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.

 GCSE OCR GATEWAY Biology Complete Revision Summary

• 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

HOMEOSTASIS – The process of maintaining the constant internal environment

Nervous System and the Hormonal System

NEURONES

• 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 Neurones connect sense organs with the Central Nervous System.

• 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

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

• Touching hot object, Sudden closure of light with bright light
• It is rapid
• It is quick Automatic, Instantaneous without conscious thoughts

Stimulus

Receptor

Spinal Chord

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.

• Consciousness
• Memory
• Intelligence
• Language

• Muscle Coordination
• Balance

• Unconscious Activities like Heart Rate, Breathing.
• Gut Movement

Coordination and control – The nervous system

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BRAIN SCAN

• 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.

DEFECTS OF VISION

• Short sightedness
• The image falls in front of the retina of the eye.
• Eye ball gets elongated
• corrected by concave lens

• Long sightedness
• The image falls behind the retina of the eye.
• Eye balls gets shortened
• corrected by convex lens

NEW EYE TECHNOLOGIES

• 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 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.

• It involves either replacing the faulty lens or inserting the correct one with the faulty one.
• Include damage risk to the eye.

Disclaimer:

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

• Human Nervous System 1 MS
• Human Nervous System 1 QP
• Human Nervous System 2 MS
• Human Nervous System 2 QP
• Human Nervous System 3 MS
• Human Nervous System 3 QP