The document describes the anatomy and physiology of the adrenal gland. It discusses the location, shape, size and blood supply of the adrenal glands. It describes the two parts of each adrenal gland - the outer cortex and inner medulla. The cortex contains three zones that secrete different hormones. The medulla contains chromaffin cells that secrete catecholamines. Diseases associated with adrenal gland dysfunction are also mentioned.

1. ENDOCRINE UNIT
Prepared By
Dr. Ahmed

2. ADRENAL GLAND
(suprarenal gland)
5th Lecture

3. Adrenal gland
LOCATION
 paired , retroperitoneal
 related to upper pole of kidney
 Yellowish in colour
SHAPE AND MEASUREMENTS
Shape: Each gland is flattened A-P
1. RT. : pyramidal in shape
2LT.: crescentric in shape like
Measurements:
Length 50 mm.
Breadth 30 mm.
Thickness 10 mm.
Weight= About 5 g.
At birth the gland is 1/3 of the size of kidney, in adults it is only 1/30th of the
size of kidney

4. Adrenal gland
LOCATION
retroperitoneal
in the epigastric region of abdomen,
anterosuperior to the upper part of
each kidney
 yellowish in color
SHAPE AND MEASUREMENTS
Shape: Each gland is flattened A-P
1. RT. : pyramidal in shape
2. LT.: crescentric in shape
Measurements:
Length 50 mm.
Breadth 30 mm.
Thickness 10 mm.
Weight= About 5 g.
At birth the gland is 1/3 of the size of kidney, in adults it is only 1/30th of the
size of kidney

5. Adrenal gland

6. Adrenal gland
Sheath
surrounded by two sheaths :
1. Surrounded by fat called perirenal fat.
2. Outer to this, renal fascia encloses
the suprarenal gland together with the
kidney
3. but the gland is separated from the
kidney by a septum.

7. Adrenal gland
ARTERIAL SUPPLY
Each gland is supplied by three arteries
from three different sources :
1. Superior suprarenal artery: A branch of
the inferior phrenic artery.
2. Middle suprarenal artery: A branch of the
abdominal aorta.
3. Inferior suprarenal artery: A branch of the
renal artery.

8. Adrenal gland
VENOUS DRAINAGE
Each gland is drained by only single vein
which emerges from the hilus of the
gland :
1. Right suprarenal vein drains into the
inferior vena cava.
2. Left suprarenal vein drains into the left
renal vein.

9. Adrenal gland
Parts
divided into
 outer cortex 80%
 inner medulla 20%
outer cortex
contains parenchymal cells synthesize
& secrete but do not store various
steroid hormones.
Intracellular lipid droplets
characteristic cytologic features
inner medulla
 contains two populations of
parenchymal cells, called chromaffin cells
which synthesize, store, and secrete
the catecholamine

10. Adrenal gland
Endocrine Cells are generally characterized
according to hormones they produce:
1. Nitrogenous-hormone secreting cell:
RER.
Golgi.
Secretory granules.
2. Steroid-hormone secreting cell:
SER.
Lipid droplet: raw materials.
Mitochondria: with tubular- vesicular cristae.

11. Adrenal gland

12. Adrenal gland

13. Adrenal gland
Zona glomerulosa
Occupy 15% of the cortex
Immediately beneath the capsule
 cells arranged in closely packed,
rounded cluster like glomeruli
 cells are smaller , Columnar or
pyramidal with dark stain cytoplasm

14. Adrenal gland
Zona Fasciculata
Occupy 65% of the cortex
 Intermediate zone
 Arranged in one or two – cell
thick straight cords(perpendicular
to surface of the gland)
 cells are Polyhedral, binucleated
light staining ( a lot of lipid droplets
in their cytoplasm)
Cells are also called spongyocytes
(foamy cell) due to vacuolization

15. Adrenal gland
Zona Reticularis
occupy 7% of the cortex
Innermost layer - lies between zona fasciculata and
medulla
 Small cells arranged in irregular cords forming
network
Cells are darkly stained, characterize by presence of
lipofuscin pigment granules ( with age)

16. Adrenal gland
Medulla
Lies in the center of the adrenal
gland
Clear line of demarcation
Composed of polyhedral cells
arranged in clusters surrounded
by an extensive capillary network& ,
supported by reticular fiber
network
 Composed of :
Chromaffin cells of 2types
 A – CELLS
 N – CELLS

17. Adrenal gland

18. Adrenal gland
Medulla
A – CELLS Characterized by
80%
containing small granules
 Store epinephrine
N – CELLS Characterized by
20%
containing large dense granules
 Store Norepinephrine

19. Adrenal gland
Medulla
has a dual blood supply that arises
from
(1) medullary arterioles that bypass
the adrenal cortex
(2) capillary sinusoids that perfuse the
adrenal cortex (adrenocortical
sinusoids).
 central adrenomedullary vein drains
to IVC(Rt.)
or
Lt. renal V.(Lt.)

20. Adrenal gland
Nerve supply of adrenal gland
cortex is regulated by ACTH secreted by the anterior lobe of the pituitary gland
Medulla is regulated by sympathetic NS (myelinated preganglionic sympathetic fibers ) derived from
splanchnic nerves & distributed to the chromaffin cells (modified postganglionic sympathetic neurons)
release of catecholamine from secretary granules stored in chromaffin cells by
process called exocytosis

21. Adrenal gland

22. Adrenal gland
Radiology of Suprarenal Gland
 deeply located difficult to visualize on plain X-ray.
 CT scan of abdomen inverted Y shape with medial & lateral limbs

23. Adrenal gland
Adrenalectomy
( removal of the adrenal glands)
Rt. suprarenal vein must be ligated
before manipulating the gland
1. Short ,wide
2. To prevent surge of catecholamines to
the circulation.
 surgical removal of Lt. gland is easier
because the identification & clamping of
the left suprarenal vein is easy
Rt. gland is more difficult to approach
than the left because part of it lies
posterior to IVC

24. Adrenal gland

25. Adrenal gland

26. Adrenal gland

27. Adrenal gland

28. Adrenal gland

29. Adrenal gland

30. Adrenal gland

31. Adrenal gland
Conn’s disease
HYPERALDOSTERONISM
usually caused by adrenal tumor
Na and water retention
K+ (hypokalemia)
Hypertension

32. Adrenal gland
Cushing disease / syndrome
secretion of cortisol from Adrenal hyperplasia
 4X more frequent in females
Primary-tumor on the adrenal cortex
Secondary-tumor on the anterior pituitary gland
- truncal obesity
- buffalo hump
- “moon face”
 Adrenal hyperplasia with excessive
secretion of sex steroids leads to
feminization of male and masculanization of
female.

33. Adrenal gland
Cushing disease / syndrome
secretion of cortisol from Adrenal hyperplasia
 4X more frequent in females
Primary-tumor on the adrenal cortex
Secondary-tumor on the anterior pituitary gland
- truncal obesity
- buffalo hump
- “moon face”
Adrenal hyperplasia with excessive
secretion of sex steroids leads to
feminization of male and masculanization of
female.

34. Adrenal gland

35. Adrenal gland
Addison’s disease
hypofunction of adrenal cortex
What hormones will you have too little
of???
- glucocorticoids or _______
- mineralocorticoids or _______
- sex steroid or ____________

36. Adrenal gland
Addison’s disease
hypofunction of adrenal cortex
What hormones will you have too little
of???
- glucocorticoids or _______
- mineralocorticoids or _______
- sex steroid or ____________

37. Adrenal gland
Pheochromocytoma
rare, benign tumor of the adrenal medulla
Hallmark is hypertension-200/150 or greater

38. Adrenal gland
Embryologically : adrenal gland
consists of two parts develops from two
different sources at 5th week :
(a) a large outer part called cortex :
is mesodermal in origin and develops
from celomic epithelium
(b) a small inner part called medulla.
develops from neural crest.

39. Adrenal gland
A. Cortex
1. forms from two episodes of mesoderm proliferation that occur between the root of the
dorsal mesentery and the gonad.
 first episode forms the inner fetal cortex.
 second episode forms the outer adult cortex
2. During the fetal period , the suprarenal glands are very large due to the size of the fetal
cortex( 10–20 times larger than adult adrenal gland).
3. suprarenal glands become smaller as the fetal cortex involutes rapidly during the first 2
weeks after birth and continues to involute during the first year of life.
4. zona glomerulosa and zona fasciculata of the adult cortex are present at birth, but the zona
reticularis is not formed until age 3 years.
B. Medulla
1. forms when neural crest cells aggregate at the medial aspect of the fetal cortex and become
surrounded by the fetal and adult cortex.
2. The neural crest cells differentiate into chromaffin cells

40. Adrenal gland
Congenital anomalies
1. Ectopic adrenal tissue/adrenal gland:
The adrenal tissue or complete adrenal gland may be found fused to kidney deep
in its capsule or in the right lobe of the liver.
2. adrenal hyperplasia
a) Congenital adrenal hyperplasia:
 It is most commonly caused by mutation of genes for enzymes involved in adrenocortical
steroid biosynthesis (e.g., 21-hydroxylase deficiency),
b) Adrenogenital syndrome:
 It occurs due to congenital hyperplasia of the cells of the adrenal cortex, which secrete
androgen.
 C/F differ in male and female :
(a) In male: (adrenogenital syndrome)
It leads to a very early development of secondary sexual characters.
(b) In female: (pseudohermaphroditism)
female child may be mistaken as a male.

41. Abdominopelvic splanchnic nerves
Notes related to lecture
chromaffin cells
celomic epithelium

42. chromaffin cells

43. Neural Crest cells

44. Neural Crest cells
Derivatives of neural crest:
1. C.T. and bones of the face and skull.
2. ganglia of the cranial nerves.
3. C-cells of the thyroid gland.
4. conotruncal septum of the heart.
5. odontoblast cells.
6. dermis of the face and neck.
7. spinal ganglia.
8. autonomic ganglia.
9. Chromaffin cells (adrenal medulla).
10. schwan cells.
11. glial cells of the brain.
12. melanocytes.
13. arachnoid and pia matter

45. Adrenal gland
Sites of chromaffin tissue :
1. para-aortic bodies
2. Along sympathetic chain near sympathetic ganglia
3. Along sympathetic plexuses
4. Near splanchnic nerves.
chromaffin tissue
1. stain intensely with chromium salts
yellow-brown .
2. Neural crest derivatives
Chromaffin cells can be found in
extrasuprarenal sites at birth, but these sites
normally regress completely by puberty.
In a normal adult, chromaffin cells are found
only in the suprarenal medulla
Pheochromocytoma:
tumor arising from chromaffin cells
usually from extra-adrenal

46. celomic epithelium

47. • Formation
intraembryonic celom

49. Abdominopelvic splanchnic nerves

50. Sympathetic Chain
Extension:
from the base of the skull to the coccyx.
bears a number of ganglia along its length
On either side of V. column (paravertebral ganglion)
Parts
cervical, thoracic, lumbar and sacral
Ganglion
Cervical :3
usually one ganglion less than the number of nerves:
11 thoracic; 4 lumbar; and 4 sacral
2 neurons
 (pre & postganglionic )
Preganglionic N : T1- L2 in lat. horn
Communication with spinal nerves
T1-L2 : by grey &white communicants
Above & below this level: only grey communicants
NO white communicants
Why?

51. Fate of preganglionic fibres
 preganglionic fibres arise from the lateral horns of spinal segments with ventral root
 4 options
Sympathetic ganglion of sympathetic trunk
(paravertebral ganglion
prevertebral ganglion

52. preganglionic fibres arise from the lateral horns of spinal segments with ventral root
 preganglionic fibres enter the sympathetic ganglion via white rami communicantes of the
spinal nerve.
Rely (synopsis) in the ganglion
Postganglionic fibres from the ganglion re-enter the spinal nerve via grey rami
communicantes
supply the corresponding dermatome of the upper limb and the body wall.

53. BRANCHES of thoracic part
Visceral & somatic Efferent Fibers
divided into two groups: medial & lateral
Medial branches(visceral)
1) postganglionic fibres
 from 1st to 5th ganglia
 distributed to the heart, great vessels,
lungs, and esophagus through the
following plexuses:
a) Pulmonary plexus bronchodilatation
b) b) Cardiac plexus. vasoconstriction
c) Aortic plexus. Secretion
d) Esophageal plexus
HR & dilate coronary art.
2) preganglionic fibres
 5th to 12th thoracic ganglia
form three splanchnic nerves :
a) Greater splanchnic nerve(5-9th)
b) Lesser splanchnic nerve(10 &11th )
c) Least (lowest) splanchnic nerve(12th (renal)

54. BRANCHES of thoracic part
Lateral branches(somatic)
 supply:
• erector pili of hair follicle ( pilomotor)
• Sweat gland (sudomotor)
• Bl. V of the skin ( vasomotor)
dilate Cutaneous Bl. V of limbs and
body wall