body water balance and diabetes insipidus A W7 Flashcards
area in brain sensitive to osmotic pressure? where is it located and what is it connected to?
osmoreceptor/osmosensor
floor of 3rd ventricle
thirst centre and 2 nuclei in hypothalamus (supraoptic and paraventricular)
where is ADH released and what does it act on?
ADH is released from the posterior pituitary gland and acts on the kidneys to regulate body water balance
thirst pathway?
deficit of water raises plasma osmolarity and plasma sodium, thirst is stimulated, higher centres alter behaviour so water is found and ingested
what can cause loss of thirst sensation?
hypothalamic damage
ADH release pathway?
increased plasma osmolarity causes ADH release from posterior pituitary
this acts on V2 receptors allowing increased urine concentration so water is retained by the kidney, causing decreased plasma osmolarity.
another name for ADH?
vasopressin
V1a receptors action?
vasopressor effects-
maintain blood volume and circulation
V1a receptors main site?
vascular/cardiac muscle
V2 receptors action?
appropriate water retention
maintain osmolality
V2 receptors main site?
distal nephon
V1b(V3) receptors action?
role in ACTH/stress responses
V1b(V3) main site?
anterior pituitary
OT receptors action?
uterine contraction at birth
OT receptors main site?
myometrium
different receptors affinity for AVP?
V2»V1>OT
