Digestive Physiology Flashcards
1
Q
GI Tract Sensory Receptors
A
- Mechanoreceptors for stretch
- Chemoreceptors for food intake, osmolarity changes, and pH changes
- Both initiate reflexes that activate or inhibit glands, and stimulate smooth muscle
2
Q
Types of Smooth Muscle Motility
A
- Peristalsis: propulsive motion
- Segmentation: mixing to promote digestion and facilitate absorption
3
Q
Carbohydrate Digestion
A
- Starch (2/3 of carb intake) -> Disaccharides -> Monosaccharides
- Fibre is digested by E. Coli in large intestine (fermentation, causes gas)
- Occurs in mouth and small intestine (first 1/2 of jejunum)
4
Q
Carbohydrate Digestive Enzymes
A
- Amylase from salivary glands and pancreas (starches -> disaccharides)
- Brush border enzymes such as lactase, maltase, sucrase, etc. break disaccharides down further
5
Q
Protein Digestion
A
- Proteins broken into amino acids
- Protein -> polypeptide -> dipeptide -> amino acid
6
Q
Protein -> Polypeptide Enzymes
A
- Pepsin (stomach)
- Trypsin, chymotrypsin (SI)
7
Q
Polypeptide -> Dipeptide Enzymes
A
- Carboxypepsidase (SI)
- Aminopepsidase (SI)
8
Q
Dipeptide -> Amino Acid Enzymes
A
- Brush border enzymes (SI)
- Amino acids absorbed directly into the blood
9
Q
Fat Digestion
A
- Requires an emulsifier since fat is non-polar
- Bile is the emulsifier (increases surface area)
- Lipase = fat -> glycerol (to blood) and fatty acids (to lymph, then blood)
10
Q
Fat Absorption
A
- Fatty acids either enter absorptive cells or form micelles (clumps of fatty acid)
- Within absorptive cells, chylomicrons are formed and absorbed into the lymph
11
Q
Nucleic Acid Digestion
A
- Digested by nucleases (from pancreas)
12
Q
Vitamin Absorption
A
- Absorbed by whole carriers
13
Q
Functions of Chewing
A
- Increases surface area
- Decreases choking risk
14
Q
Swallowing Reflex Trigger
A
Food in the pharynx
15
Q
Acid Reflux Cause
A
- Faulty gastroesophageal (cardiac) valve closure
16
Q
Stomach Sections
A
- Fundus
- Body
Antrum
17
Q
Stomach Secretions
A
- Acid (converts pepsinogen into pepsin)
- Pepsin
- Mucous
- Intrinsic factor (vitamin B12 absorption in SI)
18
Q
Stomach Absorption
A
- Aspirin
- Alcohol
19
Q
Gastrin
A
- Increases HCl production, pepsinogen presence, and motility
- Stimulated by proteins, distension, smelling food
20
Q
Peptic Ulcer
A
- Hole caused by inflammation or necrosis
- Can be caused by pepsin, helicobacter pylori
- Occurs in stomach and duodenum
- Symptoms include pain and bleeding
- Treatment includes reduction of contributing factors, antacids, surgery
21
Q
CCK
A
- Triggered by food entering SI (distension, fat content increase)
- Acts on pancreas and gallbladder to release enzymes and bile
22
Q
Secretin
A
- causes pancreas to release bicarbonate
- Increases bile production in liver
- Inhibits gastric motility
23
Q
Motilin
A
- From duodenal mucosa
- Released every 1-2 hours
- Stimulates motility
24
Q
Electrolyte Absorption
A
- Na is coupled with glucose and amino acids
- Ca is regulated by vitamin D and PTH
25
Q
Haustral Contractions
A
- Slow movement of the LI
26
Q
Large Intestine Absorption
A
- Water
- Na
- Incomplete Fiber Digestion
27
Q
Pancreatic Cell Types
A
- Duct Cells (Bicarbonate)
- Acinar Cells (Enzymes)
- Endocrine Cells (insulin and glucagon)
28
Q
Liver Functions
A
- Metabolic processing of major nutrients
- Detoxifying
- Make blood proteins
- Storage
- Activate vit. D
- Remove bacteria
- Make bile
29
Q
Cirrhosis
A
- Chronic, irreversible, degenerative
- Loss of liver cells, disorganization, scar tissue
- Symptoms include nausea, weight loss, inflammation, degeneration, ascites
- Treatment includes transplant
30
Q
Ascites
A
- Hight abdominal venous pressure
- Organs swell
- Bleeding
31
Q
Gallstones
A
- Cholesterol, bilirubin, calcium
- Can block ducts
- Called gravel if small
- Five risk factors: female, fair complexion, fat, fertile, forty or older
