Osmoreceptor
An osmoreceptor is a
vascular organ of the lamina terminalis, and the subfornical organ. They contribute to osmoregulation, controlling fluid balance in the body.[1] Osmoreceptors are also found in the kidneys where they also modulate osmolality
.
Mechanism of activation in humans
Osmoreceptors are located in two of the circumventricular organs — the vascular organ of lamina terminalis (VOLT) and the subfornical organ. These two circumventricular organs are located along the anteroventral region of the third ventricle, called the AV3V region.[2] Between these two organs is the median preoptic nucleus, which has multiple nerve connections with the two organs, as well as with the supraoptic nuclei and blood pressure control centers in the medulla oblongata.[2]
The osmoreceptors have a defined functionality as neurons that are endowed with the ability to detect extracellular fluid
SNARE protein attached to the arginine-vasopressin (AVP) containing vesicle membrane. This causes the fusion of the vesicle with the neuronal post synaptic membrane. Subsequent release of AVP into the posterior pituitary gland occurs, whereby vasopressin is secreted into the blood stream of the nearby capillaries.[4]
Macula densa
The
Angiotensin II exerts system wide effects, triggering aldosterone release from the adrenal cortex, direct vasoconstriction, and thirst behaviors originating in the hypothalamus. This is commonly known as the renin-angiotensin-aldosterone system
.
See also
- Hypothalamus
- Vasopressin
- Baroreceptors
References
- S2CID 205504313.
- ^ OCLC 1129099861.)
{{cite book}}: CS1 maint: location missing publisher (link - ISBN 978-3-540-23735-8.
- ISBN 978-0-19-959254-8.
- ^ "The Urinary System". www2.highlands.edu.