Homeostasis: Aging, Senescence, and Death

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Aging is inevitable and just as essential as birth and death. Read on to know how homeostasis affects health on a cellular level. 

 

In this article:

 

  1. Cellular Homeostasis: Definition, Parameters, and Importance
  2. Homeostatic Imbalance and Cellular Senescence
  3. Role of Homeostasis and Senescence in Diseases and Aging

 

Cellular Homeostasis: Definition, Parameters, and Importance

 

Homeostasis is the equilibrium or balance within the cell or the body. It is an organism’s capacity to maintain a stable internal environment through constant adjustments brought by changing conditions inside and outside the cells.

 

Although it refers to maintaining stability within the system, homeostasis is a dynamic and changing state. Through homeostatic regulation, adjustments are made continuously to maintain the normal range. Body organs, including the liver, the pancreas, the kidneys, and the brain’s parts, help maintain homeostasis.

 

The following are some of the parameters for proper functioning and balance in the biological system:

 

Temperature

 

A man having temperature test with tired reaction - CA | Homeostasis: Aging, Senescence, and Death

 

Humans are endothermic creatures who are capable of generating internal heat, thus, aiding in the maintenance of near to constant body temperature. High temperatures cause stress for the human body that may lead it to the danger of injury or even death. In order to manage changing temperatures, humans have generated physiologic and cultural modes of adaptation. 

 

Iron

 

Iron is an essential element for human beings. When body iron levels are too low, an iron-sensitive hormone called hepcidin drops in the duodenal epithelium (lining of the small intestine). 

 

Sugar

 

glucose and blood cell in the human body visualisation - CA | Homeostasis: Aging, Senescence, and Death

 

Blood glucose is regulated with two hormones, insulin, and glucagon, both released from the pancreas. Insulin is released and taken up cells when the blood sugar levels spike. On the other hand, glucagon is released by the pancreas when the blood sugar drops.

 

Osmoregulation

 

Osmoregulation manages osmotic pressure in the body to maintain water balance in the body. The kidneys play a role in removing excess ions from blood and are expelled as urine. This is also vital in maintaining blood pH.

 

Water Volume

 

The kidneys influence the overall water volume maintained within the body. This is through the help of vasopressin, an Antidiuretic Hormone (ADH), and Aldosterone. When the body is fluid deficient, the fluid is retained, and the urine is reduced. In reverse, excessive fluids result in more urine being produced through suppressed excretion of aldosterone.

 

Cells are the basic unit of the body for tissues, organs, and systems. Cellular homeostasis involves maintaining a balance of several factors that make a cell healthy. These are ions, water, acidic lysosomes, and membrane fluidity in order to maintain stability by performing the following functions:

 

  • Ions flow through the membrane of the brain cells, or neurons to allow it to create signals.
  • Water is regulated by the cell membrane to maintain certain concentrations of iron.
  • Acidic lysosomes are internally acidic and serve as a cell’s recycling center. Digested unwanted proteins, RNA, DNA, fats, and carbohydrates. These, when damaged, clogs up the whole cell.
  • Membrane Fluidity manages cholesterol to prevent lipids from crystalizing.

 

Automatic cellular mechanisms, neural and endocrine controls, and behavior all contribute significantly to homeostasis.

 

Homeostatic Imbalance and Cellular Senescence

 

Homeostatic Imbalance

 

The homeostatic imbalance is the result of a deficiency in the body. This occurs when an unhealthy diet causes cells in nutritional deficiencies or when cells are exposed to toxins.

 

Homeostatic imbalances may result from three main influences:

 

  • Internal influences (aging and genetics)
  • External influences (physical activity, mental health such as stress, nutritional deficiency, drug, and alcohol abuse)
  • Environmental influences (exposure to toxins)

 

Homeostatic imbalance, which causes cellular malfunction, is believed to be an underlying factor responsible for most diseases.

 

Cellular Senescence

 

Cellular senescence is referred to as the permanent arrest of cells. It occurs when the cells are no longer able to undergo cell division. Replicative senescence can be triggered by DNA damage

 

This inability of cells to divide may be both beneficial and detrimental to the body. On a positive note, senescent cells affect wound healing and possibly the development of the placenta and the embryo, tumor suppression, and play a pathological role in age-related diseases.

 

On the other hand, senescent cells contribute to the impairment of tissue regeneration, cellular dysfunction, and impact on the microenvironment.  Soluble factors secreted from senescent cells can facilitate cellular proliferation and formation in neighboring cells.

 

The Role of Homeostasis and Senescence in Diseases and Aging

 

Homeostasis and senescence play a crucial role in diseases,  within the internal functions increases the risk of illness and physical changes associated with aging. 

 

Disease is any disorder in structure or functions that result in signs and symptoms, which is often caused by infection or injury. Diseases generally involve homeostatic imbalance. For instance, in Type 1 diabetes, patients do not produce insulin due to the insulin-producing cells’ auto-immune destruction. This causes symptoms such as weakened blood vessels and frequent urination.

 

In researches about the root causes of aging and age-related diseases, also referred to as geroprotection, calorie restriction has been shown to prolong the lifespan of organisms such as roundworms and primates to 30%-50% as long as malnutrition does not occur. While this is promising, there is no data conducted on humans to support geroprotective agents. 

 

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