Chapter 31 Sensory Function of the Nervous System
Chapter 31 Sensory Function of the Nervous System
Contents Sensory receptors and sensory organs Pain The visual system The auditory Systems
Contents • Sensory receptors and sensory organs • Pain • The visual system • The Auditory Systems
Sectⅰon1 Sensory receptor and sensory organ
Section 1 Sensory Receptor and Sensory Organ
Part I Sensory receptors specialized nerve cells that transduce energy nto neural signals mode?specific Law of Specific Nerve Energies.(神经特殊能量 定律)” sensory messages are carried on separate channels to different areas of the brain detect a small range of energy levels Eye:400-700nM Ear:20-20000Hz Taste buds: specific chemicals
Part 1 Sensory Receptors • specialized nerve cells that transduce energy into neural signals • “mode” specific – “Law of Specific Nerve Energies（神经特殊能量 定律）”: sensory messages are carried on separate channels to different areas of the brain • detect a small range of energy levels – Eye: 400-700 nM – Ear: 20-20,000 Hz – Taste buds: specific chemicals
Spectrum of the electromagnetic Wave ncreasing energy M Increasing wavelength 0.001 11010000.011 100 n nm nmnm cmcm X- UV Gamma rays rays light Infrared Microwaves Radio waves Visible light 380430 500 560600650 750 nm nm nm n
Spectrum of the Electromagnetic Wave
Somatic sensory Nerve endings Free nerve Expanded tip Tactile hair endings receptor Pacinian Meissner Krauses corpuscle corpuscle corpuscle Ruffini's Golgi tendon Muscle end-organ apparatus spindle
Somatic Sensory Nerve Endings
Stimulus Free Nerve endings Free nerve endings dendrites interspersed among other Unmyelinated cells/tissues pain, temperature, touch Cell body Simple neural receptor
Free Nerve Endings • dendrites interspersed among other cells/tissues • pain, temperature, touch
Encapsulated Stimulus Nerve endings Layers of connective tissue Enclosed nerve nding · dendrites with special supporting structures Myelinated axor · mechanoreceptors Cell bod and proprioceptors Comley neural redentor
Encapsulated Nerve Endings • dendrites with special supporting structures • mechanoreceptors and proprioceptors
Classification of Receptors Location Exteroceptors Located on the body surface or specialized to detect external stimuli Pressure, pain, temp touch, etc Ⅴ isceroceptor within internal organs, detect internal stimuli Blood pressure, pain, fullness Proprioceptors Limb and body position and movement in the joints and muscles in the vestibular structures and the semicircular canals of the inner ear
Classification of Receptors: Location • Exteroceptors – Located on the body surface or specialized to detect external stimuli – Pressure, pain, temp, touch, etc. • Visceroceptor – within internal organs, detect internal stimuli – Blood pressure, pain, fullness. • Proprioceptors – Limb and body position and movement. – in the joints and muscles – in the vestibular structures and the semicircular canals of the inner ear
Classification of Receptors: Modalities lechanoceptive Detects stimuli which mechanically deform the receptor; Pressure vibration touch sound Thermoceptive Detects changes in temperature hot/cold Nociceptive(pain) Detects damage to the structures Photoreceptors Detect light; vision retinal of the eye Chemoceptive Detect chemical stimuli CO, and o, in the blood glucose, smell, taste
Classification of Receptors: Modalities • Mechanoceptive – Detects stimuli which mechanically deform the receptor; – Pressure, vibration, touch, sound. • Thermoceptive – Detects changes in temperature; – hot/cold • Nociceptive (pain) – Detects damage to the structures • Photoreceptors – Detect light; vision, – retinal of the eye • Chemoceptive – Detect chemical stimuli – CO2 and O2 in the blood, glucose, smell, taste