Science B6 (Nervous system and Neurones)

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  • Created by: Lydia
  • Created on: 08-04-13 18:32
What are the two communication systems?
The Nervous System and the Hormonal System
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What is the Nervous System and what does it do?
The Nervous system sends messages using neurons which produce a quick, short response; nerve impulse is electrical; has specialised organs-brain and spinal cord
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What is the Hormonal System and what does it do?
The hormonal system produces chemical messages in the form of hormones. The system is slower than the nervous system but responses are longer
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What does the Central Nervous System (CNS) consist of?
The Brain and the Spinal Cord (humans and other vertebrates only)
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In the mammalian nervous system, what is the CNS connected to?
The peripheral nervous system (PNS). This is the neurons, which connect the CNS to the whole body
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What are the different types of neurons?
Sensory Neurons and Motor Neurons
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What are Sensory Neurons?
They connect eg the ears, eyes and skin, which detect changes in the environment (stimuli), with the CNS
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What are Motor Neurons?
They connect the CNS to effectors eg muscles, which produce a response
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What are Hormones?
Chemicals that are produced by glands. They are transported in the blood- only affect 'targeted' cells
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In the Hormonal system responses are slower and last longer because...? (Examples)
Insulin is produced by the pancreas. It acts on the liver, muscles and body cells to take up glucose from the blood; Oestrogen is produced by the ovaries, controls the development of the female body during puberty and menstrual cycle
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What are neurons?
Specialised cells for carrying nerve impulses-often very long
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Description of neurons
Consist of the cell body, which contain the nucleus and a long axon. Branches on the cell body called dendrites receive inputs from other cells (receptors & nerves) and conduct impulses towards the cell body
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What are axons?
Axons are long extensions of the cytoplasm in a neuron that communicates with the CNS or effector and carry impulses away from the cell body. Some are covered with Myelin
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What is myelin sheath?
A insulating fatty sheath (which cover some axons)
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The speed of the nerve impulse is affected by?
Temperature, the diameter of the axon, the myelin sheath
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What are synapses?
Synapses are small gaps between one neuron and the next, through which messages have to be transmitted
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As the nerve impulse reaches the end of the first neuron...
A chemical transmitter substance is released
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The transmitter diffuses across the synapse and ...
Binds with receptor molecules on the membrane of the next neurone
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Card 2

Front

What is the Nervous System and what does it do?

Back

The Nervous system sends messages using neurons which produce a quick, short response; nerve impulse is electrical; has specialised organs-brain and spinal cord

Card 3

Front

What is the Hormonal System and what does it do?

Back

Preview of the front of card 3

Card 4

Front

What does the Central Nervous System (CNS) consist of?

Back

Preview of the front of card 4

Card 5

Front

In the mammalian nervous system, what is the CNS connected to?

Back

Preview of the front of card 5
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