The Nervous system

Structure and function of the CNS
1. The CNS is composed of the brain and the spinal cord
2. The peripheral nervous system is made up from sensory neurones carrying impulses from the receptors to the CNS and motor neurons to move the skeletal muscles
Peripheral nervous system
1. Somatic nervous system
  1. Deals with functions under conscious control like walking and speaking
2. Autonomic nervous system
  1. Controls bodily functions like heart rate, these are controlled unconsciously
  2. Made up of nerves cells inside the brain and emerge at various points down the spinal cord to reach effectors like cardiac muscle, smooth muscle and glands.
    1. They stimulate nerve impulses to carry out homeostatic control.
  3. Divided into the sympathetic and parasympathetic systems
    1. Known to be antagonistic as they affect the same structure but have opposite effeccts.
    2. The parasympathetic part is dominant at times of resting when heart rate is low, breathing rate is reduced and the blow flow to the muscles is reduced and increased to the digestive system and its muscles.
      1. Known as the 'rest and digest' response, it calms the body down to conserve resources and energy.
    3. The sympathetic is during times when the body is active causing an increased heart and breathing rate, perspiration and redistribution of blood to the muscles instead of the digestive system
      1. Known as the 'fight of flight' when the body is preparing for action
Parts of the brain
1. Central Core
  1. Contains the medulla which regulates the basic life processes of breathing, heart rate, arousal (being awake and aware fo the external environment) and sleep
  2. Also contains the cerebellum which is responsible for control of balance, posture and movement
2. Limbic System
  1. part of the brain involved with processing information for memories, regulating emotional states and influencing biological motivation like hunger
3. Cerebral coretex
  1. Outer layer of the cerebrum
    1. The cerebrum is divided into two cerebral hemispheres
      1. The left side processes information from the right visual field and controls the right side of the body
      2. The right side processes information from the left visual field and controls the left side of the body
      3. The sides are connected by a bundle of nerves called the corpus callosum
  2. Contains 3 types of functional areas: sensory, association and motor.
    1. The sensory receives information as sensory impulses from the body's receptors
    2. The association areas analyse and interpret these impulses to make sense of them and take decisions.
    3. The motor areas receive information from the association area and carry out orders by sending motor impulses to the appropriate effectors

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The Nervous system

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	Created by Gordon Morrison over 9 years ago