HP axis Flashcards
What forms the link between the nervous and endocrine system?
Hypothalamus
Pituitary gland
Where is the hypothalamus located?
Base of brain
Where is the pituitary gland located?
Below hypothalamus
What structure contains the pituitary gland?
The sella turcica - socket of bone
What is the pituitary gland made up of?
Anterior pituitary gland
Posterior pituitary gland
Which is physically connected to the hypothalamus - the anterior or posterior pituitary?
The posterior pituitary gland
How is the posterior pituitary gland connected to the hypothalamus?
By the infundibulum - stalk-like structure
What is the anterior pituitary physically connected to then?
The posterior pituitary
What does the anterior pituitary gland arise from? And how?
Oral ectoderm - primitive gut tissue
Upwards growth
What does the posterior pituitary gland arise from? And how?
Neuroectoderm - primitive brain tissue
Downwards growth
What are the hormones produced by the hypothalamus?
Oxytocin
ADH
TRH
CRH
GnRH
PRIH
GHRH
GHIH
What exactly in the hypothalamus produces oxytocin and ADH?
By the supraoptic and paraventricular nuclei
Which of these hormones are transported to the posterior pitutary gland?
Oxytocin
ADH
What does the posterior pituitary gland do with oxytocin and ADH?
Stores them
releases them when stimulated
How does the posterior pituitary gland release oxytocin and ADH?
Neurocrine secretion
What does oxytocin do?
Milk let down
Uterus contractions during birth
What does ADH do?
Increase aquaporin expression in kidneys
increase reabsorption of water
The other hormones that the hypothalamus produces are called … hormones? Why?
Tropic hormones
because they affect the secretion of hormones from the anterior pituitary gland
What happens once the hypothalamus has synthesised the tropic hormones?
Transported down nerve axons
stored in median eminence
How does the hypothalamus release the stored tropic hormones from the median eminence?
When stimulated to do so
releases them into hypothalamo-hypophyseal portal system
What does thyrotropin releasing hormone TRH do?
Stimulates release of TSH from anterior pituitary
Also minor release of prolactin from anterior pituitary
What does corticotropin releasing hormone CRH do?
Stimulates release of ACTH from anterior pituitary gland
What does gonadotropin releasing hormone GnRH do?
Stimulates release of leuteinising hormone LH and follicle-stimulating hormone FSH from anterior pituitary
What does prolactin-release inhibiting hormone PRIH do?
Inhibit release of prolactin from anterior pituitary
