Nervous system

• The Human Nervous System:

  • The human system is a complex network of nerve cells that carry messages to and from the brain and spinal cord to different parts of the body to communicate with each other.
  • Controlling the nervous system is the brain, the ‘powerhouse’ of the body. - Even though it only makes up 2% of the body’s weight!
  • This organ has billions of neural cross-connections. The brain oversees the workings of the body, while its higher functions provide us with consciousness and makes us who we are.
• The human nervous system is divided into the central nervous system (CNS) and the peripheral nervous system, with each of these further divided into different components, each with a different function but all working together.
• Nervous system

  • CNS (Spinal cord and brain)
  • Peripheral nervous system
  • -> Somatic Nervous system
  • -> Automatic nervous system (Sympathetic and parasympathetic NS)
• The Central Nervous System:

  • The CNS, comprising the brain and spinal cord, has two main functions.

  -> The control of behaviour

  -> The regulation of the body’s physiological processes

  • In order to do this, the brain must be able to receive information from the sensory receptors (eyes, ears, skin etc.) and be able to send messages to the muscles and glands of the body.
  • This involves the spinal cord, a collection of nerve cells that are attached to the brain and run the length of the spinal column
• The main function of the spinal cord is to relay information between the brain and the rest of the body. This allows the brain to monitor and regulate bodily processes, such as digestion and breathing, and to coordinate voluntary movements.
• • The spinal cord is connected to different parts of the body by pairs of spinal nerves, which connect with specific muscles and glands. For example, spinal nerves which branch off from the thoracic region of the spinal cord, carry messages to and from the chest and parts of the abdomen.
• • The spinal cord also contains circuits of nerve cells that enable us to perform some simple reflexes without direct involvement of the brain, for example pulling your hand away from something that is hot.
  • If the spinal cord is damaged, areas supplied by spinal nerves below the damaged site will be cut off from the brain and will stop functioning.
• The four main areas of the brain are divided into:

  • Cerebrum
  • cerebellum
  • diencephalon
  • brain stem
• Cerebrum divided into two hemispheres and 4 lobes

  eg.

  • Frontal lobe
  • Occipital lobe
• Frontal lobe:

  • Thought and production of speech
• Corpus callosum:

  • Allows two hemispheres to communicate
• Occiptal lobe:

  • Processing visual images
• Cerebellum:

  • Controls motor skills and balance
• Hypothalamus:

  • Regulation of body temperature, hunger and thirst
• Thalamus:

  • Relay centre for nerve impulses from senses
• Brain stem:

  • Regulating autonomic functions essential for life eg breathing heartbeat and swallowing.
• CNS:

  • brain and spinal cord. Receives info from senses and controls body responses.
  • Brain coordinates sensation, intellectual and nervous activity (made up of cerebrum, cerebellum, diencephalon, and brain stem).
  • Spinal cord: bundle of nerve fibres enclosed in spinal column connects brain with nearly all of the body
• • 2014, chinese woman had vertigo - scientists found her cerebellum missing, but only mild to moderate motor deficiency as rest of brain compensated