Answer:
The correct option is: <em>a deficiency of dopamine in the substantia nigra.</em>
Explanation:
The substantia nigra is the principal site involved in the physiopathology of Parkinson´s disease.
Cells from this area degenerate and die progressively causing important degeneration in the central nervous system. The cells that die -with no known reason- are those that produce dopamine and proportionate dopaminergic innervation to the encephalon. In fact, almost all the symptoms exhibited by patients with the disease can be explained by the lack of dopamine in the substantia nigra.
This area uses the neurotransmitter to communicate neurons from the base ganglia. Ganglia are responsible of modulating and modifying movements.
The nigrostriatal system participates in planning and automatic execution of learned movements. When the ganglia activity decreases, so it does the amount and velocity of movements, something typical of the disease.
It would be fittest
hope this helps
Answer:
They are propogated down the length of the dendrite
Answer/Explanation:
<h3>Incomplete dominance</h3>
In incomplete dominance, one allele is not entirely dominant over the other, so heterozygotes (organisms with two different alleles for the gene) show an intermediate or blended phenotype.
For example, consider flower colour.
- If the allele for red flowers (R) was dominant over the allele for white flowers (r), then there are three possible genotypes (RR, Rr, and rr) and two possible phenotypes. (Red (RR and Rr) and white (rr)).
- However, if the allele for red flowers (R) was incompletely dominant over the allele for white flowers (r), then there are three possible genotypes (RR, Rr, rr), and three possible phenotypes (red (RR), white (rr), and pink (Rr))
<h3>Co-dominance</h3>
In incomplete dominance, two alleles are both expressed, one is not dominant over the other. Therefore, heterozygotes (organisms with two different alleles for the gene) express both traits.
For example, consider flower patterns.
- If the allele for spots (F) was dominant over the allele for stripes (f), then there are three possible genotypes (FF, Ff, and ff) and two possible phenotypes. (Spots (Ff and ff) and stripes (ff)).
- However, if the allele for spots (F) was co-dominant to the allele for stripes (f), then there are three possible genotypes (FF, Ff, ff), and three possible phenotypes (spots (FF), stripes (ff), and spots and stripes (Ff))
