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29983240
Nervous System
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nervous system
biology
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Mind Map by
Fionnuala Gillain
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Fionnuala Gillain
over 3 years ago
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Resource summary
Nervous System
Central Nervous System (CNS) - Brain and Spinal Cord
Peripheral Nervous System (PNS) - All other nerves from brain and spinal cord
Neurons- Specialized to carry messages around the body
3 Types:
1) Sensory- Carry impulses towards CNS
2) Motor- Carry impulses away from CNS to an effector Eg; Muscle
3) Interneurons- Carry info between sensory and motor
Parts of the Neuron:
Cell Body- Contains Nucleus. Group of cell bodies called Ganglia
Dendrites- Picks up impulse
Axon- Transports Electrical Message away from cell body
Myelin Sheath- Fat rich cover. Insulates Electrical Impulse
Schwann Cell- Makes Myelin Sheath
Synapse- Gap between Neurotransmitter swelling of 1 Neuron and Dendrite of the next
Neurotransmitter Swellings- Contain chemicals called neurotransmitters
Features of Nerve Impulses:
Threshold- Min. stimulus required to cause an impulse to be carried in a neuron
All or Nothing Law- If threshold reached, impulse is carried. If it is not reached, impulse is not carried
Refractory Period- Short time span after impulse is carried, where a stimulus fails to cause a response
Synapse- Region where 2 neurons come into close contact
Synapse Cleft- Gap between 2 neurons bridged by chemicals (Neurotransmitters)
Neurotransmitter: Chemical released across a Synaptic Cleft to carry a signal from 1 Neuron to another
*Impulses can be blocked by certain chemicals~ Drugs*
The Brain:
Composed of over 100 billion neurons, each receiving messages simultaneously from thousands of other neurons.
Meninges- Membrane covering brain and spinal chord. Contains cerebrospinal fluid
Cerebrum- Controls voluntary movements Eg; Thinking and Memory
Cerebellum- Controls Muscular Co-ordination and learned movements Eg; Riding a bike
Medulla Oblongata- Controls involuntary movements Eg; Breathing and Swallowing
Hypothalamus- Monitors blood temp and Bp (Homeostasis)
Studied Disorder:
Parkinson's Disease:
Cause - Failure to produce Dopamine
Prevention- No way to prevent or cure it
Treatment- Exercises and Drugs
Spinal Cord:
White Matter- Axons Only
Grey Matter- Cell Bodies and Dendrites
Cord is located in the Central Canal
Dorsal Root located towards front of body and contains Motor Neurons
Reflex Action- An automatic. unthinking response to a stimulus Eg; Burning your finger
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