1. The Adrenal Gland

2. Adrenal or Suprarenal Glands

3. Definition
These are the endocrine glands which secrete
a) glucocorticoids = cortisol
b) mineralocorticoids = aldosterone
c) Androgens
d) Oestrogens
e) Catecholamines
epinephrine = adrenalinand
norepinephrine = noradrenaline)
f) Dopamine
Situation
Two adrenal glands
On the upper pole of each kidney
Located immediately anterior to the kidneys
Retroperitoneal
Enclosed within the renal fascia

4. Medulla and cortex are organized into a single gland,
But they are functionally different endocrine organs,
They have different embryological origins.
The medulla derives from ectoderm (neural crest)
The cortex develops from mesoderm.

5. Structure
Two parts
Outer cortex
Inner medulla
Inner medulla, A source of the catecholamines : epinephrine and norepinephrine.
The chromaffin cell is the principal cell type and they contain catecholamine granules
. The medulla is richly innervated by preganglionic sympathetic fibers and is, in essence, an extension of the sympathetic nervous system.
Three concentric zones of cells – zona glomerulosa, zona fasciculata, zona reticularis
Secretes steroid hormones
(glucocorticoids and mineralocorticoids, plus a few others).

6. Arterial blood supply – from abdominal aorta and renal arteries
Venous return – by suprarenal veins
The right gland into the inferior vena cava
The left gland into the renal vein

7. Adrenal Cortex
Adrenal cortex produces three groups of hormones from cholesterol
cortisol
I Glucocorticoids corticosterone
II Mineralocorticoids aldosterone
III Androgens
IV Oestrogens

8. norepinephrine and epinephrine.
Adrenal medulla
norepinephrine and epinephrine.
same effects as direct sympathetic nervous stimulation.
Major effects mediated by epinephrine and norepinephrine :
Increased rate and force of contraction of the heart muscle: this is predominantly an effect of epinephrine acting through beta receptors.
Constriction of blood vessels: norepinephrine, in particular, causes widespread vasoconstriction, resulting in increased resistance and hence arterial blood pressure.

9. Dilation of bronchioles: assists in pulmonary ventilation.
Stimulation of lipolysis in fat cells: this provides fatty acids for energy production in many tissues and aids in conservation of dwindling reserves of blood glucose.
Increased metabolic rate: oxygen consumption and heat production increase throughout the body in response to epinephrine. Medullary hormones also promote breakdown of glycogen in skeletal muscle to provide glucose for energy production.
Dilation of the pupils: particularly important in situations where you are surrounded by velociraptors under conditions of low ambient light.
Inhibition of certain "non-essential" processes: an example is inhibition of gastrointestinal secretion and motor activity.
Common stimuli for secretion of adrenomedullary hormones include exercise, hypoglycemia, hemorrhage and emotional distress.