labeled parts of this image?

A

microvilli

apical plasma membrane

actin cytoskeleton (terminal web)

ZO zonula adherens: tight junction - barrier function

ZA: zonula adherens - structural

D: desmosome or macula adherens - ‘spot weld’

15
Q

What is this an image of?

A

Submucosa of the stomach

arrow = muscualris mucosae

ME = muscularis externa

16
Q

What is this an image of?

A

Left side - stomach comprised of simple columnar epithelium

Right - esophagus stratified squamous epithelium

17
Q

What is this an image of?

A

Muscularis externa - myenteric plexus (intestine)

Arrows = neurons

Arrowheads = supporting cells

-circular layer is on the left, longitudinal layer is on the right of the image

18
Q

What are the functions of the intestinal epithelium (6)?

A

Barrier and immune defense

Fluid and electrolyte absorption

Protein synthesis and secretion

Nutrient digestion and absorption

Fluid and electrolyte secretion and IgA secretion

Mediator production

19
Q

What is this an image of?

A

Lamina propria of the small intestine

20
Q

What is this an image of?

A

Lamina propria - plasma cells (small intestine) main secretor of IgA in the small intestine

21
Q

What are an important parts of the small intestine?

A

Villi and crypts

Villi are absor

Crypts are secretory

22
Q

What is this an image of?

A

Goblet cells

Exocrine cells

Mucins = glycoproteins

  • >50% carbohydrate by mass
  • principally O-glycosylation in the Golgi
  • bind various microbes
  • MUC2 produced by goblet cells - secreted mucin
  • MUC3 produced by enterocytes - cell associated mucin

Mucus = mixture of mucins, other glycproteins, etc., fluid and electrolytes.

R = rough ER

G = Golgi apparatus

SG = secretory granules

M = microvillus of adjacent enterocyte

23
Q

How is water absorbed in the intestine?

A

Reabsorption of solutes and H2O follows

Na/K ATPase

24
Q

What is the MM and what is the red line pointing to? What is circled?

A

Small intestine

MM - muscularis mucosae - smooth muscle

Red line - Paneth cells

Circled - mitotic figure

25
Q

Explain the difference in the cell renewal of the GI tract in the stomach and the small intestine

A
  • stem cells in stomach at neck of glands
  • stem cells in intestine in crypts
  • stem cells give rise to all the differentiated functional epithelial cell types of their respective organs
26
Q

What is this an image of? What are the different parts?

A

Large intestine - epithelium are simple columnar - absorptive with secretory potential

M = mucosa

MM = muscularis mucosae

SM = submucosa

ME = muscularis externa

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