final review Flashcards
Epimysium
surrounds entire muscle belly
Perimysium
surrounds bundles of fasicles
Endomysium
surrounds individual muscle fibers
Plasmalemma (cell membrane) [structure of muscle fiber]
fuses with tendon, conduction of AP, maintains pH, transports nutrients
Satellite cells [structure of muscle fiber]
muscle growth, development, response to injury/training
Sarcoplasm [structure of muscle fiber]
cytoplasm, assists with glycogen storage
Transerve (T-Tubules) [structure of muscle fiber]
extensions of the plasmalemma, carry AP deeper into muscle fiber
Sarcoplasmic reticulum (SR) [structure of muscle fiber]
Ca2+ storage
Myofibrils
muscle –> fascicle –> muscle fiber –> myofibril
Sarcomeres
basic contractile element of skeletal muscle, end to end for full myofibril length, distinctive striations
common boundary structure: z-disk
used for muscle contraction: shortening
Actin
thin filaments, shows up lighter under microscope, l-band contains only actin
Myosin
thick filaments, shows up darker under microscope, H-zone contains only myosin
Motor units
a- motor neurons innervate muscle fibers
Neuromuscular junction
site of communication between neuron and muscle
consists of synapse between motor neuron and muscle fiber
Excitation-Contraction
Coupling
- Action potential (AP) starts in the brain
- AP arrives at axon terminal of neuron, releases
acetylcholine (ACh) - ACh crosses synapse, binds to ACh receptors on
plasmalemma - AP travels down plasmalemma, T-tubules
- Triggers Ca2+ release from SR
- Ca2+ enables actin-myosin contraction
Relaxed state of muscles
- No actin-myosin interaction= no CB
- Myofilaments overlap a little
Contracted state of muscles
- Myosin head pulls actin toward sarcomere (power stroke)
- Filaments shorten
Sliding filament theory
After power stroke ends:
* Myosin detaches from active site
* Myosin head rotates back to original position
* Myosin attached to another active site farther down
Process will continue until:
* Z-disk reaches myosin filaments OR
* AP stops, Ca2+ gets pumped back into SR
Muscle Relaxation
AP ends, electrical stimulation of SR stops
Ca2+ pumped back into SR
* Stored until next AP arrives
* Requires ATP
Without Ca2+ , troponin & tropomyosin return to
resting conformation
* Covers binding site
* Prevents cross-bridge formation
Muscle fiber type I
slow twitch
Muscle fiber type II
fast twitch, fatigue quickly
type IIa- short, high intensity
type IIx- used for every day activities, short, explosive sprints
Pulmonary Circulation
- Sup/Inf Vena cavae
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary valve
- Pulmonary arteries
- Lungs
Systemic Circulation
- Lungs
- Pulmonary veins
- Left atria
- Mitral/bicuspid valve
- Left ventricle
- Aortic valve
- Aortabody
Myocardium
cardiac muscle, only has one fiber type (similar to type I), cardiac muscle fibers connected by intercalated discs
left ventricle
has most myocardium, must pump blood to entire body, thickest walls (hypertrophy)
Right coronary artery
- Supplies right side of the heart
- Divides into marginal, posterior interventricular
Left (main) coronary artery
- Supplied left side of the heart
- Divides into circumflex, anterior descending
Atherosclerosis
coronary artery disease
Intrinsic heart rate
100 bpm
SA node: cardiac conduction system
initiates contractional signal
* Pacemaker cells in upper posterior RA wall
* Signal spreads from SA node via RA/LA
* Stimulates atrial contraction
AV node: cardiac conduction system
delays/relays signal to ventricles
* Located in wall of RA, towards the center
* Delay allows RA/LA to contract before RV, LV
AV bundle: cardiac conduction system
relays signal to RV/LV
* Travels along interventricular septum
* Divides into right and left bundle branches
* Sends signal towards apex of heart
Purkinje fibers: cardiac conduction system
send signal into RV/LV
* Terminal branches of right and left bundle branches
* Spread throughout entire ventricular wall
* Completes ventricular contraction
Stroke volume (SV)
volume of blood pumped into one heartbeat
Ejection fraction (EF)
percent of EDV pumped
Cardiac output (Q)
Q = HR * SV
resting= 4.2-5.6 L/min
arteries
carry blood away from the heart
arterioles
control blood flow, feed capillaries
capillaries
site of nutrient and waste exchange
venules
collect blood from capillaries
veins
carry blood from venules back to the heart
systolic blood pressure (SBP)
highest pressure in artery (during systole)
diastolic pressure (DBP)
lowest pressure in artery (during diastole)
mean arterial pressure (MAP)
average pressure over entire cardiac cycle
smooth muscle
involuntary, hollow organs
skeletal muscle
voluntary, skeletal
cardiac muscle
involuntary, heart
respiratory system
carry O2 to and remove CO2 from all
body tissues
pulmonary ventilation
moving air in and out of lungs, lungs suspended by pleural sacs
pulmonary ventilation: inspiration
active process, diaphragm flattens, rib cage & sternum move up and out
expands volume of thoracic cavity and lungs
Boyles law
lung volumes increases –> intrapulmonary pressure decreases
pulmonary ventilation: expiration
passive process, lung volume decreases –> intrapulmonary pressure increases
Milking action from changing pressures assists
right atrial filling (respiratory pump)
pulmonary volumes
measured using spirometry
total lung capacity
sum of vital capacity and residual volume
vital capacity
greatest amount of air that can be expired after maximal inspiration
tidal volume
amount of air entering and leaving lungs with each normal breath
residual volume
amount of air remaining in the lungs after maximal expiration
pulmonary diffusion
gas exchange between alveoli and capillaries
Replenishes blood oxygen supply
Removes carbon dioxide from blood
respiratory membrane
Surface across which gases are exchanged
heart size with training
heart mass and LV volume increase
resting HR after training
– decrease Markedly (~1 beat/min per week of training)
– increase Parasympathetic, decrease sympathetic activity in heart
submaximal HR after training
decreased HR for same given absolute intensity
maximal HR after training
no change, decrease with age
cardiac output after training
no change at rest/submaximal
Maximal Q* increases considerably (due to increased SV)
cardiovascular adaptations that increase
blood flow to active muscle, capillarization, total blood volume, systolic BP at max
cardiovascular adaptations that decrease
blood flow to inactive regions, BP at given submaximal intensity, diastolic BP at max
muscular adaptations
increase size and # of type I fiber (II –> I) (IIx may perform more like IIa)
increase capillary supply
increase myoglobin
increase size and # of mitochondria
oxidative enzymes increase activity
metabolic adaptations
decrease lactate production, increase lactate clearance
resting and submaximal VO2 unchanged
increase max VO2
substrates
Fuel sources from which we make energy (adenosine
triphosphate [ATP])
Bioenergetics
- Process of converting substrates into energy
- Performed at cellular level
Metabolism:
chemical reactions in the body
carbohydrates
accessed the quickest (easy breakdown)
fat
efficient storage, prolonged & less intense exercise
protein
used the least for energy, during starvation
ATP-PCr
anaerobic, 100m, occurs in cytoplasm
glycolysis
anaerobic, 400-800m, occurs in cytoplasm
oxidative
aerobic (mile+), occurs in mitochondria
muscular strength
maximal force that a muscle or muscle
group can generate
muscular power
rate of performing work
muscular endurance
capacity to perform repeated muscle
contractions (or sustain a single contraction over
time)
FITT
frequency
intensity
time
type
aerobic power
rate of energy release by oxygen-
dependent metabolic processes
Maximal aerobic power: maximal capacity for
aerobic resynthesis of ATP
anaerobic power
rate of energy release by
oxygen-independent metabolic processes
* Maximal anaerobic power: maximal capacity of
anaerobic systems to produce ATP
principle of individuality
not everyone equal, genetics impact, variations in cell growth rates
principle of specificity
- Exercise adaptations specific to mode and
intensity of training - Training program must stress most relevant
physiological systems for given sport - Training adaptations highly specific to type of
activity, training volume, and intensity
principle of reversibility
- Use it or lose it
- Training –> improved strength and endurance
- Detraining reverses gains
principle of progressive overload
must increase demands on the body to make further improvements
principle of variation
systematically changes one or more variables to keep training challenging
exercise order
large muscle groups before small, multi-joint before
single joint, high intensity before low intensity
Free weights (constant resistance)
- Tax muscle extremes but not midrange
- Recruit supporting and stabilizing muscles
- Better for advanced weight lifters
Machines
- May involve variable resistance
- Safer, easier, more stable, better for novices
- Limit recruitment to targeted muscle groups
Threshold of training
Minimal level of exercise needed to achieve desired benefits
Target zone
- HRMAX= 220 bpm-age
- Target zone= 55-90% HRMAX
Exercise Physiology
- The study of the effects of exercise on the body
- Body’s responses and adaptations to exercise
Population served - Elite performers
- People of all ages and abilities
