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.
What will be an ideal response?
The two 2-mm vessels would deliver considerably less fluid for two reasons: (1) the resistance in the smaller vessels is much greater and (2) the volume of the 4-mm vessel is greater than that of two 2-mm vessels. Draw a 4-inch circle; then put two 2-inch circles in it and notice the volume difference.
You might also like to view...
Glycolysis, formation of acetyl CoA, Krebs cycle and the electron transport chain are all involved in
a) Lipogensis b) Gluconeogenesis c) Glucose catabolism d) Formation of Glycogen e) Formation of vitamin C
The __________ division carries signals to the smooth muscle in the large intestine.
A. visceral sensory B. somatic sensory C. visceral motor D. somatic motor E. afferent
The vessel that supplies blood to the face is the
A) internal carotid artery. B) external carotid artery. C) basilar artery. D) anterior cerebral artery. E) middle cerebral artery.
The pupillary light reflex is an example of a(n) ________
A) somatic reflex B) special senses reflex C) autonomic reflex D) voluntary reflex