Knowledge clips gut 2

Question 1

What are CAM (complementary and alternative medicine) approaches: for parkinson’s, epilepsy, migraines?

Answer 1

PD: protein restriction diets (facilitate levodopa uptake: which is used as a drug)
Epilepsy: ketogenic diet, GABA concentration up
Migraines: 5-HT disturbances

Question 2

Where does most of the 5-HT synthesis come from?

Answer 2

gut, via the ECC cells (enterochromaffin)
Contractility/secretion

Question 3

What is the role of the microbiome in 5-HTP synthesis?

Answer 3

dietary fiber helps:
SCFA synthesis: acetate, butyrate, propionate
SCFA improve synthesis of serotonin via ECC cells

Question 4

What can cross the BBB instead of serotonin (5-HTP)?

Answer 4

tryptophan

Question 5

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

Answer 5

False

Question 6

Which of the following factors affect the digestion process in the small intestine:

A bioavailability
B food processing
C temperature
D chemical stucture

Answer 6

A, B, D

Question 7

Food fermentation by bacteria is important for food digestion and absorption in the small intestine
True/false

Answer 7

(false: degradation by host enzymes dominates the digestion process in the small intestine)

Question 8

 During which period(s) in life is the brain most vulnerable for defects in the absorption of nutrients by the small intestine?

Answer 8

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

Question 9

Increased brain volume is a psychopathology which can occur due to micronutrient deficiencies
True/false

Answer 9

False: (Reduced but not increased brain volume can occur due to nutrient deficiencies)

Question 10

 The small intestine mainly contributes to malnutrition in the elderly by reduced proteolytic enzyme levels
True/false

Answer 10

True

Question 11

 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

Answer 11

B

Question 12

Multifactorial diseases in which disturbances in the gut health may play an important role:

Answer 12

• ADHD
• PD
• Autism
• Depression
• AD
• Aggression

Question 13

Enteric nervous system:

Answer 13

located in and around the GI tract

Question 14

Afferent signalling pathway small intestine:
1. Nutrients
2. Hormone signalling

Answer 14

ok

Question 15

What are two structures mediating the intestinal immune response?

Answer 15

1. peyer’s patch
2. Mesenteric lymph node

Question 16

What are the structures of the peyer’s patch and what do they do? p. 22

Answer 16

1. M-cells on peyer’s patch: mediate the entrance of antigens
2. Yellow structure: contain resident DC’s. Present antigens to b-cells present in..
3. follicles (pink structures) -> they present antigens to T-cells in the blue space of peyer’s patch..
4. (interfollical space)

Question 17

What cells go to the mesenteric lymph node + what happens during infection?

Answer 17

Activated immune cells + immunoglobulin can go here
Enlarge when intestinal infections occur

Question 18

Important factor in intestinal immune response:

Answer 18

IgA (produced by b-lymphocytes, most abundant in the intestines)

Question 19

Secretory IgA can bind to bacteria and internalize them into the intestine via..

Answer 19

1. DC’s (extensions in intestinal lumen)
2. M-cells

Question 20

What do DC’s do?

Answer 20

releases cytokines, triggers activation of T-cells. Then, secretion pro-inflammatory cytokines. When pathogen is neutralized: anti-inflammatory cytokines (Il-10, tgf-beta)

Question 21

What are chemokines?

Answer 21

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.

Question 22

What are AMP’s?

Answer 22

(antimicrobial peptides)

Question 23

AMP’s originate from…

Answer 23

1. Paneth cells (bottom of crypt)
   Store AMPS, synthesize them
2. Intestinal epithelial cells
3. Infiltrating neutrophils
4. Healthy microbiota
   p. 23

Question 24

Four layers of the colonic wall (inside (lumen) to outside)

Answer 24

1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa

Question 25

Mucosa contains crypts. Covered by (from lumen to intestinal wall)

Answer 25

1. Continuous layer of epithelial cells
2. Lamina propria (connective tissue with blood vessels, lymph nodes,..)
3. Muscularis interna

Question 26

Cells of the crypts:
Stem cells at the bottom, migrate to the top and differentiate into…
Also recall their functions.

Answer 26

1. Enterocytes -> absorption
2. Enteroendocrine -> synthesis gut hormones
3. Goblet -> mucus production

Question 27

Colon: two mucus layers. Explain

Answer 27

1. Inner mucus layer covers epithelial cells, which prevents invasion of microbes
2. Outer layer: loose structure, mucus-consuming bacteria are located here

Question 28

What two types of transport of compounds over the epithelial cell layer are there?

Answer 28

1. Transcellular route (through cell) driven by transporters
2. Paracellular route (through tight junction) driven by gradients

Question 29

Recall the four types of barriers, from inside the gut to the lumen:

Answer 29

1. Immunological barrier (immune cells of the lamina propria)
2. Physical barrier =epithelium
3. Chemical barrier = mucus layer (inner layer)
4. Microbial barrier = commensal bacteria (outer layer mucus)