Chapter 6 - Hunger

Homeostasis is maintained through a process similar to that of your thermostat at home. Briefly list the 4 steps of this process discussed in class.

1. sensor monitors the set point,

2. error detection when temp deviates from set point,

3. response element activates,

4. negative feedback loop shuts off response element

What does the "hunger thermostat sensor" in our brain track in order to know whether we are at or below our set point and need to eat? (give 2 things)

glucose and ghrelin

How does the brain know when our stomach is empty?

ghrelin is released from the stomach into the bloodstream then hypothalamus, causing us to feel hunger

After the _____ hypothalamus receives the hunger hormone telling it that our stomach is empty, it releases _____, which stimulates food-seeking behavior (and wakefulness!).

lateral;

orexin

When the stomach is full, it stretches. The _____ nerve then informs the _____, which sends this information to the _____ of the hypothalamus. This is how we know we are satiated (satisfied/full).

vagus;

medulla;

paraventricular nucleus (PVN)

Why can't you trick your brain into thinking you are full by drinking a ton of water instead of consuming calories?

CCK is only released by the intestines if we eat actual food/nutrients

Eating and digestion of food is one of the major functions of the _____ nervous system. This is why eating is (or should be!) so relaxing, and why we often feel sleepy after eating a big meal.

parasympathetic NS

Explain neurologically why we eat desserts or extra helpings even when we're full.

activates midbrain dopamine neurons

Explain neurologically why obese people feel more rewarded by food (something Dr. J has been saying FOR YEARS!).

obesity is associated with a hyperresponsiveness of midbrain dopamine neurons

Give 2 examples of how we override hunger homeostasis.

1. we can resist the urge to eat,

2. we can eat our feelings