A person in good health and optimal well-being is apparently in a state of homeostasis. This is a harmonious state. It mirrors our ability to maintain reasonably constant metabolic activity, notwithstanding zillions of incessant goings-on within the body. Such functions are, of course, part of the normal physiological process — internal, or external — during which the body responds to changes suitably.
Homeostasis denotes an unchanging condition. However, in reality, it connotes a dynamic, ever-changing state within the perimeter of ‘tapered’ limits. Whenever such a ‘fine’ balance is in jeopardy, or misplaced, in the wake of illness, or disease, there is peril waiting to happen — to destabilising the well-being of the individual.
When we have our breakfast, before we rush to office, the whole process brings about certain internal changes. The first thing you know is there is enough ‘ammo’ in your tummy, and you have to do something about it. The next thing you know, or have heard someone tell you, is the food is being broken down into simple chemicals your body can use. The protein in your breakfast, to pick one example, is digested into amino acids, or chemical building blocks. These are, thereafter, used by the cells in the body to produce their own specific proteins.
What does this signify, or connote? That our body functions with a sense of regularity, or dynamic balance. In other words, it relates to the functional realm of our being, our physiology, or self-regulatory mechanisms, or feedback chains, or systems, that ‘fuel’ basic adjustments in our functional sphere. For example, when carbon dioxide content of our blood begins to ascend, we breathe-in air more deeply. Likewise, when we drink just too much coffee, or tea, we pass more urine.
All is well, when everything is hunky-dory. However, if one, for instance, has a fault in the urinary system, they may develop symptoms of a bladder infection, or renal [kidney] disease. Likewise, if your skin has a flaw, you may develop rashes, herpes, dermatitis [eczema], or warts. If your digestive system is the ‘focus’ of something having gone askew, you may present with symptoms of hyperacidity, flatulence [gas], constipation, piles, or ulcers.
Feedback Systems
There are two forms of feedback systems: positive and negative feedback mechanisms. In a positive feedback mechanism, the response to stimulus does not stop, or reverse the stimulus. It instead keeps the progression of events fluid. Take for instance, childbirth and its sequence of events. There is stretching of the uterine cervix which stimulates the secretion of the hormone, oxytocin. This, in turn, arouses the contraction of the uterine muscle. This causes additional stretching, leading to supplementary contractions. The mechanism stops with the delivery of the baby and the placenta.
Each body structure contributes in some way to homeostasis, through such feedback mechanisms. When glucose [sugar] increases in the blood, the pancreas secretes insulin. This causes the cells to make use of ‘additional’ glucose. It is this amplified uptake of glucose and subsequent drop in blood sugar level that serves as a signal for the pancreas to reduce insulin secretion. As a result, the secretion of insulin is ‘inverted.’ This form of a self-regulating feedback loop is also ‘employed’ by the endocrine system to maintaining proper levels of hormones.
Picture this. Feedback mechanisms closely monitor and maintain normal blood pressure. When our blood pressure rises, negative feedback mechanisms bring it to normal limits. When such ‘normal’ mechanisms fall short, high blood pressure, or hypertension, may be the unpleasant outcome — the scourge of frenzied living and stressful distress.
Our body is somewhat like a spinning wheel. So long as it is spinning, or working, dynamically, all our systems stay in good shape, or balance. No matter the assault from outside forces, our body has the resilience and also the innate ability to return to its upright position, naturally.
To highlight an exemplar — when our immune system identifies a protein foreign in the system, it produces antibodies to drive the protein out of transmission, much before it can cause harm. Such self-regulating activities happen without our knowledge; they are also not tangible. What guides the organising principle, our physiology, that runs us all — from our immune function to our bio-clocks — is, of course, difficult to observe directly. Physiologists suggest that there is a fundamental principle that guides our body to live, think, eat, digest, reproduce and move. It is this defence mechanism that aids our body to repel invading organisms. It also keeps all of our internal biological functions running efficiently.
Homeostasis is seamlessly integrated to control systems which identify and counter changes in our internal environment. It has three components: a detector, control centre and effector. The control centre determines the limits within which changeable factors can be maintained. It receives inputs from the detector, or sensor. Besides, it integrates all inward-bound information.
Fine-Tuning
When an incoming signal, for instance, indicates that some ‘fine-tuning’ is needed, the control centre responds and its output to the effector is altered. When our body temperature drops below certain preset level, it is detected by specialised temperature sensitive nerve endings, which, in turn, transmit information to groups of cells in the hypothalamus in the brain. This triggers physiological mechanisms to raise our body temperature, accordingly.
Let’s look at the sequel that follows. The stimulation of the skeletal muscles causes shivering and narrowing of blood vessels in the skin, followed by heat loss. This leads to behavioural changes. This prompts us to put on more clothes, or curl up in bed with a refreshing, steaming cup of coffee too. In like manner, when our body temperature rises to ‘normal’ levels, the temperature sensitive nerve endings no longer arouse the cells in the control centre. The resultant effect, or output, to the effectors is ‘shut down.’
Yet another typical physiological pattern is seen when the external temperature reaches the crescendo as in peak summer. This triggers excess sweating, so that surplus body heat is lost by the evaporation of sweat on the outside of the skin. This response may not impart the cooling effect, at times. It can spurt adverse internal change — dehydration, or lack of fluids in the body. What happens next is predictable. When our body water reserves dwindle, we feel thirsty and reach out for a glass of nature’s most wholesome beverage — to replenish the fluid lost by way of the sweating mechanism.
