Lecture 08: Hypothalamic-Pituitary Axis & Hormones

What is the hypothalamus composed of

Clusters of neuron cell bodies

What is a region of neuron clusters called

Hypothalamic nucleus

What does the hypothalamus control

Repro cycles, pregnancy, lactation, growth, stress response, temperature regulation, water balance, sleep, emotions

List the lobes of the pituitary gland

* Anterior pituitary/adenohypophysis
* Posterior pituitary/neurohypophysis

When in fetal development does the pituitary differentiate

Before bone and cartilage development

What tissue does the neurohypophysis differentiate from

Diencephalon

What tissue does the adenohypophysis differentiate from

Rathke’s pouch, from the soft palate tissue

Describe the purpose of the hypothalamo-hypophyseal portal system

The portal system allows the hypothalamus, consisting of brain tissue an neurons, to communicate across the blood brain barrier with the anterior pituitary, which consists of glandular tissue and blood vessels.

List the two capillary beds of the hypothalamo-hypophyseal portal system

* primary portal plexus
* secondary portal plexus

What connects the two capillary beds of the hypothalamo-hypophyseal portal system

Hypophyseal portal veins/vessels

Characteristics of a peptide hormone

* small, low molecular weight
* made of amino acids
* joined by peptide bonds

What classes of hormones are released from the hypothalamus

Peptide hormones

Characteristics of a glycoprotein hormone

* large, high molecular weight
* 2 peptides joined by Van der Waals forces
* composed of the alpha and beta subunits
* alpha subunit is the same for all glycoprotein hormones
* CHO side chains on each subunit

What classes of hormones are released from the anterior pituitary

Peptide, glycoproteins

List the 6 adenohypophysis hormones

* FSH (glycoprotein)
* LH (glycoprotein)
* Prolactin (peptide)
* GH (peptide)
* ACTH (peptide)
* TSH (glycoprotein)