Wingfield 1

Hormone systems for osmoregulation pressor effects

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: st
phase
is
followed
by

 inappropriate
an=diuresis,
which
is

 caused
by
an
uncontrolled
release

 of
AVP
into
the
bloodstream
from
the
 degenera=ng
nerve
terminals
in
the

 posterior
pituitary.
A>er
all
of
the
AVP
 stored
in
the
posterior
pituitary
gland

 has
been
released,
a
third
phase
of
 diabetes
insipidus
develops
.
 Loh
JA
and
Verbalis
JG
(2007)
Diabetes
insipidus
as
a
complica=on
a>er
pituitary
surgery 
 Nat
Clin
Pract
Endocrinol
Metab
3:
489–494
doi:10.1038/ncpendmet0513 
 Oxytocin
 Prostaglandin
 synthase
 Estradiol‐17β What
about
other

 osmoregulatory
and
pressor
 processes?
 Concentrations of many ions are also regulated by hormones. Homeostatic mechanisms work to maintain the concentration of salt in water (about 70% of body weight) and blood pressure. This is done in a variety of ways including active, coupled, and passive transport of water and solutes across cell membranes, and control of smooth muscle fibers in the walls of blood vessels. The osmoregulatory organs (e.g. kidney and G.I. tract) function independently under constant conditions. Blood pressure can vary as a function of activity and osmoregulatory state. Constant environmental conditions rarely prevail for long and osmoregulatory/blood pressure adjustments are inevitable from time to time. Water is lost through the skin and respiratory tract (especially in hot and arid climates). In addition sweat glands lose both water and salt. Water and salt are voided in urine. Some must be voided to assist excretion of wastes (e.g. urea). Excess water and salt are also voided this way. At intervals, considerable losses may be incurred during parturition or hemorrhage. These deficits are made up by feeding and drinking. Salt and water are replenished through the G.I. tract and can be retained by the kidney. Blood pressure is directly regulated by the heart and by smooth muscles fibers in some blood vessels. Hormone Systems for Osmoregulation, Pressor Effects. Vasopressin Prolactin (in specialized cases such as lactation) Renin – angiotensin – aldosterone system. Glucocorticosteroids from the adrenal cortex Atrial and brain natriuretic factors. Some hormones of the gastro-intestinal tract (uptake of ions and water). Autonomic nervous system and epinephrine (alpha and beta adrenergic receptors). Hormone Systems for Osmoregulation, Pressor Effects. Vasopressin Prolactin (in specialized cases such as lactation) Renin – angiotensin – aldosterone system. Glucocorticosteroids from the adrenal cortex Atrial and brain natriuretic factors....
View Full Document

Ask a homework question - tutors are online