adrenal medulla
TRANSCRIPT
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