Adrenal Glands: Adrenal Glands:
The adrenal glands are split into the outer
adrenal cortex & the inner adrenal medulla.
The adrenal cortex is split into the Zona
Glomerulosa (outer), the Zona Fasciculata
(middle) & the Zona Recticularis (inner).
The Zona Glomerulosa secretes mineral
corticoids.
These help to maintain blood pressure by
controlling the absorption of ions into the
blood.
This acts on the distal & collecting ducts in
the kidneys.
The Zona Fasciculata secretes
glucocorticoids.
These help control metabolism & stimulate
the production of glucose.
These act in the liver & are released in
response to stress or low blood pressure.
The Zona Recticularis secretes androgens.
These are taken in by the ovaries & testes &
are converted into sex hormones.
Action of Adrenaline: Action of Adrenaline:
Adrenaline binds to a receptor on the plasma
membrane of the target cell.
This causes the release of a G protein that
activates the enzyme adenyl cyclase.
Adenyl cyclase converts ATP into cyclic AMP.
Cyclic AMP is a secondary messenger &
activates a cascade of enzyme-controlled
reactions.
The enzymes which cAMP activate are called
protein kinases.
The adrenal glands are split into the outer
adrenal cortex & the inner adrenal medulla.
The adrenal cortex is split into the Zona
Glomerulosa (outer), the Zona Fasciculata
(middle) & the Zona Recticularis (inner).
The Zona Glomerulosa secretes mineral
corticoids.
These help to maintain blood pressure by
controlling the absorption of ions into the
blood.
This acts on the distal & collecting ducts in
the kidneys.
The Zona Fasciculata secretes
glucocorticoids.
These help control metabolism & stimulate
the production of glucose.
These act in the liver & are released in
response to stress or low blood pressure.
The Zona Recticularis secretes androgens.
These are taken in by the ovaries & testes &
are converted into sex hormones.
Action of Adrenaline: Action of Adrenaline:
Adrenaline binds to a receptor on the plasma
membrane of the target cell.
This causes the release of a G protein that
activates the enzyme adenyl cyclase.
Adenyl cyclase converts ATP into cyclic AMP.
Cyclic AMP is a secondary messenger &
activates a cascade of enzyme-controlled
reactions.
The enzymes which cAMP activate are called
protein kinases.
