Week 3: Hypothalamus and pituitary micro anatomy

Question 1

pituitary gland development

Answer 1

• anterior pituitary from ectoderm, develops from protrusion from roof of mouth called Rathke’s pouch
• posterior pituitary from brain tissue and is directly connected with the hypothalamus

Question 2

posterior pituitary (aka pars nervosa )

Answer 2

• oxytocin mainly made in paraventricular nucleus
• vasopressin made mainly in supraoptic nucleus in hypothalamus
• cell types: pituicytes (glial cells)
• herring body: bulging part of nerve axon that contains secretory vesicles

Question 3

pars intermedia

Answer 3

• tissue next to pars nervosa and pars distalis
• contains large pale cells that often surround follicles filled with colloid
• can contain cysts
• pars intermedia makes melanocyte stimulating hormone

Question 4

anterior pituitary cell types

Answer 4

• acidophils: most numerous cell type in anterior pituitary. Includes somatotrophs (release GH) and lactotropes
• basophils: B FLAT: FSH, LSH (gonadotrophs), ACTH (corticotrophs), TSH (thyrotrophs)
• chromophobes: have little staining in cytoplasm, represent degranulated or resting acidophils and basophils

Question 5

Hypothalamic-hypophyseal portal system

Answer 5

• the median eminence (below the optic chasm) is supplied by superior hypophyseal artery
• this vessel branches to form capillaries of median eminence, and they converge for form portal veins that branch out to form secondary capillaries that supply the anterior pituitary
• releasing hormones from hypothalamus secrete into the capillaries of median eminence