Guyton And Hall Questions Flashcards
What is a neuroendocrine secretion?
Secretion of chemical messengers from neurons to blood.
Example of a neuroendocrine secretion?
Oxytocin. Stimulates breast and uterus.
Where are thyroid and peptide hormones stored?
In their endocrine producing glands.
Where are steroids stored and what is an example?
Not in endocrine producing glands. Like aldosterone, which is stored in adrenal cortex.
What is a paracrine secretion?
Cell secretions that diffuse into extra cellular fluid to affect neighboring cells.
What does aromatase do?
Cause conversion of testosterone to estradiol.
Describe peptide hormones.
Water soluble but not highly bound by plasma proteins, resulting in short half lives. Produce biological effects by binding to cell membrane receptors. Stored in secretion granules in endocrine producing cells.
Describe ADH.
A neurohypophyseal peptide hormone unbound by plasma proteins. Increases permeability of collecting tubules and ducts to water and not sodium, decreases water secretion and increasing urine concentration and diluting plasma.
Describe steroid and thyroid hormones.
Highly bound to plasma proteins.
What are ADH and oxytocin?
Peptides containing nine amino acids.
Why do peptide hormones have a more rapid onset than steroid and thyroid hormones?
Protein synthesis is not required.
Where is ADH synthesized?
Supraoptic and paraventricular nuclei of hypothalamus.
Where is inhibitory hormone somatostatin synthesized and stored?
Thalamus.
Where are TSH and LH synthesized and stored?
Anterior pituitary gland.
Where is ADH synthesized and stored?
Synthesized in hypothalamus but stored in posterior pituitary gland.
Where is somatomedin (IGF-1) synthesized?
Liver.
What is the function of testosterone in male embryo?
Formation of male sex organs.
What happens if FSH is blocked to serotoli cells of seminiferous tubules?
Sperm production inhibited.
Why would there be high testosterone in a female embryo?
Embryo has male genitalia. Mother could have adrenal tumor synthesizing testosterone at a high and uncontrolled rate.
Explain secretion of inhibin by Sertoli cells.
Sertoli cells secrete inhibin at a rate proportional to sperm cell production rate. Inhibits anterior pituitary FSH secretion.
What does FSH do in male reproductive system?
Binds to receptors of Sertoli cells to stimulate sperm production.