nutrition
taking food in/breaking down food; using food done by animals; heterotrophs: herbivore, carnivore, omnivores; need to eat correct amount + types of food
chemcial energy
ingest chem E to produce ATP
Calorie
1000 calories; kilocalories; amount of heat to raise tmep of 1kg of H2O by 1 degress C
carbs
source of chem E; starch + cellulose; main source of E; ~50% total Calories; 1g = 4C
proteins
source of chem E; 1g about 4C
lipids
source of chem E; 1 g about 9C; as triglycerids: glycerol + 3 FAs
organic building blocks
assembled into essential macromolecules; source of C; source of N (protein)
essential nutrients
can’t be amde by body must be ingested; essential AAs and essential FAs
essential amino acids
20 AA required to make al needed proteins; most animals can make half on their own; must ingest sulfur + nitrogen; adult humans need 8 essentail AAs; infant humans need 9 essential AAs w dev make more
types of protein sources
complete proteins: food w all essential AA in proper ratios; incomplete proteins: lack some essential AAs (ex: plants); vegetarians need varied consumption
essential fatty acids
can make most FAs can’t make some w double bonds bc lack enz; ingest linoleic + linolenic acid; polyunsat; in seeds, grains, veggies; common in diet
vitamins
organic compounds; need small amounts; support biochem functions (ex: conenzymes); non protein aid to enz
water soluble vitamins
B complex; vit C
B3
niacin; part of NAD+ and NADH+; cell resp; water sol
B9
folic acid; if difficent: neural tube defects, anemia; water sol
vit C
ascorbic acid; collagen syn; antioxident; deficiency = survy…skin, teenth, blood vessels genenerate and weak, low immunity, delayed wound healing; inc iron absorption; water sol
antioxident
destroys reactive oxygen molecules; H2O2
fat soluble vitamins
can be stored in body; vit A, vit D, vit K
vit A
retinol; converted to retinal; part of rhodopsin = eye pigment; deficiency = blindness; fat sol
vit D
inc Ca2+ absorption; deficiency: defective bond growth in kids (rickets), osteomalacia (bone softening); skin exposure to UV skin rxn vit D production; fat sol
vit K
syn of blood clotting proteins; produced by large intestine bac: E Coli, antibiotic lowers vit K production; fat sol
minerals
inorganic nutr required by cells; ingested as salts dissolved w/i food/water
major minerals
at least 200mg/day; magnesium, calcium, phosphorous, sulfur, choloride, potassium + sodium
magnesium
enz cofactor; muscle + nerve function
calcium
bones + teeth; blood clottin; nerve transmission + muscle function
potassium + sodium
main + ions in cells and ISF; water balance; nerve function; ion balance
phosphorous
bones + teeth; ATP; nucleic acids S-P backbone; phospholipids
sulfur
disulfide bonds in proteins
choloride
main neg ion; water balance; nerve function; gastic juice HCl
trace elements
<200 mg/day; iron + iodine
iron
hemoglobin O2 transport; cytochroms ETC
iodine
thyroid hormones; homeostasis + metabolism
malnutrition
diet lack 1 or more essential nutr; less E than required undernutr; diseases, death, deformities
kwashiokar
severe protein deficiency in children; diet lack essential AAs: stunted growt, muscle atropy, adema of abdomen due to fluid imbalance casues swelling
hormonal regulation of digestion
arrival of food in alimentary canal compartments triggers peristalsis + chem digestion secretions
HRD in oral cavity
NS triggers saliva production swallowing triggered
HRD in stomach
food arrival stretches stomach triggers release of gastrine from bloodstream to stomach stomach stimulated produces gastic juices triggers churning physical mixing of food; also reg by enter division of ANS
small intestines HRD
chyme; if chyme w lots of fats inc secretin + inc CCK act on stomach to inhibit peristalsis + gastric juices; slows down digestion material to brekak down
chyme
acidic mix of partiall digested food; AA + FA w/i it trigger release of digestive hormones by duodenum
digestive hormones
CCK + secretin
CCK
stimulates release of digestive enz from pancreas + bile from gallbladder
secretin
stimulates pancreas to secrete HCO3-; nutralized chyme acidity
E storage regulation
if you ingest more E rich molecules than needed store excess; 1st site of storage: liver + muscle cells; stored as glycogen if glycogen stores = full; store excess E as fat in adipose cells; if fewer C than need ingested use stored E: liver glycogen used first, muscle glycogen + fat used 2nd
glucose
cell resp; imp source of C for macromolecules; levels must be maintained w/i normal range: normal blood glucose 70-110 mg/100 mL
pancreas functions
exocrine: PJ w digestive enz, through ducts to SI; endocrine: cluster of cell (pancreatic islets) each cluster w/i 2 types of cells…alpha and beta cells
alpha cells
secrete glucagon hormones
beta cells
secrete insulin hormone
insulin + glucagon
secreted into ISF to blood; antagonistic relationship: work in opposition to maintain homeostasis sugar; secretion of both controlled by blood glucose level
high blood glucose levels
beta cells in pancreas secrete insulin; target tissue = all cells except brain; insulin bind to insulin receptors on pm stimulates cells to take up glucose from blood once inside used as fuel or stored as glycogen (glucose homeostasis; brain takes glucose w/o insulin needs access to E at all times
low blood glucose levels
alpha cells in pancreas secrete glucagon; target tissue = liver, not whole body; liver cells convert glycogen to glucose secreted into blood raises blood glucose levles (glucose homeostasis)
diabetes mellitus
endocrine disorder caused by dec insulin production inc response to insulin @ target tissue; very high blood gluc lvels bc cells can’t take us glucose fat becomes main E substrate for cell resp; bad bc it produces acidic metabolites: dec pH blood, dec Na+/K+ nerve conduction probs; leading cause of blindness, kidney disorder, gangrene due to circ sys probs; kidney excretes glucose in urine
type I diabetes
insulin dependent (10%); autoimmune disease; own antibodies destroy beta cells to inc sulin production; onset @ <30 yo; need daily injections
type II diabetes
non-insulin dependent (90%); target cells don’t respond well to insulin (insulin resistance) insulin produced but no binding w TC receptors (glucose not taken into cell); on set @ >40 yo; obesity + no exercise significant risk factors
overnutrition
consuming more C than needed can lead to obestiy
feedback circuits
control fat sotrage + metabolism to maintain homeostasis
nervous system
neuron networks; Brain’s Satiety Center
neuron networks
relay + integrate info from DS to regulate secretion of homones
brain’s satiety center
target of homones; generates nerve impulses of fullness or hunger
gherlin
secreted from stomach walls; hunger
insulin
produced after meal bc inc blood glucose; satiety center supresses hunger = fullness
PYY
secreted SI after meals; appetite suppressant
leptin
produced by advpose tissue; satiation in brain; dec levels of leptin, body fat decreased; inc appetite