1. THE NERVOUS SYSTEM THE NERVOUS SYSTEM

2. THE NERVOUS SYSTEM The nervous system is the master controlling and communicating system of the body. The nervous system has 3 overlapping functions 1.The nervous system monitors changes – millions of sensory receptors monitor change inside and outside the body. The gathered info is called sensory input 2.The nervous system processes and interprets sensory input – then makes decisions about what should be done. This process is called integration 3.The nervous system then effects a response – it activates muscles or glands. This response is called motor output EX. You are driving and see a red light (sensory input),the nervous system integrates the info, (red means stop) and your foot steps on the brake (motor output)

3. NERVES Nerves are connected to the spinal cord and carry messages or impulses to and from the brain. Nerve tissue is composed of 2 types of cells: 1.Neuroglia cells – they nourish, protect, and insulate the neurons 2.Neurons – transmit information. There are 3 parts to a neuron 1Dendrites – have branches and conduct electrical currents toward the cell body 2Nucleus – keeps the cell alive 3Axon –generate nerve impulses away from the cell down to the axon terminals (the end of the axon) and stimulate chemicals called neurotransmitters The spaces between the neurons are called synapses.

4. NERVES HOW IS INFORMATION PASSED ALONG? The information received in a dendrite, passes through the cell body, travels down the axon, out the axon terminal, over/across the synapse, and on to the next dendrite. Nerves are easily damaged and take a long time to heal/regenerate (if at all). Some nerve fibres have a protective coating called the myelin sheath, which also insulate the nerve fibre Nerve fibres with a myelin sheath can conduct impulses faster than those without.

5. BASIC NERVE CELL

6. THE NERVOUS SYSTEM STRUCTURAL CLASSIFICATION The nervous system has 2 subdivisions 1.The Central Nervous System (CNS) 2.The Peripheral Nervous System (PNS)

7. THE NERVOUS SYSTEM THE CENTRAL NERVOUS SYSTEM (CNS) Consists of the brain and spinal cord The CNS acts as the integrating and command centre BRAIN Contained in and protected by the skull and covered by meninges The 3 main parts of the brain are: 1.The cerebrum – the largest part of the brain, It controls the senses, thought, memory, and learning. Also controls certain voluntary muscles, such as those used for walking, talking and writing. Divides into 2 halves, the right and left hemisphere The right hemisphere controls the left side of the body and vice versa The outside of the cerebrum is called the cerebral cortex. It controls the highest functions of the brain.

8. THE BRAIN The cerebrum is divided into 4 sections: 1.The Frontal Lobe – controls intellect, behaviour, attention, creative thought etc. 2.The Occipital Lobe – controls vision and reading 3.The Parietal Lobe – sense of touch, some language and reading 4.The Temporal Lobe - controls music, fear, some hearing, language and speech

11. THE NERVOUS SYSTEM 2.THE CEREBELLUM Regulates and controls balance and equilibrium Makes body movement smooth and co-ordinated 3.THE BRAINSTEM Connects the cerebrum to the spinal cord. Contains the: Midbrain – relays messages between the medulla and the cerebrum Pons - relays messages between the medulla and the cerebrum. Also controls breathing Medulla oblongata – controls heart rate, BP, breathing, swallowing and vomiting. Controls rage and aggression http://www.youtube.com/watch?v=VF5PyeMG8Lo

13. THE NERVOUS SYSTEM THE SPINAL CORD Approx 17-18 inches long. 2 way conduction pathway to and from the brain Major reflex centre Covered by 3 layers of meninges 1.Dura mater – tough outer layer 2.Arachnoid – middle layer 3.Pia mater – delicate inner layer The space in between the arachnoid and pia mater is called the subarachnoid space. This space is filled with CSF – cerebral spinal fluid, a watery fluid that circulates around the brain and spinal cord and protects the CNS by acting like a cushion

14. THE NERVOUS SYSTEM THE PERIPHERAL NERVOUS SYSTEM (PNS) Consists mainly of the nerves that extend from the brain and spinal cord. Spinal nerves carry impulses to and from the spinal cord Responsible for carrying impulses from the skin, extremities, and internal structures 31 pairs Cranial nerves carry impulses to and from the brain Primarily serve the head and neck Responsible for senses, temp, pressure, voluntary and involuntary muscle control 12 pairs

15. THE NERVOUS SYSTEM The PNS is subdivided into 2 systems: 1.The Somatic Nervous System – sends sensory info to the CNS and allows us to voluntarily control our skeletal muscles 2.The Autonomic Nervous System (ANS) – regulates involuntary activities (heart, organs, glands). The ANS is then further subdivided into 2 more systems:

16. THE NERVOUS SYSTEM 1.The Sympathetic Nervous System – speeds up functions, such as when you are frightened, angry, excited or exercising. Often called the “fight or flight” response. The sympathetic nervous system: Increases heart rate, BP, and BS (blood glucose) Dilates the bronchioles and skeletal muscles 2.The Parasympathetic Nervous System – slows down body functions and is activated when you relax and your body is not threatened in any way. Referred to as the “resting and digesting” system. This system is concerned with: Digestion Elimination of urine and feces Conserving energy

17. The Nervous System Central Nervous System Brain Cerebrum Frontal Lobe Occipital Lobe Parietal Lobe Temporal Lobe CerebellumBrainstem Midbrain Pons Medulla Oblongata Spinal Cord Peripheral Nervous System Somatic Nervous System Autonomic Nervous System Sympathetic Nervous System Parasympathetic Nervous System