Knowledge clips gut 2 Flashcards
What are CAM (complementary and alternative medicine) approaches: for parkinson’s, epilepsy, migraines?
PD: protein restriction diets (facilitate levodopa uptake: which is used as a drug)
Epilepsy: ketogenic diet, GABA concentration up
Migraines: 5-HT disturbances
Where does most of the 5-HT synthesis come from?
gut, via the ECC cells (enterochromaffin)
Contractility/secretion
What is the role of the microbiome in 5-HTP synthesis?
dietary fiber helps:
SCFA synthesis: acetate, butyrate, propionate
SCFA improve synthesis of serotonin via ECC cells
What can cross the BBB instead of serotonin (5-HTP)?
tryptophan
Only the small and large intestine contribute to brain-health but the other organs of the GI tract do not play a role
True/false
False
Which of the following factors affect the digestion process in the small intestine:
A bioavailability
B food processing
C temperature
D chemical stucture
A, B, D
Food fermentation by bacteria is important for food digestion and absorption in the small intestine
True/false
(false: degradation by host enzymes dominates the digestion process in the small intestine)
During which period(s) in life is the brain most vulnerable for defects in the absorption of nutrients by the small intestine?
early life and in the elderly. The first 1000 days (so pregnancy and the post-natal period) and during aging when the body becomes vulnerable are the most sensitive periods
Increased brain volume is a psychopathology which can occur due to micronutrient deficiencies
True/false
False: (Reduced but not increased brain volume can occur due to nutrient deficiencies)
The small intestine mainly contributes to malnutrition in the elderly by reduced proteolytic enzyme levels
True/false
True
The second important afferent (afferent: naar brein) signalling pathway in the small intestine mediating the gut-brain cross-talk under healthy conditions is regulated by ..
A micronutrients
B gut hormones
C digestive enzymes
D cytokines
B
Multifactorial diseases in which disturbances in the gut health may play an important role:
- ADHD
- PD
- Autism
- Depression
- AD
- Aggression
Enteric nervous system:
located in and around the GI tract
Afferent signalling pathway small intestine:
1. Nutrients
2. Hormone signalling
ok
What are two structures mediating the intestinal immune response?
- peyer’s patch
- Mesenteric lymph node
What are the structures of the peyer’s patch and what do they do? p. 22
- M-cells on peyer’s patch: mediate the entrance of antigens
- Yellow structure: contain resident DC’s. Present antigens to b-cells present in..
- follicles (pink structures) -> they present antigens to T-cells in the blue space of peyer’s patch..
- (interfollical space)
What cells go to the mesenteric lymph node + what happens during infection?
Activated immune cells + immunoglobulin can go here
Enlarge when intestinal infections occur
Important factor in intestinal immune response:
IgA (produced by b-lymphocytes, most abundant in the intestines)
Secretory IgA can bind to bacteria and internalize them into the intestine via..
- DC’s (extensions in intestinal lumen)
- M-cells
What do DC’s do?
releases cytokines, triggers activation of T-cells. Then, secretion pro-inflammatory cytokines. When pathogen is neutralized: anti-inflammatory cytokines (Il-10, tgf-beta)
What are chemokines?
Another group that plays a crucial role in immune response: chemokines.
Chemokines: cytokines that induce chemotaxis of nearby cells. Migration of neutrophils from bloodstream in intestinal tissue.
What are AMP’s?
(antimicrobial peptides)
AMP’s originate from…
- Paneth cells (bottom of crypt)
Store AMPS, synthesize them - Intestinal epithelial cells
- Infiltrating neutrophils
- Healthy microbiota
p. 23
Four layers of the colonic wall (inside (lumen) to outside)
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
Mucosa contains crypts. Covered by (from lumen to intestinal wall)
- Continuous layer of epithelial cells
- Lamina propria (connective tissue with blood vessels, lymph nodes,..)
- Muscularis interna
Cells of the crypts:
Stem cells at the bottom, migrate to the top and differentiate into…
Also recall their functions.
- Enterocytes -> absorption
- Enteroendocrine -> synthesis gut hormones
- Goblet -> mucus production
Colon: two mucus layers. Explain
- Inner mucus layer covers epithelial cells, which prevents invasion of microbes
- Outer layer: loose structure, mucus-consuming bacteria are located here
What two types of transport of compounds over the epithelial cell layer are there?
- Transcellular route (through cell) driven by transporters
- Paracellular route (through tight junction) driven by gradients
Recall the four types of barriers, from inside the gut to the lumen:
- Immunological barrier (immune cells of the lamina propria)
- Physical barrier =epithelium
- Chemical barrier = mucus layer (inner layer)
- Microbial barrier = commensal bacteria (outer layer mucus)
