L1;C1 Flashcards
There are two types of responses the body has with respect to exercise, what are they?
Acute- single bouts of exercise
Chronic- repeated exercise bouts, this chronic adaptation changes the body efficiency
There are two types of physiology that we are interested in, what are their names and give a brief description of them?
Exercise physiology-body function and structure is altered by chronic/acute bouts of PA
Sports physiology- concept of exercise phys to trained athletes and sports performance
What are the three types of muscles?
Skeletal
Smooth
Cardiac
What is a alpha motor neuron? What is a motor unit?
These are neurons that innervate many muscle fibres. Together the alpha motor neuron innervates all the fibres in itself.
A motor unit is the alpha motor neurons and all the fibres it innervates
Explain the following fibres:
Type I
Type IIa
Type IIx
Type I- slow oxidative fibre type. These are fatigue resistant, abundance of mitochondria and myoglobin. Appears black in pictures
Type IIa- fast twitch, oxidative, fatigue-able, appear white in photos. Has a low [] of Pi and is constantly fluctuating.
Type IIx- oxidative glycolic, fast twitch, fatigue-able, appears grey in photos. Has low [] of Pi and is constantly fluctuating.
What is a Magnetic Resonance Spectroscopy?
This determines fibre type based on biogenetic metabolites. This is a measurement of mitochondrial function and glycolysis.
Fibre types are sometimes ________ determined
Genetically
Fibre type is determined by the ________ neuron that innervates the muscle fibre
Alpha-motor
Fast Motor neurons—>__________
Slow motor neurons—> ________
Fast Motor neurons—> fast fibres
Slow motor neurons—> slow fibres
What can cause a shift in myosin isoforms?
Endurance training, strength, muscular inactivity.
Exercise decreases _______ _______ and increases _____ ______ muscle fibre types
Type IIx, type IIa
What occurs to motor units with aging?
Number of MU decreases in older adults, and the size of the MU increases
What happens when MU die, what do neighbouring MU perform?
The neighbouring MU reach out and innervate the other fibres. The total MU have decreases but they still are innervated.
What is the size principle with respect to recruitment of MU?
Motor units will be recruited from smallest to largest (Type I, Type IIa, Type IIx) but the intensity of the contraction predicts the amount of MU
What’s the relationship between force and frequency with muscles?
Faster the delivery of stimuli, the less time for twitch to recover. This means a higher tension/force occurs from increased stimulation.
Other than stimulation, what is force of a muscle also determined by?
The amount of cross bridges. Too little or too much overlap will not generate enough force.
Concentric shortening contraction=
Eccentric lengthening contraction=
Concentric shortening contraction= slow—>more force/ fast—> less force
Eccentric lengthening contraction= slow—>less force/ fast—> more force
Name the three types of connective tissues within muscles, starting with the outer most layer.
Epimysium- outer most layer of the muscle
Perimysium- surrounds each individual fascicles
Endomysium- surrounds each individual muscle fibre
What si the role fo the sarcoplasm and T tubules?
Sarcoplasm- the cytoplasm of muscle fibres that contain protein and matrix
T-tubules- extensive portion of the plasmalemma that interconnects myofibrils
What type of muscle fibre is recruited most frequently?
Type I
What are the percentages of recruitment of the muscle fibres?
Type I - 50%
Type IIa- 25%
Type IIx- 25%
