Human Body as Perfect Complex Machine

Body coordination is a skill that significantly affects how well our bodies operate, even when we carry out a simple specific motion like fluttering our eyelashes, a process from molecular level takes place inside our body. As soon as we wake up, every organ in the body is at work.  Like a mechanical device, when in use, the human body moves. 

The human body is a complicated machine that utilizes numerous systems in combination to function correctly and effectively. The muscular, skeletal, cardio-respiratory, integumentary, nervous, and endocrine systems are just a few examples of the systems that are needed to function in order to complete a simple action.

The cardiovascular and respiratory systems carry and deliver the oxygen and nutrients the body needs to move; the integumentary system shields all other organs from physical harm while moving; the muscular system, which is made up of muscle fibers are responsible for majority of human movement;  the nervous system which helps send message back and forth to brain and the body to carry out movement; the skeletal system, which serves as the foundation of the human body and also aids in allowing the human movement; and the endocrine system which helps regulates biological processes in human body. 

The human body need energy to sustain and carry out physical action, much like a mechanical engine would cease to operate when its fuel ran out. Humans therefore require food that provides energy in order to move and function effectively. Studying energy expenditure, particularly the metabolic rate at which the body consumes energy during physical exercise, would help us better understand this.

As mentioned by W. Larry Kenny et.al. in Physiology of Sport and Exercise, "the range for total daily expenditure is highly variable and depends on physical activity, age, sex, body size, weight and body composition".  Each physical activity uses different amount of energy. They also made it clear that intensity and duration of the activity must be considered in determining the expended energy. 

However, no matter the age, body types, sex, gender, or body composition,  the human body wears out and eventually breaks down like any other machine. The impairment of muscle performance with sustained effort and generalized feelings of exhaustion are symptoms of fatigue.  Like a mechanical engine, the human body can become exhausted or run out of fuel, which is why it's important to rest.

Follow-up Questions: 

1. What are the several body systems mentioned in the article?

2. How do these body systems support human movement?

3. Do you agree that the human body is an ideal example of a complex machine? Why?

References: 

1.  W. Larry Kenny, PhD, Jack H. Wilmore, PhD, David L. Hostiel, PhD. 2015. Physiology of Sport and Exercise. ISBN 978-1-4504-77767-3 (print).