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The larger the axon the faster the impulses travel. These larger axons are also myelinated (coated in an insulating substance known as myelin), which further increases the speed of impulses.
Terminal buttons at the end of axons, ‘are responsible for sending the signal on to other neurons’ (about.com).Following a terminal button is a gap or synapse. Signals are carried across a synapse to other neurons via neurotransmitters (Acytylcholine, Endorphins, Dopamine), which are released by an axon hillock when a signal reaches a terminal button. Along with these purpose specialized structures, neurons also contain a nucleus, mitochondria, Golgi apparatus, cell membrane and a cytoskeleton.
Even though neurons are such a necessity, they stop reproducing after birth. As a result of this, the number of neurons decreases with age even though new connections are being made as we …show more content…
To optimize the synthesis of glucose, these cells are positioned under the epidermal cells (top layer) of the leaves in the plant, are cylindrical, a varying size that depends on the plant and their chloroplasts are close to the cell wall. However, some ferns and conifers have been found to have irregular, or branched palisade parenchyma …show more content…
The greater the amount of sunlight, the more layers of palisade parenchyma cells. Whereas, if the leaf gets a limited amount of sunlight and carbon dioxide, only one layer of palisade parenchyma forms.
Spongy Parenchyma Cells
Lying beneath the palisade layer, its cells are irregular in shape, have no constant size and are loosely packed. Although they contain a few chloroplasts, their main function seems to be the temporary storage of sugars and amino acids synthesized in the palisade layer. They also aid in the exchange of gases between the leaf and the environment. During the day, these cells give off oxygen and water vapor to the air spaces that surround them. They also pick up carbon dioxide from the air spaces. The air spaces are interconnected and eventually open to the outside through pores called stomata (sing. stoma).
Epidermal
Terminal buttons at the end of axons, ‘are responsible for sending the signal on to other neurons’ (about.com).Following a terminal button is a gap or synapse. Signals are carried across a synapse to other neurons via neurotransmitters (Acytylcholine, Endorphins, Dopamine), which are released by an axon hillock when a signal reaches a terminal button. Along with these purpose specialized structures, neurons also contain a nucleus, mitochondria, Golgi apparatus, cell membrane and a cytoskeleton.
Even though neurons are such a necessity, they stop reproducing after birth. As a result of this, the number of neurons decreases with age even though new connections are being made as we …show more content…
To optimize the synthesis of glucose, these cells are positioned under the epidermal cells (top layer) of the leaves in the plant, are cylindrical, a varying size that depends on the plant and their chloroplasts are close to the cell wall. However, some ferns and conifers have been found to have irregular, or branched palisade parenchyma …show more content…
The greater the amount of sunlight, the more layers of palisade parenchyma cells. Whereas, if the leaf gets a limited amount of sunlight and carbon dioxide, only one layer of palisade parenchyma forms.
Spongy Parenchyma Cells
Lying beneath the palisade layer, its cells are irregular in shape, have no constant size and are loosely packed. Although they contain a few chloroplasts, their main function seems to be the temporary storage of sugars and amino acids synthesized in the palisade layer. They also aid in the exchange of gases between the leaf and the environment. During the day, these cells give off oxygen and water vapor to the air spaces that surround them. They also pick up carbon dioxide from the air spaces. The air spaces are interconnected and eventually open to the outside through pores called stomata (sing. stoma).
Epidermal