SI317 Nerve 3 2024 Physiology Lecture PDF
Document Details
AMA School of Medicine
Leo Quinlan
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Summary
This document details a lecture on nerve impulses and synaptic transmission, focusing on action potentials, receptors, and neurotransmitters. It includes diagrams and learning objectives.
Full Transcript
Physiology School of Medicine Semester 1 Module: SI317 2024/2025 Lecture Title: Receptors and Synapses Lecturer: Leo Quinlan [email protected] LEARNING OUTCOMES Describe the kinetics (timing) of an AP. Describe the basic role of neurons in senso...
Physiology School of Medicine Semester 1 Module: SI317 2024/2025 Lecture Title: Receptors and Synapses Lecturer: Leo Quinlan [email protected] LEARNING OUTCOMES Describe the kinetics (timing) of an AP. Describe the basic role of neurons in sensory physiology Explain with examples how physical stimuli are translated to nerve APs How are stimuli classi ed. Explain what is meant by sensory adaptation What is a synapse and how does it work fi UNMYELINATED NERVE IMPULSE MYELINATED NERVE IMPULSE SENSORY RECEPTORS Essential to our ability to respond to changes in external environment Many stimuli are experienced consciously Some at subconscious levels Much of internal stimuli we receive never reaches the level of consciousness BASIC COMPONENTS Receptors Peripheral nerves Spinal cord Tracts Thalamus Thalamocortical projection Somatosensory cortex 8 THE STIMULUS Modality - general nature of stimulus Sub modalities Taste can be sweet, bitter, sour Light can be red green and blue Location Intensity Duration ADEQUATE STIMULUS Normally each stimulus has a speci c type of receptor I.e Taste buds - taste I.e. Rods and cones - light The stimulus to which a speci c receptor is speci cally sensitive is termed the ADEQUATE STIMULUS fi fi fi Excitatory Transmission Na+ Ca2+ Na+ Ca2+ Excitatory Transmission Na+ Ca2+ Na+ Ca2+ Excitatory Transmission Na+ Ca2+ Na+ Ca2+ Excitatory Transmission Na+ Ca2+ Na+ -70mV Na+ Na+ Excitatory postsynaptic Ca2+ potential (EPSP) Inhibitory Transmission Na+ Ca2+ Na+ Ca2+ Inhibitory Transmission Na+ Ca2+ Na+ Ca2+ Inhibitory Transmission Na+ Ca2+ Cl- -70mV Na+ Cl- Inhibitory postsynaptic Ca2+ potential (IPSP) MR. SYKES TTX SUMMARY Sensory neuron carry info into the CNS Physical stimuli are translated by receptors to nerve APs Carrying lots of information Sensory adaptation - not all receptors adapt Synapse - point of contact between two neurons excitatory neurotransmitters - glutamate inhibitory neurotransmitters - GABA
