Neuromuscular Control

Question 1

Electrophysiology

Answer 1

Neurons and myocytes maintin resting potential of -70 mV
K+ - intracellular
Cl- - extracellular

Question 2

Neuromuscular Communication

Answer 2

Development and propagation of action potentials

Influx of Na+ -> depolarizes membrane form -70 to 30 mV -> efflux of K+ hyperpolarizes

Question 3

Absolute Refractory

Answer 3

Can’t generate another action potential

When Na+ channels are open

Question 4

Relative Refractory

Answer 4

Difficult but possible to regenerate action potential (need strong stimulus)

Question 5

Factors Determining Velocity of AP

Answer 5

Diameter - larger is faster

Myelin - from 200 m/s

Question 6

Graded Potential

Answer 6

Local disturbances in post-synaptic membrane potential

Arise from ion channels

Question 7

Excitatory Post-Synaptic Potentials

Answer 7

Increase Na+ permeability

Question 8

Inhibitory Post-Synaptic Potentials

Answer 8

Decrease Na+ permeability

Increase Cl- permeability

Question 9

Motor Unit

Answer 9

Basic functional unit of skeletal muscle
Fibers innervated by same motor neuron contract/relax together
1 neuron can innervate 1-200 fibers

Question 10

Thalamus

Answer 10

Contributes to motor generation and self-monitoring (corollary discharge)

Question 11

Hypothalamus

Answer 11

Regulates internal environment to maintain homeostasis

Question 12

Hypothalamus Functions

Answer 12

Temperature
BP/HR
Respiration/digestion/emotion
Sleep-wake
Appetite

Question 13

Cerebellum

Answer 13

Receives visual and proprioceptive input
Compares actual movement to motor plane
Coordinates timing and sequence of muscle activity

Question 14

Cerebellum Example

Answer 14

Touching nose with eyes closed

Question 15

Brain Stem

Answer 15

Autonomic regulatory centers for respiratory and cardiovascular centers

Question 16

Reticular System (Brain Stem)

Answer 16

Coordinates muscle function
Maintains muscle tone
Contributes sleep-wake and consciousness
Pain control

Question 17

Sensory System

Answer 17

Transmits info from sensory organs, skins, blood and lymph vessels, tendons, and muscle to central somatosensory areas

Question 18

Pyramidal Motor System

Answer 18

Innervate motor neuron in spinal cord and brainstem

Voluntary movement

Question 19

Extrapyramidal Motor System

Answer 19

Located in reticular formation

Involved in reflexes, postural control and coordination of movement

Question 20

Sympathetic

Answer 20

Fight or Flight

Important implications for exercise due to control of HR, vasculature and respiration

Question 21

Parasympathetic

Answer 21

Feed and Breed

Promote synthesis of glycogen