unit 8

what are the 6 basic processes of digestion.

ingestion secretion motility digestion absoption defecation

define mechanical digestion

organs physically breaking up food into smaller peices

define chemical digestion

enzymes break bonds to further break food into monomers.

highly regulated process in the digestive process

secretion digestion absorption motility

secretions can be endocrine or exocrine define both

endocrine= hormones=into the blood

exocrine= into the lumen of the GI tract

feeding and satiety centers are located herei

hypothalamus

feeding center

tonically active (we are always hungry)

satiety center

inhibits feeding center when activated (tells us we are not hungry)

glucose levels controls what? where?

controls the feeding and satiety centers in the hypothalamus

motility must be slow enough to allow time for digestion and absoption

what system regulates motility?

parasympathetic system “rest and digest"

decreased glucose levels stimulates increased activity in which center of the hypothalamus

feeding center

increased glucose levels stimulates increased activity in which center of the hypothalamus

satiety center; this inhibits feeding center

what is ghrelin

hormone released via the stomach depending on gastric stretch

decreased gastric stretch leads to and INCREASE in ghrelin which then leads to what?

leads to an increase in appetite via stimulation of the feeding center

increased gastric stretch leads to a DECREASE in ghrelin which then leads to what?

leads to decrease in appetite via stimulation of the satiety center

define leptin

leptin is the hormone produced by adipose tissue

decrease leptin from low body fat % leads to an

increase in appetite

Increased leptin from fat storage leads to a

decrease in appetite

what is neuropeptide Y

a neurotransmitter that stimulates food intake

what can inhibit NPY

leptin can because an increased body fat % = increase leptin = u should decrease food intake