specific functional anatomy

Question 1

characteristics type 1 muscle fibre

Answer 1

• large capillary network: increase the delivery of oxygen and removal of co2 to working muscle
• high number mitochondria: maximises utilisation of aerobic fuel stores (increase storage of triglycerides) and oxygen to produce large amounts of energy (ATP)
• Large number of myoglobin enhances O2 extraction from the blood stream, increases delivery and storage of O2 for utilisation by the mitochondria

Question 2

Characteristics type 2b muscle fibre

Answer 2

• large amount of PCr stores: preferred fuel source for anaerobic activity and is readily available as the presence of o2 isn’t required. This will increase the capacity of this system
• high number anaerobic enzymes: facilitates faster reactions and breakdown of anaerobic fuels
• stimulated by large motor neuron: more forceful contraction

Question 3

fibre recruitment (how increase contraction force of a muscle)

Answer 3

1. increased number of motor neurons recruited: more motor units activated and more muscle fibres contract
2. Increased frequency of impulse: greater frequency of arrival of nerve impulse greater force is produced by muscle

Question 4

what is a motor unit

Answer 4

a motor unit consists of the motor neuron and specific muscle fibres it innovates
- motor unit consists of only 1 fibre type

Question 5

Motor neuron - what is consists of

Answer 5

motor neuron consists of cell body, axon and dendrites. allows it to transmit electrochemical impulses from spinal cord to muscle. this impulse travels towards the axon terminal branches at the motor end plate

Question 6

force velocity definition

Answer 6

the force a muscle can create decreases with increasing velocity of shortening. while the force a muscle can resist increases with increasing velocity of lenghtening

Question 7

force length definition

Answer 7

force length relationship states the amount of force a muscle can produce will vary at different lengths

Question 8

muscle at resting length

Answer 8

there is optimal overlap of actin and myosin myofilaments resulting in optimal cross-bridge formation. this formation increases the overall force production

Question 9

contracted beyond resting length (shorted)

Answer 9

There is too much over lap of actin and myosin this disrupts cross-bridge attachment as there is less space available for optimal binding (there is little cross-bridge formation). this results in less force being produced

Question 10

stretched (lengthened) beyond resting length

Answer 10

myofilaments have minimal overlap resulting in less available binding sites and inefficient cross-bridge attachment. therefore less force is being produced