3 Hypothalamus Pituitary Flashcards
(49 cards)
Which endocrine gland sits at the base of the brain in the sella turcica of the sphenoid bone?
Pituitary gland
T/F: The neurohypophysis receives blood from a branch of the Superior Hypophyseal Artery.
F; the adenohypophysis receives blood from a branch of the Superior Hypophyseal Artery.
Which vessels connect the primary and secondary hypophyseal plexuses?
Long hypophyseal portal veins
What are the main functions of the hypophyseal portal system?
1) facilitate communication between hypothalamus and anterior pituitary
2) allow high concentrations if hypothalamic inhibiting and releasing hormones to reach anterior pituitary
What are synaptosomes?
Neurosecretory granules in the nerve terminals of hypothalamic neurons that store releasing and inhibiting hormones.
After stimulation of hypothalamic cells, releasing or inhibitory hormones are discharged into the _____ and enter the capillary plexus.
Median eminence
T/F: The intermediate lobe of the pituitary gland is absent in humans but present in lower animals.
T
The anterior and posterior lobes of the pituitary gland are also known as…?
Anterior = adenohypophysis, posterior = neurohypophysis
What are the five types of specialized secretory cells in the adenohypophysis?
Somatotrophs, mammotrophs, corticotrophs, gonadotrophs, thyrotrophs
Which of the five specialized secretory cells in the adenohypophysis is most abundant?
Somatotrophs, 40 - 50% of cells
Which of the five specialized secretory cells in the adenohypophysis is least abundant?
Thyrotrophs, 3-5% of cells
Which of the five specialized secretory cells in the adenohypophysis secretes prolactin?
mammotrophs/lactotrophs
What hormone(s) do gonadotrophs secrete?
LH and FSH
What hormone(s) do somatotrophs secrete?
Growth hormone
What is the most common pituitary tumor?
prolactinoma
T/F: tropic hormones regulate the secretion of hypothalamic releasing and inhibiting hormones.
F; the opposite is true
Which hormone stimulates the release of ACTH?
Corticotropin-releasing hormone
Which hormone tonically inhibits prolactin (PRL) release?
Prolactin inhibitory factor, AKA dopamine
T/F: hypothalamic releasing hormones are generally secreted tonically.
F: they are secreted in pulses.
Do hypothalamic hormones act on cytoplasmic or membrane receptors?
Membrane receptors
T/F: hypothalamic releasing hormones can only stimulate the release of stored target hormones via exocytosis and do not affect hormone synthesis.
F; hypothalamic releasing hormones both stimulate the release of stored target hormones via exocytosis and stimulate systhesis at the transcriptional level.
T/F: hypothalamic releasing hormones can modify the biological activity of target hormones by post-translational effects such as glycosylation.
T
T/F: hypothalamic releasing hormones cannot modulate their effects by up- or down-regulation of their receptors.
F
What are the two classifications of feedback signals that influence the Hypothalamic-pituitary axis
Humoral and neural feedback