Muscular System Flashcards
(30 cards)
Myology
Scientific study of muscles
Musculoskeletal system
Integrated system of bones, muscles, and joints
Orthopedics
The branch of medical science concerned with the prevention or correction of disorders of musculoskeletal system
Striations
Alternating light and dark protein bands, visible under microscope
Three types of muscle
Skeletal - striated; voluntary
Cardiac - striated; involuntary
Smooth - nonstriated; involuntary
4 key functions of muscular tissue
Producing body movements: integrated movement of skeletal muscles, bones, joints
Stabilizing body positions: maintain body posture; postural muscles contract continuously
Storing and moving substances within the body: sphincters in digestive/urinary systems; cardiac muscle contractions; smooth muscle in walls of blood vessels/digestive system; skeletal muscle returns veinous blood to heart
Producing heat: Heat is produced as muscles contract
Muscle fibers
Muscle cells - elongated
Fascicles
Bundles of 10-100 or more muscle fibers
How many muscle fibers can be in a whole muscle?
Hundreds to thousands of muscle fibers
Endomysium
Connective tissue that wraps each muscle fiber
Perimysium
Connective tissue that wraps each fascicle
Epimysium
Connective tissue that wraps whole muscle
Fascia
Dense sheet or broad band of dense irregular connective tissue that surrounds muscles
Allows free movement, carries nerves, blood vessels, and lymphatic vessels; fills space between muscles
Subcutaneous layer (hypodermis)
Separates muscle from skin
Composed of areolar connective tissue and adipose tissue
Provides pathway for nerves, blood vessels, and lymphatic vessels to enter and exit muscles
Tendon
Cord of dense regular connective tissue composed of parallel bundles of collagen fibers - an extension of the epimysium, perimysium, and endomysium beyond the muscle
Describe skeletal muscle tissue’s nerve and blood supply.
Well supplied with both - prolonged muscle contraction depends on a rich supply of oxygen and nutrients and removal of waste
-each muscle fiber makes contact with a portion of a neuron
Sarcolemma
Plasma membrane covering each muscle fiber
Transverse tubules
Tunnel in from the surface to the center of each fiber
Sarcoplasm
Cytoplasm in muscle fibers
True or false
Muscle fibers contain multiple nuclei in one fiber.
True
Myoglobin
Reddish pigment; stores oxygen until needed by mitochondria
Numerous in the sarcoplasm
Myofibrils
Cylindrical structures extending along the entire length of a fiber
Consists of two protein filaments
Thin filaments: contain actin, tropomyosin, and troponin
- anchored to the z discs; contains myosin-binding site
Thick filaments: contain myosin - project myosin heads
Sarcomeres
Basic functional units of striated muscle fibers
Sarcoplasmic reticulum
Network of fluid-filled membrane-enclosed tubules that stores calcium ions required for muscle contraction
