Pituitary Function and Failure Flashcards
What is the hypothalamic hypophyseal portal system?
the vascular link between the hypothalamus and the anterior pituitary
What is the advantage of the hypothalamic hypophyseal portal system?
less hormone secretion is required and the hormones are transported directly
What is the difference between the anterior and posterior pituitary?
the posterior pituitary is nervous tissue with a neural link to the hypothalamus, the anterior pituitary is glandular epithelial tissue with a vascular link to the hypothalamus
What is the infundibulum?
the stalk which connects the pituitary to the brain
What are the anterior pituitary hormones?
ACTH, prolactin, GH, TSH, LH and FSH
What are the posterior pituitary hormones?
vasopressin and oxytocin
Which nuclei in the hypothalamus control posterior pituitary?
supraoptic and paraventricular
Which nuclei in the hypothalamus control anterior pituitary?
arcuate and other
Which hypothalamic hormone stimulates release of prolactin?
PRFs
Which hypothalamic hormone stimulates release of TSH?
TRH
Which hypothalmic hormone stimulates release of ACTH?
CRH
Which hypothalamic hormone stimulates release of GH?
GHRH
Which hypothalmic hormone stimulates release of FSH and LH?
GnRH
What is the target tissue of ACTH?
adrenal cortex to release cortisol
What is the target tissue of TSH?
thyroid gland to release thyroid hormones
What is the target tissue of LH and FSH?
gonads to release sex steroids
What is the target tissue of prolactin?
breasts for growth and milk secretion
What is the target tissue of GH?
the liver to produce IGF
What alters hypothalamic control?
senses, stress, growth, emotion, diurnal and circardian rhythm
What is growth?
the lengthening of long bones, net synthesis of protein and increase in size and number of cells in soft tissue
What are the requirements for growth?
growth hormone, genetic determination, diet, absence of chronic stress and disease, growth influencing hormones
Where is growth hormone from?
the anterior pituitary
What is the chemical structure of growth hormone?
peptide
How is growth hormone transported in circulation?
half free half bound to a plasma protein
What is the action of growth hormone?
bone and cartilage growth, soft tissue growth, increase in plasma glucose
What are somatomedins?
insulin like growth factors I and II
What is somatostatin?
growth hormone inhibiting hormone produced by the hypothalamus
What is somatotropin?
growth hormone
Which hormone plays a permissive role in growth?
thyroid hormone
Which hormone closes epiphyseal plates of long bones?
oestrogen
What is Laron dwarfism?
growth hormone insensitivity
What is acromegaly?
overproduction of growth hormone as an adult
