CSCS CH 1 Structure & Function of Body Systems Flashcards
Musculoskeletal system
consists of bones, joints, muscles, & tendons configured to allow the great variety of movements characteristics of human acitivty
Skeleton
muscle attachment points, to cause bony levels to enforce pushing and pulling forces from muscles.
Axial skeleton
consists of the skull, vertebral column, ribs, & sternum
Appendicular skeleton
includes the shoulder girdle; bones of the arm, wrist & hands. The pelvic girdle; bones of the legs, ankles, & feet.
Fibrous joints
allow virtually no movement; EX) sutures of the skull.
Cartilaginous joints
Allow limited movement; EX) intervertebral disks.
Synovial Joint
Allow considerable movement. EX) elbow & knee
Hyaline Cartilage
Articulating bone ends are covered in.
Synovial Fluid
The entire joint is enclosed in a capsule filled of
Uniaxial joints
Allows 1 axis of movement. EX) Hinge joint, elbow or knee
Biaxial Joints
Allows movement in 2 perpendicular axes. EX) ankle & wrist
multiaxial joints
Allows movement in all three perpendicular axes; EX ball-n-socket joint, hip or shoulder
Vertebral column make up
Vertebral bones separated by flexible disks that allow movement to occur 7 cervical 12 Thoracic 5 Lumbar 5 fused sacral 3 to 5 coccygeal
Epimysium
fibrous connective tissue, covers the body’s more than 430 skeletal muscles
tendon
connective tissue that attaches muscle to bone
Bone periosteum
specialized connective tissue covering all bones
proximal
closer to the trunk
distal
farther from the trunk
superior
closer to the head
inferior
closer to the feet
muscle fibers
muscle cells; long, cylindrical cells; Nuclei situated on periphery of the cell
Fasciculi
bundles of muscle fibers under the epimysium may consist of 150 fibers
perimysium
fasciculi bundle being surrounded by this connective tissue
endomysium
connective tissue that surrounds each muscle fiber of fasciculi
sarcolemma
encircled & is contiguous with endomysium; inside a fasciculus
Sarcoplasm
interior structure of a muscle fiber. Cytoplasm of a muscle fiber, contains contractile components; protein filaments, other proteins, stored glycogen, enzymes, fat particles, mitochondria, the sarcoplasmic reticulum. Surrounds the myofibril
myofibrils
within the sarcoplasm; contains apparatus that contracts the muscle cells (myofilaments actin and myosin)
myofilaments
where the sarcomere is located actin and myosin
motor neuron
nerve cell located in central nervous system (CNS)
neuromuscular junction
where the motor neuron & muscle fiber meet & is innervated (motor end plate)
motor unit
a motor neuron & the muscle fiber it innervates contract together when stimulated by motor neuron
cross-bridge
myosin thick head protrudes away from myosin filament & connects to, innervates with, actin thin.
sarcomere
Smallest contractile unit of the skeletal muscle
A-band
Dark; corresponds with the alignment of the myosin and actin attachment point
I-band
Light; corresponds with the areas in two adjacent sarcomeres that contain only actin filaments
Z-line
middle of the I-band (actin) & appears as a thin, dark line running longitudinally through the I-band
H-zone
Area in the center of the sarcomere where only myosin filaments are present
M-line
Center of the A band & sarcomere.
Action potential
An electrical nerve impulse. Arrives nearly simultaneously from surface to all depths of the muscle fibers. Calcium is thus released throughout the muscle, producing a coordinated contraction
Sliding-Filament theory
States that the actin filaments at each end of the sarcomere slide inward on myosin filaments, pulling the z-lines toward the center of the sarcomere & shortening the muscle fiber.
SFT; Resting Phase
Resting conditions, little calcium is present in the myofibrils (stored in sarcoplasmic reticulum) very few myosin cross-bridges are bound to actin.
SFT; Excitation-contraction coupling phase
Before myosin cross-bridges can flex, they must first attach to the actin filaments
troponin
A protein that is situated at regular intervals along the actin filaments & has a high affinity for calcium ions.
tropomyosin
protein molecule that runs the length of the actin filament in the groove of the double helix. The myosin cross-bridge attaches more rapidly.
SFT; contraction phase
when calcium binds to troponin
power stroke
The energy of pulling action hydrolysis (breakdown) of adenosine triphosphate (ATP) to Adenosine diphosphate (ADP) & phosphate (P), catalyzed by enzyme myosin adenosine triphosphate (ATPase).
SFT; Recharge phase
measurable muscle shortening transpires only when this sequence of events binding of calcium to troponin, coupling of the myosin, cross-bridge with actin, power stroke, dissociation of actin & myosin, & resetting of the myosin head position. Repeated over & over again.
SFT; Relaxation phase
Occurs when the stimulation of a motor nerve stops. Calcium is pumped back into the sarcoplasmic reticulum, prevents binding between actin & myosin filaments
Neuromuscular system
muscle fibers are innervated by motor neurons that transmit impulses in the form of electrochemical signals from the spinal cord to the muscles
Acetylocholine
Arrival of the action potential at the nerve terminal causes release of this neurotransmitter. It diffuses across the neuromuscular junction causing excitation of the sarcolemma
All-OR-none principle
All of the muscle fibers in the motor unit contract & develop force at the same time. If none contract than there is no contraction
Twitch
Each action potential traveling down a motor neuron results in a short period of activation of the muscle fibers within the motor unit.
Tentanus
The stimuli may be delivered at so high a frequency that the twitches begin to merge & eventually completely fuse. Maximal amount of force the motor unit can develop.
Fast-Twitch fibers
A motor unit that develops force & also relaxes rapidly & has a short twitch time. Type IIa & IIx
Slow-twitch fibers
A motor unit that develops force & relaxes slowly & has a long twitch time. Type I
Type I fibers
efficient & fatigue resistant & have a high capacity for aerobic energy supply; limited potential for rapid force development. Low myosin ATPase activity & low anaerobic power
Type II fibers
Inefficient & Fatigable & have low aerobic power; rapid force development high myosin ATPase activity & high an anaerobic power.
Type IIa
Have greater capacity for aerobic metabolism & more capillaries surrounding them. Great resistance to fatigue
Type IIx
Less capacity for aerobic metabolism & less capillaries surrounding. Less resistance to fatigue.
Proprioception
specialized sensory receptors located within joints, muscles, & tendons sensitive to pressure & tension
Muscle spindles
proprioceptors that consist of several modified muscle fibers enclosed in a sheath of connective tissue. Intra & extrafusal fibers.
Intrafusal fibers
muscle spindles-sensory receptors for muscle control & movement.
Extrafusal fibers
Build up the muscle mass, generate force & execute movements.
Golgi Tendon Organs (GTOs)
Proprioceptors located in tendons near the myotendinous junction & are in series, attached end to end with extrafusal muscle fibers. Activated when the tendon attached to an active muscle is stretched inhibitory process thought to provide a mechanism that protects against excessive tension
Atrium
chambers Left & right deliver blood into the left & right ventricles
Ventricle
Supply the main force for moving blood through the pulmonary & peripheral circulations. Let & Right ventricle
Tricuspid valve & mitral valve
Atrioventricular (AV) valves prevent the flow of blood from the ventricles back into the atria’s during ventricular contraction.
Systole
Ventricular contraction
Aortic valve & pulmonary valve
semilunar valves, prevent backflow from the aorta & pulmonary arteries into the ventricles during ventricular relaxation
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 the ventricles
atrioventricular (AV) bundle
conduct the impulse to the ventricles
Left & right bundle branch
conducts impulses to all parts of the ventricles
Purkinje fibers
continuation of the right bundle branch
myocardium
The heart muscle
autonomic nervous system
involuntary contractions from the Central Nervous system. Splits into sympathetic and parasympathetic nervous systems.
Sympathetic Nervous system
Fight or Flight. Causes depolarization of SA node to make heart beat faster.
Parasympathetic Nervous System
Rest or Digest. Slows the SA node. Slows the heart rate.
Bradycardia
Fewer than 60 beats/min
Tachycardia
more than 100 beats/min
Electrocardiogram (ECG)
electrical activity of the heart can be recorded at the surface of the body. A graphic representation of activity.
P-Wave
generated by the changes in the electrical potential of cardiac muscle cells that depolarize the atria & results in atrial contraction.
QRS complex
Q-wave, R-wave, & S-wave. Generated by the electrical potential that depolarized the ventricles & results in ventricular contraction.
T-wave
electrical potential generated as the ventricle recover from the state of depolarization
Repolarization
Occurs in ventricular muscle shortly after depolarization.
Arterial system
carries blood away from the heart to supply oxygenated blood to the body.
Venous system
Returns deoxygenated blood toward the heart
Arteries
rapidly transport blood pumped from the heart. Strong muscular walls
arterioles
Small branches of arteries. act as control vessels through which blood enter the capillaries.
capillaries
facilitate exchange of oxygen, fluid, nutrients, electrolytes, hormones, & other substances between the blood & the interstitial fluid in the various tissue of the body. Very thin & very permeable.
Venules
collect blood from the capillaries & gradually converge into large veins
Veins
transport blood back to the heart. Low pressure, thin walls, although muscular.
Hemoglobin
transport of oxygen, iron-protein molecule carried by the red blood cells.
Red blood cells
Major component of the blood, contains carbonic anhydrase, catalyzes carbon dioxide & water for carbon removal.
Respiratory System
Primary Function of the respiratory system is the basic exchange of oxygen & carbon dioxide.
Trachea
first-generation respiratory passage
Bronchi
second-generation respiratory passage.
Bronchioles
The next generation of branches.
Alveoli
Where gases are exchanged in respiration.
Pleural pressure
pressure in the narrow space between the lung pleura & the chest wall pleura.
Pleura
Membranes enveloping the lungs & lining the chest wall.
Alveolar pressure
pressure inside the alveoli when the glottis is open & no air is flowing into or out of the lungs.
Diffusion
simple random motion of molecules moving in opposite directions through the alveolar capillary membrane.
