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Ch. 6 Muscles
flashcards
Question | Answer |
---|---|
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 |
Zygomaticus | smiling muscle |
Levator Labii Superioris | sneering |
Depressor anguli oris | frowning |
Mastication | chewing |
Intrinsic Tongue Muscles | change the shape of the tongue |
Extrinsic Tongue Muscles | move the tongue |
Sternocleidomastoid | lateral neck muscle and prime move |
Erector spinae | group of muscles on each side of the back. Responsible for keeping the back straight and the body erect. |
Thoracic muscles | muscles that move the thorax |
Diaphragm | accomplishes quiet breathing. Dome-shaped muscle. Aids in breathing. |
Trapezius | rotates scapula |
Serratus anterior | pulls scapula anteriorly |
Pectoralis major | adducts and flexes the arm |
Latissimus dorsi | medially rotates, adducts, and powerfully extends the arm. “Swimmer muscles” |
Deltoid | attaches the humerus to the scapula and clavicle, and is the major abductor of the upper limb |
Triceps branchii | extends the forearm. Occupies the posterior compartment of the arm. |
Brachialis | flexes forearm |
Biceps brachii | flexes the forearm. occupies the anterior compartment of the arm. |
Brachioradialis | flexes and supinate the forearm |
Flexor carpi | flexes the wrist |
Extensor carpi | extends the wrist |
Flexor digitorum | flexes the fingers |
Extensor digitorum | extends the fingers |
Gluteus maximus | buttocks |
Quadriceps femoris | extends the leg; anterior thigh muscles |
Sartorius | “tailors muscle,” flexes the thigh |
Hamstring muscles | posterior thigh muscles; flexes the leg and extends the thigh |
Gastrocnemius | form the calf muscle |
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 |
actin myofilaments | thin myofilaments. they resemble 2 minute strands of pearls twisted together. |
myosin myofilaments | thick myofilaments. they resemble bundles of minute golf clubs |
motor neurons | |
nerve cells that carry action potentials to skeletal muscle fibers | |
muscle twitch | a contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers |
tetany | where the muscle remains contracted without relaxing |
ATP | needed for energy for muscle contraction |
anaerobic respiration | without oxygen |
aerobic respiration | without oxygen (more efficient) |
oxygen debt | the amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells. |
muscle fatigue | results when ATP is used during muscle contraction faster than it can be produced in the muscle cells |
isometric | the length of the muscle does not change, but the amount of tension increases during the contraction process |
isotonic | the amount of tension produced by the muscle is constant during contraction, but the length of the muscle changes. |
muscle tone | muscle tome refers to constant tension produced by muscles of the body for long periods of time. |
fast-twitch fibers | contract quickly and fatigue quickly. |
slow- twitch fibers | contract more slowly and are more resistant to fatigue. |
origin | the most stationary end of the muscle |
insertion | the end of the muscle undergoing the greatest movement |
synergists | muscles that work together to accomplish specific movements |
tendinitis inscriptions | cross the rectus abdominis at three or more locations |
peroneus | the lateral muscles of the leg |
myosin myofilaments | anchored in the center or the sarcomere at a dark staining band called the M line |
Acetylcholinesterase | Acetylcholine released into the synaptic cleft between the neuron and muscle cells |
Sliding filament mechanism | the sliding of a tin myofilaments past myosin myofilaments during contraction |
Threshold | when a muscle fiber contracts maximally |
lag phase | the time between application of a stimulus to a motor neuron and the beginning of a contraction |
relaxation phase | the time during which the muscle relaxes |
What happens when an action potential reaches the nerve terminal? | It causes the synaptic vesicles to release acetylcholine into the synaptic cleft by exocytosis |
What happens during muscle contraction? | Actin and myosin myofilaments slide past one another causing the sarcomeres to shorten. |
What are the four major functional characteristics of skeletal muscle? | Contractility, excitability, extensibility, elasticity |
Myofibrils consist of what 2 major kinds of protein fibers? | Actin myofilaments, Myosin myofilaments |
Each ____ is a light area called an I band, it consists of actin. | Z line. |
How is a neuromuscular junction formed? | It is formed by an englarged never twrminal destiny in an indentation of the muscle cell membrane. |
What happens when an action potential reaches the nerve terminal? | It causes the synaptic vesicles to release acetylcholine into the synaptic cleft by exocytosis. |
What do muscles do? | They help to produce heat essential for maintenance of normal body temperature. |
What are the two energy requirements? | ATP, ADP |
The myosin myofilaments are anchored in the center of the ____ | sarcomere |
During periods of inactivity as excess ATP is produced in the muscle cell, the energy contained in ATP is used to synthesize | creatine phosphate |
The point of attachment of each muscle are it’s ____ | origin and insertion |