Autoregulation matches local blood flow to local need

The autoregulatory mechanisms that adjust the flow of blood to a tissue are local mechanisms, but they can be influenced by the nervous system and by certain hormones.

Blood flow through a capillary bed is controlled by the constriction of smooth muscle in the arteries and arterioles.

Vein

Artery

Arteriole

Capillary

Vein Smooth Muscles Blood Movement

Thoroughfare channel

Venule

Muscle fibers (cells)

Thoroughfare channel

Muscle fibers (cells)

49.17 Local Control of Blood Flow Low O2 concentrations or high levels of metabolic by-products cause the smooth muscle of the arteries and arterioles to relax, thus increasing the supply of blood to the capillary bed.

Autoregulatory widening of vessels

Arterial pressure falls

Kidney releases

Decreased blood flow to tissue

Kidney releases

Hypothalamus releases vasopressin

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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