Motor Nervous System

Question 1

What are the components in the motor nervous system?

Answer 1

Central motor control area, primary neuron, synapse, spinal cord, motor neuron, neuromuscular junction and muscles.

Question 2

Where do cell bodies of motor neurons lie in the spinal cord?

Answer 2

In the ventral horn

Question 3

What are the steps of neurotransmission at the neuromuscular junction?

Answer 3

Action potential –> Ca2+ enters –> Vesicle fusion –> Ach released –> Ach receptors activated –> Current propagation –> Ach removed

Question 4

Myofibrils is made up of protein strands containing:

Answer 4

Actin and myosin

Question 5

What are the basic contractile units of muscles called?

Answer 5

Sarcomeres

Question 6

Briefly describe the sliding filament model of muscle contraction

Answer 6

Ca2+ attaches to troponin causing it to move and unblock the myosin binding sites. Myosin heads attach to actin to form cross bridges. Myosin heads rotate and pull actin filament. ATP binds to myosin head and breaks cross bridge. ATP broken down by ATPase on myosin heads.

Question 7

What is the neurotransmitter at the mammalian neuromuscular junction?

Answer 7

Acetylcholine

Question 8

What is myasthenia gravis?

Answer 8

Autoimmune disease where there are antibodies against Ach receptors leading to muscle weakness and fatigue due to ineffective detection of Ach

Question 9

Which cells in cardiac muscle help contraction?

Answer 9

Pacemaker cells

Question 10

Function of cardiac muscle?

Answer 10

Blood circulation and maintenance of hydrostatic pressure.