Transcript Bio Animated PPt

Learning Objectives
To consolidate our understanding of the neural
mechanisms involved in controlling satiation
and hunger
Recap - do you know what they
do?
Ghrelin
Insulin
Glucagon
VMH
LH
CCK
Ghrelin
• Hormone released from the stomach.
• The less food in the stomach - the higher the
level of ghrelin released
• Gastric bands lower levels of ghrelin
• It works directly on the hypothalamus and
‘switches on’ feeding behaviour.
Insulin
• Released from the pancreas
• Enables the body to convert glucose in the
blood to glycogen for storage.
• The pancreas may become unable to release
either enough insulin or become damaged.
These problems will lead to diabetes.
Glucagon
• This is the hormone released from the
pancreas that will turn stored glycogen back
to glucose.
• The glucose is then released into the blood
for use.
V-M-H
•
•
•
•
Ventro-Medial Hypothalamus.
This area of the brain inhibits feeding.
Research in rats quite conclusive.
If the rat’s VMH is damaged you will end
up with obese rats – the ‘stop’ signal no
longer works
LH - ‘GO GO GO’
• An area of the hypothalamus called the
Lateral Hypothalamus (Lunch Here I
come!)
• This area stimulates feeding.
• Research on rats confirmed that if the LH is
damaged the rat stops eating (aphagia) as
the ‘on switch’ no longer works
CCK – STOP!
• Cholecystokinin is a hormone released from
the duodenum.
• It is released once the food has passed from
the stomach to the small intestine.
• It acts on the hypothalamus as a satiety
signal when there is food present.
Hunger, Eating and Satiation: the process
Eating
Increase in
Ventromedial Satiety
blood glucose hypothalamus reached
activated
Hunger
develops
Lateral
Blood glucose Eating stops
hypothalamus levels drop
activated
Review: neural explanations for eating &
satiation