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Term 3 Science 2013 Chapter 7 Body Coordination There are three sections 7.1 Nervous control 7.2 Chemical Control 7.3 Coordinated Body Systems Assessment A short exam (about 30 minutes) at the end of each section A research activity All four pieces will count towards your term 3 result. Time table for this term Week Topic Assessment 22-26 July 7.1 Nervous Control Exam 5-9 August 7.2 Chemical Control Exam 12-16 August Research Activity Report 2-6 Sept 7.3 Coordinated Body Systems Exam Workbook You will be given a workbook for the term You are to use this workbook for writing up your science practicals and homework The workbook will be handed up for regular marking during the term It is your responsibility not to lose this workbook – it is part of the assessment for the term Neural (nerve) Control http://yr-9-health.wikispaces.com/Unit+Outline Chapter 7.1 page 225 Nervous System By the end of the unit you should be able to Describe the transmission of impulses from senses to central nervous system and back to muscles. Describe the reflex action and the pathway of the reflex arc. Describe the function of reflex response. Describe the role of the central nervous system. Let us watch a…..Movie http://www.bbc.co.uk/schools/gcsebitesize /science/aqa/nervesandhormones/thenerv oussystemact.shtml nervous system Human Nervous System Consists of 2 main parts The Central Nervous System (spinal cord and brain) and, The Peripheral Nervous System (all of the other nerves in your body and limbs. Organization of the Nervous System Figure 7.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Basic Tasks of the Nervous System Sensory Input: Monitor both external and internal environments. ( Changes= stimuli) Integration: Process the information and often integrate it with stored information. Motor output: If necessary, signal effector organs to make an appropriate response. Did you know…..You have a nerve along your whole arm. The “funny bone” is the only place on the arm where the nerve is not protected. The “funny bone” is on the elbow. Histology of neural tissue Two types of neural cells in the nervous system: Neurons - For processing, transfer, and storage of information Neuroglia – For support, regulation & protection of neurons Nerve diagrams Basic nerve cell structure •Many vertebrate peripheral neurons have an insulating sheath around the axon called myelin which is formed by Schwann cells. •Myelin sheathing allows these neurons to conduct nerve impulses faster than in non-myelinated neurons. •Myelin sheathing has bare patches of axon called nodes of Ranvier Action potentials jump from node to node Nerve Cells - Neurons Nerve cells conduct neural (electric) impulses. Neurons consist of Cell body Dendrites (branches that receive information) and, Axons (that conduct messages away from the cell) – one direction only. Synaptic knob of the axon Myelin – an insulating lining that covers the nerves and increases neural transmission speeds. Multiple Sclerosis is a disease of the myelin sheath that may cause many different symptoms. 3 main types of nerve cells sensory neurone relay neurone motor neurone Classification of neurons Functional classification based on type of information & direction of information transmission: • Sensory (afferent) neurons – • transmit sensory information from receptors of PNS towards the CNS • most sensory neurons are unipolar( have only one process from the cell body) , a few are bipolar( have two processes- one axon and one dendrite) • Motor (efferent) neurons – • transmit motor information from the CNS to effectors (muscles/glands/adipose tissue) in the periphery of the body • all are multipolar ( have multi processes that extend from the cell body i.e. lots of dendrites plus a single axon) • Association (interneurons) – • transmit information between neurons within the CNS; analyze inputs, coordinate outputs • are the most common type of neuron (20 billion) • are all multipolar Sensory neurons Carries impulses from receptors e.g pain receptors in skin to the CNS( brain or spinal cord) Relay neuron Carries impulses from sensory nerves to motor nerves. Motor neuron Carries impulses from CNS to effector e.g. muscle to bring about movement or gland to bring about secretion of hormone e.g ADH Myelin sheath on nerves http://people.eku.edu/ritchisong/301notes2.htm Neuro-transmitters In order for neural control to occur, “information” must not only be conducted along nerve cells, but must also be transferred from one nerve cell to another across a synapse Most synapses within the nervous system are chemical synapses, & involve the release of a neurotransmitter At the junction of each nerve connection (synapse) there is a small gap where chemicals are released to transfer the impulse from an axon to the dendrite of the next nerve. Many drugs such as opium and heroin (opiates) are chemically very similar to these neuro-transmitters and this can lead to addiction to the drug. They produce a similar effect on the brain as do naturally occurring Endorphins – that act to kill pain, cause sensations of pleasure (addiction to running), and cause sleepiness. Transmission of signals • A synape divides 2 neurons • The action potential will not move across the synape • Neuro transmitters-Released by the signal cell to the receiver cell -Move by diffusion How Neurons Communicate at Synapses Figure 7.10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 7.22 The Synapse Neural Tissue Organization Today’s activities Open up your textbook and go to page 225 Create a power point/pressi/word doc to provide a diagram and succinct definition for the following important terms: CNS, PNS, neurones, dendrites, axons, effectors, sensory neurones, sheath, cerebrum, cerebellum, brain stem, medulla, primative (old) brain, new brain * The Central Nervous System controls all of the body’s activities. * The Central Nervous System is made of two main organs. 1. The brain 2. The spinal cord * The spinal cord sends messages to the brain. * The spinal cord is the part of the nervous system that connects the brain to the rest of the nervous system. * The brain controls everything in the body. * The brain is made of more than 10 billion nerves! * The brain is divided into three parts and is protected by the skull. * The Brain has three main parts… 1. The Cerebrum 2. The Cerebellum 3. The Brain Stem * The Cerebrum is the largest part of the brain. 1. The cerebrum controls your thinking. 2. The cerebrum controls your memory. 3. The cerebrum controls your speaking. 4. The cerebrum controls your movement and identifies the information gathered by your sense organs. 5. Cerebrum’s made of two parts- right and left cerebral hemispheres. Right part controls the left side of body and vice versa * The cerebellum is below and to the back of the cerebrum. 1. The cerebellum controls you balance. 2. The cerebellum controls your posture. * The Brain Stem connects the brain to the spinal cord. * The nerves in the brain stem control your heartbeat, breathing, and blood pressure. * The vertebrae are the many bones that protect the nerves in the spinal cord. * The outer nervous system carries messages between the central nervous system and the rest of the body. * The Outer Nervous System’s job is to connect the Central Nervous System to the rest of the body. * The outer nervous system is made of the nerves and the sense organs. Ear Skin Eye Nerves Tongue * The outer nervous system controls the body’s activities that you don’t think about. * The outer nervous system controls activities in your small intestine, your breathing, and your heartbeat. controls Sense organs carry messages about the environment to the central nervous system. The eyes, ears, nose, tongue, and skin are examples of sense organs. The sense organs gather information (light, sound, heat, and pressure) from the environment. The environment is everything outside the body. The sense organs gather information from outside the body, then send the messages to the brain. Vision is your ability to see. Vision involves the eye and the brain. When a sound is made, the air around the sound vibrates. Hearing starts when some of the sound waves go into the ear. There are nine main parts of the ear. 1. Pinna 5. Anvil 2. Ear canal 6. Stirrup 3. Ear drum 7. Cochlea 4. Hammer 8. Eustachian tube 9. Auditory nerve The pinna is the part of the ear that you can see. The ear canal is the tube between the outside of the ear and the ear drum. The ear drum is in the middle ear. It vibrates when sound waves hit it. The three smallest bones in the body, the hammer, the anvil, and the stirrup, are in the middle ear. The hammer gets the vibrations from the eardrum, then sends them to the anvil. The anvil passes the vibrations to the stirrup. The stirrup passes the vibrations to the inner ear. The Eustachian tube controls the amount of pressure in the ear. The inner ear is made of the cochlea and liquid. The cochlea is in the inner ear. The cochlea looks like a shell. The auditory nerve carries the hearing information to the brain and the brain tells us what we heard. The ear works with the brain to control your balance. All of your movements are controlled by balance and muscles. The liquid in your inner ear is responsible for your balance. The liquid in your ear moves when we move. The liquid movement sends information to the brain to tell it how we are moving. The sense of touch is located in the skin. The nerves in the skin allow us to feel texture, pressure, heat, cold, and pain. Texture is how something feels. The nose controls your sense of smell. The nose is able to smell 80 different kinds of smells. Your sense of taste comes from the taste buds in the tongue. Taste buds are the parts on the tongue that allow us to taste. The four kinds of taste buds are sweet, sour, bitter, and salty. Tastes and smells work together to make flavors. Flavors are the tastes of food and drinks. * An automatic reaction that happens without thinking about it. * A reflex happens quickly in less than a second. The Reflex Arc Reflex – rapid, predictable, and involuntary responses to stimuli Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector Figure 7.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 7.23 Simple Reflex Arc Figure 7.11b, c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 7.24 Types of Reflexes and Regulation Autonomic reflexes Smooth muscle regulation Heart and blood pressure regulation Regulation of glands Digestive system regulation Somatic reflexes Activation of skeletal muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 7.25