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48 terms

Chapter10 A&P 1

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Movement
muscular contraction allows locomotion and movement of body contents
Stability
maintain posture by resisting gravity and preventing unwanted movements
Communication
facial expression, body language, writing, speech
Control of body openings and passages
sphincter: ring of muscle
Heat Production
skeletal muscles produce up to 85% of body heat
Muscle Cells
are also called muscle fibers- 10-100um diameter, <30cm long
Endomysium
areolar connective tissue sheath surrounding every muscle cell/fiber
Fascicle
bundle of muscle fibers, make grain in muscle tissue
Perimysium
connective tissue sheath surrounding each fascicle
Muscle
bundle of fascicles
Epimysium
connective tissue sheath around whole muscle
Deep fascia
epimysium sheet between muscles
Superficial Fascia
epimysium sheet between muscles and skin
Tendon
collagen fibers of epimysium that merge into periosteum of bone
Aponeurosis
broad, sheet-like tendon
Retinaculum
band of connective tissue that covers multiple tendons
Origin
stationary end of a muscle; also called the head of the muscle
Insertion
mobile end of the muscle; insertion is pulled towards origin
Belly
middle of muscle
Fusiform
thick in the middle, tapered at the ends; strong contraction
Parallel
long strap-like muscles of uniform width; weaker contraction
Convergent
broad at origin and narrow at insertion; very strong
Pennate
feather-shaped with all fascicles inserting on a long tendon
Circular
(sphincters) rings of muscle around body openings
Muscle Actions
individual muscles may have more than one action
Prime Mover
(agonist) muscle that produces most of force in a joint
Synergist
assists and stabilizes prime mover
Antagonist
opposes prime mover
Fixator
muscle that prevents a bone from moving
Naming muscles: Size
maximus, medius, minimus, major, minor
Naming muscles: Shape
deltoid, trapezius, rhomboideus
Naming muscles: Location
orbicularis oculi, quadriceps femoris, brachialis
Naming muscles: Direction of Fibers
rectus abdominus, external obliques
Rectus
parallel to the body midline
Oblique
diagonal to the body midline
Transverse
horizontal to the body midline
Naming muscles: # of Attachments
biceps brachii, sternocleidomastoid
Naming muscles: Action
pronator teres, adductor magnus, flexor carpi ulnaris
Responsiveness/Excitability
when stimulated by chemical signals, stretch, and other stimuli, muscle cells respond with electrical impulses
Conduction
stimulation can occur locally, but the impulse travels in a wave of excitation over the entire cell
Contractility
muscle cells are unique in their ability to shorten when stimulated
Extensibility
muscle cells can be stretched beyond their resting length
Elasticity
muscle cells recoil to their original resting length after stretching and/or contracting
Skeletal Muscle
attached to one or more bones, has striations of light and dark bands in each cell, has multinucleate cells, and is usually voluntary;
Vermiform Cells
(worm-like) are multinucleate due to their formation from multiple stem cells called myoblasts
Sarcoplasm
Cytoplasm of a muscle cell with an abundance of glycogen (stored glucose polymer) and myoglobin (red pigment to store oxygen)
Sarcolemma
Plasma membrane of a muscle cell. This organelle can receive neurotransmitters from connected neurons and conduct an electrical impulse over its surface and into the interior of the cell
Transverse Tubules (t-tubules)
tube-like extensions of the sarcolemma that descend into the interior of the muscle cell and out the other side