Presentation on theme: "Coordination and Response Nervous control in Humans"— Presentation transcript:
1Coordination and Response Nervous control in Humans *Describe the structure of the nervous system**Distinguish between voluntary and involuntary actionsHomework:Revise Homeostasis and Excretion for test on 3/5/11
2BlinkingWe think about this action/ We don’t think about this action
3CoughingWe think about this action/ We don’t think about this action
4KickingWe think about this action/ We don’t think about this action
5Pupils changing sizeWe think about this action/ We don’t think about this action
6All living organisms are sensitive to changes in their environment All living organisms are sensitive to changes in their environment. The changes they detect are called stimuli. E.g. ? The cells that detect these changes are called receptors. E.g.? The responses are brought about by muscles and glands because of a stimuli and they are called effectors. Which system is responsible for the detection? Which system is responsible for the coordination of responses ?sensorynervous
7Match the words with the definitions StimulusThe part of a control system that brings about a change to the systemEffectorAction or behaviour that is caused by a stimulus.ResponseA change in the environment that causes a response.ReceptorThe part of a control system that detects changes in the system and passes this information to the processing centre.
8Human Nervous System Brain Protected by? Cranial i Nerves connected in pairs to the brainiCNSSpinal CordProtected byPNSThe nerves are made up of specialised cells called neuronsCranial nerves link the brain to all organs in the head and some organs of the abdomen and thoraxSpinal nerves link brain to legs ,arms , thorax and abdomenSpinal nerves connected in pairs to the spine.
9Voluntary Response.EffectorVoluntary responses are under the control of our brains.For example;ResponseMotor NeuronStimulusCoordinatorReceptorTransmits electrical 1-120m/sSensory neuronSpinal Cord
10Some facts Bundles of neurons are called nerves. The neurons joining the sensory and the motor neurons are called relay neuronsEffectors are muscles or glands.
11Putting it all together! coordinatorReceptor --> sensory neurone → CNS(relay neuron) → motor neurone → effector.Write one more examples of voluntary action.In the last example who was the receptor and who was the effector?
12Involuntary Response or Reflex Action What is an involuntary response?What do you think will happens to the man’s hand?
13Involuntary Response or Reflex Action An involuntary response bypasses the brain to give a fast response to a stimulus.This helps protect the body from harm.
14Involuntary Response For example; Motor Neurone Stimulus Receptor EffectorFor example;Motor NeuroneStimulusReceptorTransmits impulsesSensory neuroneSpinal Cord
15Give one more examples of reflex action Give one more examples of reflex action. Draw one of your examples from both voluntary and involuntary actions as a flow diagram.
16Sense Organs and Reflex Arcs Objectives: *Define sense organs ** Describe their functioning in a reflex action Starter: Complete the flow diagram 1.Receptor What are five senses in your body?
17Brentwood Gazette Weekly Rainbow Control of a possible football situationRISU are trailing 1-0 to ISU in the final of the Rainbow Cup. All of a sudden (student A) pulls up with a suspected torn hamstring. (Student B) spots this and immediately sends a message to Mr Colley what happens. Mr Colley makes a decision. He decides to replace (student A) with (Student C). Student C went on to score a hat trick.Final Score RISU 3 ISU 4In terms of response:1.What kind of response is this?2. What was the stimulus?3. What was the effector?4. What was the response?
19Nervous systemParts of our body we use to sense things are called SENSE ORGANS – eye, ear, mouth, skin, nose.Each SENSE ORGAN has special cells called RECEPTOR CELLS. Each receptor cell is sensitive to different things.SENSE ORGANS are a group of receptor cells that respond to a particular stimuli
21Senses Receptors in eye sensitive to light Receptors in ear and sensitive to soundReceptors on tongue and sensitive to chemicalsReceptors in nose and sensitive to chemicalsReceptors in the skin and sensitive to touch, pressure, pain, temperature
22Reflex actions In a reflex action: A receptor detects a stimulus. The receptor sends an electrical impulse along a sensory neuronThe tap on the knee in the knee jerk test is a stimulus.Its detected by receptors in the thigh muscle connected to your knees.The receptor sends signals to your spinal cord.The spinal cord sends nerve impulses to your leg muscles.The leg muscles respond by contracting which pulls your lower leg upwards.These impulses are sent to the CNS.The CNS sends an electrical impulse along a motor neuron to an effector.The effector responds to the stimulus.A reflex action is a fast, automatic response to a stimulus.
23Reflex Arc Stimulus picked up by Receptor cells in finger (skin) Impulse passed on to sensory neuronSensory neuron passes impulse to spinal cordSpinal cord sorts out response and send message to motor neuronMotor neuron sends impulses to finger muscles to pull awaystimulusRelay neuroneffector
24Arrange them in right order 3Spinal cord or brain sorts out messageImpulse carried along nerve cell (motor neurone) to effector organ4Effector organ brings about a response5Stimulus (change) picked up by receptor1Impulse carried along nerve cell (Sensory neurone) to spinal cord2Arrange them in right order
25NeuronesObjectives: *Describe and distinguish between three types of neuron **Describe the functioning of these neurons in a reflex action Starter: How many neurons are there? Name them.
26Relay neurons short pass on impulses from sensory to motor neuron located inside the CNS It carries information from the nervous system as electrical impulses.These cell that carry this information are called nerve cells or neurones.Nerve ending in a sense organnucleuscytoplasmThis is a sensory neuron.It carries information from the receptor to the CNS.(Insulation)Neurone ending in an effector(muscle or gland)This is a motor neuron.It carries information from the CNS to the effector.in CNS
27The Structure of the Neuron Cell body contains nucleus cytoplasm and nerve fibresFibres carrying impulses away from cell body are AxonsFibres carrying impulses towards cell body are Dendrons with smaller Dendrites extending from cell bodyThe Myelin Sheath is a thick insulating material (fat) that encloses the axon. It enables fast conduction of impulses up to 100m/sto fast transmission)
28Impulse arrives at a synapse in a particular direction The neurones do not touch each other. The gap between them is called synapseImpulse arrives at a synapse in a particular directionChemical molecules released by the sensory neuron diffuses across and fits on to the receptor molecules on the membrane of the motor neuronNerve impulse passes from sensory neuron to motor neuronThe chemical is absorbed back in the sensory neuronSince chemicals are produced on one side impulses travel in only one directionMany drugs produce their effects by acting at synapsesSome facts:Synapses are 20 nm wide and slows down the speed of your impulse by 15m/sThe synapse is a tiny gap between one neurone and the next. The electrical signal reaches the end of the first neurone, and this triggers the release of chemicals. The arrival of these chemicals at the next neurone triggers the start of an electrical impulse. This is how the impulse gets from one neurone to the next. For most GCSE syllabuses, students do not need to know the terms ‘axon terminal’, ‘synaptic vesicles’ (‘sacs containing chemicals’ will do) or ‘neurotransmitter’ (‘chemicals’ is enough).
29Homework: due 12/05/11 Complete the following table STRUCTUREFUNCTIONMyelin sheathAxonCell bodyDendrites
31Reflex actions In a reflex action: A receptor detects a stimulus. The receptor sends an electrical impulse along a sensory neuroneThe tap on the knee in the knee jerk test is a stimulus.Its detected by receptors in the thigh muscle connected to your knees.The receptor sends signals to your spinal cord.The spinal cord sends nerve impulses to your leg muscles.The leg muscles respond by contracting which pulls your lower leg upwards.These impulses are sent to the CNS.The CNS sends an electrical impulse along a motor neurone to an effector.The effector responds to the stimulus.A reflex action is a fast, automatic response to a stimulus.
32Reflexes and Reaction time Objectives: *Explain the importance of reflex action in the body ** Calculate reaction time *** Represent data in different ways Starter: Reflex actions are a…….., f… and usually p………fastautomaticprotective
33Reaction time The time between a stimulus and a response Eg. If someone is driving and they see a cow in the middle of the road. Their reaction time is the time taken to see the cow (stimulus) and to press the brake (response).
35How fast are your reflexes?? How can we measure our reflexes?Practical experiment….Using a ruler1.Using a ruler you have to see how quickly you can catch it.2. Each person will try three times and record their results in a table3. We will then collect the class data and find out who has the fastest reflexes!!!
36ResultsNameResult 1Result 2Result 3AverageNOTE : To work out the average you add all the result up, then divide by three…….EASY!!
37Who is the fastest - Class results NameAverage reflex (cm)PeaceYashKidusAmandaLairKatrinaBryanRachaelHow else can we display our results?GraphRemember Title,label axis,