Parkinson's disease is caused by a loss of nerve cells in the part
of the brain called the substantia nigra.
Nerve cells in this part of the brain are responsible for producing
a chemical called dopamine.
Dopamine acts as a messenger between the parts of the brain
and nervous system that help control and co-ordinate body
movements.
If these nerve cells die or become damaged, the amount of
dopamine in the brain is reduced.
This means the part of the brain controlling movement cannot
work as well as normal, causing movements to become slow
and abnormal.
The loss of nerve cells is a slow process. The symptoms of
Parkinson's disease usually only start to develop when around
80% of the nerve cells in the substantia nigra have been lost.
it's believed a combination of genetic changes and
environmental factors may be responsible for the condition.
Genetics
A number of genetic factors have been shown to increase a
person's risk of developing Parkinson's disease, although exactly
how these make some people more susceptible to the condition
is unclear.
Parkinson's disease can run in families as a result of faulty genes
being passed to a child by their parents. But it's rare for the
disease to be inherited this way.
Environmental factors
Some researchers also feel environmental factors may increase
a person's risk of developing Parkinson's disease.
It's been suggested that pesticides and herbicides used in
farming and traffic or industrial pollution may contribute to the
condition.
Other causes include:
medication (drug-induced parkinsonism) – where symptoms
develop after taking certain medications, such as some types
of antipsychotic medication, and usually improve once the
medication is stopped
other progressive brain conditions – such as progressive
supranuclear palsy, multiple systems atrophy and corticobasal
degeneration
cerebrovascular disease – where a series of
small strokes cause several parts of the brain to die
Effects of parkinson’s disease
Tremor. A tremor, or shaking, usually begins in a limb, often
your hand or fingers. You may rub your thumb and forefinger
back and forth, known as a pill-rolling tremor. Your hand may
tremble when it's at rest.
Slowed movement (bradykinesia). Over time, Parkinson's
disease may slow your movement, making simple tasks
difficult and time-consuming. Your steps may become shorter
when you walk. It may be difficult to get out of a chair. You
may drag your feet as you try to walk.
Rigid muscles. Muscle stiffness may occur in any part of your
body. The stiff muscles can be painful and limit your range of
motion.
Impaired posture and balance. Your posture may become
stooped, or you may have balance problems as a result of
Parkinson's disease.
Loss of automatic movements. You may have a decreased ability
to perform unconscious movements, including blinking, smiling
or swinging your arms when you walk.
Speech changes. You may speak softly, quickly, slur or hesitate
before talking. Your speech may be more of a monotone rather
than have the usual inflections.
Writing changes. It may become hard to write, and your writing
may appear small.
Ethiopia possesses an estimated number of 6000 species of higher
plants of which 10% are endemic. The country has 284 species of
wild mammals and 861 species of birds. Data on other wild animals
are scanty; and the number of reptile, fish, amphibian and
arthropod species identified so far are 201, 200, 63 and 1,225,
respectively. Of these faunal resources, 29 wild mammal, 18 bird,
10 reptile, 40 fish, 25 amphibian and seven arthropod species are
endemic to Ethiopia. The country has rich resource of indigenous
farm animals also. These are comprised of 28 cattle, 9 sheep, 8
goat, 7 camel, 6 donkey, 8 horse, 2 mule and 7 chicken breeds.
Main direct threats to Ethiopia’s biodiversity are habitat conversion,
unsustainable utilization of biodiversity resources, invasive species,
replacement of local varieties and breeds, climate change and
pollution. Indirect causes of biodiversity loss in the country are
demographic change, poverty, and lack of awareness and
coordination. Due to direct and indirect pressures, ecosystems and
a number of wild plants and animals including endemic species, as
well as farmers’ varieties and indigenous animal breeds are vi
declining. Therefore, 103 tree and shrub species, 31 bird, one
reptile, nine amphibian, two fish and 14 other invertebrate species
are threatened. Ethiopia is a centre of origin for many cultivated
plants such as Tef (Eragrostis tef), noug (Guizotia abyssinica),
Ethiopian mustard (Brassica carinata), enset (Ensete ventricosum),
anchote (Coccinia abyssinica) and coffee (Coffea arabica). The
country is also a centre of diversity for species such as wheat
(Triticum sp.), barley (Hordeum vulgare), sorghum (Sorghum
bicolor), pea (Pisum sativum), cowpea (Vigna unguiculata), chickpea
(Cicer arietinum), lentil (Lens culinaris), chat (Catha edulis), shinyleaf buckthorn (Rhamnus prinoides), cotton (Gossypium
herbacieum), castor bean (Ricinus communis), oats (Avena
abyssinica) and clovers (Trifolium sp.). Wild relatives also exist for
In Ethiopia, some institutions have so far identified limited
number of microbial species out of which 381 species of bacteria,
fungi and microalgae have been conserved in national gene bank.