Carbohydrates Flashcards
What are the 4 categories for carbohydrate classification
- size of carbon chain
- location of CO functional group
- number of sugar units
- stereochemistry
What are the two forms of carbs
Aldose and ketose
What display of carbohydrates is the most accurate
- Hawthorne
- open Fischer
- cyclic Fischer
Hawthorn
what is the purpose of microvilli
increase surface area on intestines to increase absorption
what must polysaccharides be converted to to enter the blood
monosaccharides
glycogenesis
creation of glycogen in liver and muscle
glycogenolysis
break down of glycogen to release glucose
gluconeogenesis
creation of new glucose from non carb sources such as fatty acids
glycolysis
formation of atp, CO2 and water from glucose
lipogenesis
conversion of carbs to fatty acids
lipolysis
decomposition of fat
glycogen
storage form for glucose
what is the renal threshold
where blood sugar is so high, glucose spills past kidney filtration and into urine (>180 mg/dL)
A diabetic patient comes into the doctor’s office with a fasting blood sugar of 192 mg/dL and a HbA1c value of 14%. Based on these results, what statement best describes the patient.
- diabetes mellitus is managed
- diabetes mellitus is not managed
- values not indicative of diabetes mellitus
diabetes mellitus not managed
Of the following glucose levels, which would you expect to result in glucose in the urine?
- 32 mg/dL
- 162 mg/dL
- 172 mg/dL
- 192 mg/dL
192 mg/dL
>180 mg/dL is over the renal threshold
Diabetic condition formed when a person’s own immune system destroys the islet cells of the pancreas, resulting in impaired production of insulin.
- type 1 diabetes
- type 2 diabetes
- gestational diabetes
type 1
describe glucose processing during a ‘fed state’
insulin from pancreatic beta cells released to lower blood glucose levels
what glucose pathways are activated from insulin release during ‘fed state’
- lipogenesis (fat creation)
- protein synthesis
- glycogenesis
what glucose pathways are activated in low insulin level environments
lipolysis (breakdown of fat)
ketone formation
gluconeogenesis
glycogenolysis
during ‘fasting state’ where does the body get glucose
glucagon triggers glycogen conversion to glucose in the liver -> released into the blood
what is the purpose of somatostatin and what cell releases it
released by delta cells in the pancreas to regulate alpha and beta cell activity
what cell in the pancrease releases glucagon
alpha pancreatic cells
-> converts glycogen to glucose for low glucose lvl response
what cell in the pancreas releases insulin
beta cells to convert glucose uptake in adipose tissue or muscle or glycogen creation
(lipogenesis, glycolysis or gluconeogenesis)
how does epinephrine impact insulin and glucagon
inhibits insulin and stimulates glucagon/glycogenolysis to increase blood glucose
define hyperglycemia
high blood glucose
describe endocrine disorders linked to high blood glucose lvls
- acromegaly (inc growth hormone)
- cushing syndrome (inc cortisol)
- thyrotoxicosis (increase pancreatic activity)
- pheochromocytome (inc epinephrine)
- diabetes mellitus
list diagnostic criteria for diabetes mellitus with symptoms
- Hgb A1c >6.5%
- fasting plasma >126 mg/dL
- 2hr plasma glucose >200 mg/dL
- random blood glucose >200mg/dL with symptoms
describe type 1 diabetes
beta cell destruction by autoimmune process leading to absolute insulin deficiency
describe type 2 diabetes
insulin resistance in peripheral tissue and an insulin secretory defect of beta cells
name other types/causes of diabetes
- pancreatic, hormonal disease
- drug/chemical toxicity
- insulin receptor abnormalities
- no renal or retinal complications
define normal fasting glucose
70-99 mg/dL or 3.9-5.5 mmol/L
define impaired fasting glucose
100-125 mg/dL or 5.6-6.9mmol/L
define provisional diabetes diagnosis (fasting plasma glucose levels)
> 126 mg/dL or >7 mmol/L
describe gestational diabetes mellitus
- diabetes due to pregnancy
- 50g glucose screen >140 mg/dL
what are the two approaches to diagnosing gestational diabetes
- one step: 3 measurements over 2 hrs
- two step: 4 measurements over 3 hrs
define normal and impaired glucose tolerance in oral glucose test
- normal 2 hr plasma glucose <140 mg/dL
- impaired 2 hr plasma glucose 140-199 mg/dL
define levels of hypoglycemia classification
- lvl 1: glucose <70mg/dL
- lvl 2: glucose <54 mg/dL
- lvl 3: no specific glucose threshold, pt not responding
true or false:
not separating serum/plasma from cells soon after collection will cause a false decrease of glucose
true
cells will continue to metabolize glucose and lower levels
how can a whole blood specimen be preserved for glucose testing
NaF for 24 hrs
RR for plasma/serum glucose
70-105 mg/dL
what method is commonly used to measure glucose
hexokinase - endpoint rxn
how does hgb A1c indicate management of diabetes mellitus
- hgb is glycated for full life cycle
- hgb A1c = 80% of total glycohgb
- measurements of A1c can indicate past glucose intake levels
- RR 3-6% hgb
define inborn errors of carbohydrate metabolism
- lactose intolerance: deficiency in intestinal mucosal lactase
- ketones: complication of uncontrolled diabetes mellitus (acid base imbalance)
examples of disaccharides
- lactose
- sucrose
- maltose
hyperglycemia causes (etiology)
- diabetes mellitus
- endocrine disorders (acromegaly, cushings, pheochromocytoma, thyrotoxicosis)
- drugs (anesthetics and steroids)
what happens if hyperglycemia goes untreated
diabetes complications
- nerve damage
- eye disease
- kidney damage
hypoglycemia etiology
- insulin over dose
- drugs
- alcoholism
- insulinoma
- galactosemia
- glycogen storage diseases
long term effects of untreated hypoglycemia
brain starved of glucose
- seizures
- coma
- death
most common non-reducing substance
sucrose
C-peptide
by-product of insulin production
define reducing substances
carbs that can reduce other compounds while being oxidized
what is the Hgb A1c percent relating to 126 mg/dL glucose
6%
what is the Hgb A1c percent relating to 154 mg/dL glucose
7%
what is the Hgb A1c percent relating to 212 mg/dL glucose
9%
