Lecture 7 - Involuntary Movement Flashcards
What are the two types of movement?
Voluntary movement and involuntary movement
What is voluntary movement?
Conscious decision to perform an activity. It is goal directed, highly modifiable movement
What is involuntary movement?
Subconscious. Involves posture and reflexes. Less modifiable
What is posture?
The configuration of the body. How your body is oriented. The situation or disposition of the several parts of the body with respect to each other for a particular purpose
What is the importance of posture?
Posture supports the head and body against gravity and external forces and stabilizes supporting body parts while others are moved
How must posture be maintained to prevent falling from occurring?
Center of mass must be over base of support
What is the base of support?
The area in and around contact area to the ground
What is the center of mass?
The concentration point of mass in the body, usually around the naval
What are the types of postural adjustments?
Anticipatory postural adjustments and compensatory postural adjustments
What are anticipatory postural adjustments?
Predicted disturbances that are modified by experience that occur before voluntary movement. “Preprogrammed responses”
What are compensatory postural adjustments?
Adjustments dependent on sensory feedback following a loss of balance. It is rapid, stereotyped movement that can be modified.
What are spinal motor reflexes?
A stereotyped response to a specific sensory stimulus
What do spinal motor reflexes represent?
The basic form of motor coordination
What are the characteristics of spinal motor reflexes?
Involuntary, rapid, and stereotyped
What type of responses are reflexes?
Graded responses. Response is based on the intensity of the stimulus and locus/location of the stimulus
What do spinal motor reflexes test?
The integrity of neural circuitry/pathways
Why are spinal reflexes essential in voluntary movement?
They are recruited by higher brain centers. They are elementary circuits on which more complex behaviors are built upon
What is it the reflex pathway?
Stimulus -> sensory receptor -> afferent pathway -> CNS (spinal cord) -> efferent pathway -> muscle (response)
Where does afferent information enter in a reflex pathway?
Dorsal horn
Where does efferent information enter in a reflex pathway?
Ventral horn
How long does latency last during a reflex pathway?
75 ms
What factors affect latency?
Length of pathway and number of synapses
What is the function of a spinal stretch reflex?
To regulate muscle length
What is the simplest spinal stretch reflex?
Monosynaptic
