CHAPTER 5 Flashcards
LI is absorption of what?
electrolytes
SI is absorption of what?
food, absorption of water, nutrients nd electrolytes
Digestion in CHO happens where
mouth, duodenum, pancreas
Lipid digestion happens where
mouth, stomach, SI
Protein digestion happens where
stomach, small intestine and pancreas
in lipid digestion, which enyzmes digest primarily short and medium chain FA?
lingual lipase and gastric lipase
Explain how LCFA are broken down.
bie and pancreatic lpase in small intestine causes breakdown of fat into FA, diacyglerols, and monoacylglycerols. Turns into micelles
majority of digestion for proteins happens where
in small intestine
What do proteases do
breaks down proteins and peptides, provided by small intestine and pancreas
What do petidases do
hydrolyzes peptide bonds
takes short chains and transforms them into less than or equal to 3 amino acids
What dos trypsin do?
used for protein digestion
comes form pancreas
breaks peptide bonds,
Why does no digestion happen in the stomach for CHO digestion?
no digestions in stomach (HCl deactivates enzymes)
Absorption of carbs: glucose and galactose
help of sglt carrier mediated transport
Need an Na+ and ATP
Leaves with help of GLUT 2
Goes to portal vein to liver to be converted to glucose
Absorption of carbs: fructose
help of glut5 carrier mediated transport
NO ATP needed
Leaves with help of GLUT 2
At rest or low [Insulin] in the blood, which transporter is used?
GLUT1
When [Glucose and Insulin] are high or muscle is active, which transporter is used?
GLUT4
Explain absorption of LCFA
micelle goes inside SI via carrier that acts like lipid bus.
TAG + apolipoproteins or phospholipids = chylomicrons
chylomicron leaves SI by passive diffusion
go to lymph system through subclavian vein
More fat is absorbed with _______ than without.
bile
Explain medium chain FA absorption
goes straight through passive diffusion
to the blood, portain vein to the liver
What do the lipoprotein lipase do?
At the endothelial cells of adipose tissue, lipoprotein lipase (aka LPL)made by adipocytes and transported to endothelium breaks down triglycerides from chylomicron and VLDL particles liberating fatty acids.
in order to store TAG in adipose tissue
Explain absorption of aa
Dipeptides tripeptides come in without help of Na+
amino acids need na+ help
ATP needed for both
di and tri turn into aa before leaving and heading to liver through portal vein
Which absorbs faster; BCAA or AA?
BCAA
Essential vs non essential: which absorbs faster?
essential
Peptides or free aa: which absorbs faster?
peptides
After aa are absorbed, what happens?
many are used by villus for protein synthesis
enzymes, hormones, N-containing compounds, glutamine used for energy, apoprotein
When you take away the amino group from an aa, what can the carbon skeleton do (3 things)?
turn into FA
turn into glucose
used for energy
exogenous protein
supplies 1/3 of the 300g of body protein synthesized daily
endogenous protein
supplies 2/3 of the 300g of body protein synthesized daily
one osmole means?
number of solute particles
osmole is expressed how?
as density
osmolarity of most bodily fluids is around what?
290 mOsm
With consumption of some drinks during exercise with high osmolarity, where is that water going?
Into gut!
vitamin absorption?
water soluble vitamins = absorbed in blood stream
fa soluble vitamins = give to blood by micelles then chylomicrons are transported via the lympth to the bloodstream and eventually to the liver
are minerals well absrbed in intestine? whats the conclusion then?
no
so need to eat more than our bodies require
Function of bacteria in digestive tract
Digest carbohydrates, proteins, and lipids that escape digestion and absorption.
Ferment cellulose.
Produce vitamin K, B12, thiamin, riboflavin
positive stomach signals, explain
Nervous signals (stretch stomach) Gastrin release
cause relaxing of pyloric sphincter
says ok for chyme to pass
negative signals at duodenum, explain
Prevents dumping of excessive chyme into intestine
fat content, carb content, rptein content, energy content, osmolarity, particle size
Factors that affect gastric emptying
Volume of food ingested Exercise intensity Osmolarity Energy density Meal or beverage temperature Psychological stress Other factors
and positive/neg signals
