G matter White Dorsa matter Cell body in dorsal root gangion Sensor Receptor Interneuron M Sp neuron Effector FIGURE 51.31 (muscle A cutaneous spinal reflex. This reflex is more involved than a knee-jerk reflex because it involves interneurons as well as sensory and motor neurons
contracted Trice FIGURE 51.33 Conscious control of skeletal muscles. (a) A light micrograph shows axons branching to make contact with several individual muscle tibers.(b) When you flex your arm, one set of muscles, the flexors or biceps, contracts, and another set, the extensors or triceps, relaxes. When you extend your arm, the extensors contract and the flexors relax
Interneuron Dorsal ganglion Preganglionic neuron Postganglionic neuron Autonomic gang neuron FIGURE 51.34 An autonomic reflex. There are two motor neurons in the efferent pathway. The first, or preganglionic neuron, exits the CNS and synapses at an autonomic ganglion. The second, or postganglionic neuron, exits the ganglion and regulates the visceral effectors (smooth muscle, cardiac muscle, or glands)
统 三、神经冲动的传导 §什么是“神经冲动” 神经细胞接受刺激,而兴奋时产生的动作电位( action potentia), 称为神经冲动。 5静息电位( resting membrane potentia) 细胞未受到刺激时存在于细胞膜两侧的电位差,称为跨膜静息电位 是K+的平衡电位,外正内负。 动作电位: 细胞受到刺激兴奋时产生的膜两侧的快速、可逆并有扩散性的电位 变化包括去极相和复极相 是Na的平衡电位
第七节 神经系统 三、神经冲动的传导 § 什么是“神经冲动” 神经细胞接受刺激，而兴奋时产生的动作电位（action potential）, 称为神经冲动。 § 静息电位（resting membrane potential）: 细胞未受到刺激时存在于细胞膜两侧的电位差，称为跨膜静息电位. 是K+的平衡电位，外正内负。 § 动作电位: 细胞受到刺激兴奋时产生的膜两侧的快速、可逆并有扩散性的电位 变化,包括去极相和复极相. 是Na+的平衡电位
The establishment of Voltmeter resting membrane Intracellular Extracelular potential electrode K Fixed anions Electrical KKKKK Diffusion"K 70 mV ⊙ Fixed anions
The establishment of resting membrane potential