answer | question |
contractility | the ability of skeletal muscle to shorten with force. |
excitability | the capacity of skeletal muscle to respond to a stimulus. |
extensibility | the ability to be stretched. |
elasticity | ability to recoil to their original resting length after they have been stretched. |
what do muscles help produce? | Heat, essential for maintenance of normal body temperature. |
epimysium | (skeletal muscle) surrounded by connective tissue sheath. |
fascia | another connective tissue located outside the epimysium.(surrounds and separates muscles). |
perimysium | muscle composed of visible bundles called fasciculi (fascicle). |
fibers | single muscle cell. |
endomysium | (fiber surrounded) by connective tissue sheath. |
myofibrils | threadlike structure that extends from one end of the fiber to the other. |
actin myofilaments | thin myofilaments, they resemble 2 minute strands of pearls twisted together. |
myosin myofilaments | thick myofilaments. (resemble bundles of minute golf clubs) |
sarcomeres | joined end to end to form the myofibril. |
what is the sarcomeres job? | structural and functional unity of the muscle. |
resting membrane potential | charge difference across the membrane. |
action potential | reversal back of a charge. |
motor neurons | nerve cells that carry action potentials to skeletal muscle fibers. |
neuromuscular junction | branch that connects to the muscle. |
synapse | center of a cell. |
motor unit | a motor neuron |
motor neuron | nerve cells that carry skeletal muscle fibers |
presynaptic terminal | enlarged nerve terminal |
synaptic cleft | the space between the presynaptic terminal and the muscle cell |
postsynaptic terminal | muscle fiber |
synaptic vesicles | each presynaptic terminal contains this |
acetylcholine | secrete neurotransmitter |
acetylcholinesterase | breaks down enzymes |
sliding filament mechanism | sliding of actin during contraction |
muscle twitch | contraction of an entire muscle |
threshold | muscle fiber that will not respond to stimulus |
all or none response | this phenomenon is called (all or none response) |
lag phase | motor neuron and beginning of an contraction |
contraction phase | the time of a contraction |
relaxation phase | time of which muscles relax |
tetany | where muscles remain contracted with out relaxing |
recruitment | the increase in number of motor units being activated |
energy requirements (4 of them) | ATP, ATP, ATP, ADP |
creatine phosphate | necessary for muscle cells |
anaerobic respiration | without oxygen |
aerobic respiration | with oxygen (more efficient) |
oxygen debt | amount of oxygen needed in chemical reactions |
muscle fatigue | results when ATP is used during muscle contraction faster than it can be produced in the muscle cell |
isometric | equal distance |
isotonic | equal tension |
muscle tone | keeps head up and back straight |
fast twitch fibers | contract quickly and fatigue quickly |
slow twitch fibers | contract more slowly |
origin | (head) most stationary end of a muscle |
insertion | end of the muscle undergoing the greatest movement |
belly | portion of the muscle between the origin and the insertion |
synergists | muscles that work together to accomplish specific movements |
antagonists | muscles that work in opposition to one another |
prime mover | one muscle plays the major role in accomplishing the desired the desired movement |
smooth muscle | muscle tissue in which the contractile fibrils are not highly ordered, occurring in the gut or other internal organs |
fascicle | a bundle of structures, such as nerve or muscle fibers or conducting vessels in plants. |
cardiac muscle | heart muscle, one of the three major types of muscle, the others been skeletal and smooth |
sarcolemma | the fine transparent tubular sheath that envelopes the fibers of skeletal muscles. |
sarcomere | a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer |
Occipitofrontalis | raises the eyebrows |
Orbicularis oculi | closes the eyelids and causes “crows feet” wrinkles in the skin at the lateral corners of the eye. |
Orbicularis oris | puckers the lips |
Buccinator | flattens the cheeks. Trumpeter’s muscle. |
two types of mouth muscles | Orbicularis oris and buccinator are the kissing muscles. |
Zygomaticus | smiling muscle. |
Levator labii superioris | sneering |
Depressor anguli oris | frowning |
Mastication | chewing |
4 pairs of mastication muscles: | 2 pair of pterygoids, temporalis, and masseter |
Intrinsic Tongue Muscles | change the shape of the tongue |
Extrinsic Tongue Muscles | move the tongue |
Neck Muscle | Sternocleidomastoid |
Sternocleidomastoid | lateral neck muscle and prime mover. Rotates and abducts the head |
Erector spinae | group of muscles on each side of the back. Responsible for keeping the back straight and the body erect |
Most involved in breathing | External intercostals – elevate the ribs during inspiration.
Internal intercostals – contract during forced expiration.
Diaphragm |
External intercostals | elevate the ribs during inspiration |
Internal intercostals | contract during forced expiration |
Diaphragm | accomplishes quiet breathing |