ADRENAL MEDULLA

DR. LAXMIKANTA SAY

HORMONES OF ADRENAL MEDULLA

EPINEPHRINE

NOREPINEPHRINE

DOPAMINE

SYNTHESIS OF CATECHOLAMINES

SECRETION OF CATECHOLAMINES

Mechanism of

Secretion

Nervous Control

Physiological &

Psychological

Nervous ControlSympathetic

Activation

Nerve Impulse travel across Preganglionic sympathetic fiber

Activation Ach receptor

• Epinephrine• NE• ATP• β –

hydroxylase• Chromograni

n

Chromaffin Cell

Na +

Ca 2+

Physiological & Psychological stimuli

Anxiety - Perception or anticipation of Danger

Pain, trauma Hypovolaemia Anoxia Exposure to extremes of temp. Hypoglycemia Severe exercise

CONTROL OF SECRETION

1. Negative feedback mechanism by Dopamine and Norephrine

2. During sleep secretion decreases

3. Increases during fight or flight reaction

4. Increases during cold

HYPOTHALAMUS

SYMPATHETIC PATHWAY

ADRENALINE STRESS RESPONSE

FIGHT-or-FLIGHT

RECEPTORS

α β D

Alpha – receptors (α1 & α2)

α 1- Post junctional on effector organ

Location

- Blood vessel, Non- pregnant Uterus, Glands

Functions - Excitatory

- Vasoconstriction

- Inhibit intestinal Motility

α 2- Pre junctional on nv. Ending

Location

- Pre-synaptic nerve Terminal

Functions

- Inhibitory

Actions of α-receptor

Vasoconstriction Iris dilation Intestinal relaxation Intestinal sphincter contraction Pilomotor contraction Bladder sphincter contraction Inhibition of neurotransmitter

release

β – receptor (β1, β2 & β3) β1

Location – Heart, JG Cell, Renal

β2 Location – Heart, Bronchi, BV, Uterus,

Liver, GIT, Urinary Tract,, Eye, Skeletal Muscle

β3

Location – Adipose Tissue

Beta - Receptor

Vasodilation (β2) Cardioacceleration (β1) Increased myocardial strength (β1) Intestinal relaxation (β2) Uterus relaxatation (β2) Broncho dilation (β2) Calorigenesis (β2) Glycogenolysis (β2) Lypolysis (β1) Bladder wall relaxatation (β2) Thermogenesis (β2)

ACTIONS OF E & NE

Cardiovascular Alertness Blood glucose Metabolic rate Lipolysis K+

ACTIONS OF DOPAMINE

Generalised vasoconstriction – release of NE

(+)ve ionotropic action SBP Kidney 1. Vasodilatation – specific dopaminergic

receptors

2. Natriuresis – inhibiting Na+-K+ATPase

(Treatment of shock)

Applied

ADRENAL

ADRENAL CORTEXADRENAL MEDULLA

MINERALOCORTICOIDS

GLUCOCORTICOIDS

CATECHOLAMINES

MINERALOCORTICOID (ALDOSTREONE)

Primary Hyperaldosteronism(CONN’S SYNDROME) Cause - adenoma, tumor of zona glomerulosa

Clinical Features - Sodium absorption ( Sodium content in Sweat, Saliva, GIT secretions) - Extracellular volume - Hypokalemic Nephropathy - Hypertension - Metabolic alkalosis

HYPERSECRETION

Hyposecretion (ADDISON’S DISEASE)

Acute – Adrenalectomy, abrupt withdrawal, Sudden stress or Infection

Chronic – Auto-immune diorders, TB, Carcinoma, Water – house Friderichensen syndrome)

Clinical Features - Cutaneous & Mucocutaneous pigmentation - Hypotension - Hypoglycemia - Fatigability - Weakness - Weight Loss - Anorexia

Glucocorticoid (Cushing’s Syndrome) ACTH – dependent Cushing’s (80%)

Cause - 1. Hyperactivity of Pituitary - 2. Ectopic ACTH production – Ca. Lungs,

viscera - 3. Hypothalamic disorders - 4. Excessive ACTH therapy

ACTH – independent (20%)

Cause - adrenal adenoma, carcinoma, Iatrogenic

Clinical Features -1. Trunkal Obesity or centripetal Obesity - 2. Buffallo Hump - 3. Moon Face - 4. Purple stria - 4. Muscle weakness - 5. Sodium & water retention - 6. Hyperglycemia - 7. Hirsuitism

Pheochromocytoma

Cause – Benign tumor of Chromaffin cells of adrenal medulla

Clinical Features - 1. Episodic or non-episodic Hypertension - 2. Attacks of Tachycardia, Palpitation,

Sweating, Pallor, Head ache - 3. Weight Loss & Waekness - 4. Abdominal pain, Vomiting, constipation

& Glucose intolerance

Thank You