中枢神经系统的感觉功能全(七年制)

receives the stimulus from the external world and transforms stimulus energy into electrical energy, including mechanoreceptor, thermoreceptor, nociceptor, electromagnetic receptor, chemoreceptor:
The density of sensory receptors in the retina and the size of the receptive field for each receptor determine the resolution of a visual image.
The firing rates of sensory nerves encode the stimulus magnitude. 1920s, Edgar A and Yngve Z first noted that the discharge frequency
Sensory organs develop in he heads of animals, along with
corresponding neural systems in the brain. The special sensory system include the vision, hearing, equilibrium, smell, taste, allow the animals to detect and analyze light, sound, and chemical signals in the environment, as well as signal the position of the head.
Touch-pressure receptor: all ; Warmth receptor: nerve ending; Nociceptor: nerve ending
2. Modality of receptors
3. The physiological characteristics of receptors
子通道状态以及感受器与传入神经突触传
Duration: the adaptation of Receptors. (Meissner and Pacini receptors adapt rapidly to constant stimulation, while the other two adapt slowly).
In human hand the submodalities of touch are sensed by four types of mechanorectptors.
Chapter 31 The Sensory Function of NS
Section 1 The general interview of
sensation;
Section 2 The somatic and visceral
sensation
Section 3 Visual function of eyes; Section 4 Auditory function of ear.
The mechanisms for transducing in chemo- and photoreceptors.
3. The physiological characteristics of receptors
(3) Receptor Encoding:
Modality: receptor specificity and a labeled line code.
Sensation and Perception
Knowledge of the world comes through the senses.
Most sensations are identified with a particular type
stimulus. The quantitative aspects of physical stimuli
Structural basis of receptive field of receptors for the touch.
The receptive field of each sensory neuron — the area within the receptive sheet where stimulation excites the cell.
Location: the spatial distribution of the population of receptors (position of the receptive field). Intensity: the frequency of action potentials in sensory nerves.
The fields of psychophysics and sensory physiology. Sensory physiology examined the neural consequences of a stimulus.
Section I: General interview of sensation
slowly adapting receptor：有利于
机体对某些功能进行长期监测，并根据其
变化随时调整机体活动，如颈动脉窦、肌 梭、关节囊及痛感受器。 机制：复杂，可发生在感受器换能、离
图：不同感受器的适宜现象 ----: rapidly adapting receptor; — : slowly adapting receptor.
3. The physiological characteristics of receptors
（4）感受器的适应现象(adaptation）
定义：恒定强度刺激持续作用于感受器
时，感觉神经纤维上动作电位的数量逐渐
降低的现象。
rapidly adapting receptor：对刺激
的变化敏感，适于传递快速变化的信息， 有利于感受器和反射中枢接受新刺激，产 生新反应。如皮肤压触觉、嗅觉等。
1.The concepts of sensory receptor
2. Modality of receptors
3. The physiological characteristics of receptors Receptor Specificity and Adequate stimulus
Each sensory receptor responds to a narrow range of intensities of a single type of energy (fig.). An auditory receptor most sensitive to sound at 2.0 kHz. Higher and lower frequencies require stronger amplitude stimuli to evoke a response from the receptor. sensory threshold and discrimination threshold.
of an afferent fiber increases with increasing stimulus intensity.
Strong stimuli evoke larger receptor potentials, which generate a greater number and a higher frequency of action potentials.
3. The physiological characteristics of receptors (2) Stimulus Transduction:
The process by which specific stimulus energy is
converted into an electrical signal (the receptor potential);
equilibrium, smell and taste.
How a stimulus impinges on the body?
How senseness
of events on our world? How stimuli are transduced by sensory receptors and encoded into neural signals.
Somatic sensory receptors in the skin
Merkel’s disk 梅克尔触盘 Free nerve ending 游离神经末梢
Meissner’s corpuscle 迈斯纳小体
Hair follicle receptor 毛终器 Pacinian corpuscle 环层小体 Ruffini’s ending 鲁菲尼终末
correlate with the sensations they evoke.
Each specific type of sensation is mediated by a distinct neural system comprised by receptor, their central pathways and target areas in the brain;
Stimulus Transduction
Receptor Encoding Receptors Adaptation
1. The concepts of sensory receptor
Sensory receptor is the specialized neural structures that