1. Module 6 Intro

1.9. Page 7

Lesson 1

Module 6—The Motor System and Homeostasis

Lesson Summary

 

In this lesson you explored the following essential questions:

  • How are the roles of cardiac, smooth, and striated muscles different?

  • How do specialized structures in muscles cause muscle contraction?

  • What is the relationship between energy use by muscle cells and heat production?

In this lesson you have learned about the general responsibilities of the muscular system as well as the specific structure and function of muscle tissue. The characteristics of the three types of muscle tissue (skeletal, smooth, cardiac) were indicated, as were the mechanics of skeletal muscle contraction. You focused on the sliding filament model of actin and myosin interaction.

 

With the muscular system playing such a broad role in relation to the other body systems, an efficient method of supplying energy over short- and long-term muscle use was discussed.

 

You explored the phosphagen, aerobic, and anaerobic systems of ATP generation in relation to heat production. As the high energy phosphate bonds in ATP are broken to release energy for muscle contractions, heat is also released as a by-product.

 

As you work through the remaining physiology lessons in Unit D, the importance of the muscular system in the function of almost every other body system will be revealed.

 

Lesson Glossary

 

actin: a thin myofilament consisting of two strands of actin protein molecules wrapped around each other

 

Actin works with myosin to produce muscle contractions.

 

constrict: to make smaller or narrower, especially at one place, by squeezing

 

Blood vessels will constrict to reduce blood flow.

 

dilate: to make wider or larger; cause to expand or swell; stretch

 

Blood vessels will dilate to increase blood flow.

 

muscle fibre: a single muscle cell

 

myosin: a thick myofilament consisting of two strands of mysosin molecules wound around each other

 

One end consists of a long rod, while the other end consists of a double-headed globular region. Myosin works with actin to produce muscle contractions.

 

non-striated muscle: contains contractile proteins arranged randomly and do not create bands or stripes; called smooth muscle

 

striated muscle: marked with stripes or bands that are the result of highly organized arrangements of contractile proteins within muscles