Exam 1 Flashcards
the study of how the body structure and function are altered by exposure to acute and chronic bouts of exercise
Exercise physiology
the application of the concepts of exercise physiology to training athletes and enhancing sport performance
Sport physiology
the study of the effects of the environment on the function of the body
Environmental physiology
a single bout of exercise
Acute exercise
a physiological change that occurs when the body is exposed to repeated exercise bouts over weeks or months. these changes generally improve the body’s efficiency at rest and during exercise
Chronic adaption
tests the same subjects and compares results over time
Longitudinal research
collects data from a diverse population and compares groups in that population
Cross-sectional research
single alpha-motor neuron + all fibers it innervates
more operating motor units = more contractile force
Motor unit
site of communication between neuron and muscle
consists of synapse between alpha-motor neuron and muscle fiber
Neuromuscular junction
outer connective tissue covering
surrounds the entire muscle and functions to hold it together and give it shape
Epimysium
a small bundle of muscle fibers wrapped in a connective tissue sheath within a muscle
fascicle
the connective tissue sheath surrounding each muscle fascicle
Perimysium
Muscle fiber contraction
- Action potential (AP) starts in the brain
- AP arrives at axon terminal release ACh
- ACh crosses synapse, binds to ACh receptors on plasmalemma
- AP travels down plasmalemma, T-tubules
- Triggers Ca2+ release from sarcoplasmic reticulum
- Ca2+ enables actin-myosin contraction
- Myosin head attaches to binding site on actin
- Energy from release of ADP + Pi causes the power stroke
- ATP attaches to myosin head , and causes the disconnect
- ATP is hydrolyzed to ADP and Pi and energy is restored
- Cessation of action potential = return on Ca to TC via SR, and binding sites are covered
a sheath of connective tissue that covers each muscle fiber
endomysium
No actin-myosin interaction at binding site
myofilaments overlap a little
Relaxed State
Myosin head pulls actin toward sarcomere center (power stroke)
filaments slide past each other
sarcomeres, myofibrils, muscle fibers all shorten
Contracted state
an individual muscle fiber is surrounded by a plasma membrane
plasmalemma
a muscle fiber’s cell membrane
sarcolemma
gelatin-like substance that fills the spaces within the myofibrils
sarcoplasm
extensions of the plasmalemma that pass laterally through the muscle fiber
T-tubules
longitudinal network of tubules
Sarcoplasmic reticulum
the basic functional until of a myofibril and the basic contractile unit of muscles
sarcomere
order of recruitment of motor units directly related to size of alpha-motor neuron
Size principle
optimal sarcomere length = optimal overlap
too short or too stretched = little or no force develops
Length-tension relationship
maximal force development decreases at higher speeds
Concentric
maximal force development increases at higher speeds
Eccentric
the protruding part of a myosin filament. It includes the myosin head, which binds to an active site on an actin filament to produce a power stroke that causes the filaments to slide across each other
Myosin cross-bridge
the tilting of the myosin head, caused by a strong intermolecular attraction between the myosin cross-bridge and the myosin head, that causes the actin and myosin filaments to slide across each other
Power stroke
explaining muscle action: a myosin cross-bridge attaches to an actin filament, and then the power stroke drags the two filaments past one another
Sliding filament theory
conscious control of skeletal muscle movement
Primary motor cortex (frontal lobe)
clusters of cell bodies deep in cerebral cortex
help initiate sustained or repetitive movements
walking, running, posture, muscle tone
Basal ganglia (cerebral white matter)
Maintains homeostasis, regulates internal environment
Neuroendocrine control, appetite, food intake, thirst/fluid balance, sleep, BP, HR, breathing, body temp
Hypothalamus
Controls rapid, complex movements
coordinates timing, sequence of movements,
compares actual to intended movements and initiates correction
accounts for body position and muscle status
receives input from the primary motor cortex, helps execute and refine movements
Cerebellum
regulates visceral activity
Autonomic
stimulates skeletal muscle activity
Somatic
Fight or Flight
Increases:
HR, BP, blood flow to muscles, bronchodilation, metabolic rate, glucose levels, FFA levels, mental activity
Sympathetic Nervous System
Rest and digest
Increases digestion and urination
conservation of energy
decreases HR and diameter of vessels and airways
Parasympathetic Nervous System
localized changes in the membrane potential, either depolarization or hyperpolarization
triggered by a change in the neuron’s environment
Graded potentials
site of action potential transmission from the axon terminals of one neuron to the dendrites or soma of another
Synapse
primary neurotransmitter for the motor neurons that innervate skeletal muscle as well as for most parasympathetic autonomic neruons
Acetylcholine
Instant, preprogrammed response to a given stimulus
response to stimulus identical each time
occurs before conscious awareness
Motor reflex
the process by which protein or fat is converted into glucose
Gluconeogensis
the process of converting protein into fatty acids
Lipogenesis
an enzyme found early in a metabolic pathway that determines the rate of the pathway
Rate-limiting enzyme
the enzyme that facilitates the breakdown of PCr to creatine and Pi
Creatine kinase
an energy-rich compound that plays a critical role in providing energy for muscle action by maintaining ATP concentration
Phosphocreatine (PCr)
VCO2/VO2
Respiratory Exchange Ratio (RER)
difference between oxygen required for a given exercise intensity and the actual oxygen consumption
Oxygen deficit
the volume of oxygen consumed during minutes immediately after exercise ceases that is above that normally consumed at rest
Excess Postexercise Oxygen Consumption (EPOC)
the point at which blood lactate begins to substantially accumulate above resting concentrations during exercise of increasing intensity
(point where blood lactate first increases above resting)
Lactate threshold
anchoring points of contact for contractile proteins
Sarcomere Z-disks
