ANP 1105 Lecture 3: Review 4

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Jacqueline Carnegie

Document Summary

Neuromuscularjunction skeletal muscles are stimulated by somatic motor neurons. Each motor neuron axon forms many branches as it enters muscle and its ending forms a neuromuscular junction (nmj) with muscle ber. Nmj is situated midway along the length of muscle ber. Axon terminal and muscle ber are separated by a gel- lled space called the synaptic cleft. Synaptic vesicles in axon terminal have neurotransmitter acetylcholine (ach) Excitationcontractioncoupling sequence of events by which transmission of an action potential along sarcolema leads to sliding of myo laments. Latent period: time between ap initiation and beginning of contraction. Ap is propagated along sarcomere to t tubules. T tubule dhpr (voltage sensitive protein) stimulate ca2+ release from sr (ryr1) Low intracellular [ca2+]: tropomyosin blocks the active sites on actin so myosin heads can"t attach to actin. 2 ca2+ can still bind troponin but at low concentration, not enough for conformational change. High intracellular [ca2+]: 4 ca2+ can bind troponin causing conformational change.