By any standards, the functioning of the human body still remains a puzzling and complex experience. After several thousand years of intricate study, civilizations are yet to unearth all their mysteries. However, as a direct result of joint efforts by scientists, researchers and other theorists, a great deal of knowledge about how our body systems operate has been brought into the light. For example, we now have a more profound understanding of how the association between the Central Nervous System (CNS) and the Peripheral Nervous System (PNS) assist in the preservation of musculoskeletal integrity (Tortora & Derrickson, 2006). This section aims at discussing the functions and interactions of the structures of the nervous, skeletal and muscular systems involved in the movement of climbing a stairway to answer a phone call.
It is imperative to start the discussion at the peripheral nervous system (PNS), the conduit used by the body to relay sensory and motor signals between the CNS on the one hand and the body organs, body surface and musculoskeletal sections on the other hand (Tortora & Derrickson, 2006). The PNS also provides the body with a link to the external environment, not only in terms of reception of external stimuli such as a ringing telephone but also in responding to the stimuli. To climb upstairs to pick the phone, the sensory (afferent) division of PNS must relay signals to the CNS via sensory neurons, and use the spinal cord as the major conduit between the body and the CNS. The brain will then process the information and relay it back via the motor (efferent) division of the PNS to the affected effector organs. In the afferent division, the dendrites function to receive signals from other neurons and pass over the same information to the cell body, while axons fibers functions to conduct the signals from the cell body to other nerve fibers through the discharge of neurotransmitters known as acetylcholine (Tortora & Derrickson, 2006).
The semicircular canals and the otolith organs, classified as vestibular apparatuses in the afferent division, will definitely assist the person in terms of deciphering the position of the phone, not mentioning the fact that these structures will assist him to sustain positional equilibrium and balance while climbing up the stairs. The eyes will provide important information about the position of the phone relative to environment (Tortora & Derrickson, 2006). The proprioceptive fibers functions to supervise the stretch or contraction of the muscles involved in climbing up the stairs to pick up the phone. For example, they will monitor the tension within the anterior trunk muscles or rectus femoris and relay the signals to the CNS for processing.
The signals transmitted by the motor neurons of the efferent division stimulate various muscles used in the movement to contract or relax (Tortora & Derrickson, 2006). The effector organs found in the muscles functions to respond to the efferent impulse. In movement, most reflex activities occasioned by the efferent division are somatic reflexes, meaning that they have the capacity to activate skeletal muscles such as the quadratus femoris, tibialis, soleus, and bicep femoris (Blakey, 2006).
In climbing up the stairs to pick the phone, the skeletal system serves two fundamental functions – provide support for tissues and underlying muscles, and facilitate movement through the use of bones and appended muscles (Tortora & Derrickson, 2006). According to the authors, the mostly utilized bones in movement comes from the hip joint (femur and pelvic girdle), knee joint (femur and tibia), and ankle joint (tibia and calcaneus). Joints make it possible for one to accomplish a multiplicity of coordinated movements in diverse parts of the body. In climbing up the stairs, each of these joints generates two phases – the driving phase (leg is in direct contact with the ground) and the recovery phase (leg is in the air).
The musculoskeletal system makes use of the lever principle to make the muscles pull the affected bones so that the movement of climbing up the stairs to pick the phone is attained. While in the driving phase, mentioned above, the hip area utilizes gluteal and hamstring muscles such as biceps femoris and semitendinosus, while the ankle utilizes gastrocnemius muscle. The knee joint utilizes such muscles as rectus femoris, vastus lateralis and vastus intermedialis (Tortora & Derrickson, 2006). While in the recovery phase, the hip utilizes the iliopsoas muscles; the knee uses the hamstrings; and the ankle makes use of the tibialis anterior muscles. Muscles such as the trapezius and stemocleidomastoid, found within the neck region, assists the person to maintain the head in position while climbing the stairs, while others such as the rectus abdominus assists in maintaining an upright posture and body position. It is important to note that sensory (afferent) receptors of the PNS rooted in the muscles constantly relay information about the position of the muscles to the CNS, effectively enabling movement to be made without straining the muscles (Mcardle & Katch, 2005).
The physiology on body movements can never be possibly exhausted. However, by viewing body movements, scientists, sports personalities, trainers and other interested parties are able to critically appraise how one body movements influences and are influenced by another via a chain reaction involving the nervous systems, muscles, skeletons and joints (Mcardle & Katch, 2005). This is an important discovery for the posterity of mankind.
Reference List
Blakey, P. (2006). The muscle book. Bethany Turnpike Honesdale, PA: Himalayan Institute Press.
Mcardle, W.D., & Katch, V.L. (2005). Essentials of exercise physiology, (3rd Ed), Lippincott Williams & Wilkins.
Tortora, G.J., & Derrickson, B.H. (2006). Principles of anatomy and physiology. River street, Hoboken, NJ: John Wiley & Sons, Inc.