L1;C1

Question 1

There are two types of responses the body has with respect to exercise, what are they?

Answer 1

Acute- single bouts of exercise

Chronic- repeated exercise bouts, this chronic adaptation changes the body efficiency

Question 2

There are two types of physiology that we are interested in, what are their names and give a brief description of them?

Answer 2

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

Question 3

What are the three types of muscles?

Answer 3

Skeletal
Smooth
Cardiac

Question 4

What is a alpha motor neuron? What is a motor unit?

Answer 4

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

Question 5

Explain the following fibres:

Type I

Type IIa

Type IIx

Answer 5

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.

Question 6

What is a Magnetic Resonance Spectroscopy?

Answer 6

This determines fibre type based on biogenetic metabolites. This is a measurement of mitochondrial function and glycolysis.

Question 7

Fibre types are sometimes ________ determined

Answer 7

Genetically

Question 8

Fibre type is determined by the ________ neuron that innervates the muscle fibre

Answer 8

Alpha-motor

Question 9

Fast Motor neurons—>__________

Slow motor neurons—> ________

Answer 9

Fast Motor neurons—> fast fibres

Slow motor neurons—> slow fibres

Question 10

What can cause a shift in myosin isoforms?

Answer 10

Endurance training, strength, muscular inactivity.

Question 11

Exercise decreases _______ _______ and increases _____ ______ muscle fibre types

Answer 11

Type IIx, type IIa

Question 12

What occurs to motor units with aging?

Answer 12

Number of MU decreases in older adults, and the size of the MU increases

Question 13

What happens when MU die, what do neighbouring MU perform?

Answer 13

The neighbouring MU reach out and innervate the other fibres. The total MU have decreases but they still are innervated.

Question 14

What is the size principle with respect to recruitment of MU?

Answer 14

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

Question 15

What’s the relationship between force and frequency with muscles?

Answer 15

Faster the delivery of stimuli, the less time for twitch to recover. This means a higher tension/force occurs from increased stimulation.

Question 16

Other than stimulation, what is force of a muscle also determined by?

Answer 16

The amount of cross bridges. Too little or too much overlap will not generate enough force.

Question 17

Concentric shortening contraction=

Eccentric lengthening contraction=

Answer 17

Concentric shortening contraction= slow—>more force/ fast—> less force
Eccentric lengthening contraction= slow—>less force/ fast—> more force

Question 18

Name the three types of connective tissues within muscles, starting with the outer most layer.

Answer 18

Epimysium- outer most layer of the muscle
Perimysium- surrounds each individual fascicles
Endomysium- surrounds each individual muscle fibre

Question 19

What si the role fo the sarcoplasm and T tubules?

Answer 19

Sarcoplasm- the cytoplasm of muscle fibres that contain protein and matrix

T-tubules- extensive portion of the plasmalemma that interconnects myofibrils

Question 20

What type of muscle fibre is recruited most frequently?

Answer 20

Type I

Question 21

What are the percentages of recruitment of the muscle fibres?

Answer 21

Type I - 50%
Type IIa- 25%
Type IIx- 25%