Muscle physiology review Syllabus is primary source Review Muscle histology: Have to know Histology to understand physiology! Know the differences between three types of muscle: Skeletal, smooth (visceral vs. multi-unit), cardiac Which types are striated? What are striations? Which types are coupled with gap junctions?

Skeletal muscle Be able to draw out all steps of the steps of the excitation / contraction coupling pathway starting with acetylcholine binding to the nicotinic acetlycholine receptor and ending with sarcomere shortening through myosin/actin interactions. Make sure to identify which ions are involved in all steps and be able to identify what may happen if ion concentrations change (e.g. hyperkalemia) or if there are mutations in ion channels Be able to explain how skeletal muscle relaxes; what is rigor mortis? COMPARE excitation/contraction coupling in skeletal muscle with smooth and cardiac muscle. Review Skeletal muscle mechanics: What is a motor unit? How is force generated? Review Skeletal muscle diseases: Malignant hyperthermia, rhabdomyolysis, muscular dystrophy and myasthenia gravis Note some alpha subunits activate phosphodiesterase resulting in reduced cAMP or cGMP

Smooth muscle Be able to draw out all steps of the steps of the excitation / contraction coupling pathway starting with the fact that MANY stimuli (Identify these) can lead to smooth muscle contraction as long as Ca2+ is involved. What is the role of calmodulin and myosin-light chain kinase in smooth muscle? COMPARE excitation/contraction coupling in smooth muscle with skeletal and cardiac muscle. Why does smooth muscle lack striations? Review smooth muscle mechanics: How is force generated? What is the difference between multi-unit and visceral (unitary) smooth muscle? Integrate with ANS physiology! What neurotransmitters / receptor pairs are responsible for causing smooth muscle relaxation and contraction? (May depend on muscle!) Integrate with ANS physiology! steps of smooth muscle relaxation (review nitric oxide signaling) & orthostatic hypotension Note some alpha subunits activate phosphodiesterase resulting in reduced cAMP or cGMP

Cardiac muscle Be able to draw out all steps of the steps of the excitation / contraction coupling pathway in a cardiac myocyte starting with epinephrine binding to the adrenergic beta 1 receptor and ending with sarcomere shortening through myosin/actin interactions. (You’re not responsible for understanding activation of pacemakers) COMPARE excitation/contraction coupling in cardiac muscle with skeletal and smooth muscle. Which type is it more similar too? How does it differ? Review Cardiac muscle mechanics: What is the greatest difference between it and skeletal muscle? What unique energy requirements does cardiac muscle have? Integrate with ANS physiology! : What neurotransmitters / receptor pairs are responsible for causing cardiac muscle relaxation and contraction? Note some alpha subunits activate phosphodiesterase resulting in reduced cAMP or cGMP

Final thoughts Use the syllabus Cases are to help you understand signaling by putting them into a clinical context Sketch out how each type of signaling molecule works from start to finish Explain this to a classmate