Carbodiedrates. Flashcards
Define and explain carbohydrate structures and classifications
Monosaccharide
A basic sugar. Examples: Galactose, glucose.
Define and explain carbohydrate structures and classifications
Disaccharide
Two monosaccharides joined by a glycosidic linkage. Example: Lactose
Define and explain carbohydrate structures and classifications
Polysaccharide
More than 3 monosaccharides joined by glycosidic linkages. Example: Starch, glycogen
Explain the process of digestion and absorption of dietary carbohydrates
Polysaccharides: Starch or glycogen are broken down by alpha amylase into disacchardies, which are picked up by micro villi in the GI tracts and broken down into monosaccharides which are released into the blood
Monosaccharides: pass into the blood directly
Explain the main transport routes and uptake of carbohydrates
(a guess)
Glycogenesis: Glucose -> Glycogen in the liver and muscle
Glycogenolysis: Glycogen -> glucose
Gluconeogenesis: Non-CHO sources -> glucose (proteins, generally)
Glycolysis: glucose -> CO2+H2O+ATP
State the main physiologic functions of carbohydrates
Glucose: Primary energy source for the body
Glycogen: Liver storage form of glucose
fats: long term storage of energy
Explain the effect of hormones in regulation of blood glucose levels
Insulin: Increases glycogenesis and glycolysis: Glucose -> glycogen ->pyruvate -> acetyl-CoA
Glucagon: Increases glycogenlysis: glycogen ->glucose
Increases gluconeogenesis: fatty acids ->acetyl-CoA ->ketones, proteins ->amino acids
Discuss the maintenance of blood glucose levels in the “fed state” (parenteral)
Fed state:
Insulin from Pancreatic beta cells (islets of Langerhans) preproinsulin ->proinsulin -> insulin and C-peptide (a byproduct)
Promotes cellular uptake of glucose
insulin increased:
lipogenesis
protein synthesis
glycogenesis
Insulin decreased:
lipolysis
ketone formation
gluconeogenesis
glycogenolysis
Discuss the maintenance of blood glucose levels in the “fasting state”
glucagon from pancreatic alpha cells
liver converts glucagon into glucose, releases to the blood
muscle converts glucagon to glucose-6-PO4, remains inthe muscle cell
Explain the formation and significance of hemoglobin A1C
HbA is glycated making HbA1c. It serves as a more accurate read of glucose levels for diabetics, since glucose varies greatly.
Explain etiology, symptoms, and effects of hypergylcemia
Type1a:
Pancreatic beta cell destruction (autoimmune disorder) leading to absolute insulin deficiency
Must take insulin to survive
usually young, onset days to weeks
islet cell antibodies present
Explain etiology, symptoms, and effects of hypergylcemia
Type1b
Idiopathic
Explain etiology, symptoms, and effects of hypergylcemia
Type2:
Insulin resistance, and secretory defect in the beta cells
variable
highly associated with family history, >40 yo, obesity and lack of exercise.
Explain etiology, symptoms, and effects of hypergylcemia
Gestational:
pregnancy
frequent, but transitory
human placental lactogen
>= 140 mg/dl one hour after 50g glucose load
Any two of the following (100G):
fasting plasma glucose >=95mg/dl
>=180mg/dl after 1 hour
>=155mg/dl at 2 hours
>=140mg/dl at 3 hours
Explain the diagnostic criteria for
Type 1
Pancreatic beta cell destruction (autoimmune disorder) leading to absolute insulin deficiency
Must take insulin to survive
usually young, onset days to weeks
islet cell antibodies present
