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For example, they innervate the spinal cord, the brain stem, cerebellum, hypothalamus, the hippocampus, the thalamic relay nuclei, the amygdala, the basal telencephalon, and the cortex. The norepinephrine from the LC has an excitatory effect on most of the brain, mediating arousal and priming the brain's neurons to be activated by stimuli.
Throughout embryonic development, the cells within the midbrain continually multiply; this happens to a much greater extent ventrally than it does dorsally. The outward expansion compresses the still-forming cerebral aqueduct, which can result in partial or total obstruction, leading to congenital hydrocephalus . [ 14 ]
Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges, blood vessels, and ducts. The two main types of cells in the brain are neurons, also known as nerve cells, and glial cells, also known as neuroglia. [1]
The following diagram is provided as an overview of and topical guide to the human nervous system: Human nervous system. Human nervous system – the part of the human body that coordinates a person's voluntary and involuntary actions and transmits signals between different parts of the body.
For example, release of the neurotransmitter acetylcholine at a synaptic contact between a motor neuron and a muscle cell induces rapid contraction of the muscle cell. [43] The entire synaptic transmission process takes only a fraction of a millisecond, although the effects on the postsynaptic cell may last much longer (even indefinitely, in ...
Schematic diagram of the primate LGN. The parvocellular neurons of the visual system receive their input from midget cells, a type of retinal ganglion cell, whose axons comprise the optic tract. These synapses occur in one of the four dorsal parvocellular layers of the lateral geniculate nucleus.
Purkinje cells use GABA as their neurotransmitter, and therefore exert inhibitory effects on their targets. [11] Purkinje cells form the heart of the cerebellar circuit, and their large size and distinctive activity patterns have made it relatively easy to study their response patterns in behaving animals using extracellular recording techniques.
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord.The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and diploblasts.