L18: Reflexes Flashcards
What are the 3 types of reflexes
Involuntary
Voluntary
Rhythmic e.g diaphragm
What happens when the posture is disturbed when the body moves
A feedback and feed forward system occurs to adjust the posture
What does out postural muscle need to do for stability
- maintain tone to counteract gravity
- corrective reflexes to maintain stability
Does the activity of skeletal muscle depend on somatic or autonomic system
Somatic
How does the skeletal muscle move
Plan to move is initiated in the motor cortex
Action is programmed
Primary motor cortex initiated the movement of the skeletal muscle
How is the skeletal muscle controlled for storement in the future
By sensory input
What are the sensory inputs
Visual system
Vestibular system
Skin receptors
Propioceptors
What do propioceptors sense
Muscle tension
What are propiceptors
Receptors in muscle
Where are propiceptors found
In muscle
What are somatic motor reflexes
Stereotypic movements elicited by specific sensory stimuli
What type of fibres are muscle spindle
Intrafusal muscle
What is the role of intrafusal muscle spindle
A sensory organ that senses
What are the 2 regions of the muscle spindle
Central region
Polar region
What does the central region of the muscle spindles involve
Primary and secondary sensory afferents that feed to the brain
What does the polar region of the muscle spindle involve
Gamma motor neurones that adjust sensitivity of the spindle
What group of sensory fibres are primary afferents
Group 1a
What group of fibres are secondary fibres
Group 2 afferents
What happens when a muscle spindle is stretched
Fire action potential to the spinal cord
Alpha motor neurone signals to extrafusal muscle
Muscle contracts
What is the role of gamma efferents
Correct the loss of muscle spindle sensitivity
What happens in a golgi tendon organ
Golgi tendon organ detects stretch
Too munch stretch switches it off to prevent out stretching
What is the alpha gamma co activation in the stretch reflex
When the muscle shortens the spindle is relieved
Sensory axons that innervate the spindle may stop
Gamma motor neurones become activated at the same time
The gamma motor neurone contract to maintain tension on the central region
What do muscle spindles sense
Stretch of the muscle
What do golgi tendon organs sense
Tendon stretch
What does muscle spindle cause
Causes muscle activation
What do golgi tendon organs cause
Muscle inhibition
What type of fibres do alpha motor neurone innervate
Extrafusal fibres
What type of fibres do gamma motor neurone innervate
Intrafusal fibres within the extrafusal fibre
What is the stimulus of the stretch reflex
A load e.g someone pouring water into your cup that you are holding
