Adrenals
Each
adrenal has two parts, an outer cortex and inner medulla.
Location: Over
the superior end of kidneys.
Adrenal Cortex. The outer part of adrenals which further consists of
three zones
(i) Zona glomerulosa:
Hormones: Mineralocorticoids (mainly aldosterone)
Functions:
Regulation of Na+ and
K+ in
blood. Increases Na+ level,
and lowers
that
of K+
(ii) Zona Fasciculata
Hormone: Glucocorticoids (Mainly cortisol)
Function: Increase
glucose level in body by changing proteins and fast to
carbohydrates.
Hypersecretion: Cushing’s
syndrome due to high glucose level, and high Na+
level
caused by excess of glucocorticoids. High B.P. and rise in blood volume.
(iii) Zona reticulosa
Hormone: Androgens (Male sex hormones)
Function: Development
of male secondary sexual characters.
Hypersecretion: Adrenal
virilism due to excess of androgens secreted in female
who
develops certain masculine features.
(b) Adrenal medulla (The inner portion of adrenals)
The
adrenals are commonly called the glands of emergency because of the role of
their
hormones.
Hormone:
(i)
Noradrenaline (= Norepinephrine) Secreted under normal
conditions.
Function: Regulate
blood pressure under normal condition by constricting small
arteries.
(ii)
Adrenaline (= Epinephrine) secreted under conditions of physical
and mental
stress
such as grief, pain, injury, anger, fall in blood pressure and blood sugar,
cold
fear, etc. In man, adrenalin is produced in much more amount than
nonadrenaline.
Function: Increase
of heart beat rate, breathing rate and blood sugar. Dilation
of
small arteries of heart, brain and skeletal muscles. Constriction of small
arteries
of skin: constriction of small arteries of skin; contraction of spleen to
squeeze
out the reserve, dilation of pupil, contraction of arrector pili muscles
(goose flesh condition).thanks for visiting All sciencess
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