Chapter 16 Flashcards
Target cells specificity
target cells must have specific receptors to which hormone binds
Target cell activation depends on three factors
- blood levels of hormone
- relative number of receptors on/in target cell
- affinity (strength) of binding between receptor and hormone
Up-regulation
target cells form more receptors in response to low hormone levels
Down-regulation
target cells lose receptors in response to high hormone levels
Glucagon is a
peptide hormone
Glucagon causes the liver to convert
stored glycogen into glucose
Hormone receptor
a protein in the cell membrane, or within the cytoplasm or nucleus, to which a hormone specifically binds to trigger its actions on a target cell
What does the posterior pituitary consist of?
axon terminals of neurons from hypothalamic neurons
Oxytocin
example of positive-feedback control mechanism
Antidiuretic hormone (ADH)
inhibited by alcohol, caffeine, diuretics
-high concentration cause vasoconstriction, so also called vasopressin
The posterior pituitary releases two hormones produced in the hypothalamus
ADH (restricts water loss) and oxytocin (stimulates contractions in mammary glands and uterus, and the prostate gland)
Thyroid Gland
increases metabolism and heat production (calorigenic effect)
If TH’s are decreased
means hypothyroidism, therefore TSH is high
If TH’s are elevated
means hyperthyroidism, therefore TSH is low
The parathyroid glands
- chief cells produce parathyroid hormone
- low blood Ca2+ triggers secretion
- PTH raises blood Ca2+
