Intro to Muscular System Flashcards
Where is smooth muscle found?
Walls of hollow organs
Muscle cells are also called ____
Myocytes
Contractions of smooth muscle are ___ movements triggered by ___
involuntary movements triggered by impulses from autonomic nervous system
What cells make up cardiac muscle?
Cardiomyocytes
What property of cardiac muscle facilitates coordinated contraction?
Branched cells allow for connections to form a network
Groups of Skeletal muscle fibers are organized into:
Fascicles
Skeletal muscle is innervated by:
motor neurons
Endomysium
CT surrounding muscle fiber
Perimysium
CT surrounding a fascicle
Epimysium
thin CT that wraps around whole muscle
Skeletal muscle origin
Attachment site where bone remains immobile during action
Skeletal muscle insertion
Attachment site where the bone moves during an action
Antagonist pairs consist of…
an agonist muscle and an antagonist muscle
Agonist
muscle that is performing an action
Antagonist
muscle that performs opposite action to agonist relaxing
Circular muscles
Circular in shape
ex. mouth, eye, sphincters of bowels and bladder
Convergent muscle structure and function
Origin is wider than insertion; triangular
Fiber arrangement allows for maximum force production
ex. pectoralis
Parallel muscles structure and function
Parallel fibers
Long muscles, large movements
Lower strength, higher endurance
ex. sartorius
Fusiform muscles structure
Muscle belly is wider than origin and insertion
ex. biceps brachii
Pennate muscles structure and function
Large number of muscle fibers insert on a tendon (instead of bone), high strength
Unipennate muscles structure
Fibers arranged to insert in diagonal direction onto the tendon
ex. lumbricals, extensor digitorum longus
Bipennate muscles structure and function
Two rows of muscle fibers, facing in opposite diagonal directions
Central tendon, like a feather
Greater power, less range of motion
ex. rectus femoris (of quads)
Multipennate muscles structure
Multiple rows of diagonal fibers
Central tendon that branches
ex. deltoid
Hypaxial back muscles are innervated by:
Ventral rami
Which back muscles are hypaxial?
Extrinsic
Which back muscles are epaxial?
Intrinsic
Epaxial back muscles are innervated by:
Dorsal rami
Action of myocytes
Contraction (shortening) of fibers
Contraction of cardiomyocytes is induced by signalling of _____
Cardiac conduction system
(APs stimulated by ANS)
Skeletal muscle function
Attach to and move bones
Skeletal muscle contracts and relaxes in response to ____ messages from ____
Voluntary
CNS/PNS
Skeletal muscle cells are long cells called ____
Muscle fibers
Organization of skeletal muscle fibers
Muscle fiber -> endomysium -> fascicle -> Perimysium -> whole muscle -> epimysium
Types of skeletal muscle classifications
Fusiform
Parallel
Convergent
Unipennate
Bipennate
Multipennate
Circular
Convergent muscles are sometimes called ____
Triangular muscles
Parallel muscles are sometimes called ____
strap muscles
Thoracolumbar aponeurosis
Anterior layer is anterior to ___
quadratus lumborum muscle
Thoracolumbar aponeurosis
Anterior layer ends medially in ___
transverse process of lumbar vertebrae
Thoracolumbar aponeurosis
Anterior layer combines laterally with
aponeurosis of transversus abdominus
thoracolumbar aponeurosis
Middle layer is posterior to ___
quadratus lumborum muscle, attaches to TP
thoracolumbar aponeurosis
Middle layer is anterior to ___
Intrinsic muscles of the back
thoracolumbar aponeurosis
Posterior layer covers ___
Erector spinae group
thoracolumbar aponeurosis
Posterior layer ends laterally in ___ by blending with ___
end laterally in lumbar by blending with aponeurosis of transversus abdominus muscle
