Summary
Skeletal, smooth and cardiac muscle produce movement and move substances inside the body.
In depth
Skeletal muscle is voluntary and striated; cardiac is involuntary and striated with intercalated discs; smooth is involuntary, found in walls of organs. Muscles pull, never push, and work in antagonistic pairs.
Skeletal muscle fibres are multinucleate. Motor units determine fine control. Tendons transmit force. Smooth muscle is controlled by the autonomic system.
Key idea: muscles shorten only by contraction and need antagonists to return.
There are about 600 skeletal muscles making up around 40 percent of body mass. Fibres are bundled in fascicles surrounded by connective tissue and attached to bones by tendons. Muscles work in antagonistic pairs (biceps and triceps), since they can only pull. Fibre types: slow oxidative (type I, endurance, red with myoglobin), fast oxidative and fast glycolytic (type IIx, power, fatigue quickly).
Muscle needs ATP for contraction and relaxation. Rigor mortis occurs because ATP is absent after death, so myosin heads stay attached. Cardiac muscle never tires because it relies on aerobic metabolism, and smooth muscle controls vessels, gut and airways. Injuries include strains and cramps. Steroid hormones and exercise influence muscle growth.
Key idea: voluntary control is by the somatic nervous system, and involuntary by the autonomic system.
Frequently asked questions
What is Muscular System?
Skeletal, smooth and cardiac muscle produce movement and move substances inside the body.
Which area of biology covers Muscular System, and how advanced is it?
Muscular System is one of the 51 topics in Human Physiology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Muscle Contraction, Circulatory System, Exercise Adaptations.
Can you give an example of Muscular System?
Biceps flex and triceps extend the elbow.
What should I learn before Muscular System?
Muscular System is a Beginner topic, so no earlier topic is required. Other Beginner topics in Human Physiology that pair well with it include Homeostasis, Tissues and Organs, Skeletal System.
What topics are related to Muscular System?
The closest topics to Muscular System are Muscle Contraction, Circulatory System, Exercise Adaptations, Diabetes Mellitus. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Muscular System?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Muscular System. To practise the whole of Human Physiology, use the Human Physiology quiz.
How is Muscular System different from Muscle Contraction?
Muscular System: Skeletal, smooth and cardiac muscle produce movement and move substances inside the body. Muscle Contraction: Actin and myosin filaments slide past each other using ATP and calcium, according to the sliding filament theory. Read both side by side and note what each one explains.
How should I study Muscular System step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Muscle Contraction and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.