Transcript File
BIOLOGY 30 – Unit 1 Nervous and Endocrine Systems http://www.youtube.com/watch?v= DF04XPBj5uc Vertebrate Nervous Systems The nervous system can be divided into two main categories, both of which can be further subdivided The Central Nervous System (CNS) Contains the nerves of the brain and the spinal cord Acts as a coordination center for incoming and outgoing information The Peripheral Nervous System (PNS) Relay of info btwn body organs and CNS – both motor and sensory neurons Autonomic: INVOLUNTARY Internal Organs Sympathetic: Prepares body for stress “Fight or Flight” Parasympathetic: Restores body to normal after stress “Rest and Digest” Work in opposition Somatic: VOLUNTARY Skeletal muscle, bones, skin Cells in the Nervous System 1. 2. Two different types of cells exist within the nervous system: Glial Cells (neuroglial cells): Nonconducting cells that are responsible for supporting the neural cells structurally and metabolism within nerve cells Neurons: Cells responsible for conducting electrochemical messages throughout the body Neuron – functional unit of nervous system Sensory Neurons: (Afferent) 1. From external environment to CNS Interneurons: (Association) 2. Link neurons Only found in brain and spinal cord Motor Neurons: (Efferent) 3. From CNS to effector (muscle, organ) The Structure of the Neuron All neurons are made up of 4 different parts: The Dendrites The Cell Body The Axon Axon Terminal The Dendrites The dendrite is responsible for receiving information either from the environment or from other neurons Dendrite The Cell Body Contains the nucleus, which acts as a cell control centre, directing cell activity Cell Body The Axon Where the impulse travels down and conducts the impulse throughout the neuron Some neurons contain a myelin sheath: •Insulated covering of axon Myelin Sheath •Speeds transmission •Produced by Schwann Cell **White Matter + myelin ***Grey Matter – myelin Nodes of Ranvier • gaps between myelin sheath Axon The Axon Terminal The end of the neuron which contains and releases neurotransmitters, allowing neurons to communicate with one another The neuron sending the message is called the pre-synaptic neuron The neuron receiving the message is called the post-synaptic neuron Repair of Damaged Nerves Sensory and motor neurons contain two addition cellular structures, absent in interneuron cells Neurilemma Membrane that surrounds some nerve cells Produced by Schwann Cells Promotes regeneration Found in PNS Not found in CNS Nerves Nerves are the visible parts of the nervous system Made up of bundles of neurons Kim Peek – The Real Rain Man http://www.youtube.com/watch?v=k2T45r5G3kA http://www.youtube.com/watch?v=NJjAbs-3kc8&feature=related http://www.youtube.com/watch?v=Auufbu_ZdDI&feature=related http://www.youtube.com/watch?v=vRPxMDj33S4&feature=related http://www.youtube.com/watch?v=a1aA5osvYgY&feature=related