Coordination and Response IGCSE Biology PDF 2024

BY CELL :00201110983031 00201110983031 [email protected]  1. Distinguish between voluntary and involuntary actions 2. Describe the structure of a synapse, including the presence of neurotransmitter containing vesicles, the synaptic cleft and...

BY CELL :00201110983031 00201110983031 [email protected]  1. Distinguish between voluntary and involuntary actions 2. Describe the structure of a synapse, including the presence of neurotransmitter containing vesicles, the synaptic cleft and neurotransmitter receptor molecules 3. Describe how an impulse triggers the release of a neurotransmitter from vesicles into the synaptic gap and how the neurotransmitter diffuses across to bind with receptor molecules, in the membrane of the neurone after the synaptic gap, causing the impulse to continue 4. State that in a reflex arc the synapses ensure that impulses travel in one direction only 5. State that many drugs, e.g. heroin, act upon synapses CELL :00201110983031 00201110983031 [email protected]  COORDINATION AND RESPONSE SENSE ORGANS Group Of Receptor Cells Respond To Specific Stimuli. EFFECTOR A Part Of The Body That Goes Into Action When It Receives Impulses. coordination The Way That In Which Receptor Pick Up Stimuli And Then Pass Information To Effector. SO THE SYSTEM NEEDS FOR CO-ORDINATION 1.Nervous System 2.Endocrine System 1.NERVOUS SYSTEM CNS (central nervous system) PNS (peripheral nervous system) FUNCTION OF THE CENTRAL NERVOUS SYSTEM : 1.RECEIVE IMPULSES FROM DIFFERENT RECEPTORS. 2.INTEGRATE IMPULSES. 3.PRODUCE NERVE IMPULSES CELL :00201110983031 00201110983031 [email protected]  SPINAL CORD ITS FUNCTION 1. Conduct from brain to the effector 2. Controls the reflex action below the neck 3. Conduct impulses from sense organs below the neck CELL :00201110983031 00201110983031 [email protected]  NEURON THE BUILDING UNIT OF NERVOUS SYSTEM TYPES 1. SENSORY NEURON FROM SENSORY NEURON TO CNS 2. MOTOR NEURON From CNS To Effector (Muscle Or Gland ) CELL :00201110983031 00201110983031 [email protected]  TRICK 1 Cell body: contains nucleus. Dendron: carries to the cell body. Axon: it carries from the cell body. MYELIN SHEATH : 1. Made of cells rich in fats and proteins. 2. Contains narrow gaps which are called nodes of ranvier. 3. Function : protection -- insulation -- increase speed of transmission CELL :00201110983031 00201110983031 [email protected]  4. NERVE IMPULSES: Series Of Electro-Chemical Signals Travels Down The Nerve Fibres 5. GANGLION : Swelling In The Sensory Neuron Contains The Cell Body Of The Sensory Neuron 6. The Cell Body Of Both Motor And Relay Neuron Are Located In The Grey Matter EXPLAIN THE ADAPTATION OF THE GAGNGLION TO ITS FUNCTION. 1. Long axon ,dendron ,nerve ending to transmit nerve impulses 2. Has dendrites to receive impulses from other cells 3. Myelin sheath REFLEX ACTION (RAPID INVOLUNTARY RESPONSE TO STIMULUS) IMPORTANCE 1. Survival value …rapid --no more time taken—doesn’t involve the higher centers of the brain. 2. Role in learning skills CELL :00201110983031 00201110983031 [email protected]  REFLEX ARC [It Is The Pathway Of Impulses In Reflex Action ] Reflex action It is automatically and rapidly integrating and coordinating stimuli with the responses of Effectors (muscles and glands) STAGES OF REFLEX ACTION 1. Receptor cells send sensory impulses along a sensory neuron to cns through dorsal root. 2. Sensory neuron forms a synapse. 3. Impulses are transmitted through the connector to the motor. 4. motor carries impulse through the ventral root to the muscles to contract. CELL :00201110983031 00201110983031 [email protected]  SYNAPSE Junction between two neurons that contains a minute gaps across through the impulses pass by the diffusion of neurotransmitter substance. STRUCTURE 1. Synaptic cleft. 2. Synabtic knob. 3. Vesicles contains neurotransmitter. CELL :00201110983031 00201110983031 [email protected]  TRANSMISSION OF IMPULSES ALONG SYNAPSE TRICK 2 IMPORTANCE OF SYNAPSE 1. Ensure one way transmission. 2. Slower transmission. CELL :00201110983031 00201110983031 [email protected]