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• Noradrenaline act on alpha and beta
• Prepare individual deal
• A sympathetic ganglion
• Post ganglionic neurones
have lost their axons and
become secretory cells
• Stimulated by
reaching gland via
• Glucocorticoid concentration is high in blood
draining from cortex to medulla/
• After hyophysectomy glucocorticoid secretion
of blood falls.
• Glucocorticoids necessary for normal
development of adrenal medulla.
• In 21 b-hydoxylase deficiency, glucocorticoid
secretion is reduced during fetal life.
• In untreated b-hydoxylase deficiency,
circulating catecholemines are low after birth.
• Norephinephrine and ephinephrine:
• Increase glycogenoliysis in liver and skeletal
• Increase insulin by ẞ receptors. Decrease insulin
by α- adrenergic receptors.
• Mobilization of FFA
• Increase plasma lactate
• Stimulation of metabolic rare
• Brought about by actions of α and ẞ adrenergic
• The initial rise in metabolic rate due to
cutaneous vasoconstriction decreases heat
loss and leads to rise in body temperature
increased muscular activity.
• Second rise is due to oxidation of lactate in
• increase the force and rate of contraction of
the isolated heart. mediated via β1 receptors.
• Cardiac muscle. SA node
• force rate
• Increase myocardial contractility
• May cause extra-systoles and arrythmias.
• Norepinephrine - vasoconstriction in most if
not all organs via α receptors.
• Increase total peripheral resistance increase .
• but epinephrine dilates the blood vessels in
skeletal muscle and the liver via β receptors.
• Decrease total peripheral resistance.
pressure force of
pressure force of
increase blood glucose level by glycogenolysis
Epinephrine and norepinephrine both cause glycogenolysis.
mobilization of FFA from adipose tissue
GIT, Urinary bladder
Smooth muscles Relaxation
• Epinephrine and norephinephrine cause an
initial rise in plasma K+ because release of K+
from the liver
• and then a prolonged fall in plasma K+
because of an increase entry of K+ into
skeletal muscle that is mediated by B-
• Physiologic stimuli affects adrenal medullary
secretion through the nervous system.
• Secretion is reduced in sleep.
• Increased in emergency situation
• During stress
• Prepare body for fight or flight
• Exposure to cold
Regulation of secretion
• Renal and mesentry vasodialation by dopaminergic
• Everywhere else, vasodialation by releasing
• Postive inotropic effect on heart by action of β
• Increase the systolic blood pressure.
• Does not affect the diastolic blood.
• Used in treatment of traumatic and cardiogenic shock.
• Causes natriuresis, inhibit Na, K, ATPase.
• Deficiency in basal ganglia cause PARKINSONISM
• Methylated & oxydized to VMA
excreted in urine.
• Epinephrine and norepinephrine are metabolized
by oxidation and methylation. The former
reaction is catalyzed by MAO and the latter by
catechol -O -methyltransferase (COMT
• After many steps
• vanillyl- mandelic acid (VMA)
• Cause-tumour in cells of adrenal medulla so
catecholamine secretion increase.
• Signs and symptoms-Headache