Muscle is a soft tissue composed of elongated cells (muscle fibres) that produce force and motion through contraction. Involuntary cardiac and smooth muscles are responsible for contraction of the ...
Each nipple contains milk duct openings through which breast milk flows. Nipples are held erect by small, smooth muscles that respond to signals from your autonomic nervous system. Nipple erection can ...
Quad muscles, or quadriceps femoris muscles, are four muscles that cover the front and sides of your thighs. The quadriceps are some of the largest and most powerful muscles in your body. They provide ...