Muscle Tissue Flashcards
Characteristics & Functions of Skeletal Muscle
Moves the skeleton; Under voluntary control; Multinucleated, long cylindrical fibers, striated
Characteristics & Functions of Cardiac Muscle
Only found in heart wall; involuntary control; striated
Characteristics & Functions of Smooth Muscle
Found in walls of hollow organs; involuntary control; no striations
What are the properties of Muscle Tissue?
Excitability, Extensibility, Contractility, Elasticity
What is excitability?
Property of muscle tissue where nerve signal excites the muscle, causing contraction
What is contractility?
A property of muscle that states when a muscle contracts, it shortens
What is extensibility?
A property of muscle that allows for the muscle to go back to resting length after contraction
What is Elasticity?
A property of muscle that allows a muscle to passively recoil and resume resting length after being stretched
What are the subunits of a whole muscle?
Fascicles
What are fascicles made of?
Muscle Fibers
What are the CT of muscles? Where are they found and what are they made of?
Epimysium: surrounds whole muscle (dense IR)
Perimysium: surrounds fascicles (Fibrous CT)
Endomysium: surrounds individual muscle fibers (Loose CT)
What are individual muscle fibers made of?
Myofibrils
What are the repeating units that make up a myofibril?
Sacromeres
What are the proteins that make up a sarcomere?
Myofilaments
What are the types of Myofilaments? And what are they made of?
Thick filament: myosin
Thin filament: Actin, Tropomyosin, Troponin
Elastic filament: Titin
Draw and Label the Parts of a sarcomere
I bands, A bands, H zones, M line
During contraction, how do the striations of the sarcomere change?
I bands shorten, A bands remain the same, H zones disappear, Z discs remain the same
What are T tubules?
Extensions of the sarcolemma that extend into muscle fiber; wrap around myofibrils; carry electrical stimulus to myofibrils
What does the sarcoplasmic reticulum do?
Stores and releases calcium ions
What is the Sliding Filament Theory?
During a contraction, actin and myosin filaments slide over each other
What is a motor unit?
1 motor neuron and all the muscle fibers it innervates
Motor units with more muscle fibers per motor unit are better for…
… powerful contractions
What is the neuromuscular junction?
Where motor neuron meets muscle fiber; stimulation of muscle fiber can occur
Characteristics & Functions of Parallel Muscles
Fascicles run parallel to axis of muscle; Tendon on either end; Longer fibers, can shorten more
Characteristics & Functions of Pennate Muscles
Tendon runs whole length of muscle; Allows for more fibers, stronger
Characteristics & Functions of Convergent Muscles
Fascicles converge into tendon at insertion
Characteristics & Functions of Circular Muscles
Fascicles arranged in a ring; Sphincter muscles
What are the different muscle attachments?
Origin: attachment site that is not moved during contraction
Insertion: attachment site that is moved when muscle shortens
What is a direct muscle attachment?
Short, dense regular CT fibers connect muscle to bone
What is an indirect muscle attachment?
Long, dense regular Ct fibers connect muscle to bone
What is a synergist?
Muscles that work together to perform an action
What is an antagonist?
Muscles that perform opposite functions
What is a prime mover/agonist?
Muscle that is primarily responsible for a movement
What is a fixator?
A synergist that assists by holding a bone firmly in place to allow the prime mover to work more effectively
What causes an increase in muscle strength and size?
With injury, satellite cells (immature cells) fuse with muscle fibers and proliferate. New satellite cells produce proteins that help repair the damaged muscle fibers
What type of cellular junction allows cardiac muscle cells to contract in a coordinated fashion?
Gap Junction
What are the 2 layers of smooth muscle? Where are they found?
Circular layer: closest to lumen of organ
Longitudinal layer: wraps around circular layer
