Do you know How our body responses towards an Injury?

Everyone has experienced injury in their lifetime. Whenever it comes to the injury, first scene comes in our mind is trauma or accident but here, i prefer "Cell Injury" .

Most of the diseases begin with cell injury and consequent loss of cell function. So, first, let us define cell injury-

“Cell injury is defined as a variety of stress a cell encounters as a result of changes in its external environment”.

The cells of our body have inbuilt mechanism to deal with changes in environment to an extent. The cellular response to stress varies and depends on-
A) The type of cell and tissue involved.
B) Extent and type of cell injury.

The cellular response to cell injury may be-

1. When there is increased functional demand, the cell may adapt to the changes which are expressed morphologically & then revert back to normal after stress is removed i.e. Cellular adaptations.
2. When the stress is mild to moderate, the injured cell may recover (Reversible cell injury),
3. When the injury is persistent, the cell may die (Irreversible cell injury).
   

Etiology of cell injury-

Whenever it comes to the causes of cell injury, first scene comes in our mind is trauma or accident. Yet, there are lots of factors involving in cell injury. I have listed many of them.

A) Hypoxia- Cells of tissues essentially requires oxygen to generate energy & perform metabolic functions.
Deficiency of oxygen or Hypoxia results in failure to carry out these activities by the cells. Most common cause of hypoxia is Ischaemia i.e. reduced supply of blood to the tissue.

B) Physical agents- include Mechanical trauma (e.g. road accidents), thermal trauma, electricity, radiations.

C) Chemicals and drugs- Examples include chemical poisons such as cyanide, arsenic, mercury, environmental pollutants, alcohol and narcotic drugs.

D) Microbial agents- infection caused by bacteria, virus, rickettsia, fungi, protozoa and other parasites.

E) Immunological agents include hypersensitivity reactions, anaphylactic reactions and autoimmune diseases.

F) Nutritional derangements-
a. Nutritional deficiency diseases may be overall deficiency of nutrients (e.g. Starvation), of proteins calorie (e.g. marasmus)
b. Nutritional excess is a problem of affluent societies resulting in obesity, heart failure and hypertension.

Here, I tried to give a brief overview of cellular response to the injury.

Let me know, what scene comes first in your mind when you read this word “injury” and what else may be the causes of oxygen deprivation in tissues leading hypoxia in the comment section below.

Thankyou