Cigarette smoke contains over 4,000 chemicals, including 43 known cancer-causing (carcinogenic) compounds and 400 other toxins. These include nicotine, tar, and carbon monoxide, as well as formaldehyde, ammonia, hydrogen cyanide, arsenic, and DDT.
Involuntary muscles are muscles that are not controllable consciously, and instead contract due to unconscious impulses sent by the autonomic nervous system or certain specialized cells or hormones.Both smooth muscle and cardiac muscle can be classified as involuntary muscles.Smooth muscle is comprised of spindle-shaped cells that have no striations and is found in numerous locations throughout the human body. Cardiac muscle is striated rather than smooth, and is found only within the walls of the heart. beating heart is one of the best examples of an involuntary muscle. Contractions of cardiac muscles push blood through the four chambers of the human heart. The process of peristalsis, which pushes food through the esophagus and small intestine, is controlled by involuntary muscles.
a voluntary muscle is a muscle that move when you tell it to Muscles in our hands (skeletal muscle) are called voluntary, because these muscles act according to the impulses (â¦ orders) given by our conscious brain. Heart (cardiac muscle) is an example of an involuntary muscle.It works all the time with impulses from our brain stem, which is involuntary. Some more examples of voluntary muscles in our body are muscles of the chest, neck, abdomen, and legs. Involuntary muscles include the muscles of the digestive system.--- Skeletal muscles, like biceps (the muscles that flex your forearm/wrist toward your shoulder) are voluntary muscles.These muscles will not flex unless you think about flexing them, and your brain sends that signal to your arm.nvoluntary muscles include the muscles of the digestive system. --- Skeletal muscles, like biceps (the muscles that flex your forearm/wrist toward your shoulder) are voluntary muscles. These muscles will not flex unless you think about flexing them, and your brain sends that signal to your arm.