Neuro 5

Question 1

What is the function of 1a and II fibres?

Answer 1

1a- rate of change

II- muscle length

Question 2

What are the three main muscle components?

Answer 2

1. Specialised intrafusal fibres with contractile polar regions and non-polar central regions
2. Type 1a primary and type II secondary (afferent) fibres that originate from non-contractile polar regions
3. y motor neurons innervate contractile polar regions of intrafusal fibres

Question 3

What are the two phases of muscle activity?

Answer 3

Dynamic phase- when muscle length is shortening

Static phase- muscle has stabilised at the static length

Question 4

What are the two different types of fibres?

Answer 4

Nuclear chain and nuclear bag fibres

Question 5

What is innervated by primary (type 1a) sensory?

Answer 5

all fibres

Question 6

What is innervated by type II sensory?

Answer 6

chain and static bag fibres

Question 7

What is innervated by dynamic y motor neuron?

Answer 7

dynamic bag fibres

Question 8

What is innervated by static y motor neuron?

Answer 8

contractile regions of chain and static bag fibres

Question 9

How are the sensory nerves activated?

Answer 9

via the stretch sensitive ions channels

Question 10

What is the function of golgi tendon organs?

Answer 10

provides information about changes in tension

Question 11

How is negative feedback regulation of mediated by muscle tension of GTO’s?

Answer 11

GTO’s contact inhibitory interneurons that decrease activity of a motor neurons innervating the same muscle

Question 12

What are the common signs of lower motor neuron dysfunction?

Answer 12

Weakness/ paralysis 
Hyporeflexia 
Neurogenic atrophy 
Muscle fasiculation
Flaccidity/ hypertonia