Flashcards in Carbohydrates Deck (63)
An aldehyde, ketone, or a compound that yields either aldehyde or ketone after hydrolysis
(*Phil setting: based on response of body based on insulin levels)
General formula of monosaccharide
Aldoses and ketoses are
Classifications of carbohydrates based on conromation
D and L Monosaccharides/
basis of fischer projetion
position of OH group (D or L)
*alpha-below beta-above (Haworth)
In the Embden-Meyerhoff Pathway, Glyceraldehyde-3-Phosphate is converted to?
Dihydroxyacetonephosphate (DHAP) or continue to the
Glycolysis converts glucose to
*If body does not need sugar, glucose is shunted to PPP and etc
hormones from pancreatic beta cells (I of L) in fed state
*promotes cellular uptake of glucose (allowing transport of sugars from blood; anabolic)
How is proinsulin converted to insulin?
removal of C peptide (proinsulin: a + b + c peptides)
What are the requirements for insulin release?
− Other amino acids that can ramp up release of insulin
(Leucine, Arginine, Histidine, Phenylalanine)
− Sulfonylureas (tolbutamides)
− ACTH, GH
o As ACTH increases, cortisol increases which leads to an increase in glycolysis
What causes release inhibition of insulin?
− Thiazide diuretics (hypertensive drug)
− Dilantin (antiseizure)
− Human placental lactogen (diabetes of pregnancy)
What causes decreased tissue response to insulin?
− Glucocorticoids (Obesity)
− Estrogens (Inactivity)
− Progestins (Low carbohydrate diet)
Insulin INCREASES these metabolic pathways
Insulin DECREASES these metabolic pathways
hormones involved in unfed/fasting state
glucagon (from pancreatic alpha cells; catabolic)
What happens to glycogen in the liver? muscle?
liver: glycogen is converted to glucose, and released into the blood
Muscle: glycogen converted to glucose-6-phosphate, and remains in the muscle for its own energy needs
Its action is similar to glucagon and it is immediately expended
“Fight or Flight” epinephrine from adrenal medulla
Hormones involved in gluconeogenesis
cortisol (hydrocortisone)- from adrenal cortex; inhibits glucose entry to muscle, connective and lymphoid tissue
Adrenocorticotropic Hormone (ACTH)- from anterior pituitary gland and stimulates prod of cortisol
Cortisols stimulates release of
gluconeogenic amino acids from the muscles
*also promotes conversion of amino acids into glucose by liver
What does cortisol stimulate in adipose cells?
lipolysis by releasing glycerol for conversion to glucose by liver
T or F: glycolysis stops in the sample once it is drawn
*Serum/plasma must be separated from cells soon after collection to avoid a falsely decreased glucose result
→ Ideally, processing must be done within 1 hour
What are the conditions of glucose reabsorption and glycosuria in PCT?
→ Reabsorbs all glucose if <180 mg/dL
→ Glycosuria results if blood glucose >180mg/dL
* >600 mg/dL in the kidney: greater than blood glucose threshold because of countercurrent mechanism
Increase in plasma glucose levels due to hormone imbalance
glucose reference ranges
increased if >110-120 mg/dL
Why does blood sugar increase at night?
fasting blood sugar (body undergoes gluconeogenesis at night to supply energy for the body's organs)
How is fasting blood sugar counteracted?
insulin production so glucose enters cells and cortisol becomes active (basal metabolic rate) to increase blood sugar
fasting blood sugar can have this effect on diabetics
Why shouldnt diabetics* take extra insulin shots before sleeping?
*in a constant catabolic state
Blood sugar goes down over the course of the night leading to hypoglycemia and a surge in cortisol from 4am-6am leads to hyperglycemia rebound leading to diabetic coma
Immediate effects of hyperglycemia
increased extracellular osmotic pressure (increased glucose in plasma = water out of cells; dehydration)
acidosis (respiratory > metabolic)