MODULE 1 Week 1: Digestive System Flashcards
1
Q
The majority of digestion takes place?
A
Small intestine
2
Q
Final B12 absorption location (organ)?
A
Ileum
3
Q
**Accessory organs of digestion
A
Liver, pancreas, gallbladder
4
Q
Pancreas is responsible for digestion what percent of fat, carbs, and protein?
A
50% protein
50% carbs
90% fat
5
Q
PH of the stomach
A
2.3
6
Q
PH of duodenum
A
8 (basic)
7
Q
6 basic processes involved in digestion
A
- Ingestion
- Secretion
- Mixing
- Digestion
- Absorption
- Defecation
8
Q
GALT
A
Gastric associated lymphatic tissue
9
Q
Organs of upper v lower digestive tract
A
Upper = Oral cavity, esophagus, stomach Lower = Small and Large intestines
10
Q
4 layers of GI tract
A
- Mucosa
- Submucosa
- Muscularis external
- Serosa (adventitia)
11
Q
What organelle produces cholesterol
A
Smooth endoplasmic reticulum
12
Q
Where is bile made versus stored
A
Bile made in liver; stored in gallbladder
13
Q
Exocrine function of pancreas (what does it release)
A
- pancreatic lipase
- sodium bicarbonate
- pancreatic carbohydrase
14
Q
3 layers of mucosa
A
- Epithelium
- Laminate propria
- Muscularis mucosae
15
Q
MALT is?
A
Mucosal associated lymphatic tissue; need it because invited foreign protein (from the outside world) into the internal system
16
Q
Inner most layer of 4 layers of GI tissue
A
Mucosa
17
Q
5 R Program to regenerate the gut
A
- Remove irritant
- Replace with digestive enzymes
- Reinoculate with probiotics
- Repair (glutamine etc)
- Rebalance
18
Q
Exocrine v Endocrine (what and where to do they secrete?)
A
Exocrine = secrete enzymes and juices into epithelium
Endocrine = secrete various hormones into the blood
19
Q
What layer of mucosa contains lymphoid tissue? What WBC types are in high numbers there?
A
Lamina propria; macrophages & lymphocytes
20
Q
Meissner’s plexus is located? Controls?
A
Located: In submucosa
Controls: secretions of mucosal glands & regulates mucosal movements and blood flow
21
Q
Visceral peritoneum versus parietal peritoneum
A
Visceral = Surrounds stomach and intestines
Parietal = lines the entire cavity
22
Q
Front teeth v back teeth & color
A
Front teeth for meat/higher pH foods and back teeth for colorful/higher pH foods (fruit & veggies)
23
Q
Sweet, sour, salty controlled by cranial nerve ?
A
7
24
Q
Bitter taste controlled by cranial nerve X ?
A
9
25
3 main salivary glands
Parotid, submandibular, sublingual
26
Parotid gland secretes?
Water, electrolytes (Na, K, Cl), and enzymes
27
Submandibular & Sublingual glands secrete X?
Same as parotid PLUS MUCUS
28
Saliva is X% water
99.5
29
**Primary enzyme in saliva is ? This enzyme hydrolyzes what bonds in starch?
Enzyme = amylase
Hydrolyzes alpha 1-4 bonds in starch
30
% of water that should be inside versus outside of the cell
Inside = 60
Outside = 40
31
Lingual lipase produced by? Hydrolyzes?
Produced by lingual serous glands; hydrolyzes triglycerides
32
IgG A found in saliva?
True
33
T.I.M.E muscles (mechanical digestion in the mouth)
```
T = Temporalis
I = Internal pterygoid
M= masteter
E = External pterygoid
```
34
Cranial nerve involved with T.I.M.E. Muscles
5
35
Esophagus
- length
- main function
10 inches
| - Passage of bolus of food from oral cavity to stomach
36
Peristalsis
Progressive wavelike motion that moves bolus into the stomach
37
What increases risk of developing GERD
- smoking
- high fat diets
- chocolate
- alcohol
38
Rugae of mucosa
Ruffled borders on the inside of the stomach which helps to break down food and allow for expansion of the stomach
39
**Stomach range when EMPTY
50mL (2 oz)
40
**Stomach range when FULL
1.5L (37-52oz)
41
Cardiac, oxyntic, and pyloric glands produce?
Gastric juice
42
Chyme is located?
Stomach
43
3 main functions of HCL in stomach
1. Kill bacteria
2. Break down protein ! (Denatures tertiary and secondary structures)
3. Convert pepsinogen —> pepsin
44
What cells are located in the gastric pits (4)
1. Mucous (neck) cells
2. Parietal cells
3. Chief cells
4. Gastric (G) cells
45
Mucous (neck) cells secrete X?
Secrete bicarbonate and mucous
46
Parietal (oxyntic cells) secrete X?
HCL & Intrinsic factor
47
Chief cells secrete X?
Pepsinogens
48
Enteroendocrine cells secrete X?
Variety of hormones
49
What do antacids do to stomach pH & how does that effect protein?
Antacids RAISE stomach pH & without ACIDIC environment, protein can not be broken down and absorbed
50
Low pH is (#s on pH scale)?
0 - 6.9999
51
High (basic) pH in stomach (#s)?
8 +
52
Pepsid is what type of acid-reducing agent ?
H2 blocker ; blocks H2/histamine from reaching parietal cell (in order to secrete H to form HCL)
53
What type of acid-reducing agent is Nexium?
PPI; blocks H+ ions from being secreted by the parietal cells (in order to form HCL)
54
Function of pepsin
Primary digestive enzyme to break down proteins
55
What do you need to convert pepsinogen (inactive) to pepsin (active) ?
Parietal cell to produce HCL and HCL does the conversion
56
Why do you need mucous in the stomach?
In order to protect the stomach tissue from digesting itself (because of acidic environment)
57
Components of gastric juice
- HCL
- Alpha amylase
- Gastric lipase
- Mucous
- Intrinsic factor
58
G cells secrete X?
Gastrin (hormone)
59
PH of stomach
2
60
Optimal pepsin activity occurs at what pH?
3.5
61
Alpha amylase function
Hydrolyzes starch and in the mouth and stomach until it is inactivated by low pH of stomach
62
Gastric lipase function
Hydrolyzes SCT (short chain triglycerides) and MCT and up to 20% of lipid digestion
63
Mucous (in stomach) is stimulated by what 2 things?
- prostaglandins
| - nitric oxide
64
Bombesin stimulates ?
* Gastrin Releasing Peptide
| - stimulates gastrin and HCL release
65
** Gastric Acid/juice stimulation process
1. Bombesin stimulates gastrin and HCL release
2. Gastrin (from G cells) acts on parietal cells to release HCL & acts on chief cells to stimulate pepsinogen
3. Gastrin stimulates gastric motility and cellular growth of stomach
66
Gastrin release occurs in response to???
- Vagal nerve stimulation
- HCL
- epinephrine
- amino acids
- alcohol
- coffee
- calcium
67
Zollinger-Ellison Syndrome
Tumor causes copious amounts of gastrin to dump into blood
68
3 mediators of HCL by parietal cells
1. Gastrin
2. ACH (acytlcholine)
3. Histamine
69
Vitamin C and mast cell activation
Vitamin C down regulates mast cell activity
70
Most common cause of peptic ulcers
- H. Pylori
- Aspirin
- NSAIDs
71
Endocrine function of pancreas
- Insulin
| - Glucagon
72
Acinar cells of pancreas: function
Exocrine function; produce DIGESTIVE ENZYMES that contain Na, K, Cl, Ca
73
Proteolytic enzymes
- Trypsinogen
- Chymotrypsinogen
- Proelastase
- Collagenase
74
Amylases break down X?
Carbohydrates
75
Lactase breaks down
Lactose (disaccharide) into glucose/galactose
76
Fiber and toxins
Fiber is like the sponge that pulls out cholesterol/toxins or else they are reabsorbed
77
What is bile? What makes bile?
Bile is an substance that emulsifiers fat once it enters the duodenum/small intestine
Made in LIVER
78
Bile salts are synthesized where? From what?
Synthesized FROM cholesterol, amino acids and synthesized IN the liver
79
CCK secreted by?
Enteroendocrine cells of the duodenum
80
2 primary bile acids
1. Cholic acid
| 2. Chenodeoxycholic acid
81
20% of bile acids made from?
Bacterial action on Chenodeoxycholic and lithocholic acid and cholic to form deoxycholic acid
82
Bilirubin and biliverdin are waste end products of X?
Hemoglobin
83
Total bile pool in human body (in grams)?
2.5 - 5.0
84
What percentage of bile (acids and salts) is reabsorbed by the ileum?
90%
85
** Circulation of bile
1. Liver
2. Gall bladder
3. Small intestine
4. Ileum (reabsorbed)
5. Hepatic portal vein
6. Liver (resynthesized)
86
Bile is transported from portal vein to liver via what transport protein?
Albumin
87
Hepatic portal vein transports all nutrients except?
Fat-soluble nutrients/vitamins
88
What are/importance of plicae circulares
Small, circular folds in the small intestine that allows for chyme to move through more surface areas in order to be fully digested
89
What is the brush border? What happens there?
Brush border is the layer of microvilli located at the surface of the epithelium of the small intestine.
The brush border is where all the digestive enzymes work/function. Where the absorption takes place!
90
Where does the Kreb Cycle take place?
The mitochondria (matrix)
91
Where does glycolysis take place?
Cytoplasm
92
Hormones involved in satiety and hormone suppression
- Ghrelin
- Insulin
- Leptin
- CCK
GLP-1
- Adiponectin
93
M Cells
- APC (antigen presenting cells)
| - Transport antigens to MALT (to mount an immune response)
94
Active v passive transport
Active = requires ATP/energy
Passive = Does not require energy (osmosis)
95
Function of Secretin
Inhibits gastric gland secretion and gastric motility during gastric phase of secretion
96
Are anaerobes or aerobes in higher amounts in the long intestine/colon/ileum?
ANAEROBES
97
What test is used to confirm lactose intolerance?
Hydrogen breath test; hydrogen gas (produced by bacteria) is measured after individual consumes lactose
Presence of gas confirms intolerance
98
What populations have highest incidence of lactose intolerance?
- African Americans
- American Indians
- Asians
99
3 main short chain fatty acids
1. Acetic acid
2. Butyric acid
3. Propionic acid
100
4 regulatory peptides
1. Gastrin
2. CCK
3. Secretin
4. Motilin
101
Regulatory peptides are?
A group of GI tract molecules that influence digestion and absorption
- motility
- absorption
- cell growth
- secretion of digestion enzymes, hormones, electrolytes
102
Enteroendocrine S cells secrete? in response to? Function of this secretion?
S cells secrete SECRETIN in response to the release of acidic chyme into the duodenum
SECRETIN acts on acinar cells to release pancreatic enzymes
103
6 classes of nutrients the body needs
Carbs, lipids, proteins, vitamins, minerals, water
104
Exocrine v endocrine cells of the mucosa do what?
Exocrine: secrete enzymes and juices into the men of the GI tract
Endocrine: secrete hormones into the blood
105
Laminate propria contains what 2 types of tissues?
- connective
| - LYMPHOID
106
The Meissner plexus is in what layer (tunic) of the digestive tract?
Submucosa
107
Meissner v Myenteric plexus (role)
Meissner = controls secretions and local blood flow
Myenteric = controls motility/contractions of GI tract
108
Types of cells coated within MALT/GALT
- B & T cells
- Natural killer
- macrophages
- Dendritic
- Plasma
109
Peyer’s patches
Aggregates of lymphoid tissue within MALT/GALT
110
Zymogens
- proenzymes (inactive enzymes)
111
** Components of saliva (4 main categories)
99.5% water
Proteins (mucus, enzymes etc.)
Electrolytes (K, Na, Cl)
Solutes
112
What does bicarbonate in saliva do?
Neutralizes acids in foods and acid produced by bacteria in oral cavity
113
Bolus
Food mixed with saliva (that enters the esophagus)
114
Peristalsis
Progressive, wave-like motion that moves the bolus through the esophagus into the stomach
115
What keeps the gastroesophogeal sphincter closed? (Hint “pressure”)
The pressure within the esophagus is higher than the stomach
116
4 main regions of the stomach
1. Cardia (top)
2. Fundus
3. Body (central region)
4. Antrum/pyloric portion
117
Chyme
A think, semi-liquid mass of partially digested food (what travel from stomach to duodenum)
118
** Main constituent of gastric juice
```
Water
Electrolytes
HCL
Mucus
Intrinsic factor
```
119
Pepsin (secreted by chief cells) is stimulated by?
Acetylcholine and/or acid
120
Optimal pepsin activity occurs at what pH?
3.5
121
What enzyme is responsible for 20% of lipid digestion?
Gastric lipase
122
Mucins
Glycoproteins in mucous
123
What 4 things stimulate release of mucous in the stomach?
1. Prostaglandins
2. Vagal nerve stimulation
3. Acetylcholine
4. Hormones
124
** 3 main SCFAs
1. Acetic acid
2. Butyric acid
3. Propionic acid
125
** Function of butyric acid
1. GI cell proliferation of the intentional epithelium
| 2. Regulates gene expression and cell growth
126
Propionic and Lactic acid are absorbed by X??? Taken up by X???
Absorbed by the colon
Taken up (for use) by the liver
127
Acetic acid is absorbed and used by X & Y?
Muscles & brain
128
In additions to SCFAs, bacterial fermentation also generate what 2 vitamins?
K and Biotin
129
Where does electron transport chain (oxidative phosphorylation) take place?
Mitochondrial matrix and intermembrane space
130
** How much ATP is formed from a complete oxidation of 1 mole of glucose?
38
131
What is the cori cycle? (Hint lactate)
Metabolic pathway in which LACTATE (produced by anaerobic glycolysis in the muscles) moves to the liver and is converted to glucose
132
** How much ATP is formed from anaerobic respiration?
2 ATP
133
What is glucose-6-phosphate?
It is the first intermediate in glucose metabolism (glycolysis)
134
** Glycemic load v glycemic index
LOAD = Measure that takes into account the AMOUNT fo carbohydrate in a portion of food with how QUICKLY it raised blood-glucose levels (glycemic index is multiplied by the amount of carbohydrate in the food)
INDEX = 1-100 scale that measures the blood-glucose raising potential of the food (how fast a carb is digested)
135
** Insulin v Glucagon (target organs?)
Insulin = Released to prevent blood sugars from getting too high (guides glucose into cells from blood) * Target organs = Liver, muscle, adipose tissue
Glucagon = Released to prevent blood sugar from getting to LOW (triggers liver and muscle cells to change stored glucose (glycogen) back into glucose)
* Target organs = Liver
136
** Gastrin stimulates what?
1. Release of HCL and pepsin
2. Release of histamine
3. (Lesser extent) gastric motility and emptying
137
** Function of SECRETIN (released by what?)
Released/secreted into blood by S cells
FUNCTION: Stimulates pancreas to release pancreatic juice (w/ bicarbonate)
138
** Function of GHRELIN (released by what?)
Released by endocrine cells of the stomach
* Acts of HYPOTHALAMUS to stimulate food intake
139
** Function of LEPTIN (secreted by?)
Secreted by white adipose tissue
Function = suppresses food intake
140
** Function fo BOMBESIN (Gastrin-releasing peptide)
Stimulates released of GASTRIN and pancreatic enzymes & cause contractions of the gallbladder (releasing bile)
141
** what is xerophthalmia (vitamin deficiency associated?)
Abnormal dryness of the conjunctiva and cornea of the eye; vitamin A deficiency
142
** What is myopia?
Nearsightedness
143
** Pre v Probiotics
PRE: Specialized plant fibers that acts as food for good bacteria in the gut
PRO: Living strains of bacteria that add to the population of bacteria in your digestive system
144
** What are the end products of cellular oxidation (of carbohydrates)?
1. ATP
2. Carbon dioxide
3. Water
145
** Is olive oil high in alpha or gamma-tocopherol?
Alpha
146
*** glycolysis v gluconeogenesis
Glycolysis = converting glucose to pyruvate & atp
Gluconeogenesis = synthesizing of NON CARB sources into glucose (to then enter glycolysis)
147
** hormones involved in glycogenolysis (2)
1. Glucagon
| 2. Epinephrine
148
** Major sites of GLYCOGEN SYNTHESIS
Liver and Skeletal muscles
149
** Can muscle glycogen contribute to blood glucose levels?
NO
150
**Hormones that REGULATE glycogenolysis
1. GLUCAGON
| 2. CATECHOLAMINES (epinephrine, norepinephrine)
151
** Does glycogenolysis release glucose in the form of glucose-1-phosphate or glucose-6-phosphate
Glucose 1 (that is then converted to glucose 6)
152
** What is cellular respiration?
Set of metabolic reactions (glycolysis, Kreb cycle, electron transport chain) that convert energy from food into ATP/ENERGY (and waste products)
153
** T/F most of the energy derived from food is stored in the adipose tissue, muscle, and liver
T
154
** Monosaccharides that can enter glycolysis
- glucose
- fructose
- galactose
155
** In the ABSENCE OF OXYGEN, pyruvate is converted to XXX?
LACTATE
156
** 90% of food energy comes from Kreb cycle and what ??
Electron transport chains (oxidative phosphorylation)
157
** When is pyruvate converted to acetyl-CoA
BEFORE entering Kreb cycle, pyruvate is decarboxylated and then CoA is attached
158
** Products of Kreb Cycle
- 1 FADH2
- 3 NADH
- GTP (ATP)
- 2 CO2
