Understanding Infectious, Autoimmune, Neoplastic, and Mental Illnesses

Posted on Mar 22, 2025 in Biology

Infectious and Immune System Illnesses

Infectious Illnesses: Caused by microorganisms, which are organisms observable only with a microscope.
Pathogenic Microorganisms: Can be prokaryotic (bacteria) or eukaryotic (fungi, protists, helminths’ larvae phase) and viruses.
Infectious illnesses are transmitted by contact and spread through:
- Direct Contact: With infected persons or objects, water, or saliva inhalation, infected food, insects, or vectors.
- Indirect Contact: Examples include AIDS and hepatitis.
- Vector: An animal that carries a germ from an infected individual to a healthy one without suffering any consequences.

The immune system defends the organism from alien pathogens such as viruses and bacteria.
Autoimmune illness occurs when the organism attacks its own tissues without warning.
Examples include Alzheimer’s disease and multiple sclerosis.

Affects the central nervous system and spinal cord.
Nerve fibers are wrapped by myelin, a substance composed of lipids and proteins that facilitates the transmission of electrical impulses.
Multiple sclerosis completely or partially destroys myelin, causing severe difficulties in the transmission of electrical impulses.
Most scientists agree that it is an abnormal response of the immune system against the organism itself.
Symptoms vary depending on the affected regions of the brain.
Currently, there is no vaccine or prevention for this illness.

The process of abnormal and uncontrolled growth of cells, resulting in a neoplasm (tumor).
Normally, our body’s cells grow and divide to produce new cells as needed. As we age, some die and are replaced.
In cancer, the cell division process alters, and cells reproduce uncontrollably.
These cells can group together, forming a controlled tumor (benign) or invade other tissues (malignant), causing metastasis.

The spread of cancer from one part of the body to another.
A tumor formed by cells that have spread is called a metastatic tumor or metastasis.
The metastatic tumor contains cells like those in the original (primary) tumor.

The nucleolus is a non-membrane bound structure within the nucleus where ribosomal RNA is transcribed.
Chromatin is the complex combination of DNA, RNA, and protein that makes up chromosomes.

There is no specific identifiable cause of mental illness.
Mental illnesses are generally thought to be caused by a variety of biochemical, genetic, and environmental factors:

Some imaging studies indicate that people with mental illness have physical changes in their brains.
Neurotransmitters may play a role in some mental illnesses.

Genes direct all body functions.
Some studies suggest that mental illness is linked to certain inherited genes.
Mental illness is more common in people whose biological family members also have a mental illness.
You may have a genetic vulnerability to developing a mental illness, and your life situation may trigger the actual development.

Environment is also thought to play a causal role.
Environmental causes are difficult life situations, such as the loss of a loved one, financial problems, and high stress.