the nervous system 1

• ·       Human nervous 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 – so it helps all
• ·       the parts in the body communicate with each other.

  ·       The brain controls the nervous system.
• · 

  ·       The brain is an organ that has many billions of neutral cross sections.

  ·       The brain oversees the workings of the body.

  ·       The brain higher functions provide us with consciousness and makes us who we are.
• Division of the nervous system

  -          the human nervous system is divided into the central nervous system which consists of the brain and the spinal cord and is where all information and signals come to and where are information and signals comes out of as well as the place information can be stored and then the nervous system is also divided secondly into the peripheral nervous system which brings the signals and information to the central nervous system and what also takes out information and signals from the nervous system

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• Division of the nervous system

  -          each of these systems can also be further divided into different components each with a different function but all by working together.
• Central nervous system

  -          The central nervous system is a compromise between the spinal cord and brain.

  -          It has two main functions the control of behaviour and the regulation of the body’s physiological process.
• Central nervous system

  -          In order for these functions to occur the brain must be able to receive information from the sensory receptors which include the eyes , ears and skin , the brain must then also be able to send messages to the muscles and glands in the body , and this process involves the spinal cord and a collection of nerve cells that are attached to the brain and run the length of the spinal cord .
• Peripheral nervous system

  -          All the nerves outside the central nervous system make up the peripheral nervous system.

  -          The function of the peripheral nervous system is to relay nerve impulses from the central nervous system (brain and spinal cord) to the rest of the body and from the body back to the central nervous system.
• Peripheral nervous system


  Part of the nervous system that connects the central nervous system (brain and spinal cord) to the rest of the body
• Peripheral nervous system


  1. Sensory division

  2. Motor division
• Sensory division


  Senses things like sight, smell, touch, and pain, and sends this information to the central nervous system through sensory neurons
• Motor division


  Takes information from the central nervous system and sends it to target cells through efferent neurons
• Divisions of the peripheral nervous system

  • Somatic nervous system
  • Autonomic nervous system
• Signals from the central nervous system can be voluntary or involuntary
• the somatic nervous system

  -          The somatic nervous system is made up of 12 pairs of cranial nerves which are nerves that emerge from the central nervous system / spinal cord. To target skeletal muscle cells for movement

  These nerves are both sensory neurons – which relay messages to the central nervous system and motor neurons which relay information from the central nervous system to other areas of the body.
• the somatic nervous system

  -          Controls voluntary movements.

  -          The somatic system is also involved in reflex actions without the involvement of the central nervous system which means a reflex action can occur very quickly
• Autonomic nervous system


  Responsible for involuntary actions that happen without conscious awareness, such as heart beating and digestion
• Autonomic nervous system


  • Necessary for vital bodily functions like heart beating to work efficiently, as they wouldn't work as well if we had to think about them
• the autonomic nervous system

  • the autonomic nervous system consists of two parts including the sympathetic and parasympathetic both of these of the autonomic nervous system tend to regulate the same organs but have an opposite effect to each other, and this is because of the different neurotransmitters associate with each division

  Generally, the sympathetic division uses the neurotransmitter called noradrenaline which has stimulating effects and the parasympathetic division uses acetylcholine which has the inhabiting effect
• The spinal cord

  -          Main function is to relay information between the brain, the peripheral nervous system and the rest of the body.

  -          The spinal cord relaying information between the brain and the rest of the body allows the brain to monitor and regulate bodily processes like digesting and breathing as well as coordinated voluntary movements.

   
• The spinal cord

  -          The spinal cord is connected to different parts of the body by pairs of spinal nerves which branch of from the thoracic region of the spinal cord which means messages can be carried to and from the chest and parts of the abdomen.
• The spinal cord

  -          The spinal cord also contains circuits of nerve cells that enable us to perform some simple reflexes without the direct involvement of the brain like pulling your hand away form a fire because of the heat although your brain will register the pain of that action it will be after your hand has been removedpulling your hand away from something hot is an example of a reflex.

   
• The spinal cord

  pulling your hand away from something hot is an example of a reflex.

  -          If the spinal cord is damaged areas supplied by spinal nerves below the damage site will be cut off from the Brian and will stop functioning

   
• The brain

  -          Its main function is to take info from the scenes interpret it and act on it.

  -          The brain can be divided into 4 main areas including the cerebrum, cerebellum, diencephalon and brain stem.
• The brain

  -          The cerebrum Is the largest part of the brain and is further divided into four different lobes, which each have a different primary functionthe further 4 divisions of the cerebrum for exampleinclude the frontal lobe which is involved in thought and the production of speech.

  Then there’s the occipital lobe which is the back of the cerebrum which is involved in the processing of visual images
• The brain

  -          The cerebrum is spilt down the middle into two halves called cerebral hemispheres and each one is specialised for particular behaviours and the two halves communicate with each other through the corpus callosum.
• The brain

  -          The cerebellum sits beneath the back of the cerebrum it is involved in controlling a person’s motor skills and balance as well as their coordinating the movement of muscles to allow precise movements.

  Abnormalities in this area of the brain can result in a number of problems including speech and motor problems and epilepsy.
• hypothalamus

  • -          the hypothalamus has a number of important functions including the regulation of body temperature, hunger and thirsthypothalamus also acts as a link between the endocrine system and the nervous system controlling the release of hormones from the pituitary gland
• thalamus

  -          the thalamus acts as a relay station for nerve impulses coming from sense, routing them to the appropriate parts of the brain where they can then be processed
• the brain diencephalon lies beneath the cerebrum and on top of the brain stem in the diencephalon there are two important structures which include the thalamus and the hypothalamus

             The

  -          The brain stem is another part of the brain responsible for regulating the automatic functions that are essential for life including breathing, heartbeat and swallowing motor and sensory neurons travel through the brain stem allowing impulses to pass between the brain and the spinal cord.
• •  The brain-----diencephalon lies beneath the cerebrum and on top of the brain stemin the diencephalon there are two important structures which include the thalamus and the hypothalamus
• the brain        The brain stem is another part of the brain responsible for regulating the automatic functions that are essential for life including breathing, heartbeat and swallowingmotor and sensory neurons travel through the brain stem allowing impulses to pass between the brain and the spinal cord.
• The parasympathetic nervous system

  Rest and digest response – more active system when we rest and eat.

  We still have no control over this system as it is also involuntary and it works by taking information form the central nervous system to a target cell involuntarily
• The parasympathetic nervous system

  Unlike the sympathetic nervous system which pushes individuals into action when they’re faced with an emergency the parasympathetic nervous stem relaxes an individual again after the emergency has passed and the purpose of this is to restore or conserve the bodies energy so the sympathetic nervous system causes the heart rate to increase whilst the parasympathetic nervous system causes heart rate to decrease
• The parasympathetic nervous system

  the parasympathetic nervous system begins digestion again which the sympathetic nervous system inhibits which is another benefit of the parasympathetic nervous system and the reason it does this is because it is concerned with energy conservation and digestion
• The sympathetic nervous systemcan be referred to as the flight or fight response.

  We have no control over this system as it is involuntary and it works by taking information form the central nervous system to a target cell involuntarily
• The sympathetic nervous systemthis system is often switched on during sports
• The sympathetic nervous systemThe sympathetic nervous system is primarily involved in responses that help us to deal with emergencies which is why its effect on the body increases the supply of blood to the brain , hear and muscles by reducing blood flow to the skin and digestive system – since it priorities the organs which are needed the most in situations so prepares them to expend energy that  might be neededtherefore it is responsible for an increase in our heart rate , blood pressure and the dilation f our blood vessels in our muscles when in fight or flight circumstances
• The sympathetic nervous systemneurons from the sympathetic nervous system travel to virtually every organ and gland in the body which then help prepare the body for the rapid action necessary when the individual is under threatThe sympathetic nervous system causes the body to release stored energy which can cause our pupils to dilate and get goosebumps when are hair stands on end , and also slows down bodily processes that are less important in emergencies like digestion and urination
• The sympathetic nervous system Some of the sympathetic nervous system effects and helps are bodies prepare to deal with emergencies is by:

  §  Increase in heart rate which allows for greater blood flow to skeletal muscles.

  §  Glycogen stored in the liver is converted into glucose for energy.

  §  Bronchial tubes in our lungs can be dilated for greater oxygen intake.