Nervous System and Neurons

Dendrites are highly branched structures that receive signals from many other neurons, often numbering in the thousands for a single neuron.

Neurons contain standard organelles like the nucleus and mitochondria, and they possess specialized structures like axons and dendrites for communication.

Neurotransmitters are the chemical messengers released by the axon terminal into the synapse to transmit signals to the next cell.

When an electrical impulse reaches the axon terminal, it triggers the release of neurotransmitters, effectively converting the electrical signal into a chemical signal.

Axons are the long, thread-like extensions of a neuron that conduct electrical impulses away from the cell body toward other neurons or effector cells.

Glial cells (or neuroglia) provide essential support, protection, and insulation (such as myelin) to neurons, ensuring efficient signal transmission.

Sensory neurons (afferent neurons) carry impulses from sensory receptors in the body toward the central nervous system (brain and spinal cord).

Motor neurons (efferent neurons) carry signals from the central nervous system to muscles or glands, causing a response.

While there are interneurons, the two primary functional categories often taught in basic biology regarding signal direction are sensory and motor neurons.

Dendrites are the branched projections of a neuron that act as the primary input sites, receiving electrochemical signals from other neurons.

Neurons are the specialized cells of the nervous system responsible for transmitting electrical and chemical signals throughout the body.

Pacinian corpuscles are specialized sensory receptors in the skin that are specifically sensitive to deep pressure and vibration.

(A)Propioceptor responds to activities of muscles and joints.

In hemichordates and chordates nerve cord is dorsally placed.