Because if we're simultaneously moving/manipulating two different variables it can be very hard to determine why one variable is changing and why the other is changing. While this can be done with more complicated experimental designs, it usually is the case that scientists will only manipulate one variable and not two different ones.
That's how the food chain works. There isn't much to it.
<span>Eating nonfood items like clay, erasers, and chalk during pregnancy is known by the medical name of geophagy. Pregnant women does crazy things that gives them a weird number of choices when it comes to food cravings. The main reason is to protect her and the baby from harmful microorganisms and toxins and to suffice the lack of vitamins. Clay though has a high mineral content, that is rich in magnesium, copper, iron and calcium. While it may be weird, these minerals are the fundamentals of a human diet especially during pregnancy.</span>
Answer:
First the proprioceptors found in the tissues will capture tissue damage and the presence of a continuity solution in the skin, then these receptors will activate the afferent pathway, which is the pathway of pain, which is sensory.
This stimulus that ascends to the central nervous system activates the "flight" mechanism in the face of pain (it is also known as the withdrawal mechanism).
It is in this way that a stimulation is sent to the alpha motor neuron in the form of an action potential as an efferent pathway to the skeletal muscles of the foot and the damaged leg, so that an automatic and involuntary muscle contraction is generated in a matter of millisemas of second after the damage, so the foot is removed from the damage area.
Explanation:
The withdrawal mechanism is a reflex that the human acquires before pain, that is why it is the muscular contraction is automatic and fast once the pain occurs.
So as a summary: 1 - the proprioceptors of the damaged tissue are activated 2- the signal of tissue damage rises as afferent to the CNS 3- the CNS responds by activating a signal that will be sent by interneuronal connections to the alpha motor neuron 4- the signal arrives as potential of action to the alpha motor neuron that innervates the muscles of the surrounding area to which it is damaged 5 - the muscles contract, generating the withdrawal of the limb.
