vessels
Why are resistant vessels called resistance vessels and which blood vessels are these?
Resistant vessels are called "resistance vessels" because they play a crucial role in regulating the flow and pressure of blood within the circulatory system.
These vessels are primarily arterioles, which are the smallest branches of arteries leading to capillaries.
Arterioles are often referred to as "resistance vessels" because they have the ability to control the resistance to blood flow due to their smaller diameter and smooth muscle tissue.
Their constriction or dilation plays a critical role in regulating blood pressure and blood flow to different tissues and organs. So, when discussing resistance vessels, it's primarily a reference to arterioles and their role in regulating resistance to blood flow.
Factors Influencing Resistance:
1) Hormonal Regulation:
Various hormones, such as epinephrine and norepinephrine, can influence arteriolar resistance. For example, in the fight-or-flight response, the release of these hormones can cause arterioles in skeletal muscles to dilate, allowing increased blood flow to support physical activity.
2) Neural Control:
The autonomic nervous system plays a crucial role in regulating arteriolar resistance. Sympathetic stimulation can cause vasoconstriction, raising blood pressure and reducing blood flow to non-essential areas during times of stress. Parasympathetic stimulation, on the other hand, can promote vasodilation.
3) Local Factors:
One of the most remarkable features of resistance vessels is their ability to respond to local factors. Tissues can release chemical signals like nitric oxide (a vasodilator) when they need more blood, and arterioles in that area will respond by dilating. Conversely, conditions like low oxygen levels can lead to vasoconstriction redirecting blood elsewhere.
Step by step
Solved in 3 steps
Is it basically because they can slow down blood flow into capillaries?
by Bartleby Expert
