NSCA CSCS - Chapter 1 Flashcards
A-Band
The section of the sarcomere that corresponds with the alignment of myosin and actin filaments.
Acetylcholine
A neurotransmitter released when an action potential arrives at the nerve terminal. The Acetylcholine diffuses across the neuromuscular junction causing excitation of the sarcolemma.
Actin
A protein that forms actin myofilaments. Actin filaments consist of two thin strands about 6nm in diameter arranged in a double helix.
Action potential
An electrical impulse from a motor nerve that signals the release of calcium from the sarcoplasmic reticulum into the myofibril, causing tension development in the muscle.
All-or-none principle
The phenomenon that a stimulus from the motor neuron will cause all fibers in that motor unit to contract. As such, stronger action potentials do not result in bigger contractions.
Alveolar pressure
Pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs.
Alveoli
The final passages in the respiratory system where gases are exchanged from the lungs.
Aortic valve
Valve in the heart that prevents backflow of blood from the aorta into the ventricle.
Appendicular skeleton
Bones of the shoulder/pectoral girdle (left and right scapula and clavicle), bones of the arms, wrists, and hands (left and right humerus, radius, ulna, carpals, metacarpals, and phalanges); the pelvic girdle (left and right coxal or innominate bones), and the bones of the legs, ankles, and feet (left and right femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges). (ESC p. 2)
Arterial system
System of tubes that carries blood away from the heart. Due to the high pressure of the blood from the heart, arteries have strong walls.
Arteriole
Smaller branches of the arterial system that deliver blood to the capillaries.
Artery
Strong tubes that rapidly transport blood from the heart.
Atrioventricular (AV) bundle
Conducts the impulse in the heart to the ventricles.
Atrioventricular (AV) node
Node in the heart that slightly delays the impulse from the SA node.
Atrioventricular (AV) valves
One-way valves that prevent the backflow of the blood from the ventricles into the atria.
Atrium
Chambers of the heart that receive blood and pump it to the ventricles. The left and right atria pump blood to the left and right ventricle, respectively.
Axial Skeleton
Bones of the skull (cranium), vertebral column (C1-coccyx), ribs, and sternum.
Biaxial joints
Joints such as the ankle and wrist that allow movement around two perpendicular axes.
Bone periosteum
A specialized connective tissue covering all bones. The tendons attach to the bone periosteum.
Bradycardia
Heart rate less than 60 bpm.
Bronchi
Second generation passages in the respiratory system that deliver air to the bronchioles.
Bronchiole
The third generation passages in the lungs that deliver air to the alveoli, where gases are exchanged.
Capillary
Small end-tubes of the arterial system that facilitate exchange of oxygen, fluid, nutrients, and other substances between the blood and other fluids in various body tissues.
Cartilaginous joints
joints that allow limited movement - i.e. intervertebral disks. (ESC p. 2).
Crossbridge
The connections between the globular heads on myosin filaments that bind with actin. The strength of a muscle contraction is directly related to the number of myosin crossbridges bound to actin.
Depolarization
The reversal of the heart membrane electrical potential and results in contraction of the atria or ventricles in the case of the P-Wave and QRS complex, respectively.
Diastole
Ventricular relaxation.
Diffusion
The simple random motion of molecules moving in opposite directions through the alveolar-capillary membrane.
Distal
The attachment of a limb muscle that is further from the trunk relative to the proximal attachment.
Electrocardiogram (ECG)
Graphic representation of heart electrical activity.
Endomysium
The connective tissue that surrounds each muscle fiber and is contiguous with the muscle fiber membrane known as the sarcolemma.
Epimysium
The outer layer of fibrous connective tissue covering the body’s more than 430 skeletal muscles. The epimysium is contiguous with the tendons at the ends of the muscle.
Extrafusal fibers
Normal muscle fibers.
Fasciculi
Bundles of muscle fibers located under the epimedium. The fasciculi can consist of up to 150 fibers and each fascicle is individually surrounded by connective tissue called perimysium.
Fast-twitch fiber
The fibers in a fast-twitch motor unit that develops force and relaxes rapidly, resulting in a short twitch time. Fast-twitch fibers are further broken into Type IIa fibers and type IIx fibers. Type II fibers and motor units can produce force rapidly but are inefficient and quick to fatigue. Type IIa fibers are more resistant to fatigue than type IIx fibers due to a greater capacity for aerobic metabolism. Type IIa fibers are still far less aerobically efficient than type I fibers.
Fibrous joint
Joints that allow little to no movement such as the sutures of the skull.
Golgi tendon organ
Proprioceptors located in the tendons attached to extrafusal muscle fibers. Golgi tendon organs relay information regarding tension in the muscle and are though to protect against the development of excess tension in the muscle.
Hemoglobin
The iron-protein molecule carried by red blood cells. Hemoglobin transports oxygen as well as provides an acid-base buffer in the blood to regulate H+ ion concentration.
Hyaline cartilage
The smooth covering on the ends of articulating bones. (ESC p. 2)
H-Zone
The area in the center of the sarcomere containing only myosin filaments. The H-zone decreases during muscle contraction as actin slides over the myosin toward the center of the sarcomere.
I-Band
The area in two adjacent sarcomeres that contain only actin filaments.
Inferior
The attachment of a trunk muscle closer to the feet relative to the superior attachment. (ESC p. 3).
Intrafusal fiber
Modified muscle fibers that run parallel to normal extrafusal fibers and relay sensory information concerning muscle length.
Left bundle branch
Fibers in the heart that send the contraction impulse to the left ventricle.
Mitral valve
Heart valve that prevents blood flow from the left ventricle to the left atria.
Motor neuron
The nerve cell responsible for innervating the muscle fibers. Each motor neuron can innervate many muscle fibers, sometimes hundreds or even thousands.
Motor unit
The motor neuron and the muscle fibers it innervates.
Multiaxial joints
Joints such and the shoulder and hip ball-and-socket joints that allow movement around all three perpendicular axes that define space.
Muscle fiber
Long, cylindrical cells 50 to 100 micrometers in diameter (about the diameter of a human hair). The fibers have many nuclei situated on the periphery of the cell and have a striated appearance.
Muscle Spindle
Proprioceptors that consist of modified muscle fibers enclosed in a sheath of connective tissue. Muscle spindles provide information concerning the muscle length and rate of change in length.
Myocardium
Heart muscle tissue.
Myofibril
Small fibrils within the muscle fiber that contain the apparatus that contracts the muscle cell.
Myofilament
small strands of protein, primarily either myosin or actin, that are responsible for muscle contraction.
Myosin
a protein that makes up myosin filaments of about 16 nm in diameter. The myosin filament has a globular head, a hinge point, and a fibrous tail. Pairs of myosin filaments form cross-bridges, which interact with actin to produce muscular contractions.
Neuromuscular junction
The junction between the motor neuron and the fibers it innervates.
Parasympathetic nervous system
Component of the autonomic nervous system. Stimulation of the parasympathetic nervous system slows heart rate by slowing SA depolarization.
Perimysium
Connective tissue surrounding each fascicle.
Pleura
The membranes that envelope the lungs and lining of the chest walls.
Pleural pressure
The pressure in the narrow space between the chest wall pleura and the lung pleura.
Power stroke
The pulling action during muscle contraction. Power stroke results from the hydrolysis of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and phosphate. This reaction is catalyzed by the enzyme myosin adenosine triphosphatase (ATPase).
Proprioceptor
Specialized sensory receptors within joints, muscles, and tendons. Proprioceptors are sensitive to pressure and tension in the muscle and relay information about muscle dynamics to the nervous system. This process allows the CNS to maintain muscle tone and perform coordinated movements.
Proximal
The attachment of a limb muscle that is closer to the trunk. (ESC p. 3).
Pulmonary valve
Valve in the heart that prevents blood flow from the pulmonary artery into the right ventricle.
Purkinje fibers
Fibers in the heart that conduct heartbeat impulse to all parts of the ventricles.
P-Wave
Recordings of electrical depolarization in the heart. The P wave is generated by changes in electrical potential within cardiac muscle cells that depolarize the atria, resulting in contraction.
QRS Complex
Recording of depolarization in the heart resulting in ventricular contraction.
Red blood cell
The major component of blood that contains hemoglobin. Red blood cells transport oxygen as well as other processes such as catalyzing the reaction that facilitates carbon dioxide removal.
Repolarization
The process that occurs as ventricles recover from depolarization.
Right bundle branch
Fibers in the heart that send the contraction impulse to the right ventricle.
Sarcolemma
the membrane surrounding each muscle fiber. (ESC p. 4).
Sarcomere
The smallest contractile unit of skeletal muscle. In a relaxed fiber, sarcomeres average about 2.5 micrometers in diameter and are repeated the entire length of a muscle fiber. Actin and myosin filaments are arranged longitudinally in the sarcomere.
Sarcoplasm
the cytoplasm fluid inside the muscle fiber connotation protein filaments, other proteins, stored glycogen, fat particles, enzymes, and specialized organelles such as mitochondria and the sarcoplasmic reticulum. (ESC p. 4).
Sarcoplasmic reticulum
An intricate system of tubules that surround each myofibril and terminate as vesicles in the vicinity of the Z-lines. Calcium ions are stored in the vesicles.
Semilunar valves
Collective term for the aortic and pulmonary valves.
Sinoatrial (SA) node
Pacemaker of the heart where electrical impulses are initiated.
Sliding filament theory
The theory of muscle contraction that states that actin filaments at the end of each sarcomere slide inwards on myosin filaments, which pulls the Z-lines towards the center of the sarcomere, shortening the muscle fiber. As the actin slides over the myosin, the H-Zone and I-Band shrink. The myosin cross-bridges pull on the actin filaments and are responsible for the movement of the actin filament.
Slow-twitch fiber
Muscle fibers, specifically Type I fibers, with high aerobic efficiency but low maximum force output.
Superior
The attachment of a trunk muscle that is closer to the head relative to the inferior attachment.
Sympathetic nervous system
Component of the autonomic nervous system. Stimulation of the sympathetic nervous system increases the heart rate by accelerating the depolarization of the sinoatrial node.
Synovial fluid
The fluid enclosed inside the joint capsule.
Synovial joints
joints that allow considerable movement with low friction and large ranges of motion (i.e elbow and knee). Sport and exercise movements occur mostly around the synovial joints.
Systole
Ventricular contraction.
Tachycardia
heart rate above 100 beats/minute.
Tendon
Connective tissue that attaches the muscles to the bone periosteum. Muscle contractions pull on the tendon which in turn pulls on the bone.
Tetanus
The process that occurs when stimuli are delivered at such a high frequency that the muscle twitches fuse, resulting in the maximal amount of force a motor unit can develop.
Trachea
The first generation respiratory passage where the air is passed to the bronchi and ultimately the bronchioles for oxygenation by the lungs.
Tricuspid valve
Heart valve preventing blood flow from the right ventricle to the right atrium.
Tropomyosin
A protein that runs along the actin filament in the groove of the double helix. When calcium binds with troponin, a shift occurs in the tropomyosin that results in rapid attachments of the actin filament to the myosin cross
Troponin
A protein situated at regular intervals along the actin filament and has a high affinity for calcium ions. When calcium is released from the sarcoplasmic reticulum, it binds with the troponin.
T-tubule
Transverse tubules that run perpendicular to the sarcoplasmic reticulum and terminate in the vicinity of the Z-line between to vesicles. T-tubules run between outlying myofibrils and are contiguous with the sarcolemma at the cell surface. This results in the action potential reaching all depths of the muscle fiber nearly simultaneously.
T-wave
Recording of the electrical potential generated during repolarization in ventricular muscle.
Twitch
Brief contraction of muscle fibers that occurs when an action potential reaches the neuromuscular junction. To develop force, multiple twitches occur before the complete relaxation of the muscle fiber. When there is resistance (ie from an external weight) to the actin-myosin binding process, multiple twitches will occur back-to-back. The force from the twitches is additive. Multiple back-to-back twitches produce more force than a single twitch.
Type I fiber
Slow-twitch fibers with high efficiency and the ability for aerobic metabolism. Type I fibers are slower to produce force and have a lower maximum force output, but are incredibly efficient.
Type IIa fiber
Fast-twitch fiber with more endurance than Type IIx, slightly less maximum force production, and less endurance than type I fibers.
Type IIx fiber
Fast-twitch fibers that have the greatest ability to rapidly produce force but are the least efficient and least able to use aerobic metabolism compared to Type I and Type IIa fibers.
Uniaxial joints
joints such as the elbow that operate as hinges, essentially rotating around only one axis.
Vein
Tubes that transport blood back to the heart.
Venous system
System of tubes that returns blood from the muscles to the heart.
Ventricle
Chambers of the heart that receive blood from the atria and pump it either to the lungs (right ventricle) or the rest of the body (left ventricle).
Venule
Small tubes that collect blood from the capillaries and converge into the larger veins.
Vertebral column
vertebral bones separated by flexible disks that allow movement to occur. Vertebrae are grouped in the following: Seven cervical vertebrae (C1-C7), the twelve thoracic vertebrae (T1-T12), five lumbar vertebrae (L1-L5), five sacral vertebrae, which are fused together and make up the pelvis, and the three to five coccygeal vertebrae, which form a vestigial internal tail extending downward front the pelvis.
Z-line
A thin dark line running longitudinally through the I-band.
