29 Questions
Where is the pituitary gland located?
In a pocket of the sphenoid bone at the base of the brain
What is the function of the pituitary gland?
To act as a coordinating center for control of many downstream endocrine glands
Which hormone produced by the anterior pituitary acts on the breast?
Prolactin
What is the function of the tropic hormones produced by the anterior pituitary?
To stimulate the secretion of hormonally active substances by other endocrine glands
Which blood vessels supply the anterior pituitary?
Portal hypophysial vessels
What is the name of the structure immediately below the hypothalamus that the portal hypophysial vessels pass through?
Median eminence
What is the function of oxytocin in the posterior pituitary?
Helping with contractions of the uterus and milk ejection during breastfeeding
What is the function of vasopressin in the posterior pituitary?
Regulating water levels in the body
What is the name of the molecule that regulates skin pigmentation in the intermediate lobe of the pituitary?
Proopiomelanocortin (POMC)
What type of cells in the anterior pituitary secrete growth hormone?
Somatotropes
What type of cells in the anterior pituitary secrete prolactin?
Lactotropes
How many types of secretory cells have been identified in the anterior pituitary?
Five
Which chromosome contains the growth hormone-hCS cluster?
Chromosome 17
What is the function of human chorionic somatomammotropin (hCS)?
Regulation of growth and development
What is the primary difference between hGH-N and hGH-V?
Variant form of growth hormone
What is the significance of the complex mixture of growth hormone peptides in the circulation?
It makes it difficult to assay for each species separately
What is the relationship between the various peptides derived from hGH-N?
They have similar functions but can exert opposing actions
What is the characteristic of human chorionic gonadotropin (hCG)?
It has α and β subunits
Before birth, what stimulates the secretion of IGF-I?
None of the above
What is the highest concentration of IGF-I typically reached?
At the time of puberty
In which organs is IGF-II expressed in adults?
Choroid plexus and meninges
What happens when IGF-II is overexpressed in human fetuses?
Several organs develop out of proportion to the rest of the body
What is the primary role of IGF-II during fetal development?
Growth regulation before birth
What percentage of the circulating pool of growth hormone activity is in the bound form?
50%
What is the approximate half-life of circulating growth hormone in humans?
6-20 min
What is the estimated daily growth hormone output in adult humans?
0.2-1.0 mg/d
What is the primary source of hGH-V and hCS in the circulation?
Placenta
What is the function of the plasma protein that binds to growth hormone?
It provides a reservoir of growth hormone to compensate for fluctuations in secretion
What is the structure of the growth hormone receptor?
A 620-amino-acid protein with a large extracellular portion, a transmembrane domain, and a large cytoplasmic portion
Learn about the pituitary gland, its function, and the hormones it secretes, including thyroid-stimulating hormone and adrenocorticotropic hormone. Understand its role in controlling downstream endocrine glands.
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