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NERVOUS COMMUNICATION


Sensory (afferent) neurons ­ Transmits impulses from a receptor to the central nervous system.
Motor (efferent) neurons ­ Transmits impulses from the central nervous system to an effector such as a muscle or
gland.
Intermediate neurons ­ Receives impulses from a sensory neurone and transmits them to a…

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Cell Body ­ Contains the nucleus, many mitochondria, endoplasmic reticulum, golgi apparatus and other organelles.
Groups of ribosomes involved in protein synthesis are also present.
Dendron ­ Long cytoplasmic processes that conduct impulses towards the cell body. They are the longest in sensory
neurones.
Dendrites ­ Short cytoplasmic processes that…

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8. Ventral root of spinal nerve
9. Motor neurone
10. Motor end plate
11. Effector (muscle that moves away from pain)


Sensory Receptors
Are energy transducers that convert one form of energy to another. Teach type of transducer is adapted to detect
changes in a particular form of energy. This…

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Action potential
1. The membrane starts in its resting state ­ polarised with the inside of the cell being -60mV compared to the
outside (inside more negative).
2. Sodium ions channels open and some sodium ions diffuse into the cell.
3. The membrane depolarises - it becomes less negative with…

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A synapse is a junction between two or more neurones. It is where one neurone can communicate with, or signal to,
another neurone. An action potential is produced by the movements of ions across the neurone membrane. The
action potential cannot bridge the gap between two neurones. Instead, presynaptic action…

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acetylcholine over a short period of time will enable the postsynaptic generator potentials to combine
together to produce an action potential. Summation can also occur when several presynaptic neurones
release small numbers of vesicles into one synapse.
The creation of specific pathways within the nervous system is thought to be…

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