The adrenal cortex consists of three layers that secrete different hormones. The zona glomerulosa secretes mineralocorticoids like aldosterone that regulate sodium and potassium levels. The zona fasciculata secretes glucocorticoids like cortisol that regulate carbohydrate, fat and protein metabolism and help the body respond to stress. The zona reticularis secretes small amounts of sex hormones. Diseases can result from too much or too little secretion of these hormones, causing symptoms like high blood pressure, muscle weakness, and changes in fat and sugar levels.

1. Adrenal Cortex
Dr. Mrs. Minakshi Ashok Randive
Professor & Head
Tilak ayurved mahavidyalaya , Pune.

2. Adrenal Cortex
There are two Adrenal glands situated on the top
of each kidney . Gland weighs about 4 to 5 gms ,
consists of two distinct parts the outer Adrenal
cortex & inner Adrenal medulla .
Cortex mass is approx. 80% of total gland .
Adrenal cortex has rich blood supply so adrenal
hormones enter directly in to systemic circulation .

3. Adrenal Cortex
Adrenal cortex has 3 layers of structures .
1 - Zona glmerulosa - outer most .
2 - Zona fasciculate - middle layer .
3 - Zona reticularis - inner layer .
Hormones - Adrenocortical hormones or
Corticosteroids classified into three groups ,
1 - Minaralocorticoids
2 - Glucocorticoids
3 - Sex hormones

4. Synthesis ,Transport ,Fate
Synthesis - these hormones are steroid in nature ,
mainly formed from Cholesterol absorbed from
direct circulating blood .
Transport - Minaralocorticoids are carried by
plasma proteins -globulins . 50% of hormones are
in free form .
Glucocorticoids - special plasma protein called as
Glucocorticoid - binding globulin or transcortin
carries 94% . About 6% are found free in plasma .

5. Synthesis ,Transport ,Fate
Corticosteroids Fate - mainly degraded in liver ,
and get conjugated to form glucuronides and to
lesser extent , form sulphates .
Near about 25% of corticosteroids excreted in Bile
and faces and 75% in urine .

6. Glucocorticoid
Glucocorticoids - mainly act on Glucose
metabolism , glucocorticoids are - 1 - Cortisol , 2 -
Corticosterone , 3 - cortisone .
Chemical structure - C 21steroids having 21
carbon atoms .
Secretion - secreted mainly by Zona fasciculata of
adrenal cortex ,a small amount is also secreted by
Zona Reticularis .

7. Glucocorticoids- functions
Life protection - cortisol is a life protecting
hormone .it helps in stress .
They have metabolic effects on fats ,
carbohydrates, protein and water .
Fat metabolism - glucocorticoids mobilise and
redistribute of fats - a) - mobilization of fatty acids
from adipose tissue , b) - increase the
concentration of fatty acids in blood , c ) - increase
the utilisation

8. Glucocorticoids - functions
Glucocorticoids decreas the use of glucose , and
use the fatty acids for liberation of energy , it leads
to formation of large amount of Ketone bodies (
ketogenic effect ) .
Hyper secretion of glucocorticoids leads to obesity
.
On Carbohydrate metabolism - glucocorticoids
increase the blood sugar level in 2 ways , a)
promotion of gluconeogenesis in liver from amino
acids , b) inhibition of glucose uptake and
utilisation by peripheral cells .

9. Glucocorticoids function
Carbohydrate metabolism - hypersecretion of
glucocorticoid increases the blood glucose level
resulting in hyperglycaemia .
Protein metabolism - promotes protein catabolism .
Glucocorticoids increase plasma amino acids and
proteins in the liver and decrease proteins in the cell
.
In hyper secretion of glucocorticoids there is
reduction in the growth , muscle wasting .

10. Glucocorticoids function
On Muscles - glucocorticoids increase the release
of amino acids from muscle by catabolism . So
there is muscular weakness .
On Water metabolism - glucocorticoids are
important in maintainance of water balance , it
accelerates excretion of water so adrenal
defficiency causes water retention and it this
condition causes intoxication .

11. Glucocorticoids function
On Mineral metabolism - Glucocorticoids enhance
the retention of Sodium and slightly increase the
excretion of potassium .
Hyper secretion of glucocorticoids is responsible
for hypertension , edema (swelling) ,hypokalemia
(reduced sodium) , decrease in blood calcium by
inhibiting absorption from intestine and increasing
excretion of calcium through urine .

12. Glucocorticoids functions
on Central Nervous system - inadequacy of these
hormones causes Irritability , lack of concentration
,sensitivity to olfactory and taste stimuli increases .
On Blood cells - eosinophils are destructed in
reticuloendothelial cells, even basophils and
lymphocytes also get decreased , and there is
increase in number rbcs,and platelets .

13. Glucocorticoids functions
Anti inflammatory effects - inflammation is protective
response induced by injury , few chemical factors are
released from the affected area this produce series of
reactions in the affected area . Glucocorticoids prevent
these inflammatory changes , it helps in rapid healing also
On Resistance to stress - in stress glucocorticoid levels
are increased to resist the stress and prevention of other
changes in the body caused by stress .
Anti allergic reaction - these hormones prevent the various
reactions in allergy .

14. Glucocorticoid functions
Immunosuppression - these hormones suppress
immune reactions - by decreasing T lymphocytes
because of suppression of lymphoid tissue (lymph
nodes and thymus) and preventing release of
interleukins -2 by T cells .
mode of action - hormone receptor- complex is
formed by binding of hormone with receptor which
activates DNA to form mRNA causes synthesis of
enzymes which alters the cell function .

15. Regulation of secretion
Hypothalamus - corticotropin releasing factor
(CRF) Anterior pituitary -secretion of
adrenocorticotropic hormone (ACTH) - - adrenal
cortex .

16. Regulation of secretion
Stress , emotion ,trauma
Hypothalamus
Corticotropin releasing hormone
Anterior pituitary
Adrenocorticotropic hormone (ACTH)
Adrenal cortex
Cortisol

17. Adrenal sex hormones
Secreted mainly by Zona reticularis and in small amount by
Zona fasciculata .
Secreted hormones are mainly male sex hormones
(androgenes) and small quantity of female hormones -
oestrogen and progesterone .
Androgenes - a) Dehydroepiandrostrone - most active ,
b) Androstenedione C) Testosterone
Androgens are responsible for masculine features of the body
, but as the secretions are low in quantity have insignificant
physiological effects .

18. Mineralocorticoids
Minaralocorticoids act on the mineral - electrocyte
metabolism especially sodium and potassium .
Mineralocorticoids are - a) Aldesterone ,
b) 11-Deoxycorticosterone .
Source of secretion - are secreted by zone
glomerulosa of adrenal cortex .
Chemistry - C12 steroids having 21 carbon atoms

19. Mineralocorticoids - functions
90% of mineralocorticoid activity is provided by aldosterone .
Life saving hormone -loss of these hormones cause death within
2 to 3 weeks .
Aldesterone - 1 - increase the reabsorption of sodium from renal
tubules . 2 - increase the reabsorption of potassium from the
renal tubules .
On Sodium ions - regulates the concentration of sodium .
On Extra cellular fluid - when sodium ions are reabsorbed from
the renal tubules water is also reabsorbed simultaneously so
there is increase in ECF volume .

20. Mineralocorticoids functions
On Blood pressure - increase in ECF the blood volume ,
increases the Blood pressure .
On Hydrogen ion concentration - aldosterone causes
tubular secretion of hydrogen ions while increasing the
sodium reabsorption , it reduces the hydrogen ion
concentration in ECF .
On potassium ions - potassium excretion is increased
through renal tubules due to aldesteron , so whenever
there is deficiency of aldesteron the amount of potassium
is increased in ECF the condition is called as
Hyperkalemia

21. Mineralocorticoids functions
Hyperkalemia condition is responsible for cardiac -
arrhythmia , in severe conditions it may cause death
also .
If aldesteron secretion increases then it lead to
hypokalaemia and muscular weakness .
On Sweat glands and Salivary glands - due to
aldesterone sodium is reabsorbed from the sweat
glands so the loss of sodium is prevented , same
effect is seen on the salivary glands .

22. Mode of action of aldesteron
Aldesteron diffuses through the lipid layer in to the interior of the
tubular epithelial cells .
In the tubular cells cytoplasm aldesteron binds with specific
receptor protein .
Aldesteron - receptor protein complex diffuses in the nucleus -
and formation of mRNA.
mRNA diffuses back in to the cytoplasm and with ribosomes it
causes protein synthesis ,most of the proteins are in form of
enzymes , sodium -potassium ATPase is the enzyme formed
which is responsible for exchange of sodium and potassium
through Sodium potassium pump .

23. Regulation of secretion
Following are the important factors when secretion
of aldosterone takes place
1- increase in potassium ion concentration in the
ECF .
2 - decrease in sodium ion concentration in the
ECF .
3 - decrease in ECF volume
4 - adrenocorticotropic hormone .

24. Applied physiology
Hyperactivity of Adrenal cortex -
1- kushings syndrome , 2 - Hyperaldosteronism ,
3 - Adrenogenital syndrome .
Hyperactivity of Adrenal cortex -
1 - Addisons disease or chronic adrenal
insufficiency 2 - Addisonian crisis or
Adrenal crisis 3 - Congenital
adrenal hyperplasia .

25. Cushings syndrome
Signs and symptoms - 1)- moon face - due to fat
accumulation , and water ,salt retention 2) torso -
fat accumulation in abdomen and chest 3) buffalo
hump - fat accumulation in upper back 4)pot belly -
fat in upper abdomen 5) purple striae - on
abdomen 6) thining of extremities 7) shining of
skin 8)darkening of skin on neck 9) pigmentation
10) facial redness 11) facial hair growth (hirsutism
) 12) muscle weakness 13) osteoporosis
14)hyperglycemia 15) hypertension
16) immunosuppression

26. Hyperaldosteronism
Signs and symptoms - 1) crease in blood volume
and ECF - so there is Hypertension 2) depletion of
potassium - polyuria and polydipsia and muscle
weakness 3) metabolic alkalosis
because there is secretion of large amount of
hydrogen ions into renal tubule .

27. Adrenogenital syndrome
Signs and symptoms - 1) development of
secondary sex characters of opposite sex .

28. Addisons disease
Signs and symptoms - 1) muscular weakness
2) pigmentation of skin 3) dehydration 4)
hypotension 5) decreased cardiac
output 6) hypoglycaemia 7) vomitting
,diarrhoea 8) susceptibility to infection .

29. Addisonian crisis
1) sudden colapse
2) death

30. Congenital Adrenal hyperplasia
Precocious body growth
Precocious sexual development with enlarged
penis even at age of 4 years .
Masculinisation in girls .

31. Bibliography
Essentials of Medical Physiology - K Sembulingam
.
Medical Physiology - Subir Chowdhary