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The nervous system segmentation confers several developmental advantages to the vertebrate body as humans possess a body plan that is bilaterally segmented at the nervous system level. The segmentation is involved at all levels of the human nervous system with increasing level of complexity in the innervation from the brain to limbs. [1]
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
The ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because much more can be said about them in a human context. The most important that are covered in the human brain article are brain disease and the effects of brain damage.
The human brain is the central organ of the human nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum , the brainstem and the cerebellum . The brain controls most of the activities of the body , processing, integrating, and coordinating the information it receives from the sensory nervous ...
In other taxa, there is some evidence of segmentation in some organs, but this segmentation is not pervasive to the full list of organs mentioned above for arthropods and annelids. One might think of the serially repeated units in many Cycloneuralia, or the segmented body armature of the chitons (which is not accompanied by a segmented coelom). [1]
Projections of the gray matter (the “wings”) are called horns. Together, the gray horns and the gray commissure form the “gray H.” The white matter is located outside of the gray matter and consists almost totally of myelinated motor and sensory axons. “Columns” of white matter carry information either up or down the spinal cord.
The homeobox genes are remarkably conserved between species as diverse as the fruit fly and humans, the basic segmented pattern of the worm or fruit fly being the origin of the segmented spine in humans.
Area of the human body surface innervated by each spinal nerve. Even mammals, including humans, show the segmented bilaterian body plan at the level of the nervous system. The spinal cord contains a series of segmental ganglia, each giving rise to motor and sensory nerves that innervate a portion of the body surface and underlying musculature.