Smooth muscles are different from skeletal muscles, the muscles usually thought of when talking about muscles. Smooth muscles are all involuntary and cannot be consciously controlled. Smooth muscles usually help maintain and control various body systems. Many smooth muscles use a contraction called peristalsis, a squeezing-type of contraction, to move body materials.
Arteries, Vein and Lymph Vessels
The vessels that carry the blood throughout the body are lined with smooth muscles to assist the heart with circulation. The lymph system with its network of vessels does not have a central pump like the heart, and it is primarily up to the smooth muscles in the vessels to transport lymph fluids through the body.
Urinary Bladder
The urinary bladder is lined with smooth muscles which contain sensory tissue that provides the sensation of needing to use the bathroom. The smooth muscles provide the pressure during the process of urination.
Uterus
The uterus in the female body is made up of smooth muscles. The involuntary uterine contractions cause discomfort during menstruation and intense pain during childbirth.
Male and Female Reproductive Tracts
Smooth muscle tissue is found in both the male and female reproductive tracts. Smooth muscle contractions move an ovum from the ovary through the fallopian tubes and uterus. In men, smooth muscles control the process of ejaculation.
Digestive System
From the moment food is swallowed, smooth muscles move the food throughout the digestive system so that nutrients can be absorbed by the body. Anything that is not utilized is further moved by smooth muscles until it is eliminated from the body.
Respiratory System
The respiratory system is lined with smooth muscle tissue. Many respiratory conditions--such as asthma--are caused by smooth muscles contracting involuntarily and constricting air flow.
