Name: _______________________________Class #: __________ Class Period: __________
Date: _______________
Muscular System
Key Points
 Over ______________________ muscles make up the muscular system
 45% of total body weight as an adult
 Contraction depends on ________________________________ (actin and myosin)
 Sliding filament theory
Basic Anatomy of Skeletal Muscle
 Each muscle is an organ
 100s to 1000s of muscle fibers per muscle
 ________________________________– fine sheath of connective tissue around each muscle fiber
 ________________________________– collagenic sheath around several muscle fibers bundled
together (fascicles)
Characteristics of Muscles
 _____________________________: the ability to respond to a stimulus such as a nerve impulse
 _____________________________: muscle fibers that are stimulated contract which causes movement
 _____________________________: the ability to be stretched
 _____________________________: allows muscle to return to its original shape after being contracted
or stretched
Three Main Kinds of Muscle
1. Cardiac muscle – forms the walls of the heart and contracts to circulate blood
o ___________________________ muscle
2. Visceral (smooth) muscle – found in internal organs of the body and contracts to cause movement in
these organs
o ___________________________ muscle
3. Skeletal muscle – attached to bones and causes body movement
o ___________________________ muscle
Functions of the Muscular System
 ____________________________– voluntary and involuntary
 Produce heat and energy for the body
 Help maintain _______________________ by holding the body erect
 _____________________ internal organs
 Stabilization of joints
Muscle Attachments
 Tendons- Strong, tough connective-tissue cords.
o EX. ______________________________________
 Fascia- Tough, sheet-like membrane that covers and protects the tissue.
 Origin- the end of the muscle attached to the ___________________________ bone.
 Insertion- the end of the muscle attached to the _________________________ bone.
Muscle Movements
 Adduction: moving the body part toward the midline
 _________________________: moving the body part away from the midline
Name: _______________________________Class #: __________ Class Period: __________
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Date: _______________
Flexion: decreasing the angle between two bones, or bending
____________________________: increasing the angle between two bones, or straightening
Rotation: turning a body part around its own axis
____________________________: moving in a circle at a joint
Muscular Information
 _______________________________– the state of partial contraction
o Muscles are partially contracted even when not in use
 Atrophy – when muscles shrink in size and lose strength
o Due to injury or severe illness
 ____________________________– a severe tightening of a flexor muscle resulting in bending of a joint
Diseases and Abnormal Conditions
 Fibromyalgia – chronic, widespread pain
o Symptoms: muscle stiffness, numbness or tingling in the arms or legs, ________________, sleep
disturbances, headaches, and depression
o Cause is unknown, but __________________, weather, and poor physical fitness affect the
condition
o Treatment: directed towards pain relief
 Myasthenia Gravis
o __________________ condition where nerve impulses are not properly transmitted to the
muscles
o Leads to progressive weakness and eventually ___________________________
o Cause is unknown
o Thought to be an ________________________ disease with antibodies attacking the body’s own
tissues
o No cure
 __________________________________
o Inflammation of the tendon caused by excessive or repetitive use of a joint.
 _________________________________
o Muscle tenderness or pain
 ________________________________
o Rupture of the muscle
 Muscular Dystrophy
o Group of ___________________________ disorders that lead to chronic, progressive muscular
atrophy (shrinking, losing strength).
o Usually appears in ________________________, most types lead to total disability and early
death.
o No cure, but physical therapy is used to slow the progression.
 ________________________
o Injury to a joint (ex. - ankle, knee, wrist). Frequently involves a stretched or torn ligament.
o Ligaments attach bone to bone.
 _______________________
o Injury to the body of a muscle or the attachment of a tendon. Usually associated with overuse
injuries.
o Tendons attach muscle to bone.
Name: _______________________________Class #: __________ Class Period: __________
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_____________________________
o Pain caused by muscle tearing away from the tibia. Usually caused by repeated stress to the
lower leg.
______________________________
o Loss of sensation and voluntary muscle movement due to disease or injury.
o Damage can be temporary or permanent.
_____________________________
o Paralysis of both legs and the lower part of the body.
o Spinal cord injury is below cervical vertebrae
______________________________
o Paralysis of all four extremities.
o Spinal cord injury involves the cervical vertebrae.
o Above C5, respiration is affected.
______________________________
o Total paralysis on one side of the body. Usually associated with stroke or brain injury.
o Damage to one side of brain causes paralysis on the ______________________ side of the body.