Define vasoconstriction and vasodilation. What is the mechanism of regulation?

What will be an ideal response?


Vasoconstriction is a reduction in the lumen diameter of a blood vessel due to smooth muscle contraction. Vasodilation is a widening of the lumen due to smooth muscle relaxation. Both are regulated by vasomotor nerve fibers of the sympathetic division of the autonomic nervous system.

Anatomy & Physiology

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Poison ivy contains a toxin that acts as a hapten by

A.  raising the body's sensitivity to a wide variety of chemicals such as penicillin. B.  cutting plasma protein antibodies in half. C.  preventing effective immune responses by blocking release of bradykinin. D.  combining with a body protein and then triggering an immune response.

Anatomy & Physiology

In bone, rings of matrix called ________ surround a central canal that contains blood vessels

A) osteoblasts B) canaliculi C) concentric lamellae D) osteoclasts

Anatomy & Physiology

An antibody binds to an antigen at a specific area called the

A) constant segment. B) light chain. C) antigen binding site. D) hapten. E) antigen-antibody complex.

Anatomy & Physiology

Cytokinesis overlaps with which phase of mitosis?

A) Metaphase B) The S phase C) Prophase D) Interphase E) Telophase

Anatomy & Physiology