Neuroendocrinology Flashcards
What are neuroendocrine cells
Neurosecretory cells that release signal molecules from synaptic terminals into the blood
Controlled by synaptic transmission from pre synaptic neurons
Parvocellular nuclei
Cluster of neurons in the hypothalamus
Involved in stress response , release CRH which stimulates ACTH from pituitary gland which causes adrenal gland to release cortisol
Regulate blood pressure , heart rate ,gastrointestinal mobility
Regulate oxytocin , vasopressin
Magnocellular nuclei
-cluster of large cell bodies of neurons found in the hypothalamus
-synthesise and release oxytocin and vasopressin
Project to posterior pituitary and release to capillaries supplied by inferior hypophysial artery
What are the posterior pituitary hormones
Oxytocin and vasopressin
How are hormones stored in the hypothalamus and released
- stored in the hypothalamic neuron terminals , released under neural control into hypophysial capillaries
What hormones increase Endocrine control of growth hormone secretion
-GH releasing hormone from hypothalamic Parvocellular neuroendocrine cells
Ghrelin secreted by the endocrine cells of the stomach
What hormones decrease endocrine control of growth hormone secretion
GH Inhibiting hormone aka somatostatin
Stimulators factors controlling GH secretion
-GHRH
-ghrelin
-hypoglycaemia
-fasting
Sleep
Exercise
Stress
Inhibitory factors that affect GH secretion
-somatostatin
-GH
-hyperglycaemia
-increased fatty acids
-IGF-1
GH action
-stimulates production of IGF-1
- increases lipolysis
-increases Gluconeogenesis
-increases amino acid uptake into muscle :protein synthesis
-stimulates chrondocytes: linear growth
-stimulates somatic growth: increased organ size
What acromegaly
-excess growth hormone
-due to pituitary adenoma : increase in GH secreting somatotropes
-less common secondary :tumour elsewhere secretes GHRH
Metabolic consequences of acromegaly
-excess GH leads to insulin resistance
-impaired glucose tolerance
-hyperinuslinemia
-dyslipidaemia
