Healthy Humans
There are a number of key factors that determine human health.
- Food: the human body needs an adequate supply of food to maintain a good level of health. It is important that humans eat a balanced diet.
- Water: the human body is about 65% water so it is important for the effective functioning of the body systems and organs that we drink sufficient amounts of water.
- Oxygen: the human body needs to take in oxygen so that the process of cellular respiration can take place. This is called aerobic respiration because it involves oxygen. Food substances (mainly glucose from carbohydrates) are combined with the oxygen resulting in the release of energy into the body.
- Heat: the human body has a temperature of 37oC, which remains constant unless the body is ill. During cellular respiration, energy is released around the body, some of which is in the form of heat. This occurs at the same time as the body is losing heat. If there is a net loss of heat, the body responds by shutting off some blood vessels near the surface of skin and making body hair stand up. If there is a net gain in heat, then the body produces sweat as means of cooling down. The human body continues to operate in the extremes of atmospheric temperatures but once these become too hot or cold, the responses of the brain and nervous system begin to change and judgements and reactions are affected.
- Exposure to harmful substances: harmful substances can very seriously damage the body and its systems, and can lead to illness, accident or death.
- Exercise and rest: regular exercise and rest are important factors in maintaining good health. Exercise can benefit the heart (making it stronger and helping to eliminate the build up fatty deposits in the arteries), keep muscles and joints in good condition and give a feeling of overall well-being. Rest is important because it gives the body the time to carry out its basic functions of repair and maintenance. Lack of sufficient sleep can lead to a hormonal in-balance in the body which can result in stress, anxiety and the inability to make clear and considered judgements.
- Safety: it is important that, as humans, we take every possible precaution to keep ourselves safe. This involves assessing the possible risks involved in carrying out the very many activities that humans do. People will often decide that the risks involved range from the minimal to the very real, and take appropriate decisions to ensure their safety. Others may choose to ignore any potential risks and risk injury or death through carrying out a particular activity.
- Freedoms from disease: humans have worked tirelessly in seeking solutions to many medical problems, including diseases, through the development of medicines and vaccines. Vaccination is one way of avoiding a disease and involves introducing a weak micro-organism into the body. This causes the body to develop antibodies that act to prevent the disease developing in the body. The antibodies remain in the body so if the person is in contact later with a full-blown version of the disease, the antibodies quickly replicate themselves to prevent the disease developing to a harmful level. Vaccinations have successfully prevented many diseases from being widespread and have contributed to the overall health of humans.