EMG

Question 1

Function of muscles

Answer 1

Convert chem energy to mechanical work
(Contraction)

1. Skeletal muscle
2. Cardiac muscle
3. Smooth muscle

Question 2

Skeletal muscle

Answer 2

Elementary building stone: muscle fiber
- Muscle fiber: in it; protein complex which can change it’s length (for contraction).

Question 3

Contraction

Answer 3

• Requires ATP and controlled by motor neurons
• each Nerve Fiber (axon of motor neuron) controls several muscle fibers (multiple) while only one nerve fiber controls a muscle fiber (motor unit)

Degree of contraction depends
1. Number of motor units involved
2. Frequency of action potential

If more motor units are needed: motor unit recruitment

Question 4

Skeletal muscle with no action potential

Answer 4

Muscle has a tonus, (low level tension so the body is ready for action but remains stable)

Question 5

Electromyograohy

Answer 5

Recording process of motor fibre recruitment.
Consequences of:
1. Propagation of motor nerve impulse and their transmission to muscle fibers
2. Propagation of impulse within the fibers to actomyosin complex

Represents multiple elementary processes

Question 6

EMG in psychology

Answer 6

Emotional expressions
Somatic concomitants of stress and anxiety

Question 7

Smooth muscle

Answer 7

• internal organs
• contraction cannot be consciously controlled
• spontaneous
• impuls spreads from cell to cell
  -slow

Question 8

Cardiac

Answer 8

• Specialized striated muscle tissue
• branched network
• persistent and rapid contractions
  -high oxygen consumption

Question 9

Structure of striated muscle

Answer 9

Muscle fiber:
- formed by fusion of many cells (shared cytoplasm+ multiple nuclei)
- no membrane
- contains actomyosin complex to contract

Muscle filament-> contraction