Coordination and Control

  • The Nervous System:
  • The Nervous System is split into two distinct parts: the central nervous system and the peripheral nervous system.
  • The Central Nervous system (CNS) is located in the central part of the body, and consists of the brain and the spinal cord.
  • The peripheral nervous system is everything else apart from the brain and spinal cord. This is spread throughout the rest of the body.
  • Homeostasis is a combination of nervous and chemical responses.

Structure of the nervous system:

  • The body is carefully regulated by the hormonal (endocrine) and nervous systems.
  • Control systems in the nervous system include the following parts:

1. Stimulus - change in the environment.

2. Receptors - detect the change.

3. Coordinator - organises the response.

4. Effectors - create a response.

5. Response - caused by an effector.

  • Neurones are specialised cells that carry elctrical impulses.
  • Sense organs include the eye that detect the stimulus light.

Reflex Arc:

  • A reflex arc creates an automatic, rapid response and is used to limit damage to the individual.
  • Reflex arc includes the following parts:

1. Stimulus - is detected.

2. Receptor - detects the change.

3. Sensory neurone - impulses travel along these towards the spinal cord.

4. Relay neurone - located within the spinal cord, and connects sensory and motor neurones.

5. Motor neurone - connect the relay neurone to the effector.

6. Effector - creates a specific response, examples includes glands and muscles.

7. Response - created by an effector as a direct result of the inital stimulus detected.

  • A synapse is a gap between the two neurones. Neurotransmitter diffuses across it.

The Brain:

  • The Brain is a very complex organ, and controls complex behaviour such as nervous responses and homeostasis, and contains billions of neurones.
  • Three main areas inside the brain that carry out different functions are:

The Cerebral Cortex - The outer layer of the cerebrum, which is split into two hemispheres. It controls memory, language, conscious, thought and intelligence.

The cerebellum is


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