Section 4 Regulation of/the/Circulation
Section 4 Regulation of the Circulation
Introduction The aim: to regulate the blood flow of organs to fit their metabolic requirement in different condition The regulation of blood flow are of three major types Neural Humoral Local
Introduction ➢ The aim: to regulate the blood flow of organs to fit their metabolic requirement in different condition. ➢ The regulation of blood flow are of three major types: ➢ Neural ➢ Humoral ➢ Local
I. NeuralRegulation of the circulation
I. Neural Regulation of the Circulation
1. Innervation of the Circulate System Cardiac innervation Innervation of blood vessels Sympathetic vasoconstrictor fiber Sympathetic vasodilator fiber Parasympathetic nerve fiber to peripheral vessels
1. Innervation of the Circulatory System ➢ Cardiac innervation ➢ Innervation of blood vessels ➢ Sympathetic vasoconstrictor fiber ➢ Sympathetic vasodilator fiber ➢ Parasympathetic nerve fiber to peripheral vessels
Cardiac innervation Sympathetic nerve-noradrenergic / fib er Parasympathetic nerve- cholinergic fiber Noradrenergic sympathetic nerve increase the cardiac rate(positive chronotropic effect Increase the force of cardiac contraction(positive inotropic effect Cholinergic vagal cardiac fibers decrease the heart rate
Cardiac innervation ➢ Sympathetic nerve – noradrenergic fiber ➢ Parasympathetic nerve- cholinergic fiber ➢ Noradrenergic sympathetic nerve ➢ increase the cardiac rate (positive chronotropic effect) ➢ Increase the force of cardiac contraction (positive inotropic effect). ➢ Cholinergic vagal cardiac fibers decrease the heart rate
Sympathetic chains agi Sympathetic S-A nexes node ympailet nerves A-V no FIGURE9-11 Cardiac nerves. (The vagus nerves to the heart are parasympathetic nerves
Cardiac innervation ( contin At rest moderate amount of tonic discharge in the cardiac sympathetic nerves a good deal of tonic vagal discharge (vagal tone) When the vagi are cut in experiment animals. the heart rate rises
Cardiac innervation (contin.) ➢ At rest ➢ moderate amount of tonic discharge in the cardiac sympathetic nerves ➢ a good deal of tonic vagal discharge (vagal tone) ➢ When the vagi are cut in experiment animals, the heart rate rises
Innervation of blood vess Vasomotor center Sympathetic Blood vasoconstrictor fiber Distribution Almost all segments of the circulation The innervation is powerful in the kidneys essel gut, spleen and skin, is less potent in both skeletal and cardiac muscle and in the brain
Innervation of blood vessels ➢ Sympathetic vasoconstrictor fiber ➢ Distribution: Almost all segments of the circulation. ➢ The innervation is powerful in the kidneys, gut, spleen and skin, ➢ is less potent in both skeletal and cardiac muscle and in the brain
Innervation of blood vesse Sympathetic vasoconstrictor fiber (contin.) >Almost all vessels. such as arteries arterioles venules and veins are innervated >except the capillaries, precapillary sphincters and most of the metarterioles >Tone: Usually the sympathetic vasoconstrictor fibers keep tonic
Innervation of blood vessels ➢Sympathetic vasoconstrictor fiber (contin.) ➢Almost all vessels, such as arteries, arterioles, venules and veins are innervated, ➢except the capillaries, precapillary sphincters and most of the metarterioles. ➢Tone: Usually the sympathetic vasoconstrictor fibers keep tonic
150 125 Total spinal anesthesia EE900 100 WAMMAAAMMA 75 50 MA WWWA 25 Injection of norepinephrine 20 Minutes