Concepts and Applications of the Exercise Sciences Flashcards
Epimysium
continuous with tendons at ends of muscle
Tendon
attaches muscle to bones
Bone Periosteum
specialized connective tissue covering all bones
Proximal
closer to the trunk
Distal
further from the trunk
Superior
closer to the head
Inferior
closer to the feet
Origin
proximal attachment of muscle (towards the center of the body)
Insertion
distal attachment of muscle (away from the center of the body)
Muscle Fibers
muscle cell; long, cylindrical cells 50-100 micrometers in diameter
Fasciculi
bundles of muscle fibers
Perimysium
connective tissue that surrounds fasciculi
Endomysium
connective tissue that surrounds each muscle fiber
Sarcolemma
muscle fiber membrane; continuous with endomysium
Motor Neuron
nerve cell
Neuromuscular Junction
motor end plate; junction between motor neuron and ther muscle fibers it innervates
Motor Unit
motor neuron and all the muscle fibers it innervates
Sarcoplasm
cytoplasm of a muscle fiber
Myofibrils
contain apparatus that contracts the muscle cell
Myosin
type of microfilament; bigger microfilament
Microfilament
apparatus that contracts muscle cell
Actin
type of microfilament; smaller microfilament; consists of two strands arranged in a double helix
Cross-Bridges
globular heads that protrude away from myosin filament at regular intervals
Sarcomere
smallest contractile unit of skeletal muscle
A-Band
myosin filament section of sarcomere
I-Band
only actin filament portion of sarcomere
Z-Line
in the middle of I-Band and runs longitudinally
H-Zone
area in center of sarcomere where only myosin filaments are present
Sarcoplasmic Reticulum
intricate system of tubules that is parallel to and surrounding each myofibril
T-Tubules
transverse tubules; run perpendicular to SR and terminate in vicinity of Z-Line
Triad
T-Tubule spaced between and perpendicular to two SR vesicles
Action Potential
electrical nerve impulse
Sliding-Filament Theory
the actin filaments at each end of the sarcomere slide inward on myosin filaments, pulling the Z-lines toward the center of the sarcomere and thus shortening the muscle fiber
Troponin
protein that is situated at regular intervals along the actin filament and has a high affinity for calcium ions
Tropomyosin
runs along length of actin filament in groove of double helix
Acetylcholine
neurotransmitter that diffsues across neuromuscular junction causing excitation of sarcolemma
All-or -None Principle
all muscle fibers in a motor neuron contract if stimulus is high enough; stronger stimulus doesn’t mean stronger contraction
Twitch
brief contraction that results from action potential traveling down motor neuron
Tetanus
maximal amount of force a motor unit can develop; stimuli delivered at such a high frequency that twitches merge and completely fuse
Slow-Twitch Fibers
develop force and relax slowly and have long twitch time
Fast-Twitch Fibers
develops force and relaxes rapidly and has a short twitch time
Type I Fibers
slow twitch
Type II a Fibers
fast-twitch fibers
Type II b Fibers
fast twitch fibers
Type II x Fibers
also known as type II b
Recruitment
number of motor units activated; increasing recruitment can increase force
Preloading
loading muscle prior to muscle action (aids in force development early in range of motion)
Proprioceptors
specialized sensory receptors located within joints, muscles, and tendons
Muscle Spindles
proprioceptors that consist of several modified muscle fibers enclosed in a sheath of connective tissue
Intrafusal Fibers
run parallel to normal fibers
Extrafusal Fibers
normal muscle fibers
Golgi Tendon Organs (GTOs)
proprioceptors located in tendons near the myotendinous junction and are in series, that is, attached end to end, with extrafusal muscle fibers
Sarcopenia
reduced muscle size and strength
Heart
muscular organ comprised of two interconnected but separate pumps
Atrium
delivers blood to ventricles
Ventricle
delivers blood to pulmonary and peripheral circulations
Tricuspid Valve
prevents flow of blood from right ventricle back into right atrium
Mitral (Bicuspid) Valve
prevents flow of blood from left ventricle back into left atrium
Atrioventricular (AV) Valve
tricuspid and mitral valves
Systole
ventricular relaxation
Aortic Valve
prevents blood of blood from aorta back into left ventricle during ventricular relaxation
Pulmonary Vlave
prevents blood flow from pulmonary arteries into right ventricle during ventricular relaxation
Semilunar Valve
aoritc and pulmonary valves
Diastole
ventricular relaxation
Sinoatrial (SA) Node
intrinsic pacemaker where rhythmic electrical impulses are normally initiated
Atrioventricular (AV) Node
where the impulse is delayed slightly before passing into ventricales
Atrioventricular (AV) Bundle
conducts impulses to ventricles
Left Bundle Branches
divide further and conduct impulses further
Right Bundle Branches
divide further and conduct impulses further
Purkinje Fibers
further divisions of bundle branches, conduct impulses to all parts of ventricles
Myocardium
heart muscle
Sympathetic Nervous System
component of autonomic nervous system, fight or flight
Parasympathetic Nervous System
component of autonomic nervous system, relaxation and digestion
Bradycardia
fewer than 60beats/min
Tachycardia
more than 100beats/min
Electrocardiogram (ECG)
a graphic representation of electrical activity of the heart
P-Wave
depolarization; generated by changes in electrical potential of cardiac muscle cells that depolarize the atria and result in atrial contraction
QRS Complex
depolarization; generated by the electrical potential that depolarizes the ventricles and results in ventricular contraction
T-Wave
repolarization; caused by the electrical potential generated as the ventricles recover from the state of depolarization
Depolarization
the reversal of the membrane electrical potential, whereby the normally negative potential inside the membrane becomes slightly positive and the outside becomes slightly negative
Repolarization
process of the ventricles recovering from the state of depolarization
Arterial System
carries blood away from the heart
Venous System
returns blood toward the heart
Arteries
rapidly transport blood pumped from the heart
Arterioles
small branches of arteries; act as control vessels through which blood enters the capillaries
Capillaries
exchange oxygen, fluids, nutrients, electrolytes, hormones, and other substances between the blood and the interstitial fluid in various tissues of body
Venules
collect blood from capillaries and gradually converge into progressively larger veins
Hemoglobin
iron-protein carried by the red blood cells; transports oxygen
Red Blood Cells
major component of blood
Trachea
first generation respiratory passage
Bronchi
second generation respiratory passages
Bronchioles
additional respiratory passages
Alveoli
where gases are exchanged in respiration
Pleural Pressure
the pressure in the narrow space between the lung pleura and the chest wall pleura
Pleura
membranes enveloping the lungs and lining the chest walls
Alveolar Pressure
the pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs
Diffusion
a simple random motion or molecules moving in opposite directions through the alveolar capillary membrane
