Neuroendocrine System - 26 Flashcards
This structures is known as the “master regulator of homeostasis.”
Hypothalamus
What kind of info does the hypothalamus receive?
The hypothalamus receives descending information from the brain, ascending visceral and somatic sensory information, and chemosensory information.
What 5 things does the hypothalamus control?
Control of blood flow/volume Regulation of energy metabolism Regulation of temperature Regulation of reproductive function Coordination of responses to stress
How does the hypothalamus control blood flow/volume?
It controls adjustments to cardiac output, vascular tone, blood osmolarity, renal clearance and the urge to drink water/take in salt.
How does the hypothalamus regulate energy metabolism?
It monitors blood glucose levels and feeding behavior, digestive functions and metabolic rate.
How does the hypothalamus regulate temperature?
It alters the amount of thermogenesis and stimulates behaviors such as seeking colder or warmer environments (getting in shade)
How is the hypothalamus in control of of reproductive function?
It influences gender identity, sexual orientation, mating behavior and (in females) menstrual cycle, lactation and pregnancy.
How does the hypothalamus coordinate responses to stress?
It regulates the amount of stress hormones and controls the balance between sympathetic and parasympathetic activity.
What are the three regions of the hypothalamus?
Anterior, tuberal, and posterior regions
What is the most inferior part of the anterior region? What does it control?
Suprachiasmatic nucleus : circadian rhythm
What does the anterior hypothalamus do?
Integrates different types of sensory info to determine if there is a deviation from physiologic norm. Controls blood pressure/composition, body temp, reproductive activity, many hormone levels, and circadian rhythm
What are the important nucleus of the Tuberal hypothalamus?
Dorsomedial/ventromedial nucleus Paraventricular nucleus Arcuate nucleus/periventricular nucleus Supraoptic nucleus
What does the Dorsomedial/ventromedial nucleus do?
Projects within the hypothalamus to regulate complex integrative functions (growth, feeding, reproduction)
What does the Paraventricular nucleus do?
Controls the posterior and anterior pituitary gland. Contains neurons that innervate both the sympathetic and parasympathetic preganglionic neurons thereby controlling autonomic function.
What type of cells are contained within the paraventricular nucleus? What do they do?
Both magnocellular and parvocellular components control the posterior and anterior pituitary gland.
What kind of neurons are contained within the periventricular and arcuate nucleus?
Parvocellular neuroendocrine neurons
What kind of neurons are contained within the Supraoptic nucleus?
Magnocellular neuroendocrine cells
Remember this picture:
What are the main regions of the posterior hypothalamus?
the Mammillary body, Posterior hypothalamic region, and tuberomammillary nucleus.
What does the posterior hypothalamus do?
Not well understood
Tuberomammillary nucleus composed of histamineric neurons that control arousal and wakefulness
Name the structures
Name the structures
Where are Parvocellular endocrine neurons located?
In the paraventricular, periventricular, and arcuate nuclei
Where are magnocellular endocrine neurons located?
In the Paraventricular and Supraoptic nuclei
Where do the magnocellular endocrine neurons project to? What do they do?
Directly to the posterior pituitary gland
They release neuropeptides directly into the bloodstream
What are the two kinds of Parvocellular cell types?
Parvocellular Neurons, and parvocellular autonomic neurons
What do parvocellular endocrine neurons do?
They project to the “portal vasculture” of the anterior pituitary gland. Release their neuropeptides through the portal blood system, down to the pituitary, that then produce/release their own hormones
Parvocellular endocrine neurons control the endocrine system ____________ by secreting regulatory hormones into the _______________________, which feeds the anterior pituitary.
Indirectly : local portal circulation
Magnocellular endocrine neurons control the endocrine system ___________ by secreting regulatory hormones into _________________.
Directly : the general circulation
What two neuropeptides are released by magnocellular neurons?
Oxytocin and vasopressin
What do the parvocellular endocrine neurons release?
Several releasing and inhibiting hormones
What do the parvocellular autonomic neurons release?
Oxytocin and vasopressin
Where do the parvocellular endocrine neurons project?
Anterior petuitary
Where do the parvocellular autonomic neurons project to?
The preganglionic autonomic neurons (medulla/spinal cord)
How are the parvocellular autonomic neurons different from the magnocellular endocrine neurons since they both release oxytocin and vasopressin?
The PAneurons release them into a synapse and they act as a neuropeptides.
the magnocellular release them into the bloodstream as a hormone.
What does vasopressin do when released by the magnocellular endocrine neurons?
Vasoconstriction, water resorption by the kidneys (^blood pressure)
What does oxytocin do when released by magnocellular endocrine neurons?
Uterine contraction and milk ejection
What 2 neuropeptides are released from the parvocellular endocrine neurons?
TRH - thyrotropin-releasing hormone, and CRH - corticotropin-releasing hormone
What is thyrotropin?
Thyrotropin - TSH - Thyroid stimulating hormone : stimulates release of thyroid hormones from the thyroid gland : enhances metabolism and grown.
What is adrenocorticotropin?
ACTH - Stimulates the production of mineralo- and gluco-corticosteroids from the adrenal gland and promotes release of androgenic steroids
What does the fact that humans maintain the same body weight for years show?
Feeding behavior is subject to a control mechanism.
What types of things can alter the “set point” of a person’s body weight?
Stress, exercise, palatability of food
What portion of the brain controls feeding?
The hypothalamus controls part of it.likely several nuclei
What hormones regulate feeding?
Ghrelin, Leptin, and POMC
What is ghrelin?
A hormone that is secreted by the stomach prior to feeding; signal for hunger
What is leptin?
A hormone secreted by adipocytes following feeding; signal for satiety
What is POMC? What is one of its neuropeptides?
Pro-opiomelanocortin; secreted by hypothalamic cells in response to ghrelin and leptin : Alpha-MSH
What is Alpha-MSH? WHat is its receptor?
A neuropeptides encoded by POMC; regulates satiety via binding to its receptor : MCR4
Where is MCR4 found?
Several brainstem nuclei
