Chapter 7 Muscles Flashcards
What are the 3 different types of muscle
Skeletal
Cardiac
Smooth
Myo
Generally refers to muscle
Sarco
Refers to muscles at the cellular level
Skeletal muscle
Voluntary
Striated
Voluntary
Can be controlled by conscious mind
Striated
Stripped pattern in muscle
Origin
The end that is generally more stable than the other. Does not move
Insertion
Site that undergoes most of the movement during contraction
Tendons
Bands of dense regular connective tissue made of collagen fibers
Aponeurosis
Broad sheets of fibrous tissue
Linea alba
Long thin white line that connects abdominal muscles
Agonist (prime mover)
Describes a muscle or muscle group that directly produces a desired movement
Synergist
A muscle that contracts at the same time as a prime mover and assists it in carrying out action
Antagonist
A muscle or muscle group that directly opposes the action of a prime mover.
Fixator
Stabilizes joints to allow other movements to take place
Muscles are generally named for what?
Action Shape Location Direction of fibers Number of heads or divisions Attachment sites
Head muscles
Control facial expressions, enable chewing, move sensory structures
Masseter
Neck muscles
Support head, allow neck to flex, extend, and move head laterally
Inspiratory muscles
Diaphragm
External intercostals
Expiratory muscles
Internal intercostals
Endomysium
Each individual skeletal muscle fiber is surrounded by this delicate connective tissue layer
Fascicle
Groups of skeletal muscle fibers
Perimysium
Connective tissue that binds together fascicles
Epimysium
Fibrous connective tissue that surrounds groups of fascicles
Actin
Thin filaments
Myosin
Thick filaments
Sarcoplasmic reticulum
Stored calcium for muscle contraction
A band
Large dark band made up of myosin filaments (thick)
I band
Large light band made up of actin filaments (thin)
Z line
Dark band in center of I band, disk that is viewed as a line and is attachment site for actin filaments.
Sarcomere
Area from one z line to the next z line. Basic contracting unit of skeletal muscle. When all sarcomeres contract, leads to overall muscle fiber shortening
Atrophy
Shrink down
Neuromuscular junctions
Sites where the ends of motor nerve fibers connect to muscle fibers
Synaptic vesticles
Sacs at end of a nerve fiber, contain neurotransmitter
Acetylcholine
Neurotransmitter chemical that travels across synapse to activate muscle fiber
Acetycholinesterase
Enzyme in the synaptic space that removes acetylcholine
Sarcolemma
Cell membrane of the muscle fiber
Sarcoplasm
Cytoplasm of the muscle fiber
Cross bridges
Levers on the myosin filaments, ratchet back and forth and pull the actin filaments on both sides toward center of the myosin filaments
Latent phase
Brief pause between nerve stimulus and beginning of actual contraction
Contracting phase
Actual contraction is taking place
Relaxation phase
When cells go back to a relaxed state
ATP
The energy source for actin and myosin to contract
Anaerobic metabolism
Produces lactic acid made from oxygen and glucose
Cardiac muscle
Involuntary and striated
Intercalated discs
Gab junctions
SA node
Sinatrial node
Sympathetic fibers
Stimulate heart to beat harder and faster as part of fight or flight response (stress)
Parasympathetic fibers
Inhibit cardiac function, causing heart to beat more slowly and with less force part of feed or breed response (relaxed)
Smooth muscle
Involuntary and unstriated
Smooth muscle is found in what two forms?
Visceral
Multiunit
Visceral smooth muscle
Large sheets of cells in the walls of some hollow organs
Multiunit smooth muscle
Small, discrete groups of cells make delicate movements
Sympathetic nervous system
Decreases activity
Parasympathetic nervous system
Increases activity