vocab

Nervous System - the organized network of nerve tissue in the body, which transmits nerve impulses between different parts of the body. is composed of 2 parts

  1. Central Nervous System (CNS) - the part of the nervous system that controls the spinal cord & brain

  2. Peripheral Nervous System (PNS) - part of the nervous system that consists of nerves that connects the CNS to the rest of the body

Neuron - a functional unit of the nervous system that transmits information using electrical & chemical signals. is composed of 3 parts - cell body, dendrites & axon

  • Cell body/Soma - contains a nucleus & cytoplasm (typical organelles, besides centrioles)

  • Dendrites - branched nerve fibres that extend from the cell body’s surface. responsible for connecting with other neurons & increase the SA for receiving signals

  • Axon - an elongated fibre that aids with transmitting the nerve impulse

  • Axon hillock - part of the cell body that connects to the axon & is where action potential is generated

  • Action potential - a rapid, temporary change in the electrical membrane potential & allows cell to transmit signals along the membrane

Myelin sheath - protects nerve fibres & allows signals to be quickly transmitted between nerve cells & support the sheath’s adhesion to the axon?

  • formed by Schwann cells in the PNS & by oligodendrocytes in the CNS

Nodes of Ranvier - the unmyelinated gaps between Schwann cells

Axon terminal - endings of the axon, which’re composed of synaptic knobs

  • these are endings of the axon that’re involved in transmitting signals

Sensory neurons - allow us to feel sensation

  • hv an elongated dendrite running from sensory receptors to cell body & axon running from cell body

Interneurons - are short & aid in transmitting signals between sensory & motor neurons

Motor neurons - make the connection between brain & muscles

  • hv multiple fine dendrites that bring in the impulses to the cell body, where a single long axon carrier these impulses away from cell body

Membrane potential - the difference in electric potential between interior & exterior of cell

  • when membrane potential of neuron rapidly rises or falls, this produces an action potential

Nerve conduction velocity - the speed at which a nerve impulse propagates down a neural pathway

Synapses - specialised junctions between 2 neurons & a neuron & an effector cell

  • allow the unidirectional flow of signals

Neuronal synapses - occur between 2 neurons

  • neurotransmitters are released from presynaptic neuron & bind to receptors on postsynaptic neuron

Neuromuscular junction - a synapse that connects motor neuron to muscle fibre

  • the binding of ACh from the motor neuron to receptors on the muscle fibre’s membrane, causes a depolarization, which releases calcium ions

Neuroglandular junction - synapses between neurons & glandular cells

Saltatory conduction - is the skipping motion done by action potential (the action potential jumps from one node of Ranvier in the myelinated neuron, to another node of Ranvier)

Hyperpolarization - change in the cell’s membrane potential, causing it to become more negative than its resting potential

Summation - the combined effect of excitatory & inhibitory stimuli

  • multiple stimuli can sometimes be stronger than a single stimuli, in generating an action potential

  • Spatial summation - is when multiple pre-synaptic neurons simultaneously send their signals to the same post-synaptic neuron at different locations

  • Temporal summation - when a single presynaptic neuron fires multiple times in rapid succession, causing postsynaptic potentials to build up & increase the threshold for reaching an action potential