Adrenal gland: structure, location and hormones
- The adrenal gland occurs in pair. each adrenal gland is made up of two separate endocrine gland. the inner portion of each gland is called Medulla and outer portion is called Cortex.
- Location: each adrenal gland is located on top of kidney as kidney cap
- Size: 4-6 cm long and 2-3 cm wide
# Structure of Adrenal gland
Divided into outer cortex and inner medulla
1. Adrenal cortex:
- It accounts for about 90% of weight of adrenal gland which weight for 5-7 gram.
- the cortex has three distinct zone
i. Zona glomerulosa:
- It lies directly beneath the capsule.
- It supplies cells for all other three zone. it is actually germinal layer.
- It produce mineralocorticoid.
ii. Zona faciculata:
- It lies beneath zona glomerulosa.
- It make up bulk of adrenal cortex.
- It secretes glucocorticoids and small amount of gonadocorticoids.
iii. Zona reticularis:
- It is the deepest layer.
- It consists of similar cell as zona faciculata but cells are arranged irregularily.
- It produce Dehydroepiandrosterone ( an intermediate hormone needed for production of sex hormone Androstenedione).
#Hormones secreted by Adrenal cortex
1. Glucocorticoid
- Regulate blood glucose level
- Stimulate gluconeogenesis
- Enhance synthesis of aminoacids which are substrate for gluconeogenesis
- Promote protein and nucleic acid metabolism
- Regulated by ACTH
- Acts as anti-inflammatory agents
2. Mineralocorticoid
- It is group of Steroid hormone (eg. Aldosterone), regulate concentration of mineral
- Help in maintaining blood pressure
- Help in Na+ reabsorption and cause excretion of K+, H+ and NH4+
3. Gonadocorticoid
- Sex hormone, stimulate gonads
- Regulated by ACTH
2. Adrenal medulla:
- It is the inner portion of adrenal gland.
- Medulla acts as a separate endocrine gland. It secretes separate hormones than cortex. However hormones produced by medulla are not as essential as cortical hormones.
- The secretory cells of adrenal medulla is called as Chromaffin cell because of their tendency to stain dark color.
- chromaffin cell synthesize, store and secrete epinephrine and nor-epinephrine which prepare body for fright, flight and fight.
#Hormones secreted by Adrenal Medulla
1. Epinephrine (adrenaline)
- commonly known as Adrenaline
- Increase rate of metabolism, heart rate and blood pressure
- Increase glycogenolysis, respiration rate, O2 consumption
2. Nor-epinephrine (Nor-Adrenaline)
- Increase heart rate, cardiac output, blood pressure
- Enhance lipid metabolism
- Relaxes smooth muscles of GI tract.
- Release free fatty acid from adipose tissue.
Disorder/disease of adrenal gland:
1. addition’s disease:
- bronze color pigmentation of skin
- low Na+ and high K+ level in blood plasma
- decrease resistance to infection
2. Cushing syndrome:
- abnormal obesity
- high Na+ and Low K+ level in blood
3. Aldosteronism:
- High Na+ level and Low K+ level in blood
- high blood pressure and increase blood volume
4. Adrenal virilism:
- male type external character such as beard, moustaches and voice develops in female