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Cards In This Set
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What is the major function of the nervous system?
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Ther servous system is a very fast communication system that responds to out boilogical needs in the micro-to-millisecond range:
1. Gather information (sensation) 2. Analyse and interpret - (aware or unaware) 3. Respond (behave) |
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What are the different types of nerves?
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 Sensory (outside to the brain = afferent) Intergration (interneuron) Motor (brain to outside = efferent) |
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In words describe the organisation of the nervous system.
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 The sensory division (sensory nerve fibres) conduct afferent impulses to the CNS through the peripheral nervous system (cranial and spinal nerves) which is the communication highways. At the central nervous system (brain and spinal cord) integration and control takes place and the message goes back through the peripheral nervous system to the motor division (motor nerve fibres) which is conducted through the efferent impulses to muscles and glands. This can be somatic (system voluntary) to the skeletal muscles or autonomic (system involuntary) to the smooth and cardiac muscles and glands. The autonomic system is split into two divisions; Sympathetic Division which mobilised body systems to deal with daily stress and the parasympathic division which conserves and replenishes energy. |
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How is the brain protected?
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Bone, meninges and cereospinal fluid.
Harmful substances are shielded from the brain by the blood-brain barrier |
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What are the three connectie tissues membranes the lie external to the central nervous system?
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 The meninges. Dura mater, Arachnoid mater, and pia mater |
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Why does the brain need to be protected?
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It is the consistancy of oatmeal and any pressure on it can cause cells to die. (bones, meninges, cerebrospinal fluid)
It also needs to be protected from infections (blood-brain barrier) |
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Describe the protection of the spinal cord.
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 The spinal cord also has bone, disks and cerebrospinal fluid the suspends the spinal cord. It is continuous from the brain |
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Describe the dura mater.
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Double layer meninge which is connected to the skull and the other side stablises the layers beneath it (arachnoid mater and pia mater).
There are gaps in between the two layers which create synases (lakes). This is were there is exchange of waste material from the brain back into the synases that eventually drain down the back of your neck to the cardiovascular system *Leathery, strong membrane composed of two fibrous connective tissue layers |
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Describe the arachnoid mater.
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Below the dura mater resembled spider webs. Beneath the archnoid mater is the cerebrolspinal fluid and theathering fibres which prevent the bain from moving too much. There are blood vessels which exchange nutrients to the cerebrolspinal fluid to provide nutrients to the brain.
The cerebrolspinal fluid from the under the arachnoid mater also feeds into the synases in the dura mater that drain waste back to the cardiovascular system * The middle tissue, which forms a loose brain covering * It is seperated from the dura mater by the subdural space * Beneath the arachoid is a wide subarahnoid space filled with cerebralspinal fluid and large blood vessels |
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Describe the pia mater.
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This is follows all the dips and creases of the brain and is slightly tougher and assists it to hold its shape.
* Deep layer composed of delicate connective tissue that clings tightly to the brain |
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What are the functions of the meninges?
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Cover and protect the central nervous system
protect blood vessels contain cerebrospinal fluid |
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What is the function of the ventricles of the brain?
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Production and circulation of cerebrospinal fluid
Help keep the brain boyant |
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What are the ventricles of the brain?
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Lateral ventricles (left and right)
third ventricle (in the middle of the brain) fourth ventricle (in the middle through the cerebellum and brain stem) |
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Describe the functions of the cerebrolspinal fluid
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(CSF)
Reduces the weight of the brain by floating it - 1500 grams becomes about 50 grams Protection from blows (other than major ones) Waste removal from the CNS Regulation of chemicals and pH in CNS |
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Give a summary of the protection og the central nervous system.
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CNS lines within bone cavity
- skull for brain - vertebrae for spinal cord CNS surrounded by meninges which are covers formed by three connective tissue wrappings - outer layer - dura mater - middle layer - arachnoid mater - inner layer - pia mater CNS bathed in cerebrospinal fluid |
