Hunger & Chemical Senses

Neuropeptide Y

Hormone from hypothalamus that indicates hunger and acts to increase carb consumption

Ghrelin

Hunger hormone made by stomach lining causing binding to neurons in the hypothalamus’ hunger centre and increases gastric motility

Glycogen

Stores glucose to be used in muscles and liver to restores low blood glucose

Insulin

Secreted in pancreas that increase glucose uptake for immediate use, glycogen, adipose tissue

Signals for Satiety

• Stomach stretches

• CCK

• Portal vein sensing macromolecules

How does stomach stretching signal satiety?

Stretch receptors send signals to the hypothalamus via vagus nerve to decrease NPY neurons

Cholecystokinin (CCK)

Hormone from small intestine that regulates short term satiety

Fat

Endocrine organ that’s highly dense in energy (1g = 9kcal)

Leptin

Secreted by fat that work on hypothalamus to decrease appetite by inhibiting NPY in hypothalamus and promotes feeding at low levels

Portal Vein

Vein connecting small intestine to liver where small molecules and nutrients absorbed

Glucocorticoids

Slow stress hormones that stimulate appetite

OB Gene

Controls leptin but doesn’t affect you if given more leptin

Injecting NPY increases

Sucrose and saccharin consumption

Endogeneous Opiods

Morphine-like analgesic effects that contribute to palatability and reward driven feeding

Nalaxone decreases

Saccharin, sucrose and saline intake

Lower opioid in rates causes

Decrease preference for saccharin

What determines someone’s palate?

• Childhood exposure

• Cultural changes

More taste buds

More sensitive taster

Women are more sensitive to

Bitter and sweet, especially pregnant women in their 1st trimester

Tasting Process

1. Taste receptors respond and dissolve molecules

2. Signals sent through gustatory nerve to medulla

3. Goes to thalamus and divides into two streams

Where are the taste receptors

Tongue, soft palate, throat

Sweet signifies

Energy rich food

Salty signifies

Essential electrolytes

Sour and Bitter signifies

Harmful, spoiled, poisonous food

Umami signifies

Aminos (glutamate, aspartate)

Hunger and Satiety process thorough (also emotional)

Hypothalamus and amygdala

Texture and Feel process through

Gustatory cortex them primary somatosensory cortex

Gustatory Cortex

Perceives tastes with specific neurons responding to the 5 tastes

Taste process through

Gustatory cortex and orbital cortex combine with smell to determine flabour

Capsaicin binds to

Heat and pain receptors

Process of Smelling

1. Chemicals dissolve in mucus to interact with olfactory cilia on olfactory epithelium

2. Olfactory receptors send signals to olfactory bulb

3. Synapse in glomeruli

4. Goes to limbic system, olfactory cortex, orbital cortex

Miraculin

Emberries that binds to sweet receptors, causing them to fire when you eat something sour

Johnson and Kenny Experiment

Group of rates given chow, food buffer for an hour or 23 hours

Johnson and Kenny Results

Group 3 became obese and even endured pain to reach it from addiction to food

Dutch Famine Pregnancies resulted in higher changes of

Obesity, diabetes in child because chemistry changed, and mothers more likely overfeed their child

Freshness of Chips are based on

Heard crispness

Crisp, fresh chips have a

Unreduced, higher frequency crunchy sound

Perceive fullness and total consumption is based on

How much you think you ate, and portion size

Social Eating behaviours match

Speed and consumption patterns

More people around

More consumption