Medical Research Council - London Institute of Medical Sciences

Now in our 8th year of bringing you beautiful imagery from biomedical science every day

Making Muscle
14 November 2012

Making Muscle

Fitness fanatics with their bulging biceps may be the envy of the gym, but there’s more to muscle-making than dumbbells and protein shakes. Muscles are made up of fibres, which form when cells called myoblasts fuse together. Myoblasts contain strands of two proteins – called actin and myosin – which slide past each other to cause muscular contraction. These developing zebrafish muscle fibres have been magnified over a thousand times using a technique called confocal microscopy. Strands of actin have been stained blue to outline the fibres, each of which contains several nuclei (stained red) that once belonged to individual myoblasts. The extra nuclei allow fibres to rapidly synthesise actin, myosin and other vital proteins. The muscle-making process occurs continuously to replace and repair damaged fibres – so even the laziest of couch potatoes are body builders on the inside.

Written by Emma Stoye

Search The Archive

Submit An Image

What is BPoD?

BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

Read More

BPoD is also available in Catalan at with translations by the University of Valencia.