Myogenic mechanism

From Self-sufficiency

The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow within the blood vessel constant.

The smooth muscle of the blood vessels reacts to the stretching of the muscle by opening ion channels, which cause the muscle to depolarize, leading to muscle contraction. This significantly reduces the volume of blood able to pass through the lumen, which reduces blood flow through the blood vessel. Alternatively when the smooth muscle in the blood vessel relaxes, the ion channels close, resulting in vasodilation of the blood vessel; this increases the rate of flow through the lumen.

This system is especially significant in the kidneys, where the glomerular filtration rate (the rate of blood filtration by the nephron) is particularly sensitive to changes in blood pressure. However, with the aid of the myogenic mechanism, the glomerular filtration rate remains very insensitive to changes in human blood pressure.

External links

Moore L.C., A. Rich, and D. Casellas. Ascending myogenic autoregulation: interactions between tubuloglomerular feedback and myogenic mechanisms.. Bull. Math. Biol. 56:391-410, 1994.

This medical article is a stub. You can help ssf by expanding it.

Cardiovascular system, physiology: cardiovascular physiology

Heart

Volumes	Stroke volume = End-diastolic volume – End-systolic volume Cardiac output = Heart rate · Stroke volume Afterload · Preload Frank–Starling law of the heart · Cardiac function curve · Venous return curve Aortic valve area calculation · Ejection fraction · Cardiac index
Dimensions	Fractional shortening = (End-diastolic dimension – End-systolic dimension) / End-diastolic dimension
Interaction diagrams	Cardiac cycle · Wiggers diagram · Pressure volume diagram
Tropism	Chronotropic (Heart rate) · Dromotropic (Conduction velocity) · Inotropic (Contractility) · Batmotropic (Excitability) · Lusitropic (Relaxation)
Conduction system / Cardiac electrophysiology	Cardiac action potential (Atrial action potential, Ventricular action potential) · Effective refractory period · Pacemaker potential · EKG (P wave, PR interval, QRS complex, QT interval, ST segment, T wave, U wave) · Hexaxial reference system
Chamber pressure	Central venous pressure/right atrial pressure → Right ventricular pressure → Pulmonary artery pressure → Pulmonary wedge pressure/left atrial pressure → Left ventricular pressure → Aortic pressure
Other	Ventricular remodeling

Vascular system/
Hemodynamics

Blood flow	Compliance · Vascular resistance (Total peripheral resistance) · Pulse · Perfusion
Blood pressure	Pulse pressure (Systolic - Diastolic) · Mean arterial pressure Jugular venous pressure Portal venous pressure
Regulation of BP	Baroreflex · Kinin-kallikrein system · Renin-angiotensin system · Vasoconstrictors/Vasodilators · Autoregulation (Myogenic mechanism, Tubuloglomerular feedback) · Paraganglia (Aortic body, Carotid body, Glomus cell)