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39 Cards in this Set
- Front
- Back
- 3rd side (hint)
Homeostasis |
Tendency of living organisms to maintain their internal environment constant with narrow limits irrespective of changes in the external environment |
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Nervous System |
1. Detects changes in environment 2. Enables coordination of various activities of the body |
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Nervous System |
Nerves»Nerve fibres»Neurons |
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Sensory Neurons |
Carry impulses from receptor(nerve endings / sense organs) to central nervous system(brain+spinal cord Neurons damaged= no stimuli picked up |
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Motor Neurons |
Carry impulses from central nervous system to efectors(muscles or glands) If damaged, you will not be able to respond to stimuli. You will not feel pain |
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Connector neurons/ interneurons |
Carry impulses inside central nervous system from sensory neuron to motor neuron Located in spinal cord |
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Neurons consist of: |
1. Cell body 2. Dendrites 3. Axon |
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Axon |
Conducts impulses away from body |
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Myelin Sheath |
Provides electrical insulation Helps speed up the transmission of impulses |
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Synaptic Contact |
Nerve impulses are carried along neuron electrical impulses but communication across synapse is by means of chemical called neurotransmitters |
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Central nervous system |
Brain+spinal cord |
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Peripheral nervous system |
Made up of all nerves outside CNS |
Physical |
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Somatic nervous system |
Parts of nervous system that enable the body to react to external changes in environment |
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Autonomic nervous system |
Parts of nervous system that control internal environment e.g. sweating, breathing |
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BRAIN |
Upper, enlarged part of spinal cord(protected by cranium) |
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Meninges |
Protective membranes surrounding brain and spinal cord |
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BRAIN functions |
1. Receives and interprets sensations 2. Controls higher thought processes 3. Voluntary and involuntary actions 4. Maintains muscle tone and balance |
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Corpus callosum |
Mass of white fibres which connect the right and left side of the brain |
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Cerebrum |
Grey matter on the outside, white matter on the inside. 1. Controls voluntary actions 2. Receives and interprets all sensations. 3. Controls higher thought processes |
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Medulla Oblongata |
Contains cerebrospinal fluid White outside, grey inside 1. Involuntary actions 2. Conducts impulses from spinal cord to higher parts of brain |
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SPINAL CORD |
Formed by successive vertebrae SPINAL nerves arise from spinal cord and leave spinal canal through tiny openings formed between successive vertebrae Surrounded and protected by meninges White matter on the outside, grey matter on inside
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Sensory neurons |
Enter dorsal root of spinal nerves Bring impulses from receptor to SPINAL cord |
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Dorsal root swelling |
Dorsal root ganglion |
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Sensory nueron |
Has cell body centrally situated |
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Dorsal root |
Has dorsal root ganglion to accommodate all cell bodies of sensory neurons |
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Connector neurons |
Found in spinal cord between sensory and motor neurons Transmits impulses from sensory neurons to motor neurons |
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Motor neurons |
Leave spinal cord through ventral root of spinal nerves Take impulses from spinal cord to effector organ(muscle/gland) |
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SPINAL cord |
1. Conducts impulses between brain and receptors and defectors 2. Serves as reflex centre for blinking, knee jerking etc. |
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PERIPHERAL NERVOUS SYSTEM |
Made up of all nerves outside the central nervous system |
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PERIPHERAL NERVOUS SYSTEM divide into: |
Somatic nervous system Autonomic nervous system |
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Somatic nervous system |
Parts of nervous system that enable the body to react to changes to external environment |
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Somatic nervous system made up of: |
1. Free nerve endings and sense organs which pick up change in external environment 2. Sensory nerves carrying impulses from receptors 3. Motor nerves carrying impulses back to muscles/glands 4. Defectors which react to these impulses |
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Autonomic nervous system made up of: |
1. Centres in brain and spinal cord 2. Nerve cells in smooth muscles, glands and internal organs 3. Sympathetic and parasympathetic nerves running to these muscles,glands and internal organs |
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Sympathetic nerves + Parasympathetic nerves |
Function metaphorically e.g. Sympathetic nerves of heart increase heart rate, while Parasympathetic nerves slow down heart rate |
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Reflex Action |
Rapid, automatic/ involuntary response to stimulus received by an organ or other receptor |
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Reflex Arc |
Path taken by an impulse in bringing about a response to a stimulus during a reflex action |
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Eye |
Long sightedness (Hypermetropia) Short sightedness (Myopia) |
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Hypermetropia |
Eyeball too rounded Lense of eye unable to become more convex |
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Hypermetropia |
The image of the near object that falls on the retina is blurred while the best image falls behind the retina |
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