Endocrine - Hypothalamus and Pituitary Glands Flashcards
What does the Hypothalamus Secrete?
Dopamine
TRH
CRH
GnRH
GHRH
SS
Where is the hypothalamus?
Above the pituitary gland
Neural Tissue
What is the function of the hypothalamus?
Integrates sensory stimuli about heat, light, and BP, etc.
Communicates with pituitary to direct physiological responses
Releasing hormones secreted into a portal capillary bed stimulate cells the anterior pituitary gland
Define
Supraoptic nuclei (SON) and Paraventricular nuclei (PVN)
What are they? Where are they?
Collections of neurons that project to the posterior pituitary gland (neural communication)
Tumors in the anteror pituitary can cause vision loss due to…
compression of the optic chiasm
What is the function of the Posterior Pituitary Gland?
Extension of the hypothalamus
Hormones synthesized in hypothalamus travel through axons to the posterior pituitary gland
APs stimulate release of hormones from posterior pituitary
What happens once hormone release is stimulated in posterior pituitary?
APs stimulate the release of hormones from the posterior pituitary gland into the vascular capillary bed
Hormones travel through the bloodstream to target organs
Define
Magnocellular
Cell bodies found in the hypothalamus synthesize hormones
What hormones are released from the Posterior Pituitary?
Oxytocin
ADH
What is the function of Oxytocin?
Uterine muscle contraction during birth and contraction of myoepithelial cells in breath
Why is oxytocin released?
Birth - in response to cervical stretch
Suckling of nipple for milk
What is the function of ADH?
Water reabsorption in the kidney to ↑ water in plasma → ↑ BP, ↓water in urine
What kind of feedback loop is the release of oxytocin?
Positive
Why is ADH released?
↓BP
↑Plasma osmolarity
Dehydration
Parvocellular Neurons
In the hypothalamus
Secrete releasing hormones into the hypothalamohypopyseal portal vessels
What is the function of the Anterior Pituitary?
Releasing hormones secreted into the hypothalamohypopyseal portal vessels stimulate anterior pituitary cells to release different tropic hormones into the bloodstream that travel to target organs to stimulate secretion of other hormones
What does the Anterior Pituitary Gland secrete?
FSH
LH
ACTH
TSH
Prolactin
I (Ignore)
GH
FLAT PIG
What needs to happen to hormones released from the anterior pituitary because they are peptide/protein hormones?
They need to bind to receptors located in the cell membrane of target cells
They will also elicit responses quickly in target cells (often stimulating release of hormone containing vesicles)
What is unique about GH and Prolactin?
Both have negative inhibitors
↓ negative regulator → remove inhibition → ↑ prolactin or GH
Gonadotrope produces _ and stimulates _
FSH or LH
Gonads
Thyrotrope produces _ and stimulates _
TSH
Thyroid Gland
Corticotrope produces _ and stimulates _
ACTH
Adrenal cortex
Lactotrope produces _ and stimulates _
Prolactin
Mammary Gland
Somatotrope produces _ and stimulates _
GH
Somatic Cells (to grow)
Hypothalamic pathway of dopamine
The hypothalamus secretes dopamine which…
Inhibits the release of prolactin from the anterior pituitary gland
Prolactin will stimulate the breast to produce milk
↑ Dopamine → ↓prolactin seceion and milk production