Appetite and satiety Flashcards
What does satiety mean
Satiety
* The desire to limit further food intake after a meal
* After a meal – post-prandial or post-cibal
What does Orexigenic
Orexigenic
* Appetite increasing (hyperphagic)
What does Anorexigenic mean
Anorexigenic
* Satiating (hypophagic)
What is the definition of motivational salience
Motivational Salience
- cognitive process and a form of attention motivating an individual’s behavior towards or away from a particular object, perceived event or outcome
Explain ATP and how it is generated
- ATP is the energy currency of the cell
- ATP can’t be stored, it must be constantly generated to support all cellular processes
- ATP is generated from macronutrients
- ATP is generated by glycolysis and oxidative phosphorylation via the citric acid cycle (TCA - tricarboxylic acid cycle)
- Glucose can enter glycolysis, fats enter the TCA via β-oxidation, amino acids also enter the TCA via several pathways
- Macronutrients must also be stored
- Fats are the best store (fats store ~6x the amount of energy per weight compared with carbohydrate
How much energy can the Adult liver store
Adult liver can store ~ 120 g of glycogen = ~2,000 kJ
Explain the energy usage of the brain
Our Brain requires glucose for 50-80% of its energy needs
- Plasma concentrations of other energy sources are low
- Free fatty acids are poorly transported across the blood brain barrier
- Hypoglycemia can lead to coma and death
- Under fasting conditions (e.g. >10 hours after a meal) glucose is supplied via de-novo glucose synthesis
What is the usual blood glucose level
Blood glucose is typically controlled in a very tight range (3.9 – 5.6 mM)
What is the resting glucose consumption by all organs and tissues
Resting glucose consumption by all organs and tissues ~2-4 mg/kg/min
What nervous system is used in fasting
Sympathetic nervous system
What occurs in fasting
- Increased glucagon secretion
- Decreased secretion
- increased Lipolysis
- Increased HGP
- Decreased GIT activity
What occurs in the Fed state and what nervous system is involved
- The Parasympathetic
- Decreased gastric emptying
- Decreased glucagon secretion
- Increased insulin secretion
- Decreased HGP
- Increased GIT activity
What Hypothalamic structures are involved in metabolism, appetite and satiety
- ARC – arcuate nucleus
- DMH – dorsomedial hypothalamus
- VMH - ventromedial hypothalamus
- LH – lateral hypothalamus
- PVN – paraventricular nucleus
What Extrahypothalamic structures are involved in metabolism, appetite and satiety
- VTA – ventral tegmental area
- AMY – amygdala
- NTS – nucleus tractus solitarius
- DMV – dorsal motor nucleus of the vagus
- AP – area postrema
What is the release site and regulation of release of Insulin
The release site is Pancreatic β-cells
The regulation of release is ↑Glucose, acetylcholine, GLP-1, GIP
What is the release site and regulation of release of Glucagon
The release site is Pancreatic ⍺-cells
The regulation of release is ↓Glucose, noradrenaline
What is the release site and regulation of release of Leptin
The release site is Adipose
The regulation of release is Reports on fat stores
What hormone is released during fasting
The Hormone Ghrelin is released by Stomach enteroendocrine cells (A cells)
What hormone is Released in response to nutrient arrival (fats & protein)
The hormone Cholecystokinin (CCK) is released by Duodenal enteroendocrine cells (I cells)
What hormone is Released in response to nutrient arrival (carbohydrate)
the hormone Glucagon-like peptide 1 (GLP-1)
What are the Orexigenic signals
- Low blood glucose
- Ghrelin
- Unknown vagal signal(s) from the gastrointestinal tract
What are the Anorexigenic signals
- High blood glucose
- Insulin
- Leptin (contextual)
- CCK, GLP-1
