Lec 6 Flashcards
Complex neuroendocrine reflex
Stimulate endocrine cells which reaches the final target (different levels of complexity)
Simple endocrine reflex
High plasma levels act on the beta cells in the pancreas which then releases insulin into the muscles, leading to glucose uptake and decrease in plasma
Neuroendocrine first order
The neurosecretion acts directly as a hormone
Neuroendocrine first order example (oxytocin)
Stimulus leads to neural integration of the hypothalamus and posterior pituitary, the neurohormone oxytocin is created and moved along the blood towards the target tissue (mammary glands)
Is the human/animal neuroendocrine pathway the same?
Yes
Neuroendocrine second order
Neurohormone is a releasing factor for the endocrine which then acts on the final target- effector hormone
Neuroendocrine third order order
Neurohormone is a releasing factor for an endocrine cell, which is a releasing factor acting on a second endocrine cell, that releases the effector hormone
Usually with hormones from anterior pituitary
Hypothalamic-pituitary axis
Major interface between the brain and endocrine system
Neurons in the hypothalamic-pituitary axis
Neurons synthesize trophic neurohormones and release them into capillaries of the portal system
Portal veins
Carry the trophic neurohormones directly to the anterior pituitary, where they act on endocrine cells
Endocrine cells
Release the hormones into the second set of capillaries for distribution to the rest of the body
Anterior pituitary
Produce and secrete hormones
Posterior pituitary
Extensions of neural tissue and secretes neurohormones produced in the hypothalamus
Posterior pituitary-store and release
Oxytocin and vasopressin (peptide neurohormones)
Vasopressin
ADH—>Kidneys (important for water balance)
Stimulus: Osmotic concentration/ blood volume
