CARBOHYDRATES LEC Flashcards
Carbohydrates contain a ___ and ___ functional groups
carbonyl and hydroxyl
How does glucose enter tissues like skeletal muscle and adipose tissue?
With the help of insulin by stimulating the expression of glucose transporter 4
Which organ is completeley dependent on glucose for energy production?
The brain
2/3 of glucose utilization in resting adults occur in ___
CNS
Carbohydrates may be classified according to:
Number of carbons
Location of carbonyl functional group
Number of sugar units
Major storage form of glucose in man
glycogen
Percentage of glycogen stored in the liver and skeletal muscle
85% and 15%, respectively
microvascular complications of DM
nephropathy, neuropathy, retinopathy
macrovascular complication of DM
atherosclerosis
intermediate products of glucose metabolism
pyruvic acid. lactic acid, acetylcoA
end products of glucose metabolism
CO2, H20, ATP
Why does no CHO degradation happens in the stomach?
The salivary amylase is inactivated by gastric acid (ph 1-3 due to HCl content)
____ of glucose on C6 into ____ by ___. This process traps the glucose inside the cell
Phosphorylation; glucose 6- phosphate ; hexokinase
____ of glucose 6-phosphate into _____ by _____
Isomerization; fructose 6-phoshapte ; phosphoglucomutase
_______ of fructose 6-phosphate on C1 forming _____ by ______
Phosphorylation;1-6 fructose biphosphate; phosphofructokinase
____ of fructose 1,6-biphosphate into isomers ___ and ____ by ____
Split; DHAP and GAP; aldolase
____ of DHAP into ____ by ____
Conversion; GAP; triose phosphate isomerase
_____ and phosphorylation at C1 into _____ by ____
Dehydrogenation; 1-3 biphosphoglycerate; glyceraldehy 3-phosphate dehydrogenase
___ of the high energy bond at C1 by _____ yielding ATP and the product ____
Hydrolysis; phosphoglycerate kinase; 3-phospholycerate
___of phosphate from C3 to ____ forming ____ by _____
Shifting;C2; 2-phosphoglycerate; phosphoglycerate mutase
___ of 2-phosphoglycerate by ___ forming
Dehydration; enolasel phosphoenolpyruvate
____ of the high energy bond yielding ___ and ___ by the enzyme ____
Hydrolysis; pyruvate; ATP pyruvate kinase
lycolysis (EMP Pathway is ____
anaerobic
In the presence of oxygen, pyruvate is further oxidized to ____
CO2
In the absence of O2, pyruvate can be fermented to
lactate or ethanol
Responsible of the synthesis of reduced glutathione and NADPH to protect cells from oxidative stress
Pentose Phosphate Shunt/Hexose Monophosphate Pathway
Maintains iron in the ferrous (Fe2+) state since ferric (Fe3+) are incapable of binding oxygen
Methemoglobin Reductase Pathway
Responsible for the synthesis of 2,3- diphosphoglycerate to enhance oxygen delivery to tissues
uebering-Rapaport Pathway
beta cells produce:
insulin, islet amyloid polypeptide or amylin
alpha cells produce:
glucagon
delta cells produce
somatostatin
PP/F cells produce
pancreatic polypeptide
ratio of C-peptide to insulin
5:1 or 15:1
Duct cells: ____ and section is controlled by ____
bicarbonate ions; secretin
Acinar cells: Digestive enzymes which include ___, ____, ___, and ___ whose secretion is controlled by ___
pancreatic amylase, lipase, trypsinogen and chymotrypsinogen; cholecystokinin
Analogy:
Post prandial state: ______
_____: Glycogenolysis
Long fasting state: _____
Glycolysis
Short fasting state
Gluconeogenesis
Only hypoglycemic hormone
Insulin
Why is the ratio of C-peptide to insulin in the serum 5:1 to 15:1
increased hepatic clearance of insulin
Actions of insulin
- Promotes cellular entry of glucose into the insulin- sensitive tissues (liver, skeletal muscle and adipose) as energy source through glycolysis
- Promotes glycogenesis
- Promotes lipogenesis
- Inhibits glycogenolysis
The primary hyperglycemic hormone
glucagon
major INHIBITORY hormone
somatostatin
Each hormone is being secreted by: Cortisol: \_\_\_\_ epinephrine: \_\_\_\_\_ Somatotrophin:\_\_\_\_\_ Thyroxine:\_\_\_\_
Zona fasciculata of the adrenal cortex
Chromaffin cells of the adrenal medulla
Anterior pituitary gland
Follicular cells of the thyroid gland
HYPERGLYCEMIA: LAB FINDINGS
- Increased plasma and urinary glucose
- Increased urine specific gravity
- Increased serum osmolality
- Ketones in serum or urine
- Decreased blood and urine pH (acidosis)
- Hyponatremia: decreased plasma sodium (due to losses [polyuria] and shift of water from cells)
- Hyperkalemia: increased plasma potassium (cellular shift secondary to acidosis)
- ↓pCO2 due to Kussmaul Kien respiration (deep rapid respirations)
- Decreased bicarbonate
- Increased anion gap
Ketosis develops in DM from excessive synthesis of _______ which can be reversed by insulin administration.
acetyl-CoA
Nerve damage, known as _____occurs in 60% to 70% of people with diabetes
diabetic neuropathy
Former names of Type 1 DM
Insulin-dependent diabetes mellitus, juvenile onset diabetes mellitus, Brittle diabetes, Ketosis-prone diabetes
Autoantibodies responsible for beta cell destruction
Antibody to GAD65: highest sensitivity (91%), more common in adults
Insulin autoantibodies (IAAs): more common in children
Autoantibodies to insulinoma-associated protein 2 (IA-2)
Autoantibodies to zinc transporter 8 (ZnT8)
Former names of Type 2 DM
non-insulin dependent DM, adult- type/maturity-onset DM, stable diabetes, ketosis- resistant, receptor-deficient DM
untreated type II DM will result to _______ due to overproduction of glucose accompanied by ___-,___,____
nonketotic hyperosmolar come; severe dehydration ; electrolyte imbalance; increased BUN and creatinine
risk factor for Type 2 DM
Overweight (BMI ≥25 kg/m2),
Sedentary lifestyle
Family history of diabetes
Advanced age (≥45 years)
Ethnicity (African Americans, Latinos, Native Americans, Asian Americans, and Pacific Islanders)
Polycystic ovary disease
History of gestational diabetes
Delivery before diabetes of a baby weighing more than 9 pounds
Hypertension, vascular disease or dyslipidemia (HDL cholesterol ≤35 mg/dL and/or triglyceride level ≥250 mg/ dL)
HbA1c of 5.7% or greater
Impaired fasting glucose or impaired glucose tolerance,
Other conditions associated with insulin resistance (i.e., acanthosis nigricans)
____ is high in diabetic ketoacidosis and ___ with treatment whereas ____ and ____ rise on treatment
Beta-hydroxybutyrate (ketone body) ; falls; acetoacetic acid and acetone
T or F: Reagent strips for detection of ketones is used to monitor recovery for diabetic ketoacidosis since the strip is sensitive to presence of beta- hydroxybutyrate.
FALSE; not used to monitor recovery for DKA since the strip is not sensitive to Beta-hydroxybutyrate
Which is used to monitor recovery from DKA?
anion gap
OTHER SPECIFIC TYPES OF DIABETES
- Pancreatic disorders/pancreatectomy
- Endocrine disorders: Cushing’s syndrome, pheochromocytoma, acromegaly, hyperthyroidism
- Drug or chemical inducers: dilantin and pentamidine (anticonvulsants)
- Genetic syndromes: Down syndrome, Klinefelter syndrome, Turner syndrome etc.
- Exocrine disorders: cystic fibrosis, neoplasia, hemochromatosis.
Screening for GDM should be performed between ___ weeks of gestation
24-28
One Step Approach: ____
Two Step: _____
IADPSG
NIH
One Step Approach:
Uses a ____ oral glucose tolerance test, measuring glucose levels after fasting and at 1 and 2 hours
75 gram
Criteria for OGTT
- Ingest at least 150 g/day of carbohydrates for the
3 days preceding the test without limitation in physical activity - The test should be performed after an overnight 8- to 14-hour fast.
- The individual should not eat food; drink tea, coffee, or alcohol; or smoke cigarettes during the test, and he or she should be seated
Major cause of hypoglycemia
use of insulin or insulin secretagogue drugs (sulfonylureas)
T or F: Severe hypoglycemia if not corrected in a timely fashion can be fatal
T
Whipple’s triad
Symptoms consistent with hypoglycemia
Low plasma glucose
Alleviation of symptoms upon glucose administration
Classification of hypolgycemia (8)
- Drug induced
- Severe medical illness
- hormonal deficiencies
- endogenous hyperinsulinism
- autoimmune hypoglycemia
- non-islet cell tumor hypoglycemia
- hypoglycemia of infancy and childhood
- alimentary hypoglycemia
____ and ____ are most commonly affected by defects in glycogen metabolism, as these tissues have abundant quantities of glycogen.
Liver, skeletal muscle
liver glycogenosis usually manifests as ___ and ____
hypoglycemia; hepatomegaly
muscle glycogenosis usually manifests as ___, ___, ___, ____
muscle cramps; exercise intolerance; fatigue; weakness
Common name and enzyme deficient for Ia(L) and Ib(L)
Von Gierke; glucose 6-phosphatase; glucose 6-phosphatase translocase
II(M): ____: acid maltase
Pompe
Congenital deficiency of one of the three enzymes involved in the conversion of galactose into glucose.
Galactose-1-phosphate uridyl transferase
Galactokinase
Uridine diphosphate galactose 4-epimerase
An autosomal recessive disorder characterized by accumulation of fructose in blood and urine due to lack of fructokinase
Essential fructosuria
What enzyme is deficient in hereditary fructose intolerance which leads to inadvertent accumulation of fructose 1-phosphate
aldolase
In fructose 1-6 biphosphatase deficiency, there is an impaired hepatic synthesis of gluconeogenic precursors ___, ___, and alanine leading to hypoglycemia
lactate, glycerol, alanine
