Question | Answer |
the ability of skeletal muscle to shorten with force | contractility |
the capacity of skeletal muscle to respond to a stimulus. | excitability |
the ability to be stretched | extensibility |
ability to recoil to their original resting length after they have been stretched | elasticity |
each skeletal muscle is surrounded by a connective tissue sheath called the | epimysium |
is another connective tissue located outside the epimysium, it surrounds and seperates muscles. | fascia |
A muscle is composed of numerous visible bundles called muscle fasciculi(fasicle), which are surrounded by loose connective tissue called the | perimysium |
the fasciculi are composed of single muscle cells called | fibers |
each fiber is surrounded by a connective tissue sheath called the | endomysium |
the cytoplasm of each fiber is filled with | myofibrils- a threadlike structure that extends from one end of the fiber to the other. |
thin myofilaments, they resemble 2 minute strands of pearls twisted together. | actin myofilaments |
thick myofilaments, they resemble bundles of minute golf clubs | myosin myofilaments |
actin and myosin myofiloaments form highly ordered units called | sacromeres |
the outside of most cell membranes is positively charged compared to the inside of the cell membrane, which is negatively charged, the charge difference across the membrane is called the | resting membrane potential |
when a muscle cell is stimulated the membrane characteristics change briefly, the brief reversal back of the charge is called | action potential |
are nerve cells that carry action potentials to skeletal muscle fibers. | motor neurons |
axons enter the muscles and branch, each branch that connects to the muscle forms a | neuromuscular junction or synapse near the center of the cell |
a single motor neuron and all the skeletal muscle fibers it innervates are called a | motor unit |
the enlarged nerve terminal is the | presynaptic terminal |
the space between the presynaptic terminal and the muscle cell is the | synaptic cleft |
the muscle fiber is the | postsynaptic terminal |
each presynaptic terminal contains | synaptic vesicles |
synaptic vesicles secrete a neurotransmitter called | acetylcholine |
the acetylcholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by an enzymes | acetylcholinesterase |
the sliding of actin myofilaments past myosin myofilaments during contraction is called the | sliding filament mechanism of muscle contraction |
is a contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers | muscle twitch |
a muscle fiber will not respond to stimulus until that stimulus reaches a level called | threshold, at which point the muscle fiber will contract maximally |
this phenomenon is called the | all-or-none response |
the time between application of a stimulus to a motor neuron and the beginning of a contraction is the | lag phase |
the time of contraction is the | contraction phase |
the time during which the muscle relaxes is the | relaxation phase |
where the muscle remains contracted without relaxing | tetany |
the increase in number of motor units being activated is called | recruitment |
it is necessary for muscle cells to constantly produce ATP. when at rest they cant stockpile ATP but they can store another high-energy molecule, called | creatine phosphate |
without oxygen | anaerobic respiration |
with oxygen (more efficient) | aerobic respiration |
is the amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replensih the depleted stores of creatine phosphate stores in muscle cells | oxygen debt |
results when ATP is used during muscle contraction faster than it can be produced in the muscle cells | muscle fatigue |
the length of the muscle does not change | isometric |
amount of tension producede through whole contraction | isotojnic |
refers to constant tension kepps good posture | muscle tone |
contract and fatique quickly | fast twitch fibers |
contract slowly fatigue slowly | slow twitch |
most stationary end end of muscle | origin |
end of muscle undergoing greatest movement | insertion |
portion bewteen origon and insertion | belly |
muscles that work togehter | synergists |
muscles that work in opposition to one another | antagonists |
one msucle plays major role in accomplishing the desired movement | prime mover |
rases eyebrows | occiptofrontalis |
orbicularis oculi | closes eyelids |
(kissing muscles) orbicularis oris | puckers lips |
buccinator | flattens cheaks |
zygomaticus | smiling muscle |
levator labii superoris | sneering |
depressor anguli oris | frowning |
mastication | chewing |
group of muscles on each side of the back. Responsible for keeping the back straight and the body erect. | Erector spinae |
elevate the ribs during inspiration | External intercostals |
contract during forced expiration | Internal intercostals |
accomplishes quiet breathing | Diaphragm |
tendinous area of the abdominal wall called the | linea alba, consists of white connective tissue rather than muscle. |
On each side of the linea alba is the | rectus abdominis |
cross the rectus abdominis at three or more locations, causing the abdominal wall of a well-muscled person to appear segmented. | Tendinous inscriptions |
rotates scapula | Trapezius |
pulls scapula anteriorly | Serratus anterior |
The arm is attached to the thorax by the | pectoralis major and latissimus dorsi muscles. |
adducts and flexes the arm | Pectoralis major |
medially rotates, adducts, and powerfully extends the arm. “Swimmer muscles” | Latissimus dorsi |
attaches the humerus to the scapula and clavicle, and is the major abductor of the upper limb. | Deltoid |
extends the forearm | Triceps brachii |
flexes the forearm | Biceps brachii |
flexes forearm | Brachialis |
flexes the wrist | Flexor carpi |
extends the wrist | Extensor carpi |
flexes the fingers | Flexor digitorum |
extends the fingers. | Extensor digitorum |
19 hand muscles called the | intrinsic hand muscles |
muscles, located between the metacarpals, are responsible for abduction and adduction of the fingers. | . Interossi |