Week 7-Movement

Question 1

muscles

Answer 1

Skeletal muscles move the body and limbs
They are also called straiated muscles because of their striped appearance
Smooth muscles produce the movements of the internal organs (digestion)
Cardiac muscles are the muscles that make up the heart

Question 2

control of muscles

Answer 2

The interneurons and motor neurons ensure that the muscles work together so that when one muscle contracts, the other relaxes
Limb muscles are arranged in pairs

Question 3

extensor

Answer 3

moves (extends) the limb away from the trunk

Question 4

flexor

Answer 4

moves the limb toward the trunk

Question 5

antagonistic muscles

Answer 5

muscles that produce opposite movements at a joint
Ex: the bicep muscle flexes the arm, and the tricep extends it
Simultaneous activation of antagonistic muscles:
Contributes smoother movements
Precise stopping
Reduction of tremor.

Question 6

fast-twitch

Answer 6

fibers produce fast contractions but fatigue rapidly (weightlifters, sprinters)

Question 7

slow-twitch

Answer 7

fibers produce less vigorous contraction without fatigue (endurance runners, cyclists)
People have varying percentages of fast and slow-twitch muscles

Question 8

proprioceptors

Answer 8

receptors that detect the position or movement of a part of the body

Question 9

golgi tendon organ

Answer 9

another type of proprioceptor that responds to increases in muscle tension
Acts as a “brake” against excessively vigorous contraction by sending an impulse to the spinal cord where motor neurons are inhibited

Question 10

spinal cord

Answer 10

Spinal cord reflexes
Movements that depend on the spinal cord alone
Scratch reflex
Paraplegia
Quadriplegia

Question 11

motor neurons

Answer 11

The “final common pathway”
The corticospinal tracts synapse with interneurons and lower motor neurons located in the ventrolateral part of the spinal cord
Interneurons projects to motor neurons
Lower motor neurons project to muscles of the body

Question 12

monosynaptic reflex

Answer 12

one synapse between sensory input and movement
Ex: patellar tendon reflex
Other more complex spinal reflexes involve connections among sensory neurons, interneurons, and motor neurons (multisynaptic connections)
Motor Pathways
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Question 13

corticospinal tract

Answer 13

a.k.a pyramidal tract
Bundle of nerve fibers directly connecting the cerebral cortex to the spinal cord
Originates mainly from layer V of the primary motor cortex
Also from premotor and somatosensory cortex
In the brainstem, these tracts produce bumps on each ventral surface that are known as pyramids

Question 14

cerebellum

Answer 14

50 billion neurons, only approx. 22 billion in cerebrum
Two hemispheres: homuncular organization

Question 15

flocculus (medial)

Answer 15

eye movements and balance

Question 16

lateral parts

Answer 16

movements of limbs, hands, feet, and digits

Question 17

medial parts

Answer 17

movements of face and midline of body