Constriction is a key regulatory process within the body that is important for proper functioning in many of our physiological systems. Learn more about the process of constriction and when it is utilized within the human body.
What Is Constriction?
The word constriction, in terms of human physiology, means a narrowing or closing of a passageway. This usually refers to structures where materials are allowed to pass.
Constriction is an autonomic process, which means you cannot consciously control it. It is used as a method of regulating, or controlling, the passage of materials, fluids, and solids within the body.So how does it work? Two words: smooth muscle.
Smooth muscle is one of three muscle types in the body and is often found in internal organs such as the stomach, bronchi, and bladder. Smooth muscle is also found in several other structures, such as in blood vessels and muscle sphincters. When smooth muscle contracts, it allows for constriction to occur in these organs and structures. This usually happens when a decrease of bodily materials is needed.
Constriction vs. Dilation
Constriction and dilation are opposite, but related, processes in the body. Whereas dilation is an opening or widening of a structure or passageway to increase material flow, constriction leads to a decrease in material flow by closing the passage.
Both of these processes are controlled by smooth muscle, so dilation and constriction can usually be seen in the same places within the body, such as in blood vessels, the pupils of the eyes, and other structures. It’s important to know that constriction and dilation work together to ensure proper flow of materials within the body.
Example of Constriction: Pupils of the Eye
Imagine that you are at the eye doctor’s office. As she is performing her routine checks, she pulls out a pen light and shines it in your eyes. She tells you that your pupils constricted, and therefore, they are functioning properly.
What does this mean?The pupils of the eye are responsible for allowing light to pass through to the receptors of the eye so that you’re able to see. However, the amount of light necessary to see a particular image may change depending on the light source. If the source is too bright, it could damage the cells of the eye and cause impaired vision.To prevent this from happening, the smooth muscles of the eye will constrict when light increases in order to reduce the amount of light that is allowed to enter the eye. By constricting, the pupil allows you the ability to focus on the images in front of you without damage. So, when your doctor shines the light in your eye, she is checking to make sure that your pupils are constricting properly.
Example of Constriction: Blood Vessels
Blood flow in the body is important for the delivery of nutrients, oxygen, and the removal of waste materials. However, the amount of blood that goes to different parts of the body will vary depending on the functions of those body parts and the circumstances.Picture this: you are running from a bear in the woods.
This is an emergency situation, and the body will start to function under emergency conditions. Therefore, you might expect that blood flow to the muscles would increase since you will need your muscles to run away. The blood vessels in the muscles will dilate in order to increase blood flow and oxygen in those areas.However, do you really need blood in areas such as the stomach or genitals? The answer is no. Imagine getting hungry or aroused during a life or death situation.
. . doesn’t make sense right? The body, in addition to dilating blood vessels in the muscles, will constrict blood vessels in non-essential areas, such as the stomach and the genitals, so that those resources can be sent to areas where they are needed.As mentioned earlier, constriction and dilation are opposite processes that are related and work together for the needs of your body, and this is an example of how constriction in blood vessels is necessary to reduce blood flow during certain situations.
Constriction is a narrowing or closing of a passageway. Constriction is a key regulation step for many different processes in the body, and is usually coupled with dilation, which is an opening or widening of a structure or passageway to facilitate the needs of the body under given conditions. Regardless of the process, it will typically involve autonomic control of smooth muscle, and when smooth muscle contracts, passageways within the body close in order to reduce flow of materials to particular areas.