Module 2 Flashcards
What is an A1C test?
- reflects the average blood glucose values of previous 2-3 mo
How does an A1C work?
- measures the % of Hb “coated” with glucose
What are A1C levels?
- normal < 5.7%
- diabetes < or = 6.5%
Where does the pancreas secrete into?
- duodenum
T/F: The pancreas has endocrine but not exocrine function.
- False, both endocrine and exocrine
What area of the pancreas is relevant to its endocrine function?
- Islets of Langerhans
What are the three cell types of the Islets of Langerhas?
- alpha
- beta
- delta
What do alpha cells of the Islets of Langerhans secrete?
- glucagon
What do beta cells of the Islets of Langerhans secrete?
- insulin
co-secretion of amylin
What do delta cells of the Islets of Langerhans secrete?
- somatostatin (technically not the same as the hypothalamic somatostatin but still think inhibitor)
What is the function of glucagon?
- prevents hypoglycemia/mobilizes “metabolic fuels”
How does glucagon achieve its function?
- increases blood glucose levels by mobilizing glucose and FFA
What is the relationship of glucagon and insulin?
- opposite
- glucagon is antagonist to insulin
T/F: Glucagon is a catabolic hormone.
- True
What is the target tissue of glucagon?
- liver
- fat
- muscle
What does glucagon do in the liver?
- glycogenolysis (breakdown of glycogen to glucose)
- glucogenesis (glucose formation)
What does glucagon do in the fat?
- stimulates lipolysis
What does glucagon do in the muscle?
- proteolysis
What is proteolysis?
- breakdown for a.a. release but not efficient
In response to _______, glucagon is trying to make “____”
- hypoglycemia
- fuel
What does glucagon increase blood levels of in response to hypoglycemia?
- glucose
- FFA & ketones
- a.a.
What is the precursor for glucose and ketone formation?
- FFA oxidation in the liver
What are used as fuel by the CNS, heart, and body?
- ketones
What does excess ketones (and glucose) blood levels lead to?
- acidosis (ketoacidosis)
What factors stimulate glucagon secretion from pancreas?
- hypoglycemia (major)
- exercise
- stress
- fasting
What factors inhibit glucagon secretion from pancreas?
- hyperglycemia
- amylin
When is amylin secreted?
- with insulin during feeding
What is the function of amylin?
- suppress glucagon which leads to increased satiety/decreased appetite and inhibits GI mobility
- inhibits plasma glucose (tells glucose to stay in pancreas)
What is the function of insulin?
- prevents hyperglycemia
- promotes “metabolic fuel” storage
How does insulin make its functions?
- decreases blood glucose levels by increasing uptake into cells
- decreases blood levels of [a.a.] and FFA/ketones
- decreases serum K+ levels by promoting uptake into cells
What two parts of the body DO NOT require insulin for glucose uptake?
- brain
- RBC
Why are insulin and glucose administered for hyperkalemia?
- decreases serum K+ levels by promoting uptake into cells
What is the target tissues of insulin?
- liver
- muscle
- adipose tissue
What does insulin increase in the liver?
- glucose uptake
- form glycogen
- lipid/protein synthesis
What does insulin decrease in the liver?
- ketogenesis
- glycogenolysis
What does insulin increase in the muscle?
- glucose uptake
- form glycogen
- a.a. uptake
- protein synthesis
What does insulin decrease in the muscle?
- glycogenolysis
What does insulin increase in the adipose?
- glucose uptake
- glucose to form glycerol phosphate
- fat storage
What does insulin decrease in the adipose?
- lipolysis
What factors stimulate insulin release from the pancreas?
- hyperglycemia (major)
- increased serum FFA & a.a. levels
- GI/digestive hormones
- parasympathetic stimulation of beta cells
What factors inhibit insulin release from the pancreas?
- hypoglycemia
- neg feedback loop
- sympathetic stimulation of beta cells
- prostaglandins (PGE2)
Describe obesity and its relationship with insulin regulation/Type II diabetes
- increased insulin will down-regulate receptors
- fewer receptors lead to glucose remaining elevated despite sufficient insulin
- elevated glucose down-regulates receptors
What is the result of type II diabetes?
- insulin resistance (decreased sensitivity)
What are the two types of diabetes mellitus?
- type I
- type II
What are the three “poly’s” of diabetes?
- polyuria (excessive urine production)
- polydipsia (excessive thirst)
- polyphagia (increased appetite)
What is DM type I?
- insulin insufficiency d/t destruction of beta cells
- ? autoimmune
T/F: DM type I is not associated with obesity.
- True
What is the result of DM type I?
- hyperglycemia
- hyperlipidemia
- increased ketone bodies/ketoacidosis
- catabolic affect on muscle mass
What is a risk of hyperlipidemia?
- atherosclerosis from lipid deposits in blood vessels
What does metabolic acidosis lead to?
- increase [H+] ==> coma & death
What is insulin shock?
- reaction to hypoglycemia
What are causes of insulin shock?
- excessive insulin admin
- increased physical activity
- poor glucose monitoring
What is the treatment for insulin shock?
- bring glucose levels back up via oral or IV simple sugar or glucagon injection
What can improve DM type II?
- diet changes
- exercise
What is OGTT?
- oral glucose tolerance test
What are the values for a fasting plasma glucose test?
- normal < 140mg/dL
- diabetes > or = 200mg/dL
What are the values for OGTT?
- normal < 100 mg/dL
- diabetes > or = 140mg/dL
What is seen on a thyroid function lab panel?
- TSH
- T4
- T3
What are the hormones of the thyroid gland?
- T4 (thyroxine)
- T3 (tri-iodothyronine)
- calcitonin
Where are T3 & T4 synthesized?
- follicle cells
Where are T3 & T4 stored?
- follicle cavities (colloid)
Are T3 & T4 hydrophilic or lipophilic?
- lipophilic
Describe the synthesis of T3 & T4
FOLLICLE CELL
- tyrosine synthesized into TGB precursor
- iodine pumped into cell
- TGB binds iodine
- TGB/I complex (aka T3/T4 with TGB) pumped into FOLLICLE CAVITY for storage
How is iodine pumped into the follicle cell?
- TSH sensitive iodine pump
- captures 25% dietary iodine