Neurons and synapses

IB2 BiologyJin Young Huh

Organization of the Nervous System• Central nervous system (CNS)– Brain– Spinal cord

• Peripheral nerves

Sensory and motor neurons

• Sensory neurons– receptors (sensory cells)– CNS

• Motor neurons– CNS– effectors (muscle and gland cells)

• Relay neurons– between neurons

Structure of a motor neuron

Synapses

• Junction between two neurons• Neurotransmitters– Pre-synaptic neuron– Post-synaptic neuron

Stages in synaptic transmission

http://www.youtube.com/watch?v=z3F5dfmQ3hkhttp://www.youtube.com/watch?v=9nUY6o-LCWY

Sources

• Study Guide• Academico– http://academic.uprm.edu/~ephoebus/id81.htm

• Wikispace– http://biologyataglance.wikispaces.com/Controllin

g+life

Vocabulary• Central nervous system (CNS): part

of nervous system that consists of the brain and spinal cord, regulating the body’s responses to external and internal stimuli

• Neurons: cells in the central nervous system that can carry messages at high speed in the form of electrical impulses.

• Spinal cord: a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain

• Peripheral nerves: nerves that connect all parts of the body to the central nervous sytem

• Sensory neurons: neurons that carry nerve impulses from sensory cells (receptors) to the CNS

• Motor neurons: neurons that carry impulses from the CNS to effectors (muscle and gland cells)

• Relay neurons: neurons that carry impulses within the CNS, from one neuron to another

• Axon: a long, slender projection of a neuron that conducts electrical impulses away from the neuron’s cell body (soma)

• Dendrites: the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to soma

• Neurotransmitters: endogenous chemicals which transmit signals from a neuron to a target cell across a synapse

• Depolarization: a change in cell’s membrane potential, making it more positive, or less negative

• Vesicles: a small membrane-enclosed sac that can store or transport susbstances