Exam 2 Flashcards
Metabolic rate
rate of heat production
Metabolism
The sum total of processes occurring in a living organism
What indicates a high metabolic capacity?
high capacity to consume and utilize O2
Transduction
Conversion of chemical energy to other forms of energy
Types of cellular work
mechanical
synthetic
chemical
osmotic
electrical
Basic unit of heat measurement
Calorie (heat required to raise one gram of water one degree)
How many calories in a kilocalorie?
1000
Indirect calorimetry measures what?
Oxygen consumption
What is a bomb calorimeter?
A device when food is ignited and burned in O2 under pressure. Determines the heat of combustion.
Respiratory Quotient (RQ)
VCO2/VO2
Why are direct calorimeters not usually used during exercise?
Expensive
Heat generated from ergometer may exceed that of the subject
Body temp increases because not all heat is liberated from body
EPOC
“O2 Debt”
Excess post-exercise O2 Consumption
Action potential
Brief electrical signal that travels along the membrane of a neuron or muscle fiber initiating a contraction in muscle
Aerobic capacity
The body’s ability to consume and utilize oxygen for energy production
Anaerobic threshold
The exercise intensity at which lactate production exceeds lactate clearance, leading to a rapid increase in blood lactate levels
Basal metabolic rate (bmr)
The minimum energy expenditure required to sustain vital bodily functions at rest
Calorimeter
The measurement of heat production or energy expenditure
Concentric contraction
Muscle shortening during a contraction
Cross-bridge
Temporary attachment between myosin and actin filaments during muscle contraction
Eccentric contraction
Muscle lengthening during a contraction
Energy expenditure
Amount of energy used by the body
Excitation-contraction coupling
The sequence of events linking the electrical excitation of a muscle fiber to its contraction
Fiber type
The classification of muscle fibers based on their contractile and metabolic properties
Golgi tendon organ
Sensory receptors in tendons that detect muscle tension
Hyperplasia
An increase in the number of muscle fibers
Hypertrophy
An increase in the size of muscle fibers
Isometric contraction
Muscle contra Aton without a change in muscle length
Isotonic contraction
Muscle contraction with a change in muscle length under constant tension
Motor neuron
A nerve cell that transmits signals from the brain or spinal cord to muscle fibers
Motor unit
A motor neuron and all the muscle fibers it innovates
Muscle fiber
Single muscle cell
Muscle fiber
Single muscle cell
Muscle plasticity
The ability of muscle fibers to adapt their structure and function in response to various stimuli (training, disuse)
Myofibril
A cylindrical structure within muscle fibers that contains contractile proteins
Myofilament
The protein filaments within myofibrils, composed primarily of actin and myosin
Oxygen consumption ( vo2)
Volume of oxygen consumed by the body
Excess post exercise oxygen consumption (epoc)
Increased rate of oxygen you body consumes after exercise
Respiratory exchange ratio
Ratio of carbon dioxide produced to oxygen consumed during metabolism, providing an indication of fuel utilization
Sarcolemma
The plasma membrane of a muscle fiber
Sarcomere
The basic contractile unit of a muscle fiber
Sarcoplasmic reticulum
A network of membranes within muscle fibers that stores and releases calcium ions
Size principle
The principle stating that motor units are recruited in order of increasing size, from smallest to largest
Sliding filament theory
Explains muscle contraction as a result of the sliding of thin (actin) filaments past thick (myosin) filaments
Summation
The additive effect of multiple muscle twitches
Tetanus
A sustained muscle contraction evoked by a high frequency of stimulation
Twitch
A single, brief contraction of a muscle fiber
Ventilatory threshold
The paint during exercise at which ventilation increases disproportionately to oxygen consumption
VO2 Max
. Max volume of oxygen a person can consume during intense exercise, reflecting their aerobic capacity
