EXAM #1 Flashcards
Skeletal System:
- Composed of _ in the adult body
- Provides leverage, support, and protection
- Pulled on by muscles to allow the body to push or pull against external objects
206 bones
Skeletal System:
Consists of the skull, vertebral column (C1-coccyx), ribs, and sternum
Axial
Skeletal System:
Consists of shoulder girdle;
bones of the arms, wrists, hands, and pelvic girdle; and bones of the legs, ankles, and feet
Appendicular
Types of Joints
- Fibrous
- Cartilaginous
- Synovial
- Uniaxial
- Biaxial
- Multiaxial
Types of Joints:
Junctions of bones
Joint
Types of Joints:
Allow virtually no movement
– Example: Sutures of the skull
Fibrous
Types of Joints:
Allow limited movement
– Example: Intervertebral
Cartilaginous
Types of Joints:
Allow considerable movement
– Example: Elbows and knees
Synovial
Types of Joints:
Operate as a hinge, rotate about one axis
– Example: Elbow
Uniaxial
Types of Joints:
Operate in two perpendicular axes
– Example: Ankle and wrist
Biaxial
Types of Joints:
Allow movement in all three axes
– Example: Shoulder and hip
Multiaxial
Vertebral Column:
Vertebral bones separated by _ that allow for movement
flexible disks
Vertebral Column:
– Cervical vertebrae (neck region): _
7
Vertebral Column:
– Thoracic vertebrae (upper back): _
12
Vertebral Column:
– Lumbar vertebrae (lower back): _
5
Vertebral Column:
– Sacral vertebrae (make up rear of pelvis): _
5
Vertebral Column:
– Coccygeal vertebrae (form vestigial tail extending
down from the pelvis): _
3-5
Motor Unit:
- A motor unit consists
of a _ and the muscle fibers it innervates.
- There are typically
several hundred _ in a single motor unit.
- motor neuron
- muscle fibers
A
Dendrites
B
Nucleus
C
Axon
D
Myelin sheath
E
Node of Ranvier
F
Neuromuscular junction
The discharge of an action potential from a motor nerve signals the release of _ from the sarcoplasmic reticulum into the _, causing tension development in muscle
- calcium
- myofibril
Muscular system:
- 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 and thus shortening the muscle fiber
Sliding-filament theory of muscular contraction
Contraction of a Myofibril:
(a) In stretched muscle the I-bands and H-zone are
_, and there is _ force potential due to reduced crossbridge–actin alignment.
- elongated
- low
Contraction of a Myofibril:
– (b) When muscle contracts (here partially), the
I-bands and H-zone are _.
shortened
Contraction of a Myofibril:
– (c) With completely _ muscle, there is _ force potential due to reduced crossbridge–actin
alignment.
- contracted
- low
Muscular system:
Sliding-filament theory of muscular contraction
– Resting phase
– Excitation–contraction coupling phase
– Contraction phase
– Recharge phase
– Relaxation phase
The number of crossbridges that are formed between actin and myosin at any instant in time dictates the _ of a muscle
force production
_ are necessary for
crossbridge cycling with actin and myosin filaments
Calcium and ATP
Neuromuscular system:
Activation of muscles
- The extent of control of a muscle depends on the
number of _ within each motor unit.
muscle fibers
Neuromuscular system:
Activation of muscles
– Muscles that function with _ may have as few as one muscle fiber per motor neuron
great precision
Neuromuscular system:
Activation of muscles
– Muscles that require _ may have several hundred fibers served by one motor neuron
less precision
All of the muscle fibers in the motor unit contract and develop force at the same time.
- There is no evidence that a motor neuron stimulus causes only some of the fibers to contract.
- Similarly, a stronger action potential cannot produce a stronger contraction
all-or-none principle
Twitch, twitch summation, and tetanus of a Motor unit:
Single twitch = _
a
Twitch, twitch summation, and tetanus of a Motor unit:
Force resulting from summation of two twitches = _
b
Twitch, twitch summation, and tetanus of a Motor unit:
Unfused tetanus = _
c
Twitch, twitch summation, and tetanus of a Motor unit:
Fused tetanus = _
d
Neuromuscular system:
Muscle fiber types
– Type I (slow-twitch)
– Type IIa (intermediate fiber)
– Type IIb (fastest twitch)
– Type IIx (fast-twitch)
Neuromuscular system:
Muscle fiber types
- _ (slow-twitch)
Type I
Neuromuscular system:
Muscle fiber types
- _ (intermediate fiber)
Type IIa
Neuromuscular system:
Muscle fiber types
- _ (fastest twitch)
Type IIb
Neuromuscular system:
Muscle fiber types
- _ (fast-twitch)
Type IIx
Motor units are composed of _ with specific morphological and
physiological characteristics that determine their functional capacity
muscle fibers
Neuromuscular system:
Motor unit recruitment patterns during exercise
- The force output of a muscle can be varied through change in the _ of individual motor units or change in the _ motor units
- frequency of activation
- number of activated
_ are specialized sensory
receptors that provide the central nervous system with information needed to maintain muscle tone and perform complex coordinated movements.
Proprioceptors
Proprioception:
Muscle spindles
- When a muscle is stretched, deformation of the muscle spindle activates the _, which sends an impulse to the _, where it synapses with a motor neuron, causing the muscle to contract
- sensory neuron
- spinal cord
Proprioception:
_ are proprioceptors located in tendons near the myotendinous junction.
- They occur in series (i.e., attached end to end) with extrafusal muscle fibers
Golgi tendon organs
Proprioception:
Golgi tendon organs
- When an _ is placed on the muscle, discharge of the GTO occurs.
extremely heavy load
Proprioception:
Golgi tendon organs
– The sensory neuron of the GTO activates an _ in the spinal cord, which in turn synapses with and inhibits a motor neuron serving the same muscle
inhibitory interneuron
Neuromuscular system:
How can athletes improve force production?
- Incorporate phases of training that use _ in order to optimize neural recruitment
heavier loads
Neuromuscular system:
How can athletes improve force production?
- Increase the _ of muscles
involved in the desired activity
cross-sectional area
Neuromuscular system:
How can athletes improve force production?
- Perform _ exercises that can be done with more explosive actions to optimize fast-twitch muscle recruitment
multi-muscle, multi-joint
Cardiovascular system:
The _ is a muscular organ made up of two interconnected but separate pumps.
- The right ventricle pumps blood to the lungs.
- The left ventricle pumps blood to the rest of the body
heart
Cardiovascular system:
Heart
- Controls the mechanical contraction of the heart
Conduction system
Cardiac conduction:
Rhythmicity and conduction properties of myocardium
– Influenced by cardiovascular center of _
medulla
Cardiac conduction:
Rhythmicity and conduction properties of myocardium
– Signals transmitted through _ nervous systems
sympathetic and
parasympathetic
Cardiac conduction:
Rhythmicity and conduction properties of myocardium
– _ (<60 beats/min)
Bradycardia
Cardiac conduction:
Rhythmicity and conduction properties of myocardium
– _ (>100 beats/min)
Tachycardia
Cardiovascular system:
Heart
- Recorded at the surface of the body
- A graphic representation of the electrical activity of the heart
Electrocardiogram
Cardiovascular system:
EKG
- Atrial contraction = _
P
Cardiovascular system:
EKG
- Ventricle contraction = _
QRS
Cardiovascular system:
EKG
- Repolarization = _
T
Cardiovascular system:
Blood vessels
- Operate in a _ system.
closed-circuit
Cardiovascular system:
Blood vessels
- The arterial system carries blood _ from the
heart.
away
Cardiovascular system:
Blood vessels
- The venous system returns blood _ the heart
toward
Cardiovascular system:
Blood
- Hemoglobin transports oxygen and serves as an
_
acid–base buffer
Cardiovascular system:
Blood
- Red blood cells facilitate _ removal
carbon dioxide
The cardiovascular system _ while helping to maintain the environment for all the body’s functions
transports nutrients and removes waste products
- The blood transports oxygen from the lungs
to the tissues for use in _; - and it transports carbon dioxide from the tissues to the lungs, where it is _
- cellular metabolism
- removed from the body
Respiratory system:
The primary function of the respiratory system is the basic exchange of oxygen and carbon dioxide
Exchange of respiratory gases
Respiratory system:
- The process of diffusion is a simple random motion
of molecules moving in opposite directions through
the alveolar capillary membrane
Exchange of respiratory gases
The mechanisms through which components interact to create movement
Biomechanics
System of muscles enables the skeleton to move
skeletal musculature
Skeletal musculature:
Proximal (toward the center of the body) attachment
Origin
Skeletal musculature:
Distal (away from the center of the body) attachment
Insertion
The muscle most directly involved in bringing about a movement; also called the prime mover
Agonist
A muscle that can slow down or stop the movement
Antagonist
A muscle that assists indirectly in a movement
synergist
Lever:
_ = force applied to the lever
FA
Lever:
_ = moment arm of the
applied force
MAF
Lever:
_ = force resisting the lever’s rotation
FR
Lever:
_ = moment arm of the resistive force
MRF
Lever:
The _ applies a force on the object equal in magnitude to but opposite in direction from FR.
lever
The ratio of the moment arm through which an applied force acts to that through which a resistive force acts
Mechanical advantage
Mechanical advantage:
Greater than 1.0 means a person can _ than the resistive force to produce an equal amount of torque
apply less (muscle) force
Mechanical advantage:
Less than 1.0 means a person must _ than the amount of resistive force present, creating a disadvantage for the muscle
apply greater (muscle) force
A lever for which the muscle
force and resistive force act on opposite sides of the fulcrum
First-class lever
A lever for which the muscle force and resistive force act on the same side of the fulcrum.
- With the muscle force acting through a moment arm longer than that through which the resistive
force acts.
- Due to the muscle’s mechanical advantage, the
required muscle force is smaller than the resistive force
second-class lever
Example of a second class lever
Standing calf raise (plantar flexion against resistance)
A lever for which the muscle
force and resistive force act on the same side of the fulcrum.
- With the muscle force acting through a moment
arm shorter than that through which the resistive
force acts.
- The mechanical advantage is thus less than 1.0, so the muscle force has to be greater than the resistive force to produce torque equal to that produced by the resistive force
third-class lever
Example of a third class lever
Bicep curl (Elbow flexion against resistance)
Mechanical advantage:
The patella _ the mechanical advantage of the quadriceps muscle group by maintaining the quadriceps tendon’s distance from the knee’s axis of rotation
increases
Mechanical advantage:
When the moment arm (M) is shorter, there is _
less mechanical advantage
Most of the skeletal muscles operate at a
considerable _
mechanical disadvantage
Most of the skeletal muscles operate at a
considerable mechanical disadvantage.
- Thus, during sports and other physical activities, forces in the _ than those exerted by the hands or feet on external objects or the ground
muscles and tendons are much higher
Tendon insertion:
Tendon insertion farther from the joint center results
in the ability to _
lift heavier weights
Tendon insertion:
Tendon insertion farther from the joint center results
in the ability to lift heavier weights.
- This arrangement results in a loss of maximum _
- This arrangement reduces the muscle’s _ during faster movements
- speed
- force capability
Anatomical planes:
The _ slices the body into left–right sections
sagittal plane
Anatomical planes:
The _ slices the body into front–back sections
frontal plane
Anatomical planes:
The _ slices the body into upper–lower sections
transverse plane
The capacity to exert maximal force
strength
The product of force exerted on an object and
the distance the object moves in the direction the
force is exerted
work
work =
force x distance
The time rate of doing work
power
power = _
Work/Time (FxD/T)
Human strength & power:
Work performed on an object by muscle force with the object moving a measurable distance and speed as a result
positive work and power
Human strength & power:
- Work performed on, rather than by, a muscle
- Occurs during eccentric muscle actions
Negative work
Biomechanical factors in human strength:
- Recruitment affects maximal force output by determining which and how many motor units are involved in a muscle
contraction
- Rate coding affects maximal force output by determining the rate at which the motor units are fired
Neural control
Biomechanical factors in human strength:
In general, the larger the cross-sectional area, the greater force capabilities
Muscle cross-sectional area
Biomechanical factors in human strength:
- Pennate muscle
- Angle of pennation
arrangement of muscle fibers
Biomechanical factors in human strength:
A muscle with fibers that align obliquely with the tendon, creating a featherlike arrangement
Pennate muscle
Biomechanical factors in human strength:
The angle between the muscle fibers and an imaginary line between the muscle’s origin and
insertion; 0°corresponds to no pennation
angle of pennation
Biomechanical factors in human strength:
- Actin and myosin filaments lie next to each other
- A maximal number of potential crossbridge sites are available
- The muscle can generate the greatest force
Muscle length (at resting length)
Biomechanical factors in human strength:
- A smaller proportion of the actin and myosin filaments lie next to each other
- Fewer potential crossbridge sites are available
- The muscle cannot generate as much force
Muscle length (when stretched)
Biomechanical factors in human strength:
- The actin filaments overlap
- The number of crossbridge sites is reduced
- There is decreased force generation capability
Muscle length (when contracted)
Muscle length & actin/myosin interaction:
Muscle force capability is
greatest when the muscle is at _ because of increased opportunity for actin-myosin crossbridges
its resting length
Biomechanical factors in human strength:
Amount of torque depends on force versus muscle length, leverage, type of exercise, the body joint in question, the muscles used at that joint, and the speed of contraction
Joint angle
Biomechanical factors in human strength:
Nonlinear, but in general, the force capability of muscle declines as the velocity of contraction increases
Muscle contraction velocity
Biomechanical factors in human strength:
There are three types of muscle action
- Concentric, Eccentric and Isometric
joint angular velocity
Biomechanical factors in human strength:
- The muscle shortens because the contractile force is greater than the resistive force.
- The forces generated
within the muscle and acting to shorten it are
greater than the external forces acting at its tendons to stretch it
Concentric/myometric muscle action
Biomechanical factors in human strength:
- The muscle lengthens because the contractile force is less than the resistive force.
- The forces generated within the muscle and acting to shorten it are less than the external forces acting at its tendons to stretch it
eccentric muscle action
Biomechanical factors in human strength:
- The muscle length does not change, because the contractile force is equal to the resistive force.
- The forces generated within the muscle and acting to shorten it are equal to the external forces acting at its tendons to stretch it
Isometric muscle action
Biomechanical factors in human strength:
- In sprinting and jumping, the ratio directly reflects an
athlete’s ability to accelerate his or her body.
- In sports involving weight classification, the ratio helps determine when strength is highest relative to that of other athletes in the weight class
strength-to-mass ratio
Biomechanical factors in human strength:
- As body size increases, body mass increases more rapidly than does muscle strength.
- Given constant body proportions, the smaller athlete has a higher strength-to-mass ratio than does the larger athlete
Body size
In sport activities such as sprinting and jumping, the ratio of the strength of the
muscles involved in the movement to the mass of the body parts being accelerated is critical
- Thus, the _ an athlete’s ability to accelerate his or her body
strength-to-mass ratio directly reflects
Sources of resistance to muscle contraction:
Gravity
- Applications to resistance training
– When the weight is horizontally closer to the joint, it exerts _
less resistive torque
Sources of resistance to muscle contraction:
Gravity
- Applications to resistance training
– When the weight is horizontally farther from a joint, it exerts _
more resistive torque
Sources of resistance to muscle contraction
Gravity
_ can affect the resistive
torque pattern during an exercise and can shift stress among muscle groups
Exercise technique
Sources of resistance to muscle contraction:
- Though the force of gravity acts only downward,
_ can act in any direction
– However, upward or lateral acceleration of the
weight requires additional force
Inertial force
Sources of resistance to muscle contraction:
- _ is the resistive force encountered when one attempts to move an object while it is pressed
against another object
Friction
Sources of resistance to muscle contraction:
- Fluid resistance is the resistive force encountered by an object moving through a fluid (liquid or gas), or by a fluid moving past or around an object or through an opening
Fluid resistance
Sources of resistance to muscle contraction:
- The more an elastic component is stretched, the greater the resistance
Elasticity
Three basic energy systems exist in muscle cells to replenish ATP
- Phosphagen system – ATP/PC
- Glycolysis
- Oxidative system – Oxidative Phosporlyation
Energy systems in muscle cells to replenish ATP:
Phosphagen system – ATP/PC, _
0-6 seconds
Energy systems in muscle cells to replenish ATP:
Glycolysis - _
30 seconds to 2 min
Energy systems in muscle cells to replenish ATP:
Oxidative system – Oxidative Phosporlyation, _
2 min to hrs
Biological Energy Systems:
- Provides ATP primarily for short-term, high-intensity
activities (e.g., resistance training and sprinting) and
is active at the start of all exercise regardless of
intensity
– Creatine kinase catalyzes the synthesis of ATP from
PCR/CP and ADP
Phosphagen system
Biological Energy Systems:
Phosphagen system
- ATP stores
– The body does not store enough ATP for _
– Some ATP is needed for basic cellular function.
– The phosphagen system uses the _
reaction to maintain the concentration of ATP.
– The phosphagen system replenishes ATP rapidly
- exercise
- creatine kinase
Biological Energy Systems:
Glycolysis
- The end result of glycolysis (pyruvate) may proceed
in one of two directions:
(1) Pyruvate can be converted to lactate
(2) Pyruvate can be shuttled into the mitochondria
Biological Energy Systems:
Glycolysis
(1) Pyruvate can be converted to lactate.
- ATP resynthesis occurs at a faster rate but is limited in
duration.
- This process is sometimes called _
anaerobic glycolysis (or fast glycolysis)
Biological Energy Systems:
Glycolysis
(2) Pyruvate can be shuttled into the mitochondria.
- When pyruvate is shuttled into the mitochondria to undergo the Krebs cycle, the ATP resynthesis rate is slower, but it can occur for a longer duration if the exercise intensity is
low enough.
- This process is often referred to as _
aerobic glycolysis (or
slow glycolysis)
Biological Energy Systems:
Control of glycolysis
- Stimulated by high concentrations of _ and by a slight decrease in pH and AMP
ADP, Pi, and ammonia
Biological Energy Systems:
Control of glycolysis
- Inhibited by markedly lower _
pH, ATP, CP, citrate, and free fatty acids
Biological Energy Systems:
Control of glycolysis
- Also affected by hexokinase, _, and
pyruvate kinase
phosphofructokinase
Biological Energy Systems:
Glycolysis
- _ represents an increasing reliance on anaerobic mechanisms
- LT is often used as a marker of the _
- Lactate threshold (LT)
- anaerobic threshold
The exercise intensity or relative intensity at which blood lactate begins an abrupt increase above the baseline concentration
Lactate threshold (LT)
Biological Energy Systems:
Glycolysis
- _ of maximal oxygen uptake in untrained individuals and at 70% to 80% in aerobically trained athletes
Lactate Threshold begins at 50% to 60%
Biological Energy Systems:
- Primary source of ATP at rest and during low-intensity activities
- Uses primarily carbohydrates and fats as substrates
Oxidative (aerobic) system
Biological Energy Systems:
Glucose and glycogen oxidation
– Metabolism of blood glucose and muscle glycogen begins with _ and leads to the Krebs cycle
glycolysis
Biological Energy Systems:
Triglycerides stored in fat cells can be broken down
by hormone-sensitive lipase
- This releases free fatty acids from the fat cells into the blood, where they
can circulate and enter muscle fibers
Fat oxidation
Fat oxidation
_ enter the mitochondria, are broken down, and form acetyl-CoA and hydrogen protons.
- The acetyl-CoA enters the Krebs cycle.
- The hydrogen atoms are carried by NADH and FADH2 to the electron transport chain
Free fatty acids
Biological Energy Systems:
- Protein can be a significant source of energy for
most activities.
- Protein is broken down into amino acids, and the
amino acids are converted into glucose, pyruvate, or
various Krebs cycle intermediates to produce ATP
Protein oxidation
Biological Energy Systems:
Control of the oxidative (aerobic) system
- Isocitrate dehydrogenase is stimulated by _
ADP and inhibited by ATP
Biological Energy Systems:
Control of the oxidative (aerobic) system
- The ETC is stimulated by _
ADP and inhibited by ATP
Biological Energy Systems:
Control of the oxidative (aerobic) system
– The rate of the TCA/Krebs cycle is reduced if NAD+
and FAD2+ are _ to
accept hydrogen
not available in sufficient quantities
The extent to which each of the three energy
systems contributes to ATP production depends primarily on the_ and secondarily on the _
- At no time, during either exercise or rest, does any single energy system provide the complete supply of energy
- intensity of muscular activity
- duration
Substrate depletion and repletion:
_ can decrease markedly (50-70%) during the first stage (5-30 seconds) of high-intensity exercise and can be almost eliminated as a result of very intense exercise to exhaustion
Creatine phosphate
Substrate depletion and repletion:
Post exercise phosphagen repletion can occur in a
relatively short period; complete re-synthesis of ATP appears to occur within 3 to 5 minutes, and
complete _
creatine phosphate re-synthesis can occur within 8 minutes
Substrate depletion and repletion:
The rate of glycogen depletion is related to _
- At relative intensities of exercise above 60% of maximal oxygen uptake, muscle glycogen becomes an increasingly
important energy substrate; the entire glycogen content of some muscle cells can become depleted during exercise
exercise intensity
Substrate depletion and repletion:
Repletion of muscle glycogen during recovery is
related to postexercise carbohydrate ingestion.
- Repletion appears to be optimal if _ is ingested
every 2 hours following exercise
0.7 to 3.0 g of
carbohydrate per kilogram of body weight
The use of appropriate exercise intensities and rest intervals allows for the “selection” of specific energy systems during training and results in _ for specific athletic events with various metabolic demands
more efficient and productive regimens
Metabolic specificity of training:
Emphasizes bioenergetic adaptations for a more
efficient energy transfer within the metabolic
pathways by using predetermined intervals of
exercise and rest periods.
- Much more training can be accomplished at higher
intensities
interval training
Metabolic specificity of training:
High-intensity interval training (HIIT)
– Suggested work-to-rest ratios _
> 1:1
