Why Are Vasodilation and Vasoconstriction the Main Mechanisms to Change

question 22

Multiple Choice

Why are vasodilation and vasoconstriction the main mechanisms to change blood flow?

• A)Blood vessel length is relatively fixed and has no effect on blood flow.
• B)Blood hematocrit has no effect on blood flow.
• C)Leakage of fluids from the capillaries has no effect on blood flow.
• D)Sympathetic activation has no effect on blood flow.

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Definitions:

Blastopore

The opening that develops in the early stage of embryonic development, which can lead to the formation of either the mouth or the anus in the developing organism.

Excretory System

A biological system responsible for the removal of waste products and excess substances from an organism's body to maintain internal chemical homeostasis and prevent damage to the body.

Mesoderm

The middle layer of an embryo in early development, which will develop into muscles, bones, and much of the circulatory, reproductive, and excretory systems.

Epidermis

The outermost layer of cells in both plants and animals, serving as a protective barrier against the environment.