The Muscular System
By: Siri Ketha and Riley Banks
The Basics
- Three main muscle types
- Visceral, Cardiac, and Skeletal
- Diseases Muscular Dystrophy, Myasthenia Gravis, Myositis
- main function is movement
- muscles only tissue in body that can contract- move parts of body
- muscles maintain posture and the body's position
- moment of substances in body- mainly cardiac and visceral muscles
- muscle tissue generates body heat
- because of 'high metabolic rate of contracting muscle,' the system makes a lot of waste heat
- small contractions in body make natural body heat
Visceral Muscle
•Also called smooth muscle
•Line internal organs such as the uterus, intestines, and stomach
•involuntary
•person cannot control smooth muscles
•inside stomach, intestines, blood vessels
•weakest muscle tissue
•called 'smooth muscle' because has smooth look under microscopic
Cardiac Muscle
•Make up the muscular portion of the heart
•The muscles that make up the portion of the heart is called myocardium
•responsible for contraction of heart
•primarily involuntary
•found only in HEART
•job: pump blood through body
•hormones/signals from brain change rate of contraction
Skeletal Muscle
•Skeletal muscles are the ones that ache after exercise
•Skeletal muscles take up about 40% of the body’s weight
•only voluntary muscle tissue (human body)
•every conscious physical action requires skeletal muscle
•job: contract to move parts of body closer to bone that muscle is attached too
Diseases
•diseases can be severe
•weakness to cramping paralysis
•Classified as primary diseases and non-primary diseases
•muscles are very interconnected with other parts of other systems
Myositis
•inflammation and frequent infection of muscle tissue
•can be caused by many: bacteria, viruses, parasites
•most inflammatory muscle diseases are destructive
•can occur at any age
Muscular Dystrophy
•group of heredity diseases that cause 'progressive weaknesses and degeneration of skeletal muscles'
•usual early evidence of degeneration and regeneration of muscle fibres
•regenerated fibres become abnormally long
Myasthenia Gravis
•chronic autoimmune disease- muscle weakness and chronic fatigue
•primarily affects muscles on face, neck, throat, limbs
•symptoms are gradual
•muscle use worsens symptoms but helps restore strength