MODULE 1 Week 1: Digestive System Flashcards
The majority of digestion takes place?
Small intestine
Final B12 absorption location (organ)?
Ileum
**Accessory organs of digestion
Liver, pancreas, gallbladder
Pancreas is responsible for digestion what percent of fat, carbs, and protein?
50% protein
50% carbs
90% fat
PH of the stomach
2.3
PH of duodenum
8 (basic)
6 basic processes involved in digestion
- Ingestion
- Secretion
- Mixing
- Digestion
- Absorption
- Defecation
GALT
Gastric associated lymphatic tissue
Organs of upper v lower digestive tract
Upper = Oral cavity, esophagus, stomach Lower = Small and Large intestines
4 layers of GI tract
- Mucosa
- Submucosa
- Muscularis external
- Serosa (adventitia)
What organelle produces cholesterol
Smooth endoplasmic reticulum
Where is bile made versus stored
Bile made in liver; stored in gallbladder
Exocrine function of pancreas (what does it release)
- pancreatic lipase
- sodium bicarbonate
- pancreatic carbohydrase
3 layers of mucosa
- Epithelium
- Laminate propria
- Muscularis mucosae
MALT is?
Mucosal associated lymphatic tissue; need it because invited foreign protein (from the outside world) into the internal system
Inner most layer of 4 layers of GI tissue
Mucosa
5 R Program to regenerate the gut
- Remove irritant
- Replace with digestive enzymes
- Reinoculate with probiotics
- Repair (glutamine etc)
- Rebalance
Exocrine v Endocrine (what and where to do they secrete?)
Exocrine = secrete enzymes and juices into epithelium
Endocrine = secrete various hormones into the blood
What layer of mucosa contains lymphoid tissue? What WBC types are in high numbers there?
Lamina propria; macrophages & lymphocytes
Meissner’s plexus is located? Controls?
Located: In submucosa
Controls: secretions of mucosal glands & regulates mucosal movements and blood flow
Visceral peritoneum versus parietal peritoneum
Visceral = Surrounds stomach and intestines
Parietal = lines the entire cavity
Front teeth v back teeth & color
Front teeth for meat/higher pH foods and back teeth for colorful/higher pH foods (fruit & veggies)
Sweet, sour, salty controlled by cranial nerve ?
7
Bitter taste controlled by cranial nerve X ?
9
3 main salivary glands
Parotid, submandibular, sublingual
Parotid gland secretes?
Water, electrolytes (Na, K, Cl), and enzymes
Submandibular & Sublingual glands secrete X?
Same as parotid PLUS MUCUS
Saliva is X% water
99.5
**Primary enzyme in saliva is ? This enzyme hydrolyzes what bonds in starch?
Enzyme = amylase
Hydrolyzes alpha 1-4 bonds in starch
% of water that should be inside versus outside of the cell
Inside = 60
Outside = 40
Lingual lipase produced by? Hydrolyzes?
Produced by lingual serous glands; hydrolyzes triglycerides
IgG A found in saliva?
True
T.I.M.E muscles (mechanical digestion in the mouth)
T = Temporalis I = Internal pterygoid M= masteter E = External pterygoid
Cranial nerve involved with T.I.M.E. Muscles
5
Esophagus
- length
- main function
10 inches
- Passage of bolus of food from oral cavity to stomach
Peristalsis
Progressive wavelike motion that moves bolus into the stomach
What increases risk of developing GERD
- smoking
- high fat diets
- chocolate
- alcohol
Rugae of mucosa
Ruffled borders on the inside of the stomach which helps to break down food and allow for expansion of the stomach
**Stomach range when EMPTY
50mL (2 oz)
**Stomach range when FULL
1.5L (37-52oz)
Cardiac, oxyntic, and pyloric glands produce?
Gastric juice
Chyme is located?
Stomach
3 main functions of HCL in stomach
- Kill bacteria
- Break down protein ! (Denatures tertiary and secondary structures)
- Convert pepsinogen —> pepsin
What cells are located in the gastric pits (4)
- Mucous (neck) cells
- Parietal cells
- Chief cells
- Gastric (G) cells
Mucous (neck) cells secrete X?
Secrete bicarbonate and mucous
Parietal (oxyntic cells) secrete X?
HCL & Intrinsic factor
Chief cells secrete X?
Pepsinogens
Enteroendocrine cells secrete X?
Variety of hormones
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
Low pH is (#s on pH scale)?
0 - 6.9999
High (basic) pH in stomach (#s)?
8 +
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)
What type of acid-reducing agent is Nexium?
PPI; blocks H+ ions from being secreted by the parietal cells (in order to form HCL)
Function of pepsin
Primary digestive enzyme to break down proteins
What do you need to convert pepsinogen (inactive) to pepsin (active) ?
Parietal cell to produce HCL and HCL does the conversion
Why do you need mucous in the stomach?
In order to protect the stomach tissue from digesting itself (because of acidic environment)
Components of gastric juice
- HCL
- Alpha amylase
- Gastric lipase
- Mucous
- Intrinsic factor
G cells secrete X?
Gastrin (hormone)
PH of stomach
2
Optimal pepsin activity occurs at what pH?
3.5
Alpha amylase function
Hydrolyzes starch and in the mouth and stomach until it is inactivated by low pH of stomach
Gastric lipase function
Hydrolyzes SCT (short chain triglycerides) and MCT and up to 20% of lipid digestion
Mucous (in stomach) is stimulated by what 2 things?
- prostaglandins
- nitric oxide