Normal GI Flashcards
1
Q
What is segmentation?
A
using smooth muscle to squeeze apart food particles and mix them with surrounding material
2
Q
Where does segmentation take place?
A
Small intestine
3
Q
What type of digestion is segmentation?
A
Mechanical
4
Q
What are the two types of nerve plexuses in the GI tract?
A
Short (enteric)
Long (CNS involvement)
5
Q
What are the three layers of the mucosa?
A
Epithelium
Lamina propria
Muscularis mucosae
6
Q
What is found in the submucosa?
A
Blood vessels, lymph, nerves
7
Q
What does the submucosa do?
A
Allows GI tract to expand
Differentiates parts of the small intestine
8
Q
What is the makeup of the muscularis layer?
A
2 layers
Inner circular, outer longitudinal
9
Q
What are the four layers of the alimentary canal?
A
Mucosa
Submucosa
Muscularis
Serosa or Adventitia
10
Q
What determine if a layer will be covered by serosa or adventitia?
A
Esophagus, rectal canal, parts of retroperitoneal are covered by adventitia- rest of structures by serosa
11
Q
What are the two major intrinsic plexuses?
A
Submucosal nerve plexus
Myenteric nerve plexus
12
Q
What do salivary glands do?
A
Clean mouth, taste, moisten food, chemical breakdown of starch (most are extrinsic)
13
Q
What are intrinsic salivary glands?
A
Buccal
Keep mouth moist
14
Q
How are extrinsic salivary glands described?
A
Paired, compound, tubuloalveolar glands
15
Q
What are the three extrinsic salivary glands?
A
Parotid glands
Submandibular glands
Sublingual glands
16
Q
What are the two phases of deglutition?
A
Buccal phase
Pharyngeal-esophageal phase
17
Q
Where is the swallowing center located?
A
Medulla and pons
18
Q
What cell types if mainly found in the stomach in gastric pits?
A
Goblet cells
19
Q
What layer of the mucosa is scant in the stomach?
A
Lamina
20
Q
What type cell in the gastric gland cells produce intrinsic factor?
A
Parietal cells
21
Q
What do chief cells produce?
A
Pepsin
22
Q
What extra layer is added to the muscularis in the stomach?
A
Inner oblique layer
23
Q
What is the only enzymatic digestion that occurs in the stomach?
A
Protein degradation
24
Q
What is rennin
A
Digests casein in infants
25
What is pepsin?
Protein digesting enzyme
26
What does protein degradation denature?
HCl
27
What does gastrin do?
Stimtulates secretion of enzymes, HCl & other hormones
28
What are the three phases of gastric secretion?
Cephalic (reflex)
Gastric
Intestinal
29
What triggers the cephalic phase in gastric secretion?
Aroma, taste, sight or thought of food
| Conditioned reflex
30
What does the cephalic phase of gastric secretion do?
Prepares stomach for digestion
31
What happens during the gastric phase of gastric secretion?
Distention- stimulates stretch receptors
Causes impulses to medulla along vagus
Gastrin stimulates HCl production
32
When does the intestinal phase of gastric secretion starts?
When food enters small intestine
33
What is the excitatory subphase of intestinal secretion?
Presence of acidic chyme in small intestine causes intestine to release gastrin- stimulates gastric glands to produce even more HCl
34
What are the two subphases of the intestinal phase?
Excitatory subphase
| Inhibitory subphase
35
What sets peristalic wave rate in the stomach?
Pacemaker cells
36
How much chyme enters the small intestine at a time?
3 ml
37
What are the three surface area modifications in the small intestine?
Plicae circularis
Villi
Microvilli
38
What do the plicae circularis do/ where are they found?
Slow chyme and mix with digestive juices
Cork-screwed shaped
Found in duodenum
39
What do the villi look like?
Finger like projections
40
What is found in villli?
Lamina propria
Capillary bed
lacteal (lymph cell for fat)
41
What is microvilli?
```
Brush border (+ their enzymes)
Increases surface area
```
42
Where are paneth cells found?
interstinal crypts
43
What do Paneth cells do?
Secrete lysozyme
44
What does bile do?
Emulsifies fats- facilitates digestion (makes fat water soluble)
45
What works with the gallbladder to produce and store bile
Liver
46
What are the three vessels at the portal triad?
hepatic arteriole
portal venule
bile duct
(there will also be lymph)
47
What is the main function of the hepatocytes?
Form bile
48
What do hepatocytes do with glucose?
Store and release it
49
What other things does the liver store?
Fat-soluble vitamins
| Amino acids
50
what are the cells that are macrophages in liver sinusoids?
Kupffer's Cells
51
How is bilirubin formed?
From heme; happens in liver
52
What happens to the bilirubin in the small intestine?
Converted in small intestine to urobilinogen- brown pigment
53
what do bile salts do?
Emulsify fats in small intestine (reabsorbed in ilium for resection)
54
What layer of the alimentary canal is areolar tissues covered with mesothelium?
Serosa
55
What layer of the alimentary canal is fibrous connective tissue that blends with surrounding structure? What does it cover
Adventitia
| Esophagus, rectal canal, parts of retroperitoneal
56
What does the submucosal nerve plexus control?
Glands and secretions of submucosa
57
What does the myenteric nerve plexus control?
Muscles of muscularis
58
What is found in saliva?
Salivary amylas, lysozyme, IgA, metabolic wastes, mucin
59
Does any absorption take place in the mouth, pharynx or esophagus?
No
60
What enables chemical digestions in the mouth?
salivary amylase
61
What are the four types of gastric gland cells?
Mucous neck cells
Parietal cells
Chief cells
Enteroendocrine cells
62
What is the purpose of the inhibitory subphase of the intestinal phase?
Protects small intestine from acidic chyme
Inhibition of gastric gland secretion
Pyloric sphincter tightens
63
In the small intestines, what type (histology) cells are in the mucosa layer?
Simple columnar cells
64
What type of cells are found in the mucosa in the small intestine?
Absorptive cells
goblet cells
enteroendocrine cells
T cells
65
What are most enzymes in the small intestine associated with?
Brush border
66
What emulsifies fats and facilitates digestion?
Bile
67
What is in the center of each liver lobule?
Central vein, blood travels here over hepatocytes through sinusoids
68
What is bile released into for transport to the triad?
Canaliculi
69
What does the liver store?
Glucose, fat-soluble vitamins, amino acids
70
What are macrophages that live in liver sinusoids?
Kupffer's Cells
71
What do Kuppfer's Cells do?
Remove bacteria and worn RBCs
72
What is bilirubin converted to in the small intestine
Urobilinogen (brown pigment)
73
What does cholecystokinin cause?
The gallbladder to contract and stimulate secretion of pancreatic enzymes
74
What does secretin trigger?
The liver to make more bile
| pancreatic production of bicarbonate
75
What are the endocrine islands in the pancreas?
Islets of Langerhans
76
What are the exocrine portion of the pancreas?
Acinar tissue
77
What is produced in the Islets of Langerhans?
Insulin
Glucagon
Somatostatin
78
What is produced in the acinar tissue?
Enzymes
| Bicarbonate ions
79
What are these:
Trysinogen
Procarboxypeptidase
Chymotripsinogen
Proteases produced by the pancreas.
| Turn into active form when they reach the small intestine
80
What produces gas and acidity in the large intestine?
Ferment undigestible carbs
81
What vitamins are synthesized in the large intestine?
B complex and K vitamins
82
What are the two types of the propulsions that happen in the large intestine?
Haustral contraction
| Mass movements
83
What is absorbed in the large intestine
Mainly water
| ions, vitamins
84
What is enzymatic hydrolysis?
"split with water"
| catabolic process where complex molecules are broken into simple molecules
85
What are the three type of carbohydrate monomoers
Glucose
Galactose
Fructose
86
Where does carbohydrate digestion occurs?
Mouth and small intestine
87
How does fructose cross barriers to get reabsorbed?
Facilitated diffusion
88
What is the only type of nutrient that is digested in the stomach?
Protein
89
These are all _____ enzymes
Trypsin
Chymotrypsin
Carboxypeptidase
pancreatic
90
These are all ____ enzymes
Aminopeptidase
Carboxypeptidase
Dipeptidase
Brush border
91
What cleaves between tyrosine and phenylalanine?
Pepsin
92
What digests casein (infants only)?
Rennin
93
What hydrolyzes aa one at a time from the C terminus?
Carboxypeptidase
94
What do these two enzymes do:
aminopeptidase
Dipeptidase
Liberate final aa products
95
What does lipase do?
Produces two free fatty acid and monoglyceride
96
Where are bile salts absorbed?
Ileum of small intestine
97
What is the main form of absorption
Active transport
98
In transepithelial transport, uptake occurs on the ____ side, exocytose occurs on the ____ side
Apical
| Basal
99
Whole proteins are only absorbed in ____
infants
100
What is a collection of fatty elements and bile salts?
Micelle
101
Where do micelles break apart in order to be absorbed?
Near apical surface then lipid diffuse into epithelial cell
102
What is produced in the cytoplasm of epithelium cell when triglycerides combine with phospholipids and cholesterol
Chylomicrons
103
What hydrolyzes triglycerides in capillaries?
Lipoprotein lipase
104
Does fat go through the liver?
No, enter lymph system via lacteals
105
How are fat soluble vitamins absorbed?
Incorporated into micelles
106
Where is iron and calcium absorption limited to?
Duodenum
107
How is sodium absorbed?
Coupled to cotransport of glucose and amino acids
108
What are chloride ions actively transported in exchange for?
Bicarbonate
109
How are potassium ions reabsorbed?
Vita simple diffusion (osmotic gradients)
110
Where is iron actively transported into?
Mucosa cells
111
What is calcium locally regulated by?
Vitamin D
112
What is water uptake coupled to?
Sodium uptake
