Lecture 8: Eating Flashcards
What are biological and physical hunger cues?
Stomach, intestines, mouth, fat cells..
What are cognitive hunger cues?
Thoughts, attitudes, beliefs of eating and food
What are emotional and social hunger cues?
Happiness, sadness, depression, anxiety, boredom, or stress
What is The Vagus Nerve?
It is part of the parasympathetic nervous system, which is responsible for the body’s “rest and digest” functions. The vagus nerve extends from the brainstem (specifically the medulla oblongata) down through the neck and into the chest and abdomen, affecting various organs such as the heart, lungs, and digestive system.
How do efferent and afferent neurons play a role in the vagus nerve?
- 80-90% AFFERENT neurons (carry sensory information about the organs of the body back to the CNS)
- ~10% EFFERENT neurons (carry motor signals
to certain organs and musculature)
How is The Hypothalamus involved with hunger?
It is known as the Coordination Centre. It Sits below the thalamus, and above the
pituitary gland and brainstem.
Function - Able to integrate signals from both central and
peripheral pathways to regulate appetite and
food intake through multiple mechaisms
What does the medial hypothalamus include?
- Ventromedial Nucleus (VMN)
- Paraventricular Nucleus (PVN)
What is the Ventromedial Nucleus (VMN)?
Involved in inhibiting feeding.
Overeating (due to increased meal frequency) → weight gain, high insulin levels.
What is the Paraventricular Nucleus (PVN)?
It receives inputs from anorexigenic neurons.
Inhibits feeding.
Overeating (due to increased meal size) → weight gain
What is the Arcuate Nucleus (ARC)?
Acts as a central hub.
Contains two types of neurons:
Orexigenic neurons & Anorexigenic neurons
What are orexigenic neuron’s?
Promote hunger.
- Secrete Neuropeptide Y (NPY)
What is anorexigenic neuron’s?
Promote satiety (feeling full).
- Secrete Melanocortin
What does the Lateral Hypothalamus include?
- Lateral Nucleus
What is the Lateral Nucleus?
Major site of orexigenic (hunger-promoting) neurons.
- Promotes feeding behavior and digestion.
Under-eating, weight loss, and even though some recovery is possible, it’s not a full return to normal.
What was the recovery in the rats study after damage to the lateral hypothalamus..?
At first, the rat refuses all food and drink. If kept alive for several weeks or months by force-feeding, it gradually recovers its ability to eat and drink enough to stay alive. However, even at the final stage of recovery, its behavior is not the same as that of normal rats.
Damage to the lateral hypothalamus in humans?
Damage to the lateral hypothalamus not only kills the neurons there, but also interrupts many axons containing dopamine that pass through the area.
What is the role of the stomach and Duodenum?
The stomach - Breaks down food with acid and enzymes Ghrelin → Stimulates hunger
The duodenum - CCK, PYY, GLP-1 → Signal fullness
What is the role of the pancreas?
The pancreas has two main roles: one in digestion and one in blood sugar regulation. Insulin, released by the pancreas, has dual effects—it manages glucose in the blood and influences whether you feel hungry or full.
What is the pancreas digestive role?
The pancreas helps digest food by producing enzymes and releasing them into the duodenum (the first part of the small intestine):
Amylase: breaks down carbohydrates
Lipase: breaks down fats
Proteases (like trypsin and chymotrypsin): break down proteins
Where does Insulin move glucose out of the blood and into which various tissues?
- Liver & Skeletal Muscle - Glucose is stored as glycogen (a short-term energy reserve).
- Adipose (Fat) Cells - Glucose is converted into fat for long-term energy storage.
- Brain - Insulin also influences the brain to regulate hunger and fullness.
Which two sets of neurons in the hypothalamus does insulin interact with?
Satiety Promoting - Tells your brain you’re full
Hunger Promoting - Suppresses hunger signals
What is the role of Glucagon?
Glucagon is basically the counterpart to insulin, breaks down glycogen into glucose
What is glucose?
It’s the main source of energy for your body and brain
What is type 1 diabetes?
- juvenile diabetes
- autoimmune attack on the
pancreas - cannot produce insulin
- insulin-dependent
What is type 2 diabetes?
- more common / later age
- more lifestyle related
- pancreas produces insulin but tissues are resistant
- treatment can be lifestyle changes, medications, or insulin
What is leptin?
Leptin is a hormone made In fat (adipose) cells, it suppresses appetite — it tells your brain, “We have enough energy stored”
*More body fat = more leptin
What is melanocortin?
- Suppresses appetite (helps you feel full)
- Increases energy expenditure (burning calories)
- Responds to signals like leptin, insulin, and CCK
What is ghrelin?
A hormone/neurotransmitter found mostly in the stomach and produced by cells throughout the GI tract, it Increases appetite — it tells your brain, “Hey, it’s time to eat!”
- will cause stomach
contractions and act on
hypothalamus to increase
appetite
What is Neuropeptide Y (NPY)?
Neuropeptide Y (NPY) is a powerful hunger-stimulating hormone found in the brain.
- More ghrelin = more NPY = more hunger
What is THC = Tetrahydrocannabinol?
- Primary psychoactive component of cannabis
- Binds to cannabinoid receptors found all over the body
- causes a phenomenon often called “the munchies.”
What is CB1 Receptor?
Specific receptor for THC found in the central nervous system and gastrointestinal tract
What is the difference between Glycogenesis and Glycogenolysis?
Glycogenesis = creates glycogen
Glycogenolysis = breakdown of glycogen
What is ozempic?
It mimics a natural hormone your body releases after eating to help manage blood sugar and appetite
- GLP-1 Receptor AGONIST
- GLP = Glucagon-Like Peptide
What is Bulimia nervosa?
Bulimia nervosa is a condition in which people alternate between binges of overeating and periods of strict dieting.
What is Anorexia nervosa?
Anorexia nervosa is characterized by a refusal to eat enough to maintain a healthy body weight. In some cases it becomes life threatening.
What is binge eating disorder?
It is increased food consumption, more then one would normally consume in a given time.
How Is Anorexia Nervosa & The Brain connected?
- Participants with AN showed DISENGAGEMENT with food related cues relative to controls - may help to restrict food intake
- able to ignore hunger cues - may point to deficits in interoceptive awareness (ability to sense or be aware of the internal state of our bodies)
How is bulimia nervosa and the brain connected?
- Decreased cerebral volume, decreased grey matter in the inferior frontal cortex, and volume reduction in the pituitary gland
- widespread serotonin dysfunction.
What happens when there is a difficulty feeling full?
Promotes binge eating.
What happens vomiting becomes more tolerable?
It promotes purging.
What is Subclinical Disordered Eating Behaviour?
Behaviours that do not meet diagnostic criteria for an ED but still result in negative physical or mental outcomes
