PHYSIOLOGY OF AGING

How pleasant it looks, having a picture of a man that never aged as a matter of fact everybody want such a life where aging is absent but Alas! The concept of aging is a natural phenomenon and as well a largely mysterious process that is above the power of will.

Aging is inevitable and as life expectancy increases it becomes more important to understand physiological mechanism associated with the normal aging so that the quality of life may be sustained. Physiologists are in the ideal position to test hypotheses of how genetic, molecular and cellular mechanism of aging affects human physiology—journal of applied physiology2003

Aging reflect all the changes that occur over the course of life, it is a process that begins at conception and continues for as long as we live. At any given time throughout our lifespan; the body reflects;

• It’s genetic component
• It’s environmental experiences

In other words, our bodies reflect our genetic capacity to adapt and repair as well as the cumulative damage for disease processes. Aging highlight our strengths and weakness.

In our society we currently think of ‘’young Old’’ as being around 65 to 74 years, ‘’middle Old’’ 75 to 84 years and the ‘’old Old’’ 85 years +. With advancing age, all of the body system eventually demonstrates reduced efficiency, slowed building & replacement, and actual loss of tissue. While an individual’s aging experience is unique, there are generalisations which can be observed for each of the body system.

Causes of Aging

‘’we are all amateurs; we do not live enough to become anything else’’ _charlie chaplin

Aging being a multifarious and mysterious process has been explained by many theories, which fall into two main categories;

• Damage theories
• Programmed theories

These theories have been proposed to explain the process of aging but neither of them appears to be fully satisfactory, these theories may interact with each other in a complex way.

• Damage based theories of aging

One class of theories of aging is based on the concept that Damage, either due to normal toxic by-product of metabolism or inefficient repair/defensive system, accumulates throughout the entire lifespan thereby causing aging.

• The free radicals theory of aging [FRTA]
• The DNA damage theory of aging
• Energy metabolism and aging
• Orgel’s hypotheses, protein damage and autophagy
• Programmed based theories of aging

Aging is a direct consequence of genetic programming, the cause of aging are directly built into the genome and cellular structure, as a sort of molecular clock.

• Disposable soma theory
• Genetic theory
• Immunological theory
• Telomere theory.

For the sake of this essay, broad explanation will not be done on all the theories listed above, the scope of this essay is therefore streamlined to ‘’free radicals theory of aging’’.

Free radical theory of aging

Free radicals has been thought to be one of the numerous factors responsible for aging. As series of metabolic and cellular activities which help in the sustenance of life occurs, free radicals are produced. The presence of free radicals in human body remains inevitable as metabolic processes keeps occurring.

Free radical theory of aging [FRTA] states that organisms age because cells accumulate free radicals damage over time. A free radicals is any atom or molecule that has a single unpaired electron in an outer shell while a few free radicals such as melanin are not chemically reactive. Most biological relevant free radicals are highly reactive, for most biological structure, free radical damage is closely associated with oxidative damage. Antioxidants (such as vitamin C ,trios and polyphenols). Are reducing agents which mop up free radicals and limit oxidative damage to biological structure. Free radicals theory is concerned with free radicals such as superoxide [O₂^–],Hydrogen peroxide[H₂O₂] or Peroxynitrite(OONO^–)

Aging has also been linked to DNA repair machinery allowing permanent error to become more common in order organism and many other factors as well has been linked to aging being a multifarious and mysterious process.

EFFECT OF AGING ON ORANS

• Skin

The primary function of the skin is to protect the organism from the environment. It accomplishes this by providing a barrier that regulates temperature, retains fluid and absorbs shock and ultraviolet radiation, among other things. As we age, the dermis decreases in thickness by about 20%. As it thins it loses vascularity, cellularity and sensitivity. Its ability to exchange or retain internal heat is diminished. The skin becomes thin, fragile and slow to heal. Sweat and sebaceous glands are reduced both in number and effectiveness. Sensory neurons are decreased by 30% from the age of 10 years to 90 years old.

• Subcutaneous fat

 deposition is altered in the elderly. Muscle, blood vessels and bone become more visible beneath the skin due to thinning of subcutaneous fat on the extremities. Fat deposition occurs mainly on the abdomen and thighs.

• Musculoskeletal

Muscle mass is a primary source of metabolic heat. When muscles contract, heat is generated. The heat generated by muscle contraction maintains body temperature in the range required for normal function of its various chemical processes.

As early as the third decade of life there is a general reduction in the size, elasticity and strength of all muscle tissue. The loss of muscle mass continues throughout the elder years. Muscle fibers continue to become smaller in diameter due to a decrease in reserves of ATP, glycogen, myoglobin and the number of myofibrils. As a result, as the body ages, muscular activity becomes less efficient and requires more effort to accomplish a given task. The elderly are less efficient at creating the heat necessary to drive the important biochemical reactions necessary for life.

• Respiratory function

Lung function diminishes with age. The major contributing factors are the progressive loss of elastic recoil within lung tissue, the chest wall becomes stiff, and there is a decrease in alveolar surface area. These changes diminish the efficiency of gas exchange and make it more difficult to exercise.

• Cardiovascular

Despite cardiovascular disease, often combined with a slowdown in the autonomic nervous response, the cardiovascular function of a resting healthy elder is usually adequate to meet the body’s needs. Cardiac output of healthy exercising elders can usually be maintained, allowing moderate continued physical activity throughout their lives.

• Endocrine and metabolism

Old age is accompanied by a generalized reduction in hormone production and activity. This reduction affects most metabolic functions of the body. Water,mineral, electrolyte, carbohydrate, protein, lipid and vitamin disorders are all more common in the elderly. Nutrition and the ability to use food for energy is seriously affected in the elder population.

Diabetes is common in the elderly. There are many causes but a primary mechanism involves the inability of skeletal muscle to absorb glucose. Over time skeletal muscle becomes less responsive to insulin.

Recent research indicates that the elderly are at risk for nutritional deficiencies due to anorexia. Age related anorexia has been linked to a lower satiety threshold. Elders feel “full” sooner which may be due to changes in hormone receptor or trigger mechanisms.

• Neurosensory

Like other systems, the nervous system changes with age. There is loss of neurons in both the brain and spinal cord. There is loss of neuronal dendrites which reduces the amount of synaptic transmission. The sense of smell, taste, sight, touch and hearing are all diminished over time. Depression can be the result of impaired synaptic activity. Research indicates that as many as 25% of nursing home residents are clinically depressed. Depression is one of the most common reversible causes of weight loss.

Summary

Clearly elders are at a disadvantage when it comes to generating metabolic heat. They have less muscle mass and therefore less generating apparatus. They have less alveolar surface, therefore less oxidative reserve. Their skin provides less protection from heat loss. They have impaired neurotransmission, therefore less ability and/or desire to initiate activity. All of these factors put the elderly at risk for hypothermia if their environmental circumstances expose them to heat loss greater then their resting heat generating capacity.

Possibilities of Increased Lifespan

As things stand, the maximum human lifespan is about 120 years. As a whole, human knowledge is increasing at an exponential rate. By this logic, some scientists believe the human lifespan could be increased to between 400 and 1,000 years within the next 20 years. (Of course, we wouldn’t really know for 400 more years…)

The following are some theories on increasing the human lifespan:

• By increasing the amount of antioxidants in one’s system, one will have less damaging free radicals in the body. The necessary antioxidants can be found in several sources:
• Multivitamin pills, especially Vitamins C and E.
• Beta cerotene
• Zinc
• Selenium
• Calcium
• Magnesium
• Chromium Picolinate
• Coenzyme Q-10
• Telomerase has been discovered in some germs and cancer cells, but not in most normal organisms. This enzyme replaces/repairs shortened telomeres such that the cells are able to replicate (theoretically) forever. If the telomerase gene could be activated or spliced into regular human cells (assuming telomere theory is correct), human longevity would be greatly increased.
• A mutant form of the gene age-1 in the worm C. elegans caused the worm’s lifespan to double. The gene apparently codes for an enzyme important in the mediation of cellular communication and signal transmission. Increased lifespan was observed when the age-1 gene was nonfunctional.
• Injection of growth hormone into men seemed to reverse some signs of aging. Experiments with other hormones, such as estrogen and testosterone, are ongoing.

Ajayi Oluwatobi Hezekiah,

 Physiology student,

Ladoke Akintola University of Technology.

 

   REFERENCES;

Journal of applied physiology 2003

The scientific staff /March 1, 2015/

Getting older by Christopher Lewis

Physiology of the Aging process RnCeus.com(file///accounts/1000/shared/download/PHYSIOLOGY% 200F%20THE%20AGING%20PROCESS.html)

EFFECTS OF VOLUNTARY BLOOD DONATION ON MATERNAL MORTALITY

 

After losing tremendous amount of blood during her labor, there came in another scenario of postpartum hemorrhage after the delivery of the baby. The drastic loss of blood brought about hypovolemia (low blood volume) which demanded for immediate blood transfusion, in the short time limit, as the blood to be transfused was not available, she died.

A lot of women have died as a result of being anemic probably before or after delivery and there was no or little blood in the blood banks to give as replacement.

Maternal mortality is unacceptably high, about 800 women die from pregnancy-or-child birth related complications around the world every day. In 2013, 289 000 women died during and after pregnancy and child birth. Almost all of these deaths occurred in developing countries, most especially Africa and Asia.

One of the major complications that results to maternity death is “hemorrhage/bleeding” (mostly before and after child birth i.e. antepartum and postpartum bleeding respectively), which is the heavy loss of blood. It was established that about 27% of maternal deaths globally is as a result of severe bleeding/hemorrhage, most of which are actually preventable.

Postpartum hemorrhage (PPH) is an obstetric emergency that can occur following vagina and caesarean delivery. As a result of this bleeding, the saving mother become severely anemic and this demands for blood transfusion to replace the lost blood components.

The question then is, how would the blood that is not available be transfused? This fact makes it crystal clear that Voluntary Blood Donation by individuals has an inhibitory effect on maternal mortality. If we would all rise to embrace this act of charity and give blood such that there is availability of blood to give to saving mothers at any degree or level of anemia during or after delivery. Without any element of doubt maternal death will reduce.

A microscopic view and examination of maternal mortality as a result of hemorrhage leaves me with the conclusion that: Countries and regions where there is effective blood donation tend to have reduced rate of maternal death as a result of hemorrhage and vice versa.

To our chagrin, more than half of these maternal deaths occur in sub-Sahara Africa and almost one-third in south Asia, we Africans give less blood and in turn we have increased maternal mortality rate. In Nigeria alone, maternal mortality rate reaches up to 3200 women (number of mother per 100,000 births dying within 42 days after child).

 If at all you have not seen any reason to give blood I think giving blood to those who give life really worth it.

WHY VOLUNTARY BLOOD DONATION IN NIGERIA ?

 

 

We have heard about cases of many patients that died not because they were not given the proper health care or medication but because they needed what everybody has gotten and that could have been of help if little of it was given to them “Blood”.

How do we feel when we are in need of something that we later find out that someone very close have, but decided not to give it out. Definitely we should feel ‘denied’ but the amazing part of it is that about 90% of Nigerians are guilty of this because we fail to give blood, in that there are many dying patients in our local hospitals that can be saved, just by us rolling our sleeves to donate blood for the dying patients.

Statistic has it that about 1 out of 10 people walking into the hospital needs blood and our local hospitals do not have enough blood in their blood banks to suffice these people, and also the demand has been placed on them for replacement, Should we then leave these people in need of blood to die, capital NO! If you, or one of your loved ones have ever needed blood you already know how important it is.

The country is currently reeling under the onslaught of serious shortage of safe blood and blood products.

With several interviews of medical doctors and laboratory technologists in different hospitals and blood centers across Nigeria, it was established that voluntary blood donation by individuals can be a lasting solution to the problem of insufficient blood in the blood banks of our local hospitals and blood centers,
about 10% of Nigerians donate blood and so far the blood thus collected has not been enough. A lot of people based on their dark tenets coupled with f ears about what blood donation really is, take it to be something that requires an intricate and byzantine approach. This is a wrong assumption, lager percentage of Nigerians decide not to donate blood probably because of their shallow knowledge about what it means to donate blood.

To start with, the fluid called blood, according to essentials of medical physiology sixth edition by sembu lingan k, sembulingan prema, is connective tissue in fluid form. It is considered as ‘fluid of life’ because it carries oxygen from lungs to all of the body and carbon dioxide from all parts of the body to the lungs. It is also known as ‘fluid of growth’ because it carries nutritive substances from the digestive system and hormones from the endocrine gland to all the tissues. The blood is also called the ‘fluid of health’ because it protects the body against the diseases and get rid of the waste products and unwanted substances by transporting them to the excretory organs like kidney.

The average volume of blood in normal adult is 5 liters, in new born baby the volume is 450ml. it increases during growth and reaches 5 liters at the time of puberty. In females, it is slightly less and is about 4.5 liters. It is about 8% of the body weight in a normal young healthy adult weighing 70kg.

Blood donation does not entails collection of the whole blood volume in the body, just little amount of it is being collected. The body contains about 10 to 12 Pints of blood. Your whole blood donation accounts approximately for only one pint (I.e. 470mls out of 5000mls in the body) this slight decrease in the body fluid has no effect on the body activity and your daily modus-operandi. Just in few weeks the blood thus collected is replenished by fresh blood cells.

Of a truth, not everybody is eligible to donate blood such as people with chronic hepatitis, cancer, heart disease, organ failure, anemia, HIV/AIDS…and other genetic disorders like sickle cell, and that is the very reason your health history is being asked and mini-physical is carried out to confirm your eligibility, the mini physical tests for your hemoglobin level (which should not below 12.5), weight (donor should weigh at least 110pounds) temperature and blood pressure/pulse rate. Furthermore, the donor should be 17 years above, after all these has been verified, if the donor is eligible then the donation proper folds in. but if otherwise, the donor is deferred i.e. not allowed to give blood.

Blood donation has a lot of benefits in which the recipients are not the only beneficiaries but also the donors. Did you know that you can reduce your risk of heart diseases and save a life at the same time?

That’s right! According to studies published in American journal of epidemiology, blood donors are 88% less likely to suffer a heart attack and 33% less likely to suffer any type of cardiovascular event.

Furthermore iron has a significant impact on atherosclerosis, or hardening of the arteries. When you give blood you are removing 225 to 250milgrams of iron from your system thus cutting your risk of heart disease.

Premenopausal women tend to have half of the amount of iron as men because they lose iron every month through menstruation coincidentally they also suffer half as many heart attacks. However, once a woman goes through menopause her risk of heart attack increases, but donating blood can reduce that

Why don’t we put the onus on ourselves and come off every illusory weltanschauung about blood donation. Now is the time for religion leaders, parents, business personages, academicians, craft people and every Nigerians as a whole to encourage voluntary blood donation by individual. Let us rise to embrace this act of charity and save lives out there by not making the blood banks in local hospitals and blood centers to suffer insufficiency.

Being bitten by a spider might not make you a super hero but a prick of needle and a little of your time sure can make you one through the joy you experience by saving lives.

 

 

 

Ajayi Oluwatobi

Physiology Department

Ladoke Akintola University of Technology

Ogbomoso, Oyo state , Nigeria

 

References :

Picture :  https://psgtin.wordpress.com/wp-content/uploads/2014/06/blood-donation11.jpg

 

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