L51 - Neuroendocrine Regulation And The Pituitary FINISH Flashcards
What is the neuroendocrine system like?
modified neuronal secretory cells to release hormones
What is the hypothalamus? (4)
- at base of the brain
- receives many inputs
- secretes multiple hormones to control homeostatic functions
- uses pituitary gland as an output organ
What is the secretion of hormones like of HPA? (6)
- hypothalamus - released by supraoptic/ paraventricular nuclei/ neuroendocrine regulation
- posterior pituitary synapse to blood vessels (release hormones to blood)
- to median eminence - stores releases
- blood travels hypothalamo-hypophyseal portal vessels
- anterior to venous circulation and heart
- posterior pituitary to venous circulation and heart
What are the connections of the hypothalamus? (2)
- paraventricular nucleus of the hypothalamus
- suprachiasmatic nucleus of the hypothalamus
What does the paraventricular nucleus if the hypothalamus do? (2)
- neuroendocrine role - secretes CRH, TRH
- integrates sympathetic and parasympathetic output - controls ANS activity
What does the suprachiasmatic nucleus of the hypothalamus do? (2)
- receives light input from retina
- synchronises circadian rhytms in light dark cycle
What are the endocrine functions of the hypothalamus?
- indirect - release of regulatory hormones - to anterior pituitary - release of RH and primary H - target endocrine cells
- direct - release PH oxytocin and ADH directly onto posterior pituitary
What are the different types of regulatory hormones?
- releasing factors
- inhibiting factors
What are the releasing factors regulatory hormones? (5)
- CRF - corticotropin rf (adrenal)
- TRH - thryrotropin rh (pituitary-thyroid hormone)
- GHRH - growth hrh (PH GH)
- GnRH - gonadotropin rh (pituitary-FSH, LH)
- PRF - prolactin rf (pituitary PH PRL)
What are the inhibiting factors regulatory hormones?
- GHIH - growth hih
- PIH - prolacting ih
- MSH-IH - melanocyte stimulating hih (hypothalamus controlled)
What is the anatomy of pituitary gland?
- hypothalamus
- pituitary stalk
- posterior pituitary, anterior pituitary
- pars nervosa - nerve like - ADH, oxytocin
- pars intermedia - MSH
- pars distalis - granulated - others
What are the different anterior pituitary hormones? (2)
- four trophic hormones
- two primary hormones
What are the four trophic hormones? (4)
- TSH - thyroid sh
- ACTH - adrenocorticotrophic h
- FSH - follicle sh
- LH - lutenising h
What are the 2 primary hormones?
- GH - growth h
- PRL - prolactin
What is hormone secretion by the anterior pituitary gland like? (5)
- hypothalamic neuron releases onto hypothalamo-pituitary portal vessels
- travels by vessel into anterior pituitary
- anterior pituitary releases hormone into capillaries
- venous outflow to heart
- (transport driven by arterial inflow from heart)
What is the secretion of hormones from HPA? (5)
- GnRH - LH, FSH, - testis, ovary
- TRH - TSH - thyroid
- CRF - ACTH - adrenal
- GHRH, SRIF (GHIH) - GH (somatropin) - multiple tissues
- PRF, PIH - PRL - breast
What is feedback control like in HPA? (3)
- hypothalamus -ve fb from hormone
- hypothalamus -ve fb from pituitary hormone
- anterior pituitary -ve fb from hormone
What are the effects of growth hormone? (4)
- inc cell size, num and differentiation
- stim protein synthesis
- stim fat utilisation
- alter carbohydrate metabolism
What are insulin-like growth factor? (4)
- IGF - polypeptide hormones primarily produced by liver, response to GH
- IGF-1 and GH at cell surface receptor tyrosine kinases
- long half life compared to GH
- IGF-1 important in bone growth
What is growth hormone like? (4)
- Polypeptide hormone that acts at a receptor tyrosine kinase
- IGF - acts via receptor tyrosine kinase
- GH binds to receptor - phosphorylated subunit
- causes chemical cascade
How does GH affect protein synthesis? (3)
- inc a/a uptake by transporter
- inc translation - inc protein synthesis
- inc transcription of specific gene in cell growth - inc ribosome - inc protein synthesis
What are the indirect and direct effects of GH? (3,3)
- indirect - growth effect - inc cell size, num, dif, inc protein synthesis, bone growth
- direct - metabolic effect - inc protein synthesis, fat breakdown, blood glucose
What is GH secretion like? (5)
- released in response to GHRH (regulated by)
- dec by GHIH or somatostatin (SST)
- released from ventromedial hypothalamus
- GH regulated by short feedback loop
- controlled by factors - sleep, exercise, stress
What is GH secretion like? (7)
- stimulus (exercise, stress, fasting, low plasma glucose, sleep
- hypothalamus - inc GRH sec, dec SST sec
- inc plasma GHRH, dec plasma SST
- anterior pituitary - inc GH secretion
- inc plasma GH
- liver and other cells - inc IGF-1 secretion
- inc plasma IGF-1
