The membrane surrounding a cell that separates the cell from its external environment. It consists of a phospholipid bilayer and associated proteins [goid 5886] [evidence IEA]; A protein complex that acts as an acetylcholine receptor, and forms a transmembrane channel through which ions may pass in response to ligand binding. The complex is a homo- or heteropentamer of subunits that are members of a neurotransmitter receptor superfamily [goid 5892] [evidence IEA]; A protein complex that acts as an acetylcholine receptor, and forms a transmembrane channel through which ions may pass in response to ligand binding. The complex is a homo- or heteropentamer of subunits that are members of a neurotransmitter receptor superfamily [goid 5892] [pmid 7619526] [evidence TAS]; Penetrating at least one phospholipid bilayer of a membrane. May also refer to the state of being buried in the bilayer with no exposure outside the bilayer. When used to describe a protein, indicates that all or part of the peptide sequence is embedded in the membrane [goid 16021] [evidence IEA]; A specialized region of connection between two cells or between a cell and the extracellular matrix [goid 30054] [evidence IEA]; The junction between the axon of a motor neuron and a muscle fiber. In response to the arrival of action potentials, the presynaptic button releases molecules of neurotransmitters into the synaptic cleft. These diffuse across the cleft and transmit the signal to the postsynaptic membrane of the muscle fiber, leading to a post-synaptic potential responsible of the muscle contraction [goid 31594] [evidence IEA]; The junction between the axon of a motor neuron and a muscle fiber. In response to the arrival of action potentials, the presynaptic button releases molecules of neurotransmitters into the synaptic cleft. These diffuse across the cleft and transmit the signal to the postsynaptic membrane of the muscle fiber, leading to a post-synaptic potential responsible of the muscle contraction [goid 31594] [pmid 9221765] [evidence IDA]; A specialized area of membrane facing the presynaptic membrane on the tip of the nerve ending and separated from it by a minute cleft (the synaptic cleft). Neurotransmitters across the synaptic cleft and transmit the signal to the postsynaptic membrane [goid 45211] [evidence IEA]