Endocrine regulation : EEC secretes regulatory peptide or hormones that travel via blood stream to remote target organ. Ex gastrin, secretin
Paracrine regulation : regulatory peptide secreted by EEC acts on a nearby target cell by diffusion through interstitial space. Ex histamine, 5-HT
Gastrointestinal Hormones by Pandian M, Dept of Physiology DYPMCKOP, for MBBS...Pandian M
Classify GIT hormones
List the source and functions of different GI hormones
Explain the mechanism of action and regulation of secretion of different GI Hormones
Describe the role of GI hormones in regulation of GI functions
Explain the dysfunctions produced by alteration in secretion of GIT hormones
The classical GI hormones are secreted by epithelial cells lining the lumen of the stomach and small intestine. These hormone-secreting cells - endocrinocytes - are interspersed among a much larger number of epithelial cells that secrete their products (acid, mucus, etc.) into the lumen or take up nutrients from the lumen. GI hormones are secreted into blood, and hence circulate systemically, where they affect function of other parts of the digestive tube, liver, pancreas, brain and a variety of other targets.
Gastrointestinal Hormones by Pandian M, Dept of Physiology DYPMCKOP, for MBBS...Pandian M
Classify GIT hormones
List the source and functions of different GI hormones
Explain the mechanism of action and regulation of secretion of different GI Hormones
Describe the role of GI hormones in regulation of GI functions
Explain the dysfunctions produced by alteration in secretion of GIT hormones
The classical GI hormones are secreted by epithelial cells lining the lumen of the stomach and small intestine. These hormone-secreting cells - endocrinocytes - are interspersed among a much larger number of epithelial cells that secrete their products (acid, mucus, etc.) into the lumen or take up nutrients from the lumen. GI hormones are secreted into blood, and hence circulate systemically, where they affect function of other parts of the digestive tube, liver, pancreas, brain and a variety of other targets.
LOCATION: WALL OF GUT
NEURONS: 100 MILLIONS
GIT MOVEMENTS AND SECRETIONS
COMPOSED: TWO PLEXUSES
OUTER PLEXUS (MYENTERIC AND AUERBACH'S PLEXUS)
INNER PLEXUS (MEISSNER'S PLEXUS AND SUBMUCOSAL PLEXUS)
MYENTERIC PLEXUS
GI MOVEMENTS
SUBMUCOSAL PLEXUS
SECRETION AND LOCAL BLOOD FLOW
LOCATION: WALL OF GUT
NEURONS: 100 MILLIONS
GIT MOVEMENTS AND SECRETIONS
COMPOSED: TWO PLEXUSES
OUTER PLEXUS (MYENTERIC AND AUERBACH'S PLEXUS)
INNER PLEXUS (MEISSNER'S PLEXUS AND SUBMUCOSAL PLEXUS)
MYENTERIC PLEXUS
GI MOVEMENTS
SUBMUCOSAL PLEXUS
SECRETION AND LOCAL BLOOD FLOW
Debridement is an important component of the wound bed preparation (WBP) management Model.
Cause of the wound and patient-centered concerns, debridement is a necessary step in local wound care.
Debridement is the removal of necrotic tissue, exudate, bacteria, and metabolic waste from a wound in order to improve or facilitate the healing process
Chest pain or discomfort
Common presenting symptom of cardiovascular disease
May be cardiac or noncardiac in origin.
Cardiac – angina, MI, pericarditis, mitral valve prolapse, dissecting aortic aneurysm
Non cardiac – anemia (physical exertion), cervical disc disease, anxiety, trigger points etc
Follows pattern of ulnar nerve distribution (heart supplied by C3-T4 spinal segments)
Radiating pain to neck, jaw, upper trapezius, upper back, shoulder or arms (commonly left
Biologist & gerontologist used concept of senescence to explain biological aging
Senescence or normal aging refers to a gradual, time related to biological process that takes places as degenerative processes overtake regenerative or growth processes.
or
senescence: a change in the behavior of an organism with age leading to a decreased power of survival and adjustment
Immunology plays a very important role in homeostasis but it possesses two edge sword actions. Either hypo or hyperimmunity both can cause systemic diseases which will manifest in the oral cavity.
Immunomodulators are the agents which modulate the body immunity according to
the need.
There are natural and synthetic immunomodulatory agents .
Endocrinology is a specialty of medicine; some would say a sub-specialty of internal medicine, which deals with the diagnosis and treatment of diseases related to hormones. Endocrinology covers such human functions as the coordination of metabolism, respiration, reproduction, sensory perception, and movement
non-skeletal mesodermal tissues: adipose tissue, fibrous tissue, muscle, blood vessels and peripheral nerves (despite neuroectodermal origin)
benign, malignant and intermediate (low-grade malignant – locally aggressive, can recur, no metastatic potential)
originate from primitive mesenchymal stem cells
classification according to differentiation lines (e.g. liposarcoma is not a tumor arising from adipose tissue but exhibiting lipoblastic differentiation)
Down syndrome (DS or DNS), also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual disability. The average IQ of a young adult with Down syndrome is 50, equivalent to the mental ability of an 8- or 9-year-old child, but this can vary widely.
Facial pain is pain felt in any part of the face, including the mouth and eyes.
It’s normally due to an injury or a headache, occasionally facial pain may also be due to neurological or vascular causes, but equally well may be dental in origin.
The lymphatic system is responsible for the production, transport and filtration of lymph fluid throughout the body. In addition to its important circulatory functions, the lymphatic system also has important immunological functions
The pressure of the blood in the circulatory system, often measured for diagnosis since it is closely related to the force and rate of the heartbeat and the diameter and elasticity of the arterial walls.
Eating a diet high in vegetables, fruits, whole grains, and legumes.
Choosing lean, low-fat sources of protein.
Limiting sweets, soft drinks, and foods with added sugar.
Including proteins, carbohydrates, and a little good fat in all meals and snacks.
Vectors are organisms that transmit pathogens and parasites from one infected person (or animal) to another, causing serious diseases in human populations
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- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
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TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
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2 Case Reports of Gastric Ultrasound
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
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These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
2. Regulation of GI function
• Endocrine regulation : EEC secretes regulatory
peptide or hormones that travel via blood stream
to remote target organ. Ex gastrin, secretin
• Paracrine regulation : regulatory peptide
secreted by EEC acts on a nearby target cell by
diffusion through interstitial space. Ex histamine,
5-HT
3. Regulation of GI function
• Autocrine : regulatory peptide secreted by the
cells acting on themselves ex. TGF-α, β
potentiate differentiation of crypt cell to villi cell
• Juxtacrine : 1 regulatory peptide acts on many
target cells
• Neurocrine : through nerves and
neurotransmitters
6. Enteroendocrine cell (EEC)
• Hormone-secreting cells in the mucosa of
stomach, small intestine, colon
• May produce 1 hormone : G cell, S cell
• Produce 5-HT & hormones : enterochromaffin
cell
• Produce amine or polypeptide : neuroendocrine
cell (APUD: Amine Precursor Uptake and
Decarboxylase)
7. • Have 2 types
• Open-type : apical membrane contact with GI
lumen (receptor), secretion occurs in basolateral
membrane ex. G cell
• Closed-type : No contact with luminal surface
ex. Enterochromaffin-like cell (ECL) which
secretes histamine
Enteroendocrine cell (EEC)
8. GI hormones
• Classified by similarity in structure and function
1. Gastrin family : gastrin, CCK
2. Secretin family : secretin, glucagon, glicentin,
VIP, GIP
3. Others (not fit in either family) : motilin,
substance P, GRP, guanylin
9. Gastrin
• Produced by G cell in the mucosal gland of
gastric antrum and duodenum
• Can be found in fetal pancreatic islet,
hypothalamus, medulla oblongata, vagus n.
(unidentified function)
10. Structure of gastrin
• Polypeptide hormone with multiple forms
1. Macroheterogenity : diff in length of peptide
chain
2. Microheterogenity : diff on derivatization of
amino acid residues
ex. Sulfation of tyrosine (6th aa residue from C-
terminal), amidation of the C-terminal
phynylalanine
11. Structure of gastrin
• Preprogastrin (101 aa) is processed into 3
fragments
1. G34 : 34 aa secreted mainly by duodenal G cell
2. G17 : 17 aa secreted mainly by antral G cell
3. G14 : 14 aa
All forms have the same C-terminal configuration
13. Gastrin
• Different forms, different activity, different
tissues that are found
• G17 : principal form of gastric acid secretion
(more active and more amount than G34)
• t1/2 : G14, G17 2-3 min in blood. G34 15 min
• Inactivated in kidney, small bowel
14. Action of gastrin
• Stimulation of gastric acid and pepsin secretion
• Stimulation of mucosal growth in stomach, SB,
colon (trophic action)
• Stimulation of gastric motility
• Release of histamine from ECL cell
• Stimulate insulin secretion after protein meal
(not CHO)
• +/- constriction of LES
15.
16. Regulation of gastrin secretion
• ↑ gastrin secretion
• Luminal : peptide, aa
(Phy, Tryp), gastric
distention
• Neural : vagal
stimulation via GRP
(can’t be blocked by
atropine)
• Blood : Ca,
epinephrine
• ↓ gastrin secretion
• Luminal : acid,
somatostatin
• Blood : secretin, GIP,
VIP, glucagon,
calcitonin
17.
18. Feedback inhibition of gastrin
• Acid in antrum inhibit gastrin secretion by 2 ways
1. Direct action on G cell
2. Stimulate release of somatostatin by D cell
• In condition which parietal cells are damaged,
pernicious anemia, gastrin level is elevated.
19. Cholecystokinin-Pancreozymin (CCK)
• Also shows macro- and microheterogenity
Prepro-CCK is processed into several fragments
• CCK58, CCK39, CCK33, CCK22 ,CCK12,
CCK8
• Every forms has the same 5 aa at C-terminal as
gastrin
• Every forms has amidation of C-terminal,
sulfation of 7thtyrosine from C-terminal
20.
21. CCK
• Secreted by I cell in duodenum and jejunum
• Also found in nerves in distal ileum and colon,
neurons in brain (regulation of food intake)
• CCK8, CCK22, CCK33 : principal circulating
forms secreted in response to meal
• Enteric & pancreatic nerve : CCK4
• Brain : CCK8, CCK58
22. Action of CCK
• Gall bladder contraction, sphincter of Oddi
relaxation
• ↑ pancreatic enzyme secretion
• Augment effect of secretin in producing alkaline
pancreatic juice
• ↓ gastric emptying
• Trophic effect on pancrease
23. Action of CCK
• ↑ secretion of enterokinase
• ↑ motility of small intestine and colon
• Augment contraction of pyloric sphincter (↓
duodenal reflux)
• ↑ glucagon secretion (work with gastrin)
• Induced satiety by acting through hypothalamus
24. Mechanism of action
• Through CCK receptor (2 type)
1. CCK-A : locates in periphery, brain
2. CCK-B : locates in brain
• CCK bind to receptor activate phospholipase C
→ IP3, DAG → ↑ intracellular Ca → activate
protein kinase → release of granule (pancreatic
enzyme)
25. • CCK also stimulate vagus nerve to pancrease (via
CCK-A receptor) → release of Ach, GRP, VIP
→ fusion of granule with membrane and release
of pancreatic enzyme
• Gastrin receptor is very similar to CCK-B
receptor.
Mechanism of action
27. Control of CCK secretion
• Most potent stimulator of CCK release is lipid
• Peptones, amino acid also increase CCK release
but CHO has little effect.
• Also secreted in response to CCK-releasing
factor
• Positive feedback : CCK → enzyme release →
more digestive products → more CCK (stop
when digestive products move to next part)
28. CCK-releasing peptide & monitor peptide
• CCK-RP is secreted from duodenal mucosa, and
monitor peptide by pancreatic acinar cell
• Secreted in response to fat, protein digestive
products, and also to neural input (cephalic phase)
• Match the release of CCK, pancreatic enzyme and
the need for enzyme to digest foods
• These peptides are degraded by pancreatic trypsin
(if there are proteins in duodenum, these peptides
won’t be degraded and CCK will be released )
29.
30. Secretin
• 27 amino-acid polypeptide
• Secreted by S cell located deeply in the mucosal
gland of duodenum and jejunum
• Similar structure with glucagon, VIP, GIP
• Only 1 form has been isolated
• t1/2 : 5 min
• Stored in an inactive form (prosecretin)
31. Action of secretin
• Most potent humoral stimulator of fluid and
HCO3 secretion by pancrease
• Acts in concert with CCK, Ach to stimulate
HCO3 secretion
• ↑ HCO3 secretion by duct cells of pancrease and
biliary tract→ ↑secretion of a watery, alkaline
pancreatic juice
• Acting through cAMP
32. • ↑ pancreatic enzyme secretion (augment
CCK)
• ↓ gastric acid secretion
• Pyloric sphincter contraction
• Stimulate growth of exocrine pancrease (work
with CCK)
Action of secretin
35. Effect of secretin on bile secretion
• Produce a watery bile rich in HCO3
• Activate via cAMP → stimulate CFTR (Chloride
channel) and Cl– HCO3 exchanger
• Work in concert with glucagon, VIP
38. Control of secretin secretion
• Secretin is secreted in response to protein
digestive products, bile acid, fatty food and
increased acidity in duodenal content
(pH< 4.5-5)
• Inhibited by somatostatin and Met-
enkephalin
• Secretin release may be mediated by
secretin-releasing peptide
39.
40. Gastric inhibitory peptide (GIP)
• 42 amino-acid polypeptide
• Produced by K cell in duodenal and jejunal
mucosa
• Stimulated by glucose and fat in duodenum, acid
in stomach
• Inactivated by dipeptidyl-peptidase IV (DPP-IV)
in many tissues and in portal circulation
41. Action of GIP
• Mild effect in decreasing gastric motility
• Inhibit gastric acid secretion by directly inhibit
parietal cells or indirectly inhibit gastrin release
from antral G cells (via somatostatin)
• Stimulate insulin release from pancreatic islet in
response to duodenal glucose and fatty acid
Oral glucose can stimulate larger amount of insulin
release than IV glucose
42. Enteric factors increasing insulin release
• CCK, GIP, GLP-1, Glucagon
• GIP is also called glucose-dependent
insulinotropic polypeptide by this action
• GLP-1 is more potent than GIP (limited study)
• GIP, GLP-1 act via protein kinase A pathway
(increased cAMP and cytosolic calcium)
43.
44. Glucagon-Like Peptide 1 (GLP-1)
• 30 amino-acid polypeptide
• Incretin hormone : intestinal hormone secreted
in response to nutrient ingestion which
potentiate glucose-induced insulin release
• Produced by L cell in ileum and colon,
pancreatic alpha cell, neurons in hypothalamus,
pituitary gland
• 2 bioactive forms : GLP-1[7-36] amide , GLP-
1[7-37] both forms are equipotent, same t1/2
48. Glucagon
• Produced by alpha cell of pancreatic islet
• Action :
• Increase glycogenolysis
• Increase gluconeogenesis
hyperglycemia
49. Glicentin
• 69 amino-acid polypeptide derived from
proglucagon
• Secreted from L cell along with GLP-1 and
GLP-2
• Action : stimulation of insulin secretion, inhibit
gastric acid secretion, regulation of gut motility,
stimulation of intestinal growth
50. Vasoactive intestinal peptide (VIP)
• 28 amino-acid polypeptide
• Found in ENS neurons (both myenteric and
submucosal plexus), brain, autonomic nerves
• Released in response to esophageal and gastric
distention, vagal stimulation, fatty acid and
ethanol in duodenum
• Amino acid and glucose don’t affect VIP release
• Half life 2 min in circulation
51. Action of VIP
• ↑ secretion of E’lyte and water from small bowel
• Intestinal circular smooth ms relaxation
• Longitudinal smooth muscle contraction
• ↑ pancreatic secretion
• Inhibit gastric acid secretion and motility
• Potentiate axn of Ach in salivary gland
• VIPoma : presented with profused diarrhea
52. Motilin
• 22 amino-acid polypeptide
• Secreted by enterochromaffin cell and M cell in
duodenum, jejunum
• Acts on G-protein coupled receptor on enteric
neurons in stomach, duodenum → GI tract
smooth muscle contraction
• Its circulating level increased at interval of 90-
100 mins in the interdigestive state
53. Motilin
• Major regulator of MMCs (Migrating Motor
Complex) that move through the stomach and
small intestine every 90 mins in fasted person
• Motilin secretion is inhibited after ingestion
• Vagal nerve may play some role in motilin
secretion
• Erythromycin bind to motilin receptor → ↑ GI
motility in constipated person
54. Somatostatin
• Growth hormone inhibitory hormone (GH-IH)
• First found in hypothalamus
• Secreted by D cell in stomach, duodenum,
pancreatic islet
• Secreted in larger amount into gastric lumen >
circulation
• Released in response to acid in stomach
55. somatostatin
• Presented in 2 forms
1. Somatostatin 14 : prominent in hypothalamus
2. Somatostatin 28 : prominent in GI tract
• Acts through G-protein couple receptor (inhibit
adenylate cyclase)
56. Action of somatostatin
• Inhibit secretion of gastrin, VIP, GIP, secretin,
motilin, GH, insulin, glucagon
• ↑ fluid absorption and ↓ secretion from intestine
• ↓ endocrine and exocrine pancreatic secretion
• ↓ bile flow and gall bladder contraction
• ↓ gastric acid secretion and motility
• ↓ absorption of glucose, amino acid, triglyceride
59. Neurotensin
• 13 amino-acid polypeptide
• Produced by neuron and endocrine cell in ileal
mucosa
• Released in response to fatty food
• Action : inhibit GI motility, ↑ intestinal blood
flow, ↓ gastric acid secretion
60. Substance P
• 11 amino-acid polypeptide
• Found in myenteric and submucosal plexus and
endocrine cell in GI tract
• Stimulated by distention of GI tract
• ↑ GI motility (potent spasmogenic effect on GI
smm by direct action on smm or indirect via
Ach- releasing myenteric neurons)
• ↓ HCO3 secretion
• ↑ intestinal blood flow (vasodilatation)
61. Gastrin releasing peptide (GRP)
• 27 amino-acid polypeptide
• Released by vagal nerve endings
• Stimulate gastrin release from G cell
63. Guanylin
• 15 amino-acid polypeptide
• Secreted by paneth cells in the crypts of
Lieberkuhn of small bowel and colon
• Acts via C-type guanylyl cyclase → ↑ cGMP →
↑CFTR → ↑ Cl secretion through Cl channel
into small intestine
• Mostly act in paracrine fashion
64. Guanylin
• Heat stable enterotoxin of E.coli has very similar
structure to guanylin → activates guanylin
receptor in small bowel → diarrhea
• Guanylin receptor also found in kidney, liver,
female reproductive tract → regulate fluid
movement in these tissues
65. Enkephalin
• 5 amino-acid oligopeptide
• Secreted from myenteric plexus
• 2 forms : Met-enkephalin, Leu-enkephalin
• Stimulated by GI distention
• Action : control GI peristalsis, ↓ intestinal fuild
secretion, inhibit release of Ach, substance P
(anti-diarrhea effect)
66. Pancreatic polypeptide
• Secreted by PP cell in pancreatic islet
• Released in response to vagal stimulation, gastric
distention, fat/amino acid/glucose in SB
• Action : decrease pancreatic enzyme and HCO3
secretion
67. Peptide YY (PYY)
• Produced by L cell in ileum, colon
• Secreted in response to fatty acid, glucose,
hydrolyzed protein
• Action : ↓ vagally mediated gastric acid secretion,
gastric emptying
↓ pancreatic enzyme and fluid secretion
by inhibiting neural pathway to
pancrease and ↓ pancreatic blood flow
↓ intestinal motility, food intake
68. Neuropeptide Y
• 36 amino-acid polypeptide (PP family)
• Found in CNS, postganglionic SANS, myenteric
plexus
• Action : - vasoconstriction (↓blood flow)
- inhibit fluid/E’lyte secretion from SB
- inhibit pancreatic secretion
- ↓ GI motility
- stimulate feeding
69. Effect of GI hormones on feeding
• Suppression of feeding (anorexigenic effect)
• CCK : released in response to fat in duodenum
causing activatiob of melanocortin in
hypothalamus → ↓ food intake
• PYY : secreted by cells in ileum and colon in
response to calories and composition of food
intake (esp. fat meal) → ↓ food intake by
unknown mechanism
• GLP-1 : enhance insulin secretion → ↓ appetite
70. • Increased feeding (orexigenic effect)
• Ghrelin
• Neuropeptide Y
Effect of GI hormones on feeding
71.
72.
73. Ghrelin
• 28 amino-acid polypeptide
• Secreted by oxyntic cell in gastric fundus
• Can be found in pancrease, intestine,
hypothalamus, pituitary gland
• Is first produced as preproghrelin (117 amino
acids)
74. Structure of ghrelin
• 28 amino acids
• n-octanoyl contacts to third serine from N-
terminal (important for hormone activity)
• Bind to GH-secretgogue-receptor 1a (GHS-R1a)
• G-protein coupled receptor
76. Factors influencing ghrelin secretion
• Food intake
• Most important
• Ghrelin level increases 1-2 hr prior to meal, max
just before eating and decreases dramatically
within 1 hr after meal
• Degree of ghrelin level decrease is in proportion
with calories and composition of food (CHO can
decrease ghrelin > fat)
77. • Glucose, lipid, amino acid
• Ghrelin ↓ in postprandial hypoglycemia or after
administration of IV glucose/fat diet
• High protein diet, essential amino acid →↑
ghrelin →↑ GH (controversial)
Factors influencing ghrelin secretion
79. Physiological roles of ghrelin
• Hormonal effect
• Stimulation of GH secretion
• Synergistic of GHRH
• ↓ somatostatin secretion from hypothalamus
• ↑ ACTH, PRL, cortisol
80. • Appetite
• Acting at arcuate nucleus by stimulation of
NPY/AGRP neurons (neuropeptide Y/ Agouti-
related peptide) →↑ appetite (orexigenic effect)
Physiological roles of ghrelin
81.
82. • Gastric effects
• ↑ gastric acid secretion and motility (acting
through vagus nerve which also has GHS-R1a
receptor)
Physiological roles of ghrelin
83. Other effects of ghrelin
• Inhibit proinflammatory cytokin (IL-1, IL-6,
TNF)
• Increase bone mineral density
• Decrease MAP by decreasing peripheral vascular
resistance
86. Orexins/hypocretins
• Neuropeptides synthesized by neurons in
posterolateral hypothalamus
• Derived from prepro-orexin (131 aa)
• Orexin A : 33 aa, N-terminal pyroglutamyl
residue, 2 intrachain disulfide bonds
• Orexin B : linear 28 aa
• Only orexin A can pass BBB
87. Orexin receptor
• Mediated via G protein couple receptor
• OxR1 (selective for orexin A) amd OxR2 (bind
to both orexin A, B)
• Distributed in hypothalamus, thalamus,
brainstem (locus ceruleus), spinal cord, GI tract,
pancrease, genital tissues
88. Role of orexin in feeding
• Orexin neurons in lateral hypothalamus connect
and stimulate NPY-, AGRP- neurons in arcuate
nucleus stimulate food intake
• Orexin neurons are stimulated by starvation and
hypoglycemia, and inhibited by feeding (via vagal
sensory pathway and NTS)
• Also plays an important role in regulation of
metabolic rate
89. Tumors of EEC
• 50% gastrinoma (presented with Zollinger-
Ellison syndrome)
• 25% glucagonoma
• Others : VIPoma, neurotensinoma
90. Zollinger-Ellison syndrome
• Triad of gastrinoma, hypergastrinemia, severe
peptic ulcer disease
• Gastrinoma can occur in duodenal wall (more
common), pancrease
• S&S : PU refractory to treatment, multiple ulcers,
ulcers in distal part duodenum, jejumun, GERD,
diarrhea, steatorrhea, weight loss, vitamin B12
malabsorption
91. Glucagonoma
• Pancreatic tumor (benign/malignant)
• S&S : 4D syndrome Diabetes(hyperglycemia),
Dermatitis (necrolytic migratory erythema ),
DVT (Factor X from tumor cells), Depression,
diarrhea, weight loss