Page 150 - 86 human physiology part-2

Genetics and Inheritance

Hemophilia

There are 4 types Hemophilia A (classic), Hemophilia B (Christmas), Hemophilia C (disease),
and Von Willebrand disease, only two of these are X-linked this is 1. Hemophilia A and 2.
Hemophilia B. In Hemophilia A factor VIII is deficient, in Hemophilia B factor IX is deficient.

Malaria

Malaria is a true eukaryotic one cell parasite. There are 4 species that humans can get,
Plasmodium, 1.falciparum, 2.vivax, 3.ovale, 4.malariae. The importance of recognizing this protozoa is
genetic diversity. Look at sickle cell, I know every body knows this helps with not getting malaria but I
bet what you did not know is that people who live in west Africa and are not indigenous to west Africa
are negative in their Duffy antigen receptor which in turn means they will not get this form of malaria
(Plasmodium vivax) unlike if an American should go to west Africa they would get this form of
malaria. The interesting thing about these four is the specific differences in each; look at the vivax and
the ovale they only like young RBC's this makes them easy for treatment, however the flaciparum is
very hard to treat, it likes old, new and middle age RBC's, it may cause death to the host. Finally with
the malariae it can be unnoticed for many years because of its appetite for old RBC's and therefore it
will enlarge the spleen and lymph of the host and comes with many other signs and symptoms, this will
not be brought up hear due to this chapter is about genetics not microbiology.

Mutant Genes

Mutation is a permanent change in a segment of DNA.

Mutations are changes in the genetic material of the cell. Substances that can cause genetic
mutations are called mutagen agents. Mutagen agents can be anything from radiation from x-rays, the
sun, toxins in the earth, air, and water viruses. Many gene mutations are completely harmless.

Mutations can be good, bad, or indifferent. They can be good for you because their mutation can
be better and stronger than the original. They can be bad because it might take away the survival of the
organism. However, most of the time, they are indifferent because the mutation is no different than the
original.

The not so harmless ones can lead to cancer, birth defects, and inherited diseases. Mutations
usually happen at the time of cell division. When the cell divides, one cell contracts a defect, which is
then passed down to each cell as they continue to divide.

Teratogens refers to any environmental agent that causes damage during the prenatal period.
Examples of Common Teratogens:

• drugs: prescription, non-prescription, and illegal drugs
• tobacco, alcohol,
• radiation,
• environmental pollution,
• infectious disease,

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