Week 6 Pt 2 Flashcards
What other hypothalamic nuclei does the ARC neurones communicate with?
Paraventricular nucleus
Dorsomedial nucleus
Lateral hypothalamus
Ventromedial nucleus
What are the ARC neuronal population that regulate food intake?
Orexigenic neuropeptide Y/ agouti-related peptide neurons
Anorexigenic pro-opiomelanocorticon
Cocaine and amphetamine regulated transcript neurons
What has been shown to be important in regulating food intake?
Brainstem
What is involved in ingestive behaviour?
Casual brainstem
What is the dorsal vagal complex ?
Facilitate communication between periphery and hypothalamus to control food intake
What is an important role of vagus?
Transmission of afferent and efferent neural signals between gastrointestinal system and nucleus of tractus solitarus in the DVC
What is the corticolimbic system involved in?
Learning
Liking
Wanting
What is the homeostatic control of food intake strongly related to?
Hedonism
Reward
Food experiences
What structures does the corticolimbic system consist of?
Prefrontal cortex Nucleus accumbens Ventral stratium Hippocampus Amygdala
What modulates the homeostatic appetite system?
Non-homeostatic influences from corticolimbic system
What does the gut-brain axis modulate?
Short-term satiety
Hunger responses
What does the gut-brain axis modulate the delivery of?
Nutrients and transit of nutrients thigh the GI tract
Enable efficient digestion and storage of energy
What are the other roles of brain-gut axis?
Regulation of: Blood glucose levels Adipocyte function Energy expenditure Maintenance of energy homeostasis following a meal
What is directly and indirectly relayed to the DVC and corticolimbic system?
Gustatory fibres of cranial neves VII, IX, X
Olfactory fibres of cranial nerve I
Sensory fibres of cranial nerve V
What is afferent vagus nerve mechanoreceptors sensitive to?
Gastric and gut infra-luminal distension
What is chemoreceptors sensitive to?
Variety of intra-luminal chemical stimuli
What does the neuroendocrine system consist of?
- Gut endocrine cells
2. Enteric nervous system
What does the gut endocrine cells located?
Gut mucosa
What does the enteric nervous system contain?
Peptidergic
Serotonergic
Nitric oxide - containing nerves
What does the neuroendocrine system of gut regulate?
Motility Secretion Absorption Microcirculation in the gut Local immune defence Cell proliferation
How many types of endocrine cells in the GI tract?
15 types
Why does the gut endocrine cells secrete signalling substances into lamina propria of gut lining?
Exert their autocrine and paracrine function
What is the autocrine function?
Hormones released by cell and bind onto itself and alter its own
What is the paracrine function?
Hormones released by cells and bind to other cells and alter their function
What is the important role of gut hormone?
Coordinate digestive process within GI tract
What is cholecystokinin (CCK)?
Regulate appetite
Secreted; enteroendocrine I cells of small intestine
Promote fat and protein digestion
What is the effect of cholecystokinin?
Increase satiety via cholecystokinin 1 (CCK1) receptors on:
Vagus afferent
Brain stem
Hypothalamus
What is ghrelin?
Hunger hormone
Secreted: A cells (gastric fundus)
What is the effect of ghrelin?
Increase gastric motility
Decrease fat utilisation
Stimulate growth hormone release
What is peptide YY?
Pancreatic polypeptide
Family: neuropeptide Y and pancreatic polypeptide
Bind to Y family of receptors (Y2 receptors)
Secreted: L cells of GI tract
When is there a low level of Peptide YY?
Fasting
What is Glucagon?
Pancreatic hormone
Produced: preproglucagon precursor in the alpha cells of pancreas
What is the effect of glucagon?
Main blood glucose levels during fasting and exercise
Promote: glycogenolysis and gluconeogenesis
What has anorectic properties and promote satiety?
Glucagon
What is neurotensin?
Identified as CNS neurotransmitter
Secreted: N cells of GI tract
Regulate a number of digestive processes
What is neurotensin involved in?
Acute reducing food intake
