AVP, Oxytocin, Growth hormones and Pituitary Flashcards
what is the master gland of the endocrine system?
the pituitary gland
what does the pituitary gland do?
It integrates signals and releases hormones that regulate the function of other endocrine glands
what drives the pituitary gland?
the hypothalamus
what are the 2 parts of the pituitary gland called?
- posterior neurohypophysis
2. anterior adenohypophysis
what does the neurohypophysis do?
stores & secretes hormones synthesised in the hypothalamus e.g. oxytocin, ADH
what does the adenohypophysis do?
synthesises and secretes hormones in response to hypothalamic regulation e.g. TSH, ACTH, FSH, LH, GH, PL
what does the 2 hormones released by the posterior neurohypophysis regulate?
- ADH (antidiuretic hormone)/vasopressin = regulates renal function
- Oxytocin = regulates uterine contraction
how many peptides in the posterior pituitary hormones?
9 amino acids
how does the posterior pituitary regulate renal function?
- Low blood pressure is detected by baroreceptors and high osmolarity is detected by osmoreceptors
- ADH is released from the pituitary in response
- V2 receptors in distal tubule of kidneys detect ADH and cause water reabsorption
- V1 receptors on smooth muscle also detect the ADH and cause vasoconstriction to increase blood pressure
what do we use to treat someone with too little ADH?
V2 agonists e.g. lypressin or desmopressin
what do we use to treat someone with too much ADH?
V2 antagonists e.g. demeclocycline or tolvaptan
how does the posterior pituitary regulate uterine contraction?
- Descent of foetus activates stretch receptors in uterus and high levels of oestrogen before birth increases oestrogen receptor number
- pituitary gland releases oxytocin
- uterus detects oxytocin causing uterine contraction (labour induction)
how does oxytocin control lactation?
- Suckling infant activates sensory receptors around nipples
- pituitary gland releases oxytocin
- Contraction of myoepithelial cells
(milk let down)
what are the 6 anterior adenohypophysis hormones?
- Thyroid stimulation H. (TSH)
- Adrenocorticotrophic H. (ACTH)
- Follicle stimulating H. (FSH)
- Lutenising H. (LH)
- Growth H (GH)
- Prolactin (PL)
what controls/regulates the release of the 6 anterior pituitary hormones?
hormones from the hypothalamus aka Hypothalamic releasing factors
what are the tropic pituitary hormones?
- Thyroid stimulation H. (TSH)
- Adrenocorticotrophic H. (ACTH)
- Follicle stimulating H. (FSH)
- Lutenising H. (LH)