The general features of nerve cells to include dendrites, soma, axon and axon terminals. The general layout and functions of nerve cells. Cells that provide afferent input to the CNS, interneurones (by far the most common type of neurone) and cells that carry efferent information out from the CNS. The resting membrane potential is revised (first given in element 1). The concept of equilibrium potentials is revisited as is the Nernst potential. The essential changes between resting and active membranes are considered in terms of membrane permeability to K⁺ and to Na⁺. Simulations of the Goldman equation are included here. The concept of membrane excitability is introduced.

The important features of the action potential, which include the threshold, upstroke, downstroke and afterhyperpolarization, are considered. These features are related first to the underlying changes in membrane permeability and then to the behaviour of ion channels that are sensitive to changes in membrane potential (voltage-gated ion channels). The concept of channel 'gating' is introduced and activation, deactivation and inactivation are considered. Inactivation is considered at length in relation to refractoriness that is typically observed in excitable membrane in the moments immediately after the passage of an action potential. Propagation of the action potential in myelinated and non-myelinated fibres is considered.

The fate of membrane potential changes that do not reach threshold (and so do not initiate an action potential) are considered. The idea that these changes in membrane potential reflect changes in membrane permeability is discussed in relation to inhibitory and excitatory events. Students are introduced to the idea that passive events are propagated 'decrementally' so that they eventually disappear. It is shown that these 'local' membrane events decay with an exponential time course or exponentially with distance from the source. The importance of these changes in membrane potential that propagate passively along a membrane to the ability of nerve cells to integrate synaptic input is explored. The concepts of temporal and spatial summation are thus introduced.

The structure and function of the synapse is considered. The sequence of events that describe how an action in the presynaptic cell causes an action potential in a post-synaptic cells is considered. This process defines the synapse as excitatory and having a high safety factor - inhibitory synaptic events are contrasted. The importance of voltage-gated and ligand-gated channels is explained.

Basic structure of mammalian NMJ. Recap of structure of nAChR and consideration of the permeability changes with respect to Na⁺ and K⁺. Description of the sequence of events spanning the arrival of an AP in the motor nerve to the subsequent depolarisation of the post-junctional membrane and AP generation.

Description of t-tubules, sarcoplasmic reticulum, triads etc. Description of the sequence of events that couple excitation of the NMJ to Ca release from the SR. This should include an appreciation of the essential difference between skeletal and cardiac muscle. Consideration of different types of skeletal muscle (slow, intermediate and fast) and associated each with the essential properties of that muscle type i.e. Speed of twitch (related to myosin ATPase Vmax), myoglobin content, vascularisation, reliance on oxidative metabolism.

An appreciation of the basic structure & function of skeletal muscle. Basic description of the intracellular organisation of skeletal muscle to include myofibrils, sarcomeres (to include the banding pattern and the major filaments). Description of the structure and function of actin, myosin, tropomyosin and troponin & titin in relation to the regulation of contraction of striated muscle. [Although covered in the next lecture the students should be made aware of how this scheme differs from that seen in smooth muscle]. Basics of cross bridge cycling and muscle mechanics, length tension curves (for muscle and sarcomere), velocity load curves.

The autonomic nervous system in outline. Sympathetic , parasympathetic and enteric: Structure, function and distribution of smooth muscles at tissue (unitary and multiunitary) and cellular levels (lack of striations, sarcoplasmic reticulum, dense bodies, gap junctions and syncitial nature). Basic consideration of the control of contraction by comparison to striated muscle (actin based verses myosin based regulation). Consideration of levels of control ranging from intrinsic (myogenic but including ICCs), through endocrine/paracrine to enteric NS and finally to ANS.