Somatic Motor System (3)

Question 1

what are the different types of muscle fibers

Answer 1

smooth and striated

Question 2

what are flexors and extensors

Answer 2

flexors: brings toward core
extensors: brings away from core

Question 3

what is synergistic and antagonistic

Answer 3

synergistic: work together
antagonistic: oppose eachother

Question 4

describe axial, proximal, and distal movement

Answer 4

axial: trunk
proximal: shoulder, elbow, knee, etc
distal: extremity movement

Question 5

what is the general anatomy of a muscle fiber

Answer 5

sarcolemma is membrane of the muscle fiber and opens at T tubules. myofibrils are calcium storage and surround sarcoplasmic reticulum. sarcomere is made of two z-discs with attached myosin and actin filaments

Question 6

describe the mechanism of muscle contraction

Answer 6

1. alpha motor neurons release ACh
2. ACh produce large end plate potential in muscle fiber which triggers an action potential
3. action potential releases Ca2+ and the fibers contract

Question 7

what are lower motor neurons

Answer 7

neurons in the ventral horn of the spinal cord and travel through the ventral root to get to the muscle fibers

Question 8

how are flexors and extensors organized in the ventral horn

Answer 8

flexors are dorsal to the extensors

Question 9

how are neurons controlling axial muscles and distal muscles organized in the ventral horn

Answer 9

motor neurons controlling axial muscles are medial to distal

Question 10

what are motor units

Answer 10

motor neuron and the muscle fibers it innervates

Question 11

what are motor pools

Answer 11

all the motor units that innervate a single muscle