Endocrinology of the gut Flashcards

1
Q

Pancreatic secretions components

A

pancreatic duct: water,ions and digestive enzymes - acinar cells. Bicarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Bile

A

Made by liver, stored in gall bladder - bile salts and bilirubin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Tail of pancreas

A

Connect to duodenum via pancreatic duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Arterial routes

A

Delivering blood to three separate capillary beds. Foregut, midgut, hindgut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Venous return

A

All via hepatic portal system.
One single separate capillary bed for the gut leading to the liver’s own capillary bed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

2 separate lymphatic systems

A

Lacteals - draining the villi layer
One draining the muscle layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Lymph nodes

A

Dense areas of lymphocytes and macrophages.

Role: Homeostasis of immune, fluid pressure and nutrient transport

Have defined structure with capsule of connective tissue and areas of lymph nodule tissue and sinus tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sympathetic innervation

A

From spine predominatly motor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Foregut (& adrenal medulla)

A

T5-8
Pre-ganglionic fibres synapse near target organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Midgut

A

T9-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hindgut (& kidney, bladder)

A

L1-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Parasympathetic

A

Vagus nerve for foregut and mid-gut. Pelvic splanchnic nerve for hindgut. 75-80% sensory, 20% motor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Vagus nerve

A

Afferent and efferent
Sensory neurons in vagus nerve trunks are sending information from mechano -(baro-) and chemo-receptors in GI tract to brain

Brain signals secretory or contractile messages controlling gastric capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

ENS (Enteric Nervous System)

A

Two layers - myenteric and submucosal

Operates independently of CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Submucosal plexus

A

GI blood flow - detecting nutrients and secreting hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Myenteric plexus

A

contraction and relaxation of gut wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Neurotransmitter

A

Epinephrine and Norepinephrine can move through circulation like a hormone (neurohormone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Gut-brain axis

A

Bidirectional communication between gut and brain
Involves neural, hormonal, and immunological pathways
Neural: Enteric nervous system communicates via vagus nerve
Hormonal: Gut hormones like serotonin, dopamine influence mood, appetite
Immunological: Gut immune cells produce cytokines affecting brain function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Endocrine cells

A

Glands are for absorption but also secrete substances
Pits have different specialised cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Neuronal & endocrine control of gastric function

A

Includes negative and positive feedback

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Vagal innervation via ENS

A

Stimulates parietal cells (secrete acid / HCl)
ECL cells (Histamine - stimulates parietal cells
G cells in antrum - (Gastrin - stimulates ECL cells

Inhibits: D-cells in the corpus & antrum (SST)

All acting to enhance HCl secretion for digestion in stomach - chyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

pH < 2 stimulates D-cells in atrum

A

Stimulation of D-cells - inhibit parietal & ECL cells

Chyme enters the duodenum (lowers pH. Stimulates S-cells (Secretin - stimulate D cells & stimulates pancreas to release bicarbonate)

Both working to counteract release of HCl and bring pH up for enzymes to work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Gastrin cells (G cells) in stomach

A

Predominate in antrum - secreted when food present Stimulate chief cells (pepsinogen -> pepsin), ECL cells (produce histamine) which stimulate parietal cells (HCl and intrinsic factor which helps uptake of Vit B12)

24
Q

Upper intestine cells

A

Secreted in response to chyme entering duodenum

Secretin cells
Cholecystokinin cells

25
Q

Secretin cells

A

Stimulate D cells to produce somatostatin (inhibit gastrin) and stimulate bile and pancreatic duct to secrete bicarbonate and water.

26
Q

Cholecystokinin cells (CCK, I cells)

A

stimulates pancreatic acinar cells to secrete digestive enzymes and stimulates the gallbladder to release bile

27
Q

Somatostatin (SST, D cells)

A

Inhibit parietal cells and ECL cells, thereby inhibiting the function of G-cells

28
Q

L cell secretions

A

GLP-1
GLP-2
Oxyntomodulin
PYY

29
Q

GLP-1

A

Many actions - brain, gut (slow gastric emptying) and pancreas - maintain blood glucose levels

30
Q

GLP - 2

A

Main target is gut - increase nutrient transport and enhance gut surface area

31
Q

Oxyntomodulin

A

Suppress appetite

32
Q

PYY

A

Lower enzyme, bicarb and bile secretion - slow gastric emptying

33
Q
A
34
Q

K cell hormone

A

GIP (Gastric inhibitory peptide)

35
Q

GIP (Gastric Inhibitory Peptide)

A

Pancreas - enhance insulin secretion and decrease glucagon secretion

36
Q

P/D1 cells

A

Secrete Gherlin

37
Q

Ghrelin

A

Stimulates hunger. Gastric motility and emptying

38
Q

Microbiome

A

Gut - brain axis
Produce chemicals that interact with neurons and hormone producing cells.

39
Q

Fecal microbiota transplant

A

Treat GI disease. Future hopes - obesity, insulin resistance.

40
Q

Microbiome and appendix

A

Disturbances in ecosystem result in commensal populations of microbiome repopulate from the appendix

Appendix is important for linking immune function and the microbiome.

41
Q

Gastrointestinal neuroendocrine tumours (NETS)

A

NET - tumour origination in a neuroendocrine cell, cause overproduction of hormone driving symptoms or reducte hormone production.

42
Q

GI-nets

A

Serotonin
Gastrin
Glucagon

43
Q

PNets

A

Insulin
Glucagon
Somatostatin
Gastrin
Vasoactive intestinal polypeptide (VIP)

44
Q

Gastrinoma (Zollinger Ellison Syndrome)

A

Stomach ulcers and diarrhea

45
Q

Insulinoma

A

Hypoglycemia

46
Q

Glucagonoma

A

Hyperglycemia and diabetes

47
Q

Somatostatinoma

A

Gallstones, intolerance to fat in the diet and fatty diarrhea

48
Q

GLP-1 RA

A

activates GLP1 receptors (mimics GLP1) e.g Ozempic

49
Q

DPP4 inhibitors

A

Reduces breakdown of GLP-1 and GIP (gliptins)

50
Q

GIP/GLP-1 receptor co-agonist

A

e.g. tirzepatde recently approved overseas

51
Q

GIP/GLP-1/ Glucagon receptor

A

Retatrutide in trials

52
Q

Bypass surgery

A

Most effect treatment for obesity and co-morbidities (diabetes, myocardial infarction and stroke)

53
Q

Gut hormones and bypass surgery success

A

Gut hormones: PYY & GLP-1 higher after surgery and stay higher.

54
Q

GDF15

A

Metformin is great at driving weight loss induced GDF15 and its source is the gut and kidney.

55
Q

Expression of GDF15

A

Healthy adults - low levels, upregulates in stress and intense exercise.

Pregnant - highly upregulated (produced by placenta)

Upregulated in several disease states including obesity and is secreted by tumours