Digestive Tract: Esophagus, Stomach, Small/Large Intestine Flashcards

1
Q

What are the 4 general layers of the GI and what are their components?

A
  1. Mucosa- epithelial, lamina propria (CT), and muscularis mucosa (smooth muscle).
  2. Submucosa- loose CT with blood vessels/nerves
  3. Muscularis- smooth muscle
  4. Serosa (epithelial layer underlying it) or Adventitia (connects to tissue).
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2
Q

What type of epithelial make up the gingiva and hard palate and what is the function?

A

Stratified squamous keratinized- protects from abrasion.

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3
Q

What type of epithelia make up the cheek, floor of mouth, lips (inner) and soft palate?

A

Stratified squamous non keratinized.

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4
Q

What underlies the epithelial layer of the hard palate and gingiva?

A

Lamina propria–> Bone

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5
Q

What underlies the epithelial layer of all the other structures of the mouth?

A

Lamina propria–> submucosa–> skeletal muscle

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6
Q
A 35 yr. old female presents to her dentist because her cheek feels odd. An exam reveals a white line (linea alba) or horizontal thickening of the buccal mucosa along the occlusal line of the teeth. She admits to biting her cheek often. This occurs because of:
A . Keratinization of the epithelium
B. Desquamation of the epithelium
C. Atrophy of the submucosa
D. Hypertrophy of the submucosa
E. Smooth muscle hypertrophy
A

A . Keratinization of the epithelium

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7
Q

Where are filiform and fungiform papillae located on the tongue?

A

Anterior, dorsal surface.

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8
Q

Why are filiform papillae keratinized?
A. Increase surface area for absorption?
B. Make the surface of the tongue whitish/grayish appearing?
C. Provide a rough surface for food movement?

A

C. Provide a rough surface for food movement.

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9
Q

Which papillae do not contain taste buds?

A

Filiform

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10
Q
The surface of the tongue is covered with papillae. Which is the most common?
A. Fungiform
B. Foliate
C. Filiform
D. Vallate
A

C. Filiform

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11
Q

Which papillae have salivary glands that secrete serous fluid?

A

Vallate and Foliate

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12
Q

Where are the Vallate papillae located and how many?

A

Along the terminal sulcus.

8-12, very large.

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13
Q

What type of cells do taste buds contain and what are their functions?

A
  1. Gustatory cells- connected to afferent sensory neuron. Have microvili
  2. Supportive cell- no microvilli and not connected to sensory neuron.
  3. Basal cell- stem cell needed to regenerated gustatory and supportive cells because new cells need to form every 10 days.
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14
Q

What connects the nasal cavity to the larynx and the oral cavity to the esophagus?

A

Pharynx

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15
Q

What type of epithelial layer is in the nasopharynx, oropharynx and hypopharynx?

A

Naso- Ciliated pseudo stratified columnar (because its part of the respiratory tract)
Oro and Hypo- Stratified squamous non-keratinized.

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16
Q
Achalasia is a disease in which there is a loss of peristalsis in the distal esophagus. This would be caused by a dysfunction of which of the following layers?
A. Mucosa
B. Submucosa
C. Muscularis
D. Adventitia
A

C. Muscularis

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17
Q

What type of epithelium is in the mucosa of the esophagus?

A

Stratified squamous epithelium non-keratinized- for protection.

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18
Q

What type of glands are found in the submucosa of the esophagus?

A

Mucous glands- help to move food.

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19
Q

What type of muscle does the upper third of the esophagus consist of?

A

Striated (skeletal)- swallowing is voluntary.

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20
Q

What type of muscle is in the middle third of the esophagus?

A

Mix of striated and smooth.

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21
Q

What type of muscle is in the lower third of the esophagus?

A

Smooth muscle.

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22
Q
In what section of the esophagus would you find a mix of smooth and striated muscle?
A. Muscularis mucosa- upper third
B. Muscularis mucosa- middle third
C. Muscularis externa- upper third
D. Muscularis externa- lower third
E. Muscularis externa- middle third
A

E. Muscularis externa- middle third.

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23
Q

What are some of the functions of the stomach?

A
  • Accepts food from esophagus
  • Mixes food (lg. muscularis)
  • Makes gastric acid (parietal cells)
  • Starts protein, lipid digestion (chief cells)
  • Absorbs very few substances form food (no brush border)
  • Moves food (chyme) into intestine
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24
Q

What are the 4 layers of the stomach?

A
  1. Mucosa
  2. Submucosa
  3. Muscularis externa- 3 layers
  4. Serosa
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25
Q
There are surface mucous cells all throughout the stomach, what type of cells are they?
A. Stratified squamous epithelial cells
B. Stratified columnar epithelial cells
C. Simple columnar epithelial cells
D. Simple squamous epithelial cells
A

C. Simple columnar

Need a lot of space for organelles to secrete mucous, stratified not needed because not much mechanical damage.

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26
Q

If gastric contents reflux into the esophagus, this can injure the esophageal mucosa. Why doesn’t gastric contents normally injure the stomach mucosa?

A

Mucous and Bicarbonate protect it.

27
Q

Where are cardiac glands located and what is their function?

A

Cardia region of stomach

Secrete mucus

28
Q

What portion of the stomach contains surface mucous cells, mucous neck cells, parietal cells, and chief cells?

A

Fundus/Body

29
Q

Surface mucous cells secrete:

A

Mucous and bicarb

30
Q

Mucous neck cells secrete:

A

Mucous (more neutral pH)

31
Q

Parietal cells secrete:

A

HCl

Intrinsic factor

32
Q

Chief cells secrete:

A

Pepsinogen

Gastric lipase

33
Q

How do parietal cells secrete acid?

A

H-K ATPase on membrane
Tubulovesicles fuse with canaliculi membrane
Lots of tubulovesicles when you haven’t eaten.

34
Q

Why is there acid in the stomach?

A
  • converts pepsinogen to pepsin which breaks proteins to peptides.
  • kill bacteria
  • acid and intrinsic factor important for absorption of vitamin B12.
35
Q

Where are G- cells located and what is their function?

A
In pyloric glands of stomach.
Secrete gastin (hormone)--> goes to blood
They are enteroendocrine cells.
36
Q

What differentiates pyloric glands from gastric glands?

A

Location in stomach
Type of cells.
Pyloric= deeper pits and shorter coiled glands

37
Q

Where does gastrin go?

A

Stomach distention–> activates G- cells–> gastrin released–> binds to ECL–> releases histamine–> binds to parietal cell–> acid released.

38
Q

What else can stimulate histamine to be released from ECL?

A

Food (ACh receptor)

39
Q
A 44 yr. old man had gastroesophageal reflux disease (GERD) or heartburn. Blocking the secretions of which of the following cells could potentially treat his GERD?
A. Chief cells
B. G cells
C. Mucous neck cells
D. Parietal cells
E. Surface mucous cells
F. ECL cells
A

B. G- cells- gastrin
D. Parietal cells- HCl
F. ECL- histamine

40
Q

What makes up the pyloric sphincter?

A

Smooth muscle

Middles layer of muscularis is thickened

41
Q

What are the 4 layers of the small intestine?

A
  1. Mucosa- circular folds
  2. Submucosa- blood vessels/nerve/lymphatics
  3. Muscularis- 2 layers, inner circular, and outer longitudinal
  4. Serosa
42
Q

What is the main role of the small intestine?

A

Digest and absorption of nutrients.

43
Q

What is the function of enterocytes in the small intestine?

A

Absorptive cells

44
Q

What type of cells are in the villus of the small intestine?

A

Goblet cells- mucus
Enterocytes- absorptive cells
Lymphocytes and plasma cells- dark dots in lamina propria

45
Q

Where do new cells come from in the small intestine?

A

Crypts of Lieberkuhn- where stem cells are located.

46
Q

Where are paneth cells located and what is their function?

A

Crypts of small intestine.

Secrete antimicrobial peptides to protect stem cells from bacteria.

47
Q

How do paneth cells stain?

A

Eosinophilic, bright red.

48
Q

How do parietal cells stain?

A

Eosinophilic, pinkish red.

49
Q

How do chief cells stain?

A

Basophilic, purplish blue.

50
Q
What does not increase the surface area for absorption in the small intestine?
A. Circular folds
B. Microvilli
C. Villi
D. Intestinal Crypts
A

D. Intestinal crypts- stem cells and paneth cells.

51
Q
Intestinal inflammation associated with inflammatory bowel disease may involve the dysfunction of which of the following cells in the small intestine?
A. Enterocytes
B. Enteroendocrine cells
C. Goblet cells
D. Stem cells
E. Paneth cells
A

E. Paneth cells- secrete antimicrobial.

Inflammation due to increase in bacteria

52
Q

Where can peptic ulcers occur?

A

Duodenum (most common because of acidic chyme) and stomach.

53
Q

How can you distinguish the duodenum from other sections of the small intestine?

A

Presence of Brunner’s glands in submucosa.

54
Q

How is the duodenum protected from gastric acid?

A

Brunner’s glands secrete bicarb and mucous.

55
Q

What helps with absorption of nutrients?

A

Smooth muscle in villi contracts and causes rhythmic movement.
Helps mix things, brings nutrients to surface of cell.

56
Q

What is a lacteal?

A

Lymphatic capillary

Aids in absorption of fatty acids and monoglycerides (triglycerides).

57
Q

What controls the activity in the gut?

A

Autonomic nervous system (enteric nervous system).

58
Q

Where is the ganglion of the myenteric plexus located?

A

Between the inner layer of smooth muscle and outer longitudinal layer of smooth muscle in the muscularis externa of the small intestine.

59
Q

What is the function of the large intestine?

A

Absorption of water and electrolytes
Microbial fermentation
Storage of fecal material

60
Q

What are the 4 layers of the large intestine?

A
  1. Mucosa
  2. Submucosa
  3. Muscularis- 2 layers, circular layer and 3 thin bands of longitudinal muscle (tenia coli)
  4. Serosa
61
Q

What type of cells are located in the lg. intestine?

A

Goblet cells

Colonocyte- absorptive, simple columnar

62
Q

Why is there a large number of lymphocytes in the mucosa of the large intestine?

A

Lots of bacteria

63
Q

What is the main function of colonocytes?
A. Absorb amino acids, monosaccharides and fats
B. Secrete digestive enzymes
C. Secrete mucus
D. Absorb water

A

D. Absorb water