The Muscular System

Purpose

The main purpose of the Muscular System is movement. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of the human body weight. Each

of these muscles is made up of muscle tissue, blood vessels, tendons, and nerves. Muscles also

serve to move substances through the body.

Anatomy• Muscles are a specialized tissue in the human body that can contract and relax. They contract a

lot thus, producing force to different body parts.

• 3 Types Of Muscles are found in the muscular system

• Smooth

• Cardiac

• Skeletal

• Smooth Muscles- Non-striated, Found in soft body organs, responsible for processes

• like digestion of food

• Skeletal Muscles- Striated, Found attached to skeleton, responsible for major

• movements of the body

• Cardiac Muscles- Striated, Found in heart, responsible for pumping activity in heart, very strong

• and tough

       

 

       

                                         

Cardiac Muscle

Smooth Muscle

Skeletal Muscle

Physiology• The actions your muscular system are controlled by the nervous system, which sends a

never-ending stream of messages along your nerves. When a muscle fiber receives a signal, it will either relax or contract.

• Muscle fibers contain myofibrils, which are cylinders of muscle proteins

• Thick filaments in a muscle are made up of a protein called myosin

• Thin filaments in a muscle are made up of a protein called actin

• During contraction, the myosin thick filaments grab on to the actin thin filaments to form crossbridges

• The thick filaments pull the thin filaments past them, making the sarcomere shorter.

• In a muscle fiber, the signal for contraction is synchronized over the entire fiber so that all of the myofibrils shorten simultaneously

• Tropomyosin and Troponin are two structures that enable the thin filaments along the thick filaments. Tropomyosin is long rod-like protein while Troponin is shorter and bead-

like.

Relationships

Digestive System- Provides nutrients so muscles can function

Circulatory System- Moves oxygen and glucose around so cells can work and wastes that can be disposed

Respiratory System- Provides oxygen so muscles can function and removes carbon dioxide and water that

muscle cells produce as a waste product

Excretory System- Cleans blood of waste products produced by muscular system

Skeletal System- Works with the muscular system to help the body with support and movement

Nervous System- Controls the actions of the muscular system by sending a never-ending stream of messages

along the nerves

Medical ProblemsMuscular dystrophy- Genetic disease that damages muscle

fibers. Symptoms include weakness, loss of mobility, and lack of coordination.

Cerebral palsy- Impacts posture, balance and motor functions. Brain damage during or before childbirth causes a loss of muscle tone, making it difficult to perform everyday tasks.

Myasthenia gravis- A chronic autoimmune disease that results in muscle fatigue and weakness. A breakdown of neuromuscular

junction causes the brain to lose control over these muscles, which can result in difficulty breathing or swallowing.

Amyotrophic lateral sclerosis (ALS)- often referred to as “Lou Gehrig Disease”, is a progressive neurodegenerative

disease that affects nerve cells in the brain. Leads to loss of control over voluntary muscles, making it increasingly hard to

breathe, swallow, or speak.

Fibromyalgia- A chronic disorder characterized by widespread muscle pain, stiffness, fatigue, and tenderness in localized

areas.

Sources

• http://www.montana.edu/craigs/How%20Muscles%20Work.htm

• http://www.rsd.edu/schools/carmichael/masters/pdf/hwsystmswrky.pdf

• http://www.mananatomy.com/body-systems/muscular-system

• http://www.livescience.com/26854-muscular-system-facts-functions-diseases.html

• http://www.physiologyinfo.org/mm/What-is-Physiology/Muscular/How-the-Muscular-System-Works.html