3. THE HUMAN NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM (CNS) PERIPHERAL NERVOUS SYSTEM (PNS) ORGANISATION OF THE NERVOUS SYSTEM
4. ORGANISATION OF THE NERVOUS SYSTEM Links receptors & effectors to CNS : relays signals between CNS & rest of body HUMAN NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM [CNS] PERIPHERAL NERVOUS SYSTEM [PNS] BRAIN SPINAL CORD CRANIAL NERVES [12 pairs] SPINAL NERVES [31 pairs]
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7. AN OVERVIEW OF THE FUNCTIONS OF THE NERVOUS SYSTEM Sensory receptors detect stimuli from int. & ext. environments & initiate nerve impulses carrying information to CNS CNS processes & integrates information by analysing & storing some of it, & then make decisions to initiate suitable responses Motor commands from CNS transmitted to effectors [muscles or glands] to carry out responses 1 3 2
8. THE HUMAN BRAIN HUMAN BRAIN HYPOTHALAMUS THALAMUS MEDULLA OBLONGATA CEREBELLUM CEREBRUM
9. THE HUMAN BRAIN SKULL MEDULLA OBLONGATA CEREBELLUM CEREBRUM VERTEBRA SPINAL CORD PITUITARY GLAND THALAMUS HYPOTHALAMUS
12. Medulla oblongata Pons Brainstem Cerebellum Cerebrum Thalamus Hypothalamus STRUCTURE OF THE BRAIN
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17. THE SPINAL CORD AND ITS MAIN FUNCTIONS INTERNEURONE DORSAL ROOT DORSAL ROOT GANGLION AFFERENT NEURONE RECEPTOR EFFECTOR EFFERENT NEURONE CENTRAL CANAL GREY MATTER [ contains cell bodies] SPINAL NERVE WHITE MATTER {contains myelin-coated axons] VENTRAL ROOT CROSS SECTION OF THE SPINAL CORD
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19. The spinal nerves emerge from the spinal cord through two short branches or roots. (a) The dorsal root contains the axons of the afferent neurones which conduct nerve impulses from the sensory receptors to the spinal cord. (b) The cell bodies of the afferent neurones are clustered in the dorsal root ganglion (c) The ventral root contains the axons of the efferent neurones which conduct nerve impulses away from the spinal cord to the effectors. (d) The dorsal and ventral roots join to form a spinal nerve. FUNCTION : The spinal cord (a) processes certain types of sensory information and sends out responses via the efferent neurones. (b) contains neurones that convey signals to and from the brain, (c) contains the neural pathway for reflexes
27. The transmission pathway of information Reception of stimuli by receptors Response by the effectors From the CNS to the effectors Integration & interpretation by the central nervous system From receptors to the central nervous system 1 5 4 3 2
28. Afferent neurone Efferent neurone Interneurone 1 5 4 3 2 6 Receptors in the ear Muscles in the arm Receptors in the ear pick up the ringing of the doorbell. The nerve impulses pass from the afferent neurones to the interneurones in the brain The receptors trigger nerve impulses in the afferent neurones. From the interneurones, nerve impulses are transmitted to the efferent neurones and then to the muscles The brain interprets the nerve impulses from many interneurones that the doorbell is ringing. The brain also decides that the door should be opened The muscles in the arm carry out the response and open the door 1 2 3 4 5 6 The transmission pathway of information
29. The transmission of nerve impulses along the three types of neurones Synaptic terminal dendrites axon dendrite Cell body receptor in skin axon myelin sheath Synaptic terminal on muscle fibre Cell body Cell body axon myelin sheath Efferent neurone synaptic terminal Afferent neurone Interneurone
30. DIFFERENCE BETWEEN STRUCTURE OF AFFERENT NEURONE & EFFERENT NEURONE AFFERENT NEURONE EFFERENT NEURONE Long dendrite, short axon Short dendrite, long axon Cell body at the side of the neurone [not at the end] Cell body at the end of the neurone Begins with receptor Ends with effector