Saturday, August 30, 2014

System Integration

Let’s explain one of the most common greetings we offer to those we meet. “How are you?” may signal our interest in the general well-being of our friends. Sometimes our query relates to their physical health, and may be expressed, “How are you feeling?” Notwithstanding the possible impertinence of this question, our acquaintances may actually be flattered by the personal interest expressed by the questioner. We may be inquiring about how the eleven physical body systems are operating. If all body systems are operating healthily, we also desire that they be integrated, coordinated, and cohesive. When we answer “I’m fine, thank you” to these questions, we should be aware of its potent meaning.

A breakdown in one body system is able to impede the integrated functioning of the entire body. Biology textbook resources instruct us concerning the circulatory, digestive, endocrine, excretory, immune, lymphatic, muscular, nervous, reproductive, respiratory, and skeletal systems. A visit to the hospital makes us aware of a throng of specialists eager to treat disorders related to these systems. The names of department specialties are posted over each office complex. General practice “specialists” understand the basic workings of all body systems and how the systems integrate.

In our recent series of posts we have focused on the auditory system—the ear and hearing. The human auditory system is but one of five sub-systems comprising the sensory system. The nervous system integrates the sensory organs with other body systems. Other sensory organs of the nervous system provide vision, touch, smell, taste, and balance. Auditory and visual senses provide the major portion of sensory information we glean from our physical world. However, we acknowledge the vital importance of touch, smell, taste and balance, not to mention our expectations concerning the healthy functioning of the other ten major body systems.

The outer, middle, and inner ear, together with the complex neural passageways for transmission of coded digital information from the ear to the auditory cortex consists of an integrated system in itself. But without the integration of other major body systems such as the circulatory system, sensory systems such as the auditory system would be non-functional. At every level of human bodily function, we understand the importance of system integration.

Maintaining effective integrated function of body systems relates to our adherence to healthy lifestyles. The more we understand the functional wonders of human body systems, the more we experience reverent awe of the Creator of body systems. Not only did God design each system, but he also designed the means of body system integration. Such knowledge is an example of the orderliness of God’s created works. Our expressions of awe and reverence are expressed in Psalm 29:2: “Ascribe to the Lord the glory due his name; worship the Lord in the splendor of his holiness.” (NIV) 

Thursday, August 28, 2014

Wonderfully Made

A weak analogy to the human auditory system may be found in some of the more complex machines devised by man. An automobile is a highly integrated machine functioning for a generally singular purpose—transportation. The are 1800 parts in an automobile if we count units such as engines, themselves composed of many parts. If we count individual parts from which more complex units are built, the number rises by multiples.

Our auditory organs also exist for a singular purpose—hearing. This does not include how our conscious mind analyzes and processes physical sounds with which we are surrounded. Physiologists have revealed the complexity of physical processes entailed in successful hearing. Much as scientists recognize the human mind as a far more complex processing unit than any man-devised computer, we propose that the human auditory system is superior to the most advanced man-devised sound processing system. MIT professor Barry D. Jacobson has expressed, “The auditory system…far surpasses any sound reproduction system around. No artificial intelligence based system built to date can interpret sounds with the accuracy that the auditory system can.”

The Creator has consigned man to a physical world. We may describe phenomena such as sound and sound processing with respect to multiple interactions of physical matter. Humans study and understand these physical interactions. Physiologists recognize the capabilities of human-built machines do not compare with sensory systems of the human body. We use sound processing capabilities of the human body as our present example. In terms of understanding the physical processes of human hearing, God has enabled present day scientists to identify and describe what happens in our bodies when we hear, not to mention what happens in our brains when we process the sounds we hear. Believers in intelligent design do not stumble at the handiwork of an Intelligent Designer as we study the auditory system.

In previous posts we discussed the transduction of compressional waves to digital signals. Our discussion of the sequence of action, however, was incomplete. The impulses are first converted to digital signals in the cochlea where neural coding first occurs. Re-encoded signals then travel through the nerve known as the eighth cranial nerve on their way to the processing centers of the auditory cortex. There are several processing and integrating centers along the way, including the cochlear nucleus, superior olivary nucleus, inferior colliculus, and medial geniculate body. Finally, the newly encoded auditory impulses arrive at the auditory cortex. The auditory cortex is the brain’s most highly organized sound processing unit.

Reading just a phrase or two of this post on sound consumes far more time than we ordinarily need to react to sounds and process our responses. Campbell and Reese’s AP text Biology summarizes the beauty of our senses, not only our auditory sense, but also all senses: “It is customary to think of animal behavior as a linear sequence of sensing, brain analysis, and action—similar to a computer passively waiting for instructions before it acts. This is not the case. When animals are in motion, they are probing the environment through that motion, sensing changes, and using the information to generate the next action. This is a continuous cycle rather than a linear sequence, as the brain carries on background activity that is constantly updated as sensing and acting proceed.”

Our post title is a contraction of Psalm 139:14: “…I am fearfully and wonderfully made.” Fearfully connotes a response “full of awe and wonder.” In this sense we may better understand wonderfully. We close with a quote of the full verse: “I praise you because I am fearfully and wonderfully made; your works are wonderful, I know that full well.” (NIV)  


Saturday, August 23, 2014

Digital Human Hearing

Digital electronic technology may have been an unfamiliar term just a few short decades ago in our science classrooms when I began teaching. When my science class members studied the physical qualities of sound, followed by basics of the ear and human hearing, I do not recall digital technology being part of our discussion. Perhaps we were more focused on learning the mechanical transmission of sound through the ear canal, eardrum, the auditory ossicles (small bones from the eardrum to the cochlea), and the cochlea where mechanical transmission of sound ended. We were at the cusp of the Digital Age. Many did not know what the Digital Age meant. It was triggered by the recent phenomenon known as The Digital Revolution which began after mid-20th century.

We now understand more fully the importance of digital technology. Whether or not many of our older citizens appreciate and understand it, digital technology now rules our lives. Virtually all of our communications media runs on discrete digits. We translate “digits” as Information transferred through millions of “on” or “off” signals. Often, information is conveyed as a series of zeroes or ones. On or off signals, or zeroes or ones, assume many different forms. In the human body, electrical impulse information transmitted in billions of neural passageways is also digital. 

After the transmission of sound waves from the outside world enters the snail-shaped cochlea, the auditory signals change from mechanical to electrical. The fluid of the cochlea surrounds multiple regions of hair cells each sensitive to a different frequency of sound. After the tiny hair cells are moved mechanically by compression waves traveling through the cochlear fluid, the sound transmission is transduced. That means the energy form converts from mechanical to electrical. On or off electrical impulse transmission comprises one of many different forms of digital information.

The cochlear hair cells transmit many forms of auditory information in addition to differences in the pitch of sound. For example, the ear distinguishes between loud and soft and also distinguishes directionality of sound sources. In addition, the brain interprets subtleties such as overtones, helping us distinguish among hundreds of different musical instruments. Overtones help us identify the voices of hundreds of acquaintances. A minimal scientific explanation of mechanical to electrical transduction is found in quotes such as “(hair cells)…are at the core of electro-mechanical transduction; the transformation of sound vibration into a neural signal that can be interpreted by the brain.”

Today’s young people are being raised in a digital culture. Digital technology has changed our culture in significant ways. Compared with wonderful advances in analog technology up until the digital revolution arrived full force in the latter half of the 20th century, digital technology is now a cause for jaw-dropping wonder at the onset of the 21st century. The explanation of how digital devices work and how to operate them still bewilders many people over 60 years of age.

My concern with this discussion of human hearing must not rest with stating that sound impulses through auditory neurons are simply “digital.” The real divine genius of the Creator in designing an auditory digital system which codes for communication of bewilderingly complex information in our human brain is a cause for worship. Perhaps we may better grasp what bio-science authors mean when they use the phrase the neural code. Codes are the product of a mind—God’s mind!   

Tuesday, August 19, 2014

An Ear for Truth

As we deal with the topic of sound and hearing, we would first do well to think deeply about God’s creation of our physical sphere and how the physical sphere is interlocked with the spiritual sphere. How is knowledge of the spiritual sphere interlocked? Man is created in God’s image. Our spiritual dimension enables us to contemplate God’s reality, both in sustaining our physical world from day to day and in understanding God’s original creation of the heavens and the earth. As we continue the discussion of topics such as sound and hearing, we become more aware of the Creator’s role in establishing how man accesses information about our world through sound and hearing.  

As creationists, we are reminded of Genesis 1:1: “In the beginning God created the heavens and the earth.” Heavens and earth refers to all that exists. This phrase could also apply to God’s creative acts in the intervening eons of time. God created all physical matter, including hundreds of billions of galaxies, each with billions of stars. In recent ages the phrase creation of heavens and earth might include periodic creative acts such as the origin of life and the origin of man. There is a quantitative difference between the enormous quantity of non-living matter in our universe and the relatively small amount of living matter to be found on Planet Earth. Certainly there is a qualitative difference between non-living and living matter.

God created all that exists. Genesis 1-2 stresses the creation of humanity in God’s image. The Genesis accounts underline the interaction of man with the physical creation. Humanity is immersed in a physical world. 

Humanity created in God’s image perceives two major spheres of reality. One sphere is the physical world of orderly matter governed by predictable physical constants. Another is the spiritual world—a divinely implanted God-consciousness with a deeply ingrained ability to contemplate present and future reality.

The Creator has gifted man with the ability to access information concerning the physical world through the five major physical senses. A study of the stimulus of sound energy and the sensory ability to detect it using our specialized organs of hearing triggers only the beginning of our sense of wonder. Physical sound traveling by compressional waves of air molecules transfers its energy through the canal of the outer ear into the solids of our eardrum and three small bones of the middle ear, and finally into the cochlea, the inner ear’s liquid medium.

In future posts we will extend our discussion of man’s ability to convert sound energy from physical waves of compressed molecules to billions of electrical signals called action potentials rushing to the brain from the cochlea through tens of thousands of neural circuits in the auditory nerve. This information reaches the brain in what is known as the “neural code.”

In the wisdom of God, humanity has been created to experience and enjoy both the physical world and the spiritual world. Before the creation of the heavens and the earth (all that exists), God existed as a spiritual entity. In the days of Christ on earth, he taught, “God is spirit, and his worshippers must worship in spirit and in truth” (John 4:24 NIV). God still exists as a spiritual entity. The infinite Creator brought the physical heavens and earth into existence. Earth’s recently created humanity now enjoys both physical and spiritual dimensions of reality. Our dual existence is a divine gift to man and an expression of God’s love for his created works. 


Wednesday, August 6, 2014

Sound Hearing

Our two-word post title implies two different definitions of sound. The term could apply to a physical phenomenon relating to a type of energy generation initiated by vibrations propagating mechanical pressure waves in gases, liquids, or solids. A different definition comes from the fields of human physiology and psychology: Sound is the perception of such waves by the brain. Confusion of the two meanings of “sound” is the basis of a famous riddle quoted in a recent Geico commercial. “Well, did you know that when a tree falls in a forest and no one’s around it does make a sound?” The answer depends on how we understand the differences between physical, physiological, and psychological definitions of sound. 

Sound hearing” may also connote a third meaning. Used in this manner, “sound” connotes healthy, defect-free, or robust. Sound hearing may be a treasured possession of a healthy young person. When ear infections or injuries occur, or when advancing age takes its toll on the human body, our hearing ability may diminish. Hearing may no longer be described as “sound.”

The physical phenomenon of sound has been present in this solar system since its formation. Physical sound vibrations occur in non-living matter. Our earliest planetary atmosphere, therefore, possessed physical sound, but there was no one present to perceive it. Atmosphere has been a component of Earth environment since planets appeared. Earth’s early atmosphere, very different from the composition of today’s atmosphere, obeyed physical laws and possessed “sound.” Early earth bacteria, the only living things on earth for eons, were not equipped to detect or respond to physical sound. They fulfilled divine purpose as they served to oxygenate the earth’s atmosphere and produce many other mineral resources for the benefit of life forms to appear later.

The physiological and psychological phenomena of sound assumed meaning later when living things were created with organs of hearing. Their hearing mechanisms were able to convert physical vibrations to electrical signals for transmission to the brain. Physical sound occurs in non-living matter. But without a mind to analyze, interpret, and act on its signals, the sound is devoid of any meaning. 

Ultimately, the human brain analyzes and interprets the physical sounds we perceive. We have used three words in our discussion of sound—physical, physiological, and psychological. In a sense the ear is the connecting link between physical sound and its psychological effects. If we study brain physiology, we understand that the physical ear is the center link between physical sound in the outside world and the brain. In a sense, the brain does the hearing. The brain processes the millions of electrical signals from our auditory organ—the ear. That our brains are able to make sense of millions of “action potentials,” electrical impulses arriving through neural circuits via our auditory nerve is the subject of past, present, and future research. In reality we have only begun to understand how the auditory center of the brain accomplishes its work.

Our posts have not begun to deal with how the ear functions as a link between the physical sound around us and the brain which actually hears. We may posit that the ear itself does not hear. Rather, it produces and transports action potentials to the brain. When I taught the subjects of hearing and sight, I sometimes stated, “The brain figures it all out.” That statement served as a cover, not for what we know, but rather, for what we don’t know about how human senses work.

Lessons on sound or sight should first begin with a sense of wonder for the psychological processes of hearing and seeing. “Something special” sets living things apart from non-living entities in our world. In turn, “something special” sets humanity apart from every other species, even the marvelous soulish creatures providing us so much pleasure. Understanding this special quality, even at a level young children may understand, is a starting point for understanding sensory gifts. We begin to acquire a small glimpse of what God meant when he pronounced, “Let us make man in our image” (Genesis 1:26).


Sunday, August 3, 2014

Sound Information

When we hear sounds originating at a distance, we gather information concerning events at the distant location. From personal verbal communication carried by waves of sound, we make conclusions about what is in the mind of the speaker. “Listen to the sound of my voice” is an imperative beyond merely hearing sounds. The perception of vocal sound entails comprehension of the thought processes of the speaker. The pleasure of listening to music helps us understand the mind of the composer. As we work or walk, we translate the meaning of sounds we hear. We wonder, “What is the source of the sound? What message does the sound bring? How should I respond?” The impact of sound reception extends far beyond mere transfer of physical energy from its origin to its destination.

Of course we may not always consciously analyze the superabundance of sounds in this manner, but understanding the physical science of sound may provide a dimension of enjoyment we may otherwise miss. Most people do not think about what happens in the air when they carry on a conversation, listen to music, or hear the approach of a train. Sound is considered a “remote sense.” Humans are designed to be “remote sensors.” In recent years, remote sensing technology in military reconnaissance and radar navigation has become far more useful to society. Its application was, however, an extension of the senses gifted to living things. Higher animals share our ability to sense sound and sight remotely. In humans, however, the sense of sound helps us access the quality of soul and spirit in those fellow humans with whom we communicate at a deeper level.

Consider this very brief primer on sound. The human voice produces its sound with rapidly vibrating vocal cords. Instrumental music is produced by vibrating strings, reeds, drum heads, or air columns. Many other types of sounds are produced by various mechanical processes. Vibrating objects compress millions of discrete air molecules, pushing them together into a “pressure wave.” The air pressure in the wave may be only one millionth greater than the pressure before the compression took place. The pressure wave then rushes away at 1100 feet/sec, separated by a rarefaction, a region where the air pressure is slightly less, perhaps one millionth less than normal. For example, assume the pitch of a human voice is the same as Middle C on the piano. The vocal cord and the Middle C piano string produce 256 cycles/sec (pressure waves) separated by 256 rarefactions.  

When we hear sounds of a voice or of music, we sense the arrival of pressure waves and rarefactions. Instruments measure how many pressure waves per second, also called cycles per second, or hertz, have been generated. The data do not begin to tell what happens when these pressure waves impact our body. We leave that story for future posts with a reminder that perceived pitch of the sound depends on the number of hertz, (cycles per sec (cps)) generated by the vibrating body. Our knowledge of physical sound and hearing are examples the Creator’s provision for highly efficient communication and information gathering among his created life forms.

Several 2008 posts dealt with principles of physical sound production in greater detail. They are a good introduction to a more extensive understanding of the sense of hearing: