Exam 3: Ch.7: Digestive System Pt2 Flashcards
1
Q
What are three functions of the stomach?
A
- Continue digestion of carbohydrates
- **primary fxn = food storage
- some nutrient break down; primarily chemical; little physical
2
Q
What are tiny depressions in the stomach’s surface and one pit leads to more than one gland?
A
Gastric Pits
3
Q
What is the narrow region by gastroesophageal sphincter called?
A
Cardia
4
Q
What is the dome region of the stomach often filled with gas called?
A
fundus
5
Q
What is the largest portion o the stomach?
A
body (corpus)
6
Q
What is the constricted portion by the pyloric sphincter?
A
pylorus
7
Q
What are the longitudinal folds which allow for distention in the stomach?
A
rugae
8
Q
What is the surface epithelium of the Mucosa layer of the stomach? What cells does it contain?
A
simple columnar
Cells:
1. Surface Mucous (= surface lining)
2. Regenerative cells–> bases of pits
9
Q
What are two functions of the Surface Mucous/Surface lining of the cells w/in the surface epithelium of the mucosa of the stomach?
A
- produce thick visible mucus
2. secrete bicarbonate ions
10
Q
Describe the lamina propria of the stomach.
A
loose, vascular CT
present in small amounts b/w glands
11
Q
Describe the make up of the Muscularis Mucosae of the stomach. How is it arranged?
A
smooth ms, layer, often arranged in 3 layres:
- inner circular
- outer longitudinal
- outermost circular/oblique (sometimes)
12
Q
Is the Submucosa of the stomach highly vascular or not? What is located here?
A
highly vascular
Contains:
1. AVA = arteriovenous anastomosis
2. Submucosal (Meissner’s Plexus)
13
Q
What is the function of the AVA and where are they located in the stomach?
A
Fxn: shut down activity and secretion FAST
Location: in Submucosa of stomach
14
Q
Where is the location of the Submucosal (Meissner’s) Plexus? What is its function?
A
Location: Submucosa of stomach next to inner circular layer of ms
Fxn: to influence mucosa (i.e. secretion, blood flow, ms contractions)
15
Q
Does the Muscularis Externa of the stomach have a normal pattern? Elaborate.
A
3 muscle layers possible–> esp. b/w cardia region and greater curvature; all smooth ms,
1) innermost oblique– (sometimes)
2) middle circular – well developed
3) outer longitudinal – thin
normal pattern other locations
16
Q
What is located w/in the Muscularis Externa of the stomach?
A
Myenteric (Auerbach’s) Plexus –> b/w cricular and longitudinal layers of muscle
17
Q
Where is the Myenteric (Auerbach’s) Plexus located? What is its function?
A
Location: b/w circular and longitudinal layers of muscles in stomach of Muscularis Externa
Fxn: to stimulate muscularis externa
18
Q
Does the stomach have adventitia or serosa or both?
A
Serosa only–> covers ALL of stomach (on edge of squamous cells)
19
Q
What three regions of the stomach is the Gastric Histology based on?
A
- Cardiac Region
- Gastric Region (fundus and body)
- Pyloric Region
20
Q
What is the sphincter b/w the pylorus of the stomach and the duodenum? What type of sphincter is it–anatomical of physiological?
A
Pyloric Sphincter
anatomical sphincter
21
Q
What are the two characteristics of an Anatomical Sphincter?
A
- Well-developed inner circular layer of muscle in ME
2. Inner circular layer of ME can be independently controlled
22
Q
Of the three regions of the stomach, histologically, which as shorter pits that lead to cardiac glands with a coiled base? What cells does it contain?
A
Cardiac Region
Primarily surface mucous cells
- some neck mucous and a few DNES and parietal cells
NO chief cells
23
Q
What is the smallest region of the stomach? What cells does it primarily contain?
A
Cardiac Region
surface mucous cells
24
Q
What region of the stomach contains the Gastric Glands? What do these glands extend from and to?
A
Gastric Region (body and fundus)
extends from gastric pit to Muscularis Mucosa
25
What are the three regions in a Gastric Gland (Zymogenic Gland)?
1. Isthmus
2. Neck
3. Base
26
What cell types are in the Isthmus of the Gastric Gland?
1. Surface Mucous
| 2. DNES cells (= enteroendocrine cells)
27
What cell type in the Isthmus of a gastric gland produces thick visible mucus that traps bicarbonate ions? What is the function of these cell type?
Surface Mucous
Fxn: to protect mucosa from acids and enzymes and the rougher components of chyme
28
There are different types of DNES cells in the Isthmus of gastric glands. What three things can they produce?
1. Somatostatin
2. Serotonin and Substance P
3. Gastrin
29
What does somatostsatin do that is released by DNES cells?
inhibits release of hormones by nearby DNES cells and HCl release
(in gastric gland)
30
What does serotonin and Substance P do that is released by DNES cells?
increases gut motility
| in of gastric gland
31
What type of DNES cell produces Gastrin? what effect does Gastrin have?
Type G
stimulates HCl and pepsinogen secretion, gastric motility, and regenerative cells in body of stomach
(in gastric gland)
32
What cell types are found in the Neck of the gastric gland?
1. Neck Mucous cells
2. Regenerative cells
3. Parietal (oxyntic) cells
4. DNES cells (produce same stuff as in Isthmus)
33
What do regenerative cells do in the gastric gland?
(specifically in Neck region)
replace all cell types
34
What cell type in the Neck region of the Gastric gland produces a soluble, less alkaline mucus? What is their function?
Neck Mucous Cells
Fxn: to lubricate gastric contents
35
What are the odd columnar cells with intracellular canaliculi that are in the Neck region of the Gastric gland? What do they produce?
Parietal (oxyntic) cells
Produce:
1. very strong HCl --> made at ~0.8 pH and buffered immediately to ~1-2 pH
2. Intrinsic Factor (~called Gastric Intrinsic Factor)
36
What cells produce the (gastric) intrinsic factor in the gastric gland? What is its function?
Parietal Cells in Neck region
Fxn: necessary for vitamin B12 absorption
37
What cells produce HCl?
Parietal (oxyntic cells) in the gastric glands (mainly in Neck, some in Base)
38
What cells are located in the Base region of the Gastric Gland?
1. Chief (zymogenic) cells
2. Parietal Cells (some)
3. DNES cells (produce same stuff as in Isthmus and Neck)
39
Where are the Chief (zymogenic) cells located? What do they produce?
Base of Gastric gland
Produce:
- primarily Pepsinogen--> to break down proteins
- some Gastric Lipase--> break down fats
40
What cells produce Pepsinogen? What does it do?
Chief (zymogenic) cells
to break down proteins
41
Describe the Pyloric region of the stomach. What cells are primarily found here?
Deeper pits; very twisted and branched pyloric glands
Cells:
- Primarily surface mucus
- DNES
- parietal cells
- some neck mucous cells --> that produce some lysozyme
42
What are the two general causes for a Peptic Ulcer Disease?
1. Insufficient protection from HCl and pepsin
- Damaged mucus coat
- Too much HCl and pepsin
2. Helicobacter pylori
43
What are some factors that delay healing of Peptic Ulcer Diseases?
1. cigarette smoking
2. Alcohol
3. Caffeine
4. Calcium
5. Aspirin
~ stress and spicy foods can aggravate an ulcer BUT NOT cause it
44
What are the three general functions of the small intestine?
1. Digestion
2. Absorb Nutritents
3. Produce Intestinal Hormones-- using DNES cells
45
What cells are used in the small intestine to produce intestinal hormones?
DNES cells
46
What are three surface adaptations of the small intestine? What are they for?
1. Plicae Circulares
2. Villi
3. Microvilli
increase surface area by a factor of 400 plus
47
What are permanent folds affecting the mucosa and submucosa that are found throughout duodenum, jejunum, and proximal ileum?
Plicae Circulares (valves of Kerckring)
48
What cell surface are the MIcrovilli on in the SI?
on the luminal cell surface
49
What are Pliace Circulares and where are they found?
permanent folds affecting mucosa and submucosa
found throughout duodenum, jejunum, and proximal ileum
50
What is the surface epithelium of the mucosa of the small intestine?
simple columnar (all 3 parts-- duodenum, jejunum, and ileum)
51
What 6 cell types are found in the surface epithelium of the SI?
```
simple columnar
Cell types:
1. Surface absorptive cells (=enterocytes)
2. Goblet cells
3. DNES cells
4. Regenerative cells
5. Paneth cells
6. M (microfold) cells
```
52
What is another name for the surface absorptive cells? What do these cells of the SI contain? What are their main functions?
= enterocytes
- contain microvilli
Main Fxns:
- Absorb water and nutrients*
- Terminal digestion in glycocalyx
53
What cells of the SI have the function of terminal digestion in glycocalyx and the cells produce the enzymes and absorb the monosaccharides and peptides created?
Surface absorptive cells (aka enterocytes)
54
Where in the SI are Goblet cells fewest? most numerous?
Fewest--> in duodenum
| Most--> in ileum
55
How many different types of DNES cells are in the SI? In general, what do they produce?
```
~11 types
Produce:
1. CCK (cholecystokinin)
2. GIP (gastric inhibitory peptide)
3. Secretin
```
56
What stimulates the gallbladder contraction and pancreatic secretion of enzymes from serous acini?
CKK (cholecystokinin)
57
What are the two actions of CCK?
1. CCK produced when consume food, specifically fats--> therefore need bile released from gallbladder into duodenum
2. Tells pancreas to release and produce digestive
enzymes
(in SI)
58
Where is GIP produced and what effect does it have?
(= gastric inhibitory peptide)
produced by DNES cells in SI
inhibits HCl release
59
What are the two functions of secretin that is produced by DNES cells in the SI?
1. stimulate pancreas secretion of bicarbonate from pancreatic ducts
2. inhbit HCl release and movement of chyme into SI
60
What hormone stimulates the pancreas to secrete bicarbonate from the pancreatic ducts and will inhibit HCl release and movement of chyme into SI?
secretin
61
Where are the regenerative cells in the surface epithelium of the SI found in?
crypts ( aka intestinal glands)
62
Where are Paneth cells located w/in the surface epithelium of the SI and what are their function? What is their function?
bases of the crypts (aka intestinal glands)
Fxn: produce lysozyme ( to deal w/ bacteria that may be coming back from the colon)
63
Where is the location of the M (microfold) cells?
ileum epithelium over Peyer's Patches
| NOT in duodenum or jejunum
64
What do M (micofold) cells contain and what are they fairly open to?
What do M cells do?
large intracellular pockets that are fairly open to the Lamina Propria
sample foreign antigens in gut lumen and transfer antigens to lymphocytes and dendritic cells that have entered the M cell pockets
65
What is the general function of M cells? What does this result in?
promote humoral immunity
Results in--> plasma cells producing IgA-- which is then transfered to epithelial (enterocytes) cells and released into gut lumen
66
What are M cells important in maintaining?
appropriate gut flora
67
Describe the Lamina propria of the SI. What does it contain? What does is border?
loose areolar CT
a villus core
Borders intestinal glands (aka crypts of Lieberkuhn)
68
What three things are found in the villus core of w/in the Lamina propria of the SI?
1. Lacteals
2. Vascular Components-- smaller blood vessels
3. some Longitudinal smooth ms
69
What are the Lacteals found in the villus core w/in the Lamina propria of the SI? What is their function?
are lymphatic capillary
Fxn: lipid absorption
70
What is the importance of the longitudinal smooth ms in the villus core of the Lamina Propria of the SI? What can this lead to?
if irritated then muscle contracts and the villi will shorten
--> lead to nutrient deficiencies if irritation is prolonged
71
Does the SI have a Muscularis Mucosae?
yes, thing, but present
connects to smooth muscle in vlli
72
Describe the Submucosa of the SI. Is it vascular or avascular?
dense fibro-eleastic CT
very vascular: larger blood vessels
73
What does the Submucosa of the Duodenum contain?
Duodenal (Brunner) Glands--> are mucous glands
74
Where are Brunner Glands located? What do they produce?
w/in Submucosa of the Duodenum
Produce--> alkaline mucus; important fxn to neutralize chyme!!
75
What does the Submucosa of the jejunum contain?
no significant structures
76
What does the Submucosa of the Ileum contain?
Peyer's Patches
77
Where are Peyer's Patches located? What are they?
w/in the Submucosa of the Ileum
--> are a group of regularly occurring large lymph nodules
78
What does the Submucosa of the SI contain that has parasympathetic innervation?
Submucosal (Meissner's) Plexus
79
Where is the Meissner's Plexus located? What is it close to? What is its function
in Submucsa of small intestine close to circular muscle in Muscularis Externa
Fxn: to influence mucosa
80
Does the small intestine have a normal or not normal pattern for its Muscularis Externa?
Normal pattern (inner circular, outer longitudinal)
81
What does the Muscularis Externa of the SI contain?
Myenteric (Auerbach) Plexus
82
Where is the Myenteric (Auerbach) Plexus located? What is it b/w? What is its function?
in the Muscularis Externa of the SI --> b/w circular and longitudinal layers of ms in ME
Fxn: stimulates ME for peristalsis
83
What stimulates the Muscularis externa for peristalsis?
Myenteric (Auerbach) plexus
84
Does the SI have serosa or adventitia or both?
Serosa: first and last part of duodenum and ALL of jejunum and ileum
Adventitia: vertical (descending) portion of duodenum
85
What do the following contain, serosa or adventitia:
1. duodenum
2. jejunum
3. ileum
1. MIXED; serosa; and then adventitia for vertical/descending pt
2. serosa
3. serosa
86
What is found b/w the ileum and cecum of the colon?
Ileocecal valve
87
What type of valve is the Ileocecal valve, anatomical or physiological?
BOTH physiological and anatomical sphincter
88
What is the blind pouch on the right of the body, extending from the cecum?
Appendix (aka vermiform appendix)
89
What type of surface epithelium does the Appendix contain? What type of cells?
simple columnar with:
- surface absorptive cells
- goblet cells
- regenerative cells
- DNES cells
90
Does the appendix have a Lamina Propria? What about a Muscularis Mucosae?
LP--> yes
| MM--> poorly developed
91
Does the appendix have crypts? Villi? Paneth cells?
crypts--> yes
villi --> no
Paneth cells--> no to infrequent
92
Describe the Submucosa of the Appendix. What is a notable structure it contains?
thick layer with large blood vessels
numerous lymph nodules!!
93
Does the appendix have a Muscularis Externa?
Yes, normal pattern, but thin
| inner circular, outer longitudinal
94
Does the appendix have serosa or adventita or both?
serosa
95
What are the functions of the appendix?
1. Humoral immunity
| 2. reservoir for good bacteria
96
What is the large intestine componsed of?
- cecum
- colon
- rectum
- anus
97
What does the colon of the LI consist of?
- ascending
- transverse
- descending
- sigmoid portions
98
T/F. the cecum is like the colon histologically, the rectum is also very similar to the colon.
True
99
What are the three general functions of the Colon? What is the primary function?
1. Primary Function = Absorption of water
2. compaction, lubrication, and elimination of feces
3. production of some vitamins as bacterial by-products (riboflavin, thiamin, vit K, and B12)
100
What is the surface epithelium of the colon? What type of cells does it contain?
```
Simple columnar
Cells:
- many goblets* and surface absroptive cells (aka colonocytes)
- some regenerative cells
- few DNES cells
```
101
Does the colon have a Lamina Propria?
yes, it is typical and has intestinal glands (crypts)
102
Does the colon have a Muscularis mucosae?
| Does it have a Submucosa?
yes, typical
yes, typical
103
What are two things the mucosa of the colon LACKS?
1. villi (only in SI)
| 2. paneths cells
104
Does the Muscularis Externa of the Colon have a normal pattern?
no
| - outer longitudinal muscle is gathered into bands called tenaie coli and is discontinuous
105
What do the constant tonus of teniae coli in the colon result in?
sacculations called Haustra
106
Does the colon have adventitia, serosa, or both?
mixed
- some adventitia
- mostly serosa
107
What is the general function of the rectum?
store fecal material
108
What surface epithelium does the rectum have?
simple columnar
109
The rectum is very similar to the colon's luminal layers; EXCEPT for what three things?
1. significant luminal wall folds exist--> called Transverse Rectal Folds
2. NO teniae coli in mE: longitudinal muscle is more complete
3. *Luminal wall covering is ADVENTITIA
110
The anal canal is very similar to the colon, EXCEPT for what 7 things?
1. surface epithelium = simple columnar that quickly transitions to stratified squamous
2. Glands
3. Mucosa and SM --> contain long. folds creating Anal Columns
4. MM disappears in anal canal
5. Internal anal sphincter
6. External anal sphincter
7. Luminal wall covering = adventitia
111
What type of surface epithelium does the anal canal have?
simple columnar that quickly transitions into stratified squamous
112
What is unique about the Mucosa and Submucosa of the anal canal?
contain longitudinal folds creating Anal Columns
113
Does the Anal canal have a muscularis mucosa?
no; it disappears in the anal canal
114
Does the rectum have adventitia or serosa? What about the anal canal? Is this different than the colon?
rectum--> adventitia
anal canal--> adventitia
colon--> mixed
115
What luminal wall layer is the Internal Anal Sphincter in? What type of muscle is it made up of?
w/in Muscularis Externa
thick circular layer of SMOOTH muscle
116
Were is the External Anal sphincter located? What type of muscle is it made up of?
from pelvic floor (levator ani*)
a striated (voluntary) muscle
