Carbohydrates
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An aldehyde, ketone, or a compound that yields either aldehyde or ketone after hydrolysis
Carbohydrates *Phil setting: based on response of body based on insulin levels
General formula of monosaccharide
CnH2nOn
Aldoses and ketoses are
monosaccharides
Classifications of carbohydrates based on conromation
D and L Monosaccharides/ Fischer Projection Haworth Projection
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 Kreb’s Cycle
Glycolysis converts glucose to
pyruvate *If body does not need sugar, glucose is shunted to PPP and etc
hormones from pancreatic beta cells (I of L) in fed state
insulin *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?
− Glucose − 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
lipogenesis protein synthesis glycogenesis
Insulin DECREASES these metabolic pathways
lipolysis ketone formation gluconeogenesis glycogenolysis
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
false *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? (renal threshold)
→ 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
hyperglycemia
glucose reference ranges
74-106 mg/dL increased if >110-120 mg/dL