BIO 140 Human Biology I - Questions and Solutions

2. The cells of muscles, myocytes, develop from ________.

1. myoblasts
2. endoderm
3. fibrocytes
4. chondrocytes

3. Skeletal muscle is composed of very hard working cells. Which organelles do you expect to find in abundance in skeletal muscle cell?

1. nuclei
2. striations
3. golgi bodies
4. mitochondria

1. You are watching cells in a dish spontaneously contract. They are all contracting at different rates; some fast, some slow. After a while, several cells link up and they begin contracting in synchrony. Discuss what is going on and what type of cells you are looking at.

Solution: The cells in the dish are cardiomyocytes, cardiac muscle cells. They have an intrinsic ability to contract. When they link up, they form intercalating discs that allow the cells to communicate with each other and begin contracting in synchrony.

2. Why does skeletal muscle look striated?

Solution: Under the light microscope, cells appear striated due to the arrangement of the contractile proteins actin and myosin.