GCSE OCR GATEWAY BIOLOGY : Coordination and control – The nervous system COMPLETE REVISION

This page contains the detailed and easy notes for GCSE Biology OCR Coordination and Control – The nervous System for revision and understanding Coordination and Control – The nervous System.

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 GCSE OCR GATEWAY Biology Complete Revision Summary

Coordination and control – The nervous system

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Coordination and control – The nervous system

  • The structure and function of the nervous system

  • Reflex arc

  • Practical activity

  • The brain

  • Investigating brain function

  • Treating severe head injuries

  • The eye

  • How the eye works – Higher

  • Common defects of the eye and how they can be overcome

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HOMEOSTASIS – The process of maintaining the constant internal environment

Nervous System and the Hormonal System

Homeostasis is important for the enzymes as the enzymes control all the reactions of the body and they need optimum condition to work.

NEURONES

Motor Neurone
  • Motor Neurones connect the CNS to the Effectors
  • Takes impulses away from CNS
  • Motor neurones sends the message from the central nervous system to the effectors.
Sensory Neurone
  • Sensory Neurones connect sense organs with the Central Nervous System.
Relay Neurone
  • Relay Neurones are present in the CNS and occur between the sensory and motor neurons for distant transmission of Impulses.
  • Found in CNS
  • Connect Sensory and Motor Neurones
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REFLEX ACTIONS

  • It is the automatic response of the body to a stimulus.
  • In reflex action the message from the sensory neurones is passed to the spinal chord instead of brain.
  • Spinal Chord sends the message to the effectors and produce a response
Example: Knee Jerk Reflexes,
  • Touching hot object, Sudden closure of light with bright light
  • It is rapid
  • It is quick Automatic, Instantaneous without conscious thoughts

Stimulus

Sensory neurones

Receptor

Sensory neurones

Spinal Chord

Motor neurones

Effector

Response

SYNAPSE

Message is transmitted by chemicals

BRAIN – It is the Central information processing organ of our body, and acts as the command and Control System.

CEREBRUM (Cerebral Hemisphere) – It is nearly 80% part of the brain
  • Consciousness
  • Memory
  • Intelligence
  • Language
CEREBELLUM – It lies behind the cerebrum and above the medulla oblongata. It is the second largest part of brain and is highly convoluted area which accommodates many neurons.
  • Muscle Coordination
  • Balance
MEDULLA OBLONGATA or oblong marrow is oblong cylindrical part of the brain. It forms the hindermost part of the brain.
  • Unconscious Activities like Heart Rate, Breathing.
  • Gut Movement
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Coordination and control – The nervous system

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BRAIN SCAN

Magnetic Resonance Imaging (MRI) helps to take the Images of different parts of the brain and relating it with loss of functions of the individual Problems
  • Brain is complex
  • Skull protects the brain
  • Thousands and neurones and neurotransmitter are involved
  • The functions of different parts is still not understood.
  • Drugs do not reach the brain

Eye – It is lodged in orbit of skull, hollow, spherical organ, about 2.5 cm in diameter and about 6-8gram in weight

ACCOMMODATION- Ability of eye to adjust the focal length of the lens to make clear image of the objects lying at varying distances. It is a reflex mechanism and is done with the help of ciliary muscles and suspensory ligament.

For distant vision, ciliary muscle relax making the suspensory ligaments tensed which inturn make the lens thin so that the image is focussed on the retina. For near vision, ciliary muscle contract making the suspensory ligaments to slack which inturn make the lens thick so that the image is focussed on the retina. Banner 5

DEFECTS OF VISION

MYOPIA
  • Short sightedness
  • The image falls in front of the retina of the eye.
  • Eye ball gets elongated
  • corrected by concave lens
HYPERMETROPIA
    • Long sightedness
    • The image falls behind the retina of the eye.
    • Eye balls gets shortened
    • corrected by convex lens

    NEW EYE TECHNOLOGIES

    Contact Lenses
    • Lenses are placed on the surface of the eye.
    • Includes soft, silk and disposable lenses
    • Can be used by any person at any age
    Laser Surgery
    • Laser is used to change the thickness or the curve of the cornea so that defects of vision can be corrected.
    • Can be done on adults after the growing age.
    Replacement Lens
    • It involves either replacing the faulty lens or inserting the correct one with the faulty one.
    • Include damage risk to the eye.

    Disclaimer:

    I have tried my level best to cover the maximum of your specification. But this is not the alternative to the textbook. You should cover the specification or the textbook thoroughly. This is the quick revision to help you cover the gist of everything. In case you spot any errors then do let us know and we will rectify it. References: BBC Bitesize Wikipedia Wikimedia Commons Image Source: Wikipedia Wikimedia Commons Flickr Pixabay

    Make sure you have watched the above videos and are familiar with the key definitions before trying these questions. It is also good to time yourself while doing these questions so that you can work on the speed as well

    Human Nervous System