Hypothalamus Pathways

Question 1

Hypothalamic control of the anterior pituitary —> what two nuclei are involved

Answer 1

Parvocellular endocrine cells from the Paraventricular nucleus and Arcuate Nuclei

Question 2

Where do the two nuclei terminate once they leave the neuroendocrine cells?

Answer 2

terminate in the primary capillary plexus of the superior hypophyseal artery in the infundibulum

Question 3

Once the nuclei terminate in the primary capillary plexus what is released?

Answer 3

Neuroendocrine substances are released into the primary capillary plexus which drains into the portal vein.

Question 4

In the adenohypophyseal pathway where does the portal vein lead?

Answer 4

leads the blood flow toward the anterior pituitary and into a second capillary plexus

Question 5

once blood flow is in the second capillary plexus, what happens in the adenohypophyseal pathway

Answer 5

Neurohormones controlling the anterior pituitary will either induce or inhibit hormone release from the AP

Question 6

What are the hormones of the anterior pituitary??

Answer 6

Thyrotropin releasing hormone (TRH) —> Thyroid Stimulating hormone (TSH) —> Thyroid gland T3,T4, secretion
Corticotropin Releasing Hormone –> Adrencorticotropic Hormone ( ACTH) –> Steroid production in adrenal cortex (under stress and releases cortisol)
Gonadotropin releasing hormone (GnRH) —> Luteinzing (LH) and Follicle stimulating (FSH) hormone –> Sex steriods
GHRH and inhibiting hormone Somatostain —>Growth Hormone (GH) —> Linear Growth
Prolactin inhibiting hormone (Dopamine) —>Prolactin —> Lactogensis

Question 7

Hypothalamic control of the posterior pituitary —> what nucleus are involved?

Answer 7

Magnocellular neuroendocrine cells from the paraventricular and supraoptic nucleus send axons directly to the posterior pituitary called the supraoptico-hypophyseal tract

Question 8

In the neurohypophyseal pathway where do the neuroendocrine cells release their neurohormones?

Answer 8

into capillaries of the inferior hypophyseal artery thus entering the circulation

Question 9

In the neurohypophyseal pathway how to neurohormones reach their target tissues?

Answer 9

via the circulation

Question 10

what are the two hormones of the posterior pituitary?

Answer 10

ADH (vasopressin) —> vasoconstriction, water resorption in kidney
Oxytocin —> uterine contraction and milk ejection