PHYL2001 Lecture Notes - Adrenal Medulla, Adrenal Gland, Salivary Gland
Afferent: towards the CNS (sensory)"
Efferent: away the CNS (motor - visceral (ANS) and somatic)"
Neurons:"
-preganglionic: ACh released via cholinergic neutron, binds to nicotinic receptor"
-Postganglionic = nicotini/muscarinic"
SNS: cell body nearer to SC - thoraco/lumbar"
PNS: cell body nearer to organs - sacral/cervical"
Effects of SNS:"
1. Increase HR = chronotropic/ionotropic "
-chronotropic agents (eg. NA/A) = increases HR"
-ionotropic agents (eg. Beta 1 receptors) = force of contractibility"
2. Increases CO (which increases BP = CO x TPR) "
3. Pupil dilates
-to allow more light to enter = see better"
4. Redirection of blood flow from digestive/urinary to muscles
5. Bronchodilation (beta 2 receptors)"
-more oxygen to the lungs"
6. Sweating
7. Glycogenolysis & lipolysis
-breaking glycogen -> glucose"
-TG -> glucose"
-Glucose needed for energy for brain"
Adrenal gland = adrenal cortex (3 layers - bona reticularis, fasciculata, glomerulosa) then adrenal
medulla (produce catecholamines)"
1. Reticular (after medulla) = sex hormone"
2. Fasciculata = glucocorticoids (eg. cortisol)"
3. Glomerulosa (most outer) = produces mineralocorticoids class of hormones (Eg. Aldosterone
increases Na reabsorption in kidneys, bringing water with it)"
Vasoconstriction acts on smooth muscle of BV, when sympathetic effector removed, the smooth
muscle (does not vasodilate - NO!) stops vasoconstriction"
-Only about arterioles and veins"
Salivary glands: both PNS and SNS = both stimulatory"
Medulla: respiratory and cardiac centres"
Mechanism of binding of A and NA: "
-peptide hormone (requires 2nd messenger - intracellular) -> binds to extracellular receptors "
Catecholamines short lived: enzymes break it down"
-NA/A: catechol-O-methyltransferase = found in liver"
-ACh: acetylcholinerase (~ inhibitors if want to prevent breakdown of ACh) = found extracellular"
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Document Summary
E erent: away the cns (motor - visceral (ans) and somatic) Preganglionic: ach released via cholinergic neutron, binds to nicotinic receptor. Sns: cell body nearer to sc - thoraco/lumbar. Pns: cell body nearer to organs - sacral/cervical. Chronotropic agents (eg. na/a) = increases hr. Ionotropic agents (eg. beta 1 receptors) = force of contractibility. Increases co (which increases bp = co x tpr: pupil dilates. To allow more light to enter = see better: redirection of blood ow from digestive/urinary to muscles, bronchodilation (beta 2 receptors) More oxygen to the lungs: sweating, glycogenolysis & lipolysis. Adrenal gland = adrenal cortex (3 layers - bona reticularis, fasciculata, glomerulosa) then adrenal medulla (produce catecholamines: reticular (after medulla) = sex hormone, fasciculata = glucocorticoids (eg. cortisol, glomerulosa (most outer) = produces mineralocorticoids class of hormones (eg. Aldosterone increases na reabsorption in kidneys, bringing water with it)
