Organs
How do endocrine glands differ from exocrine glands?
Endocrine glands release hormones into the blood (directly); exocrine glands have ducts
Water-soluble/amino acid-based hormones interact with target cells via what kind of proteins?
Specific receptors in the phospholipid bilayer and intracellular secondary messengers
In interstitial growth, the bone lengthens from the epiphyseal plate. What hormone controls this process?
GH
Name some effects of PTH
Increase osteoclast activity; increase calcium reabsorption in the kidney; increase calcium absorption in the intestine
What is the cause of acromegaly?
Hypersecretion of GH in adulthood
Where are endocrine cells located in the pancreas? What hormone is released by each cell type?
Islets of Langerhans
Alpha cells: glucagon
Beta cells: insulin
Delta cells: somatostatin
Is TH water-soluble or lipid-soluble?
Lipid-soluble
What is the target of almost all releasing/inhibiting hormones?
The anterior pituitary (adenohypophysis)
Name some hormones with opposing functions
Calcitonin and PTH
Insulin and glucagon
Insulin and GH
ANP and ADH/Aldosterone
GHRH and GHIH
What is the cause of Cushing's disease?
Hypersecretion of ACTH and/or hypersecretion of corticoids from the adrenal glands
Describe the structure of the adrenal gland, including zones, and the hormones produced in each area
Adrenal cortex (outside):
Capsule, Zona glomerulosa (aldosterone/mineralocorticoids), Zona fasciculata (cortisol/glucocorticoids), Zona reticularis (gonadocorticoids)
Adrenal medulla (inside; nervous tissue) = epinephrine/norepinephrine
The insulin receptor is part of what type of signaling mechanism?
Neither cAMP nor PIP2; the insulin receptor is both a receptor and an enzyme and it triggers its own intracellular messengers.
What type of hormones are classified as hormonal stimuli? What response does this elicit?
Tropic hormones = hormones that cause the release of other hormones by other endocrine organs
Blood pressure is a common stimulus for hormone release. What is the relationship between the heart, adrenal gland, and kidney in the event of high blood pressure?
The heart secretes ANP, which decreases the release of aldosterone from the adrenal cortex, and decreases the release of renin from the kidneys; as a result, more sodium is excreted from the kidney tubules, causing greater urine production, lowering blood volume and blood pressure
What is the cause of goiter?
When the body is in a fasting state, the hormone glucagon will stimulate what process(es) in the liver?
Glycogenolysis and gluconeogenesis
What type of hormone requires plasma proteins in order to travel in the blood?
Lipid-soluble
Distinguish between FSH and LH
FSH stimulates the production of gametes; LH stimulates the production of gonadal hormones
Hypersecretion of PTH results in ___, which has what impact on the nervous system?
Hypercalcemia; inhibits the opening of sodium channels, decreases nervous system function
Distinguish between type 1 and type 2 diabetes using the terms below:
Resistance/sensitivity
Alpha/beta cells
Percentage of diabetic cases
Type 1 diabetes is autoimmune; beta cells do not produce insulin; accounts for 10% of all diabetic cases
Type 2 diabetes is caused by insulin resistance (down-regulation of insulin receptors); insulin is produced, but has little effect; accounts for 90% of all cases
The kidneys release several vital hormones to maintain homeostasis. What are these hormones and what role do they play in the body?
Renin: regulating blood pressure and volume
Erythropoietin: red blood cell production
Calcitriol: active form of vit. D, aids in calcium absorption from the intestine
In the PIP2 signaling mechanism, the enzyme ___ converts PIP2 to ___ and ___. What class of messengers are these molecules?
Phospholipase C
PIP2 --> IP3 and DAG
Secondary messengers
What are some direct effects of GH?
Stimulate liver to break down glycogen-->increase blood glucose; promote protein synthesis (IGFs); break down fat
Describe the process of TH production; which form of TH is most active? Which form is produced in greatest volume?
Iodide is actively transported into the follicle and moved to the colloid; there it becomes iodine
Thyroglobulin is synthesized by the ER and exported to the colloid; there it is broken into tyrosines
Iodine attaches to tyrosines to make DIT (1 tyrosine, 2 iodines) and MIT (1 tyrosine, 1 iodine)
DIT + DIT = T4, thyroxine = less active, most produced
DIT + MIT = T3 = more active, less produced
T4 and T3 are exported, combined with lysosomes to cleave the hormones from the colloid, and sent into the blood
What are some factors that can oppose insulin?
Sympathetic nervous system
Glucagon
Epinephrine