Endocrine part 2 Flashcards
the parathyroid glands are mainly composed of ________ cells. what do these cells do?
- Mostly composed of chief cells
- Secrete parathyroid hormone
what does parathyroid hormone control?
regulator of blood calcium levels
Besides chief cells, parathyroid glands also contain ______ cells
oxyphil
- they have an unknown function
where are the parathyroid glands located?
- Four small glands
- located on the POSTERIOR surface of the thyroid gland
A decreased level of ________ stimulates the synthesis and release of PTH
blood calcium
what are the specific actions of PTH?
↑ renal tubular reabsorption of calcium
↑ urinary phosphate excretion
↑ the renal conversion of vitamin D into its active form
↑ osteoclastic activity which releases calcium from the bones
what is the overall function of parathyroid hormone?
↑ level of free calcium which inhibits further PTH secretion
________________ is an important cause of hypercalcemia
hyperparathyroidism
name the 2 types of hypoparathyroidism, and what causes each:
- Primary
caused by an autonomous spontaneous overproduction of PTH - Secondary
A secondary phenomenon in pts with chronic renal failure
Primary Hypoparathyroidism is usually the result of what 2 disorders?
Usually the result of:
A) parathyroid hyperplasia (multiglandular)
B) an adenoma (solitary)
what groups are most likely to have PRIMARY hyperparathyroidism?
1) Adults
2) Women (4X as likely as men)
what are the “Classic clinical features” of PRIMARY Hyperparathyroidism?
“Painful bones, stones, abdominal groans, and psychic moans”
- fractures from osteoporosis
- kidney stones
- constipation, ulcers, gallstones
- depression/lethargy/seizures
T/F: most cases of primary hyperthyroidism are diagnosed after clinical signs appear
FALSE
- clinically silent hyperparathyroidism is detected early
Secondary hyperparathyroidism is usually the result of what?
Usually due to renal failure
what is hyperphosphatemia ? how does it lead to the production of PTH?
= increased amounts of phosphate in the blood because of decreased excretion
- that decreases serum calcium
- decreased serum Ca = increased PTH
Renal failure not only leads to hyperphosphatemia, but also to the failure to synthesize ______
vitamin D
This reduces calcium absorption in the intestines
Clinical characteristics of Secondary hyperparathyroidism:
Calcium levels are usually near normal
Symptoms dominated by renal disease
Renal osteodystrophy (growth of bone)
why are serum calcium levels usually within the normal range during secondary hyperparathyroidism?
Compensatory increase in PTH levels sustains serum Ca
treatments for Hyperparathyroidism :
Surgical removal of hyperplastic parathyroid glands
Kidney transplant may be beneficial
T/F: Hypoparathyroidism is more common than Hyperparathyroidism
FALSE
hyper = common
hypo = uncommon
causes of hypoparathyroidism:
A) Surgically induced, removed during thyroidectomy
B) Congenital absence
C) Autoimmune
what is Di George Syndrome?
congenital absence of parathyroid glands
clinical signs of hypothyroidism:
1) Hypocalcemia
2) Increased neuromuscular excitability
3) Cardiac arrhythmias
4) Increased intracranial pressure and seizures
The endocrine pancreas is composed of the _____________________
islets of Langerhans
what are the 4 major cell types of the islets of langerhans? what is the function of each type
Beta cells: produce insulin
Alpha cells: produce glucagon
Delta cells: produce somatostatin
PP cells: produce VIP, a pancreatic polypeptide
Somatostatin suppresses both __________ and _________ release
insulin and glucagon
VIP (a peptide produced by the pancreas) exerts several effects on what?
the G-I tract
_____________ is a group of metabolic disorders resulting in hyperglycemia (excessive amounts of glucose in the blood)
Diabetes Mellitus
Diabetes Mellitus is the leading cause of what other medical conditions?
Leading cause of:
- ESRD (renal failure)
- blindness
- lower limb amputation
what are normal blood glucose levels? what levels do diabetics have?
Normal = 70-120 mg/dL
Diabetic if either:
1) A random glycemia of ≥ 200mg/dL
2) Fasting glucose levels of ≥ 126mg/dL
3) abnormal glucose tolerance test
what causes type 1 diabetes? what does it result in?
Beta cells of the pancreas get destroyed by self-reactive T cells & autoAntiboides
Results in absolute deficiency in insulin production
Clinical features of Type 1 diabetes:
- diagnosed before age 20 in patients who have a normal weight
- Characterized by decreased blood insulin
- autoAbs are detectable in the blood of 70-80% of pt’s
name the 4 symptoms of type 1 diabetes:
1) Polydipsia (thirsty)
2) Polyuria (peeing)
3) Polyphagia (hungry)
4) Ketoacidosis (acetone breath)
what is the prognosis for type 1 diabetes?
guarded
- because of all the possible complications