Question

Study the following and identify the incorrect statements
(i) Muscles of iris and ciliary body are smooth muscles of mesodermal origin
(ii) Slow and sustained involuntary contraction of smooth muscles are called spasms
(iii) Quiescent mononucleate myogenic cells of skeletal muscles are called pericytes
(iv) Skeletal muscles fibre is multinucleate and is a syncytium

• A. i, iv
• B. ii, iv
• C. iii, iv
• D. i, iii

Answer 1

The correct option is D i, iii

• The stroma and the anterior border layer of the iris are derived from the neural crest, and behind the stroma of the iris, the sphincter pupillae and dilator pupillae muscles, as well as the iris epithelium, develop from optic cup neuroectoderm. Hence, Muscles of iris and ciliary body are not smooth muscles of mesodermal origin.
• Pericytes are multi-functional cells that wrap around the endothelial cells that line the capillaries and venules throughout the body. Pericytes are specialized mural cells located at the abluminal surface of capillary blood vessels, embedded within the basement membrane. Hence, Quiescent mononucleate myogenic cells of skeletal muscles are not called pericytes.

So, the correct answer is 'i, iii'.