BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Ascending pathway to the brain: Sensory information travels from the body to the spinal cord before reaching the brain. This information ascends upwards using first, second, and third-order neurons. First-order neurons receive impulses from skin and proprioceptors and send them to the spinal cord.

Detailed explanation-2: -Nerve impulses begin in a dendrite, move toward the cell body, and then move down the axon. A nerve impulse travels along the neuron in the form of electrical and chemical signals. The axon tip ends at a synapse. A synapse is the junction between each axon tip and the next structure.

Detailed explanation-3: -Afferent, or sensory, neurons carry impulses from peripheral sense receptors to the CNS.

Detailed explanation-4: -An electrical impulse travels along the first axon. This triggers the nerve-ending of the neurone to release chemical messengers called neurotransmitters . These chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the second neurone.