Answer:
a. substantia nigra
b. substantia nigra (it is repeated)
Explanation:
Parkinson's disease is a neurodegenerative disease that is caused by the death of neurons that release the neurotransmitter dopamine in the <u>substantia nigra</u>, or locus niger, -a region of the brain that regulates brain circuits that give the 'orders' to initiate voluntary movements- .
The lack of this neurotransmitter leads to the occurrence of the main symptoms suffered by patients: decreased movements, muscle stiffness, postural instability and tremor. These failures are generated by the abnormal way in which neurons work in the absence of dopamine through a mechanism that is not known in depth.
It is the second most frequent neurodegenerative disease, after Alzheimer's disease, with a prevalence of 2% in people over 65 years. The characteristic symptoms of stiffness, bradykinesia and tremor are associated with losses of neurons in the substantia nigra and dopamine depletion in the striatum. There are large cytoplasmic inclusions, called Lewy bodies, which are the pathological mark of the disease and appear predominantly in neurons that contain melanin of the nigra substance. Genetic studies in a subgroup of families with Parkinson's disease with autosomal dominant inheritance found a locus on chromosome 4q-21 23 and a mutation in the gene that encodes a synaptic protein, α-synuclein.
Answer:
541 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in Earth history.
source- Britannica
Explanation:
Answer:
Dichloroindophenol chemical act as electron acceptor in photosynthesis
Explanation:
DCPIP (2,6-dichlorophenol-indophenol) in general is a dye of blue color which reduces to become colorless and hence act as an electron acceptor in the light reactions of photosynthesis
It is used to measure the rate of photosynthesis, because its reduction leads to identification of reducing agent (Diphenylcarbazide) in plant that is produced at the time of photosynthesis with in the chloroplasts.
Answer:
Hormones are controlled by a
(negative)
feedback system between the glands that produce this hormone and the concentration of blood calcium ions. If the level of ions is
(low)
,hormone secretion is increased. This causes resorption by cells called
which releases both calcium and phosphate ions into the blood stream.
Explanation:
Negative Feedback a the process in your body that helps to maintain Homeostasis. If some variable changes a value in your body, like your ion levels, your glands produce a hormone that causes resorption by cells. This releases both calcium and phosphate ions into the blood stream and therefore your ion levels go back to normal.
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