山东大学：《医学生理学 Medical Physiology》课程教学资源（PPT课件讲稿，人体生理学 Human Physiology）Chapter 2 Function of the Cell Section 4 Muscle Contraction

Section 4 Muscle Contraction

Section 4 Muscle Contraction

Classification of the muscle According to the structure: Striated Muscle, Smooth muscle According to the nerve innervation Voluntary Muscle, Involuntary Muscle According to the Function: Skeletal Muscle Cardiac Contraction, Smooth Muscle

3 Classification of the Muscle ➢According to the structure: Striated Muscle, Smooth Muscle ➢According to the nerve innervation: Voluntary Muscle, Involuntary Muscle ➢According to the Function: Skeletal Muscle, Cardiac Contraction, Smooth Muscle

Skeletal muscle Cardiac muscle Smooth muscle

4 Skeletal Muscle Cardiac Muscle Smooth Muscle

I Signal Transmission Through the neuromuscular junction

I Signal Transmission Through the Neuromuscular Junction

Skeletal muscle innervation otor Control Path of action neuron potential Neuromuscular Axon junction Excitation-contraction coupling Myofibril Excitation Motor end plate Calcium a Supporting cell .niggers Synaptic terminal、 Thick-thin filament interaction Mitochondrion mummer Muscle fiber fibe leads to Tension production

6 Skeletal Muscle Innervation

Illustration of the neuromuscular Junction(NMJ Motor neuron fiber Nerve fiber branches Muscle fiber nucleus Motor end plate Myofibril of muscle fiber 自A% e到 Mitochondria Synaptic vesicles Synaptic cleft Folded sarcolemma Motor end plate 7

7 Illustration of the Neuromuscular Junction (NMJ)

New lon Channel Players Voltage-gated Ca+ channel > in presynaptic nerve terminal >mediates neurotransmitter release Nicotinic Acetylcholine Receptor Channel >in muscle neuromuscular junction(postsynaptic membrane, or end plate) >mediates electrical transmission from nerve to muscle Motor neuron fibe Nerve fiber branches Motor end plate Myofibril of muscle fiber Motor end plate

8 New Ion Channel Players ➢Voltage-gated Ca2+ channel ➢in presynaptic nerve terminal ➢mediates neurotransmitter release ➢Nicotinic Acetylcholine Receptor Channel ➢in muscle neuromuscular junction (postsynaptic membrane, or end plate) ➢mediates electrical transmission from nerve to muscle

Nerve Terminal ca2+ channels Structurally similar to Nat channels >Functionally similar to Nat channels except >activation occurs at more positive potentials >activation and inactivation much slower than a channe dIs

9 Nerve Terminal Ca2+ channels ➢Structurally similar to Na+ channels ➢Functionally similar to Na+ channels except ➢activation occurs at more positive potentials ➢activation and inactivation much slower than Na+ channels

Neuromuscular transmission Axon Axon Terminal Skeletal muscle

10 Neuromuscular Transmission Skeletal Muscle Axon Axon Terminal

Neuromuscular Depolarization Nerferaetah ransmission potaqhacashadeels Step by Step axon terminal t Look here

11 Neuromuscular Transmission: Step by Step Nerve action potential invades axon terminal - - + - - - - - + + + + + + + - - - + + Depolarization of terminal opens Ca channels Look here + +