Processes of life in the human body include nutrition through digestion and absorption of nutrients in the stomach and intestines, respiration through breathing air into the lungs, and circulation of oxygen and nutrients through the heart to the body. Other key processes are excretion of waste, reproduction through sexual intercourse and development of offspring in the mother's womb, and sensitivity to the environment through the five senses of sight, hearing, touch, taste, and smell which provide information to the nervous system and brain to elicit a response from the locomotor system of bones and muscles.