The term pathophysiology simple means the study of all the changes that arise from the body system that is cause by a disease.
One gets infected when the respiratory droplets either lands on the mouth, eye or nose.
Major route of entry is the mouth or nose or eyes. It is a respiratory virus and damages the lungs, more especially, it loves the alveoli (where gaseous exchange occurs in the lungs).
One of the reason why corona virus victims cough is because of the irritant effects the virus has in the respiratory tract.
what happens when they enter the body system
Upon successful entry through any of the earlier mentioned routes, they attach to a very important type of cell in the lungs- the type 2 pneumocyte (cells of the lungs that produces surfactant which functions to reduce surface tension in the lungs thus preventing lung collapse).
It binds to a recetor located on the type 2 pneumocyte using its S-spike. Invariably, if we can produce drugs or vaccines that can make the type 2 pneumocytes resistant to the virus, we could be close to winning the war.
This receptor is known as the Angiotensin converting enzyme receptor (ACE) type 2. This binding enables them to be engulfed into the cell of the pneumocyte.
Once inside the cell, it does two things, it releases its positive sense single stranded RNA ( sSRNA) which uses the host ribosome, takes the mRNA from it and converts it into specific proteins (a process known as Translation).
Secondly, by virtue of it being a positive sense virus, it also uses an enzyme called RNA dependent RNA polymerase (RNA-D-RNA Pol).
By implication, it takes RNA and produces another RNA i.e it takes that single strand RNA and converts it to more positive sense single stranded RNA.
Using another enzyme called the proteinase that cleaves those specific proteins so that it forms the parent virus and also incorporating the sSRNA in the process; the cycle begins again.
The resultant effect is the production of tons of covid-19 virus. This cycle continues to cause damage to the type 2 pneumocytes by the virus.
How the pneumocytes respond to attack
The pneumocytes respond to the damage by releasing inflammatory mediators that are detected by the lung macrophages.
These macrophages inturn respond by releasing inflammatory cytokines (proteins released whenever there is an inflammatory condition or injury) such as interleukin1, 6, and tumour necrotic factor alpha.
One gets infected when the respiratory droplets either lands on the mouth, eye or nose.
Major route of entry is the mouth or nose or eyes. It is a respiratory virus and damages the lungs, more especially, it loves the alveoli (where gaseous exchange occurs in the lungs).
One of the reason why corona virus victims cough is because of the irritant effects the virus has in the respiratory tract.
what happens when they enter the body system
Upon successful entry through any of the earlier mentioned routes, they attach to a very important type of cell in the lungs- the type 2 pneumocyte (cells of the lungs that produces surfactant which functions to reduce surface tension in the lungs thus preventing lung collapse).
It binds to a recetor located on the type 2 pneumocyte using its S-spike. Invariably, if we can produce drugs or vaccines that can make the type 2 pneumocytes resistant to the virus, we could be close to winning the war.
This receptor is known as the Angiotensin converting enzyme receptor (ACE) type 2. This binding enables them to be engulfed into the cell of the pneumocyte.
Once inside the cell, it does two things, it releases its positive sense single stranded RNA ( sSRNA) which uses the host ribosome, takes the mRNA from it and converts it into specific proteins (a process known as Translation).
Secondly, by virtue of it being a positive sense virus, it also uses an enzyme called RNA dependent RNA polymerase (RNA-D-RNA Pol).
By implication, it takes RNA and produces another RNA i.e it takes that single strand RNA and converts it to more positive sense single stranded RNA.
Using another enzyme called the proteinase that cleaves those specific proteins so that it forms the parent virus and also incorporating the sSRNA in the process; the cycle begins again.
The resultant effect is the production of tons of covid-19 virus. This cycle continues to cause damage to the type 2 pneumocytes by the virus.
How the pneumocytes respond to attack
The pneumocytes respond to the damage by releasing inflammatory mediators that are detected by the lung macrophages.
These macrophages inturn respond by releasing inflammatory cytokines (proteins released whenever there is an inflammatory condition or injury) such as interleukin1, 6, and tumour necrotic factor alpha.
These inflammatory cytokines cause the endothelial cells to dilate thereby increasing capillary permeability (makes the blood vessels more porous)
Increased capillary permeability allows fluids like plasma to enter the alveoli and subsume or drown out the surfactant.
Remember the surfactant has a very important role to play in the lungs and which is to decrease surface tension. As the surfactant decreases, there is a resultant increase in surface tension.
Pressure and surface tension role in the lungs
If you would recall Laplace law in physics that talks about pressure and surface tension,
"It states that increased pressure causes two times (2×) an increase in surface tension divided by the radius"
So increased surface tension causes increased pressure and ultimately leading to alveoli collapse.
This is why patients with Corona virus disease find it very difficult to breath (dyspnea) once the alveoli has collapsed, they will need to work extra hard to breathe.
Since gaseous exchange is not so possible anymore, it leads to a condition known as hypoxemia (low level of oxygen in the blood).
I am sure you know that it is a very dangerous situation that can lead to coma. Hope you are now getting to fully understand how this deadly virus operates.
These inflammatory cytokines cause the endothelial cells to dilate thereby increasing capillary permeability (makes the blood vessels more porous)
Increased capillary permeability allows fluids like plasma to enter the alveoli and subsume or drown out the surfactant.
Remember the surfactant has a very important role to play in the lungs and which is to decrease surface tension. As the surfactant decreases, there is a resultant increase in surface tension.
Pressure and surface tension role in the lungs
If you would recall Laplace law in physics that talks about pressure and surface tension,
"It states that increased pressure causes two times (2×) an increase in surface tension divided by the radius"
So increased surface tension causes increased pressure and ultimately leading to alveoli collapse.
This is why patients with Corona virus disease find it very difficult to breath (dyspnea) once the alveoli has collapsed, they will need to work extra hard to breathe.
Since gaseous exchange is not so possible anymore, it leads to a condition known as hypoxemia (low level of oxygen in the blood).
I am sure you know that it is a very dangerous situation that can lead to coma. Hope you are now getting to fully understand how this deadly virus operates.
We continue next time... keep in touch.
