Neuroendocrine System Flashcards
What are the relay pathways of Hypothalamus
Nucleus of solitary tract Brain stem reticular formation Retina Limbic and Olfactory system
What are the controlled parameters of the Hypothalamus?
Digestion Body temperature control Circadian rhythm Feeding and Reproduction
What are the physiological functions of Hypothalamus?
Growth Metabolism Stress response Osmoregulation Thermoregulation Reproduction Circadian rhythm
What are the roles circumventricular organs?
Important sensory organs - provide input to Hypothalamus Allow secretion of hypothalamic hormones and their regulation by target tissue hormone (median eminence and pituitary gland)
What are the outputs if hypothalamus?
Limbic system Thalamus Reticular formation Autonomic NS Pituitary gland
What are the 3 subdivision of the hypothalamus?
Anterior/preoptic Tuberal Posterior
What are the 3 longitudinal zones of the hypothalamus?
Periventricular Medial Lateral
What structures are found within contextual information?
Cerebral cortex Amygdala Hippocampal formation
What are the main roles of hypothalamus ?
Homeostatic control Compare inputs with biological set points Coordinate occurrence and timing of physiological function
What are the inputs to the hypothalamus ?
Telencephalic input — retinal to SCN Fornicate - Hippocampus Medial forebrain bundle Dorsal longitudinal fasciculus - brainstem
And spinal cord Stria termanlis - amygdala
What is thermosensing?
Neurons that directly sense stimuli in the hypothalamus
What are the nucleus of hypothalamus
Periventricular nucleus Dorsomedial nucleus Lateral hypothalamus Supraoptic nucleus Ventromedial nucleus Arcuate nucleus Suprachiasmatic nucleus Median eminence
What mediates neuroendocrine regulation?
Pituitary gland
What are the two parts of pituitary gland?
Anterior lobe - adenohypophysis;pars distalis Posterior lobe - neurohypophysis:Pars nervosa
Where are parvocellular neurons found?
Periventricular nucleus Paraventricular, actuate nucleus and Medial preoptic nucleus
What are ultradian patterns?
Repeated period within 24hr circadian day
What does the paraventricular nucleus of the hypothalamus secrete?
Corticotropin-releasing hormone
What does corticotropin-releasing hormone release?
Adrenocorticotropic hormone
What does ACTH cause the release of?
Glucocorticoid
What are Glucorticoid?
Steroids that bind nuclear transcription factor receptors
Where does cortisol bind?
Neurosecretory cells in the PVN and on corticotrophs to decrease stimulation of its release
What does Glucocorticoid interact with?
Endocrine systems and immune system
When is the highest level of cortisol seen?
Morning
Why is glucorticoid important in neural function?
Hippocampal granule cell survival and neurogenesis Learning and memory
What is the circadian rhythm dependent upon?
Suprachiasmatic nucleus
What does CRH stimulate the release of?
Thyroid stimulating hormone (TSH; thyrotropin)
What does TSH cause the release of?
Thyroid hormone from thyroid gland
What does Thyroid hormone stimulate the decrease of?
TRH and TSH
What does thyroid hormone regulate?
Basal metabolism: cellular ATP, protein synthesis
What does arcuate nucleus secrete?
Growth hormone releasing hormone (GHRH)
What does periventricular nucleus secrete?
Somatostatin
Where are GH and insulin-like growth factor (IGF-1) made?
Liver
What does growth hormone stimulate?
Somatic (body) growth, regeneration and body homeostasis (tissues like bone and muscle)
When is GH released?
Sleep
What does anterior and Medial basal hypothalamus secrete?
Gonadotropin releasing hormone (GnRH)
What does GnRH stimulate the release of?
LH and FSH
What do LH and FSH do?
Secretion of sex hormones from ovaries and testes
Why is sex hormone important?
Development Expression of secondary sex characteristics Adult reproductive function
What do neurons in the arcuate nucleus secrete?
Dopamine
What does dopamine do?
Inhibit secretion of prolactin from anterior pituitary gland through dopamine D2 receptor
How is the inhibition of prolactin relieved?
Lactation in response to suckling
Where does prolactin act on?
Mammillary gland to stimulate the development of gland and production of milk
What does the Magnocellular neurons produce?
Neuroendocrine peptide: arginine vasopressin(AVP), anti-diuretic hormone (ADH) and oxytocin
Where are hormones of magnocellular neurons transported down?
Axons in the pituitary stalk
Where are the hormones of magnocellular neurons stored?
Terminals in the Posterior pituitary gland
Upon neural stimulation of neuroendocrine cells where are the hypothalamus hormones secreted?
Capillaries of Posterior lobe
What mediate the neuroendocrine release from Posterior pituitary gland?
Paraventricular nucleus (PVN) and Supraoptic nucleus (SON)
What does vasopressin regulate?
Osmoregulation Water/salt balance Social behaviours
What does oxytocin regulate?
Parturition Milk ejection Social behaviours
What is parturition?
Uterine contraction at labour
How many a.a is AVP and OXT?
9 a.a
Are AVP and OXT transcribed from same gene?
Yes
Are AVP and OXT secretion pulsatile and what does it depend on?
No and neural stimulation in response to changes in osmolality/blood volume - nipple/genital stimulation
What does the Posterior pituitary hormone provide a quick response to?
Haemorrhage and suckling stimuli
What does angiotensin II stimulate the neurons of?
Subfornical organ (SFO)
What does dendritic release if OT coordinate?
Neuroendocrine secretion
What does projection to the preoptic area and amygdala mediate?
Social and maternal behavioural effect
What does Vagal stimulation during labour stimulate?
Increased oxytocin secretion; uterine contraction
What neurons detect changes in osmolality?
OVLT and PVN/SON
