Histology Embryology Smooth muscle Smal Longitudinal laye intes of smooth muscle Circular layer Mucosa of smooth muscle Endomysium (b) Muscles are spindle-shaped cells oOne central nucleus o Grouped into sheets: often running perpendicular to each other ● Peristalsis No striations(no sarcomeres) o Contractions are slow sustained and resistant to fatique .Does not always require a nervous signal Nuclei of smooth muscle cells can be stimulated by stretching or hormonesSmooth muscle •Muscles are spindle-shaped cells •One central nucleus •Grouped into sheets: often running perpendicular to each other •Peristalsis •No striations (no sarcomeres) •Contractions are slow, sustained and resistant to fatigue •Does not always require a nervous signal: can be stimulated by stretching or hormones