Human Physiology & Problems encountered in measuring living systems

Human physiology is the science of the mechanical, physical, and biochemical functions of normal humans or human tissues or organs.

Physiology focuses principally at the level of organs and systems.

Major systems of Human body:

1. Cardiovascular system - can be compared to closed loop hydraulic system with a 2 synchronized isolated functioning two stage pump.

It consists of the heart and blood vessels (arteries, veins, capillaries). The heart propels the circulation of the blood, which serves as a "transportation system" to transfer oxygen, fuel, nutrients, waste products, immune cells, and signalling molecules (i.e., hormones) from one part of the body to another. The blood consists of fluid that carries cells in the circulation, including some that move from tissue to blood vessels and back, as well as the spleen and bone marrow.

2. Respiratory system - can be compared to a closed loop pneumatic system with two elastic bag and air pump to create alternatively positive and negative pressures.

The respiratory system consists of the nose, nasopharynx, trachea, and lungs. It brings oxygen from the air and excretes carbon dioxide and water back into the air.

3. Nervous System - self adapting information processor with high speed communication network and a myraid of input and output channels.

The nervous system consists of the central nervous system (which is the brain and spinal cord) and peripheral nervous system. The brain is the organ of thought, emotion, and sensory processing, and serves many aspects of communication and control of various other systems and functions. The special senses consist of vision, hearing, taste, and smell. The eyes, ears, tongue, and nose gather information about the body's environment.

Problems encountered in measuring living systems (shortcut: VIT LEAPS)

1. Inaccessibility of Variables
2. Variability of data
3. Lack of knowledge about interrelationships
4. Interaction among Physiological systems
5. Effect of Transducer on measurement
6. Artifacts
7. Energy limitations
8. Safety considerations

References:

1. Biomedical Instrumentation and mesurements by Leslie cromwell, Second Edition. pp 16 to 24.
2. http://www.innerbody.com/htm/body.html
3. http://free-ed.net/free-ed/HealthCare/Physiology/default.asp
4. http://www.stcms.si.edu/hbs/hbs_student.htm