8-Digestive system-II- Alimentary canal Flashcards
(79 cards)
1
Q
Pharynx function
A
Provide communication between nasal & oral cavities with the larynx and trachea
2
Q
Pharynx regions
A
- Nasopharynx
- Orophayrnx
- Laryngopharynx
3
Q
Pharynx lining
A
Mostly Stratified squamous non-keratinized epithelium
-respiratory areas lined with pseudostratified respiratory epithelium
4
Q
General layers of the alimentary canal
A
Pharynx Esophagus Stomach Small intestine Large intestine
5
Q
Main layer of the alimentary canal
A
- Mucosa
- Submucosa (dense irreguar CT)
- Muscularis Externa(all regions except upper 2/3rds of of esophagus
- Serosa(Mesothelium + CT) or Adventita (CT)
6
Q
Parts of mucosa(general)
A
Lining epithelium
Lamina propria
Muscularis mucosae
7
Q
Esophagus mucosa
A
- Lining epithelium- Stratified squamous non-keratinized epithelium
- Lamina propria- Loose CT w/ lymphatic nodules, MALT, esophageal cardiac glands
- Muscularis mucosae- Smooth muscle- organized
8
Q
MALT
A
Mucosa associated lymphoid tissue
9
Q
Esophageal cardiac glands
A
- Lamina propria of distal esophagus
- secrete mucus and protects esophagus from acid
10
Q
Esophagus Submucosa
A
- Dense Irregular CT with elastic fibers
- Esophageal gands proper
- Location of Meissner’s plexus
11
Q
Esophageal gland proper
A
- Located thorough out the length of esophageal submucosa
- produces mucus that lubricates the wall and offers protection
12
Q
Meissner’s plexus
A
Parasympathetic innervation to muscularis mucosae
13
Q
Esophageal muscularis externa
A
-Inner circular/outer longitudinal
-Skeletal muscle replaced with smooth muscle
Upper 1/3- skeletal
middle 1/3- mixed
Lower 1/3- smooth
-Auerbach’s plexus
14
Q
Auerbach’s plexus
A
- Between inner circular/outer longitudinal
- innervates muscularis externa
15
Q
Esophageal adventitia and serosa
A
- Adventia in thorastic cavity bind to trachea, aorta and other thoratic structures
- Serosa-covers part within the abdomen
16
Q
Gastro-esophageal junction
A
- Abrupt changes in epithelium from Stratified squamous non-keratinized epithelium to simple columnar epithelium
- Gastroesophageal sphincter- physiological sphincter- inner circular layer increases in tone
17
Q
Parts of the stomach and which are histoogically the same
A
Cardia Fundus Body Pylorus -Fundus and body are histologically the same
18
Q
Major function of the stomach
A
Physical and chemical digestion into chyme
19
Q
Rugae
A
Transient folds in the stomach
20
Q
Stomach-Mucosa-lining epithelium
A
Simple columnar epithelium covers: luminal surface, gastric pits and glands
21
Q
Stomach glands
A
- 3-7 glands per pit
- Extend from gastric pit into the lamina propria to level of muscularis mucosae
- isthmus, neck and base
22
Q
Cell types of lining epithelium
A
1) Surface mucous cells
2) Mucous neck cells
3) Stem cells
4) enteroendocrine cells
5) Parietal cells
6) Chief cells
23
Q
Surface mucous cells(location structure and function)
A
-Luminal surface of stomach and gastric pits
-Simple columnar cells, apical mucigen granules, basal nucleus
Function: release mucin, forms viscous alkaline mucus with water high in bicarbonate protects the luminal surface from acid.
24
Q
Types of stomach galnds
A
Gastric glands
Cardiac glands
Pyloric glands
25
Gastric glands(location and cell types)
```
-Body and fundus
Mucous neck cells
Stem cells
Enteroendocrine cells
Parietal cells
Chief cells
```
26
Cardiac glands(location and cell types)
```
-Cardia
Mucous neck cells
Stem cells
Enteroendocrine cells
-Some parietal cells
```
27
Pyloric glands(location and cell types)
-Pyloris
Mucous neck cells
Stem cells
Enteroendocrine cells
28
Mucous neck cells (location structure and function)
Location: Ismuth and neck of cardiac and gastric glands. Adjacent to parietal cells
- Structure: Columnar, can appear less regular. Apical Mucigen granules and basal nucleus
- Function: contribute to mucous, less alkaline than surface mucous cells. Protect parietal cells
29
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Stem cells(location structure and function)
Stomach
```
Location: Isthmus and neck of the cardiac and gastric glands
Structure: columnar cells
Function: Stem cells for all epithelial cell types in the stomach
30
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Entroendocrine cells (location structure and function)
Stomach
```
Location: Base of cardiac and gastric glands
Structure: Basally secretes granules
Function: Basal secretion of various hormones into lamina propria(blood vessels)
31
Parietal cells (location structure and function)
Location: scattered throughout the gastric glands
Structure: Large triangular with intracellular canaliculi and microvilli. Cytoplasm is eosinophillic due to abundant mitochondria.
Function: Produce H+ and Cl- separately.
32
Chief cells (location structure and function)
Location: Base of gastric glands
Structure: apical zymogen granules with pepinogen. Basal cytoplasm basophillic from rER
Function: Secrete pepsinogen, which is converted to pepsin, and gastric lipase
33
Stomach-Mucosa- Lamina propria
Surrounds gastric glands and pits
| Loose CT with few lymphatic nodules and MALT
34
Stomach-Mucosa-Muscularis Mucosae
Smooth muscle
| facilitates outflow of gastric glands
35
Stomach-Submucosa
- Dense irregular CT
- Neurovascular structure including Meissner's plexus
- No glands
36
Stomach-Musularis extrerna
- 3 layers inner oblique, middle circular, outer longitudinal layers
- Auerbach's nerve plexus between muscle layers
- Mixes chyme and moves content to duodenum
37
does the stomach have serosa or adventitia?
Serosa- covers the stomach
38
Pyloric sphincter(location, structure, function)
Located at the junction of pyloric stomach and the duodenum
| Formed by thickening of middle circular layer of muscularis externa
39
Main regions of the small intestine
Duodenum, Jejunum, and ileum
40
Small intestine major functions
Complete digestion
| Absorb nutrients
41
Absorptive feature(list)
Plicae circulares
Villi
Microvilli
42
Plicae circulares
Series of permanent circular folds mucosa and submucosa
43
Villi
evaginations of the muscosa -lined with SSE with a core of lamina propria
44
Microvilli
Located at the apical spect of enteroctyes/absorptive cells (mucosa)
45
Small intestine-Mucosa-Lining epithelium
Simple columnar epithelium covers villi and intestinal glands/crypts of Leiberkuhn
46
Small intestine-Mucosa-lining epithelium (cell types)
1. Enterocytes(absorptive cells)
2. Goblet cells
3. Enteroendocrine cells
4. Paneth cells
5. M-cells
6. Stem cells
47
Enterocytes (location, structure, and function)
| SI
Location: line luminal surface of villi migrate from the crypt
Structure: Columnar cell with microvilli, covered in glycocalyx, called striated border.
Function:
-Absorptive role: transports nutrients from lument into blood
-Secretory role: glycoprotein enzymes are secreted into the glycocalyx(digestive) also secrete water to maintain chyme consistency
48
```
Goblet cells (location, structure, and function)
SI
```
Location:line the luminal surface of villi and crypts. Scattered among enterocytes. Increase in number from duodenum to distal large intestine
Structure:Goblet shape. apical mucigen granules
Function: Mucin release apically
49
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Enteroendocrine cells (location, structure, and function)
SI
```
Location: scattered along villi and crypts
Structure: basal secretory granules
Function: Release various hormones
50
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Paneth cells (location, structure, and function)
SI
```
Location: Base of intestinal crypts
Structure: Apical eosinophilic granules that contain lysozyme
Function: lysozyme digest the cell wall of microrganisms
51
M-cells(location, structure, and function)
| SI
Location; mainly overlie large lymphatic nodules
Structure:
-Apical: lack of microvilli but have microfolds
-Basal: large intracellular pockets immune cells migrate through the discontinuous basement membrane
Function: endocytose and transport antigens to underlying immune cells
52
```
Stem cell (location, function)
SI
```
base of intestinal crypts
| Replace all lining epithelial cell types
53
Small intestine-mucosa-lamina propria
-Loose CT at the core of intestinal villus and surrounds intestinal crypts/glands. Fenestrated capillaries, lympatic vessel(lacteal), Smooth muscle fibers, MALT, and lymphatic nodules
54
Small intestine-mucosa-Muscularis mucosae
Movement of villi
55
Small intestine-submucosa
-Dense irregular connective tissue includes Meissner's plexus, blood, and lymph vessels in all three regions
56
Small intestine-submucosa-Duodenum
Large mucous gland(Brunner glands)
| -Protects epithelium and provides optimal pH for pancratic enzymes
57
Small intestine-submucosa- jejunum
no unique histologic features
58
Small intestine-submucosa-Ileum
Large lymphoid nodules called peyer patches extend from submucosa into the lamina propria
59
Small intestine-Muscularis externa
Inner circular and outer longitudinal Auerbach's plexus which is important for peristalsis
60
Small intestine-Serosa and adventitia
Serosa covers majority of the small intestine
| adventitia located where duodenum contacts the posterior abdominal wall
61
Parts of the large intestine
- Ileocecal valve(leads to cecum)
- Appendix
- Colon
- Rectum
- Anal canal
62
Large intestine major functions
- Absorption of water and Na+
| - Indigestible material(feces) is formed and expelled.
63
Ileocecal valve
Thickening of the inner circular layer of musicalris between the ileum and cecum
64
Appendix
- Extends from the cecum
- typical 4 layer wall
- high density of lymphatic nodules and little to no absorptive function
65
Large instestine-mucosa- lining epithelium
- Simple columnar epithelium. NO vili
| - Has numerous tubular lands/crypts that extend into the lamina propria
66
Large instestine-mucosa- lining epithelium(cell types)
1) absorptive cells
2) Goblet cells
3) Enteroendocrine cells
4) Stem cells
5) M-cells
67
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Absorptive cells(colonocytes/enterocytes)(location, structure, function)
LI
```
Location: luminal surface and glands/crypts
Structure:columnar, short microvilli
Function: absorb water and Na+
68
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Goblet cells (location, structure, function)
LI
```
Location luminal surface and glands/crypts
Structure: goblet shaped
Function: mucus lubricates and protects epithelium
69
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Enteroendocrine cells (location, function)
LI
```
Location: crypts/glands(1° base)
Function: basal secretion of hormones
70
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Stem cells(location, function)
LI
```
Location: crypts/glands (1° base)
Function: replace epithelial cell types
71
M-cells:(location, structure, function)
| LI
Location: Overlie lymphatic nodules
Structure: Apical microfolds, basal intracellular pockets
Function: transport antigens to underlying immune cells
72
Large instestine-mucosa- Lamina propria
Loose Ct with abundant immune cells more than small intestine
numerous capillaries in which water and sodium are absorbed
no lymphatic vessels as they organize around muscularis mucosae
73
Large instestine-mucosa- muscularis mucosae
enhance expulsion of mucus from glands
74
Large instestine- submucosa
Dense irregular CT, Meissner's plexus, blood and lymph vessels
Lymphoid tissue extending from lamina propria
75
Large instestine-Muscularis externa
- Inner circular and teniae coli
| - Auerbach's plexus in between the muscular layers
76
Teniae coli
3 evenly spread longitudinal muscle bands
77
Large instestine-serosa and adventitia
Serosa covers the intraperitoneal portions of the large intestine
Adventitia located where teh large intestine is in contact withe the posterior abdominal wall
78
Large intestine- Rectum
Dilated, distal portion f large intestine
-similar to colon but:
Crypts/glands are deeper with more goblet cells
-no teniae coli has outer longitudinal layers
-Adventitia only
79
Anal canal
Upper 1/3: Simple columnar epithelium
Middle 1/3: Stratified columnar epithelium
Lower 1/3: Stratified squamous non-keratinized epithelium becomes keratinized at the anus
Internal anal sphincter from inner curular layer of muscularis externa
External anal sphincter is skeletal msuonlcle
Adventitia only
