Involuntary Movement/ Spinal Reflexes. Flashcards
- Sensory ______
- ____________
- Motor _______
- Input
- Integration
- Output
Name the 3 main types of effectors.
Muscles, Glands and Adipose Tissue.
Where do sensory input over cranial nerves go?
Reflex centres in the brain.
Where do sensory input over spinal nerves go?
Reflex centres in the spinal cord.
What is a reflex?
An involuntary motor response to a sensory input.
What is a reflex mediated by?
By a reflex arc.
What is a reflex arc?
Reflex arc is the neural pathway used in reflex action.
What does the reflex arc consist of?
- The afferent neurons
- The nerve centre
- The efferent neurons
The afferent nerve passes the input to the_____ ________.
Nerve Centre.
The nerve centre produces activity in the ______ nerves to an ______ _______.
Efferent, efferent organ.
The reflex arc is the ______ of a _______ ________.
Wiring, single, reflex.
Where does the reflex arc begin?
At a receptor.
Where does the reflex arc end?
At a peripheral effector.
What are the basic building blocks of neural function?
Neural Reflexes.
Define what it is meant by a Neural Reflex.
A rapid, automatic response to specific stimuli.
What does one neural reflex produce?
It produces one motor response.
The arrival of a stimulus, activates a _________.
Receptor.
A physical or chemical change that activates a receptor is known as what?
A stimulus.
Once the receptor has been activated, what is activated next?
A sensory neuron.
How is the sensory neuron activated?
Through graded depolarization.
After the sensory neuron is activated, what happens next?
Information is processed by the postsynaptic cell.
What is information processing by postsynaptic cell triggered by?
Triggered by neurotransmitters.
Sensation is relayed to the _____ by axon collaterals.
Brain.
The 3rd step in a Neural Reflex is ________ processing in the ______.
Information, CNS
After information is processed in the CNS, what is the next step in a neural reflex?
The Activation of a Motor Neuron.
What is the last step in a neural reflex?
A response by the effector.
What is a Patellar Reflex an example of?
A Somatic Reflex.
What is a Somatic Reflex?
A simple reflex that responds to afferent stimulation, for the involuntary control of muscle (posture and movement).
What is the other name for a visceral reflex?
An Autonomic Reflex.
What systems do visceral (autonomic) reflexes control?
They control systems other than the muscular system.
Name some examples of visceral/autonomic reflexes.
Coughing, sneezing, swallowing and vomiting.
For somatic reflexes, think _____.
Muscle.
Where do cranial reflexes occur?
They occur in the brain.
What type of reflex is this classed as?-
“A reflex movement in response to a sudden loud noise or bright light”.
Cranial Reflex.
_____ reflexes occur in the spinal cord.
Spinal.
Name an example of a spinal reflex.
Walking.
What type of reflex ranges in complexity?
A spinal reflex.
Name the spinal reflex that is the stretch reflex.
Monosynaptic Reflex.
In a monosynaptic reflex there’s little _____ between _____ input and _____ output.
Delay, Sensory, Motor.
What does muscle stretch lead to the activation of?
Ia afferent.
Ia afferent makes monosynaptic _____ of ______ from same and agonist muscles, what does this result in?
Excitation, Motorneurons, Results in contraction of the muscle.
Stretch reflex has a short _______. The contraction is completed in 20-40 msec.
Latency
Why do we contract the stretching muscle?
To compensate the stretch of the muscle. aka. to prevent length change.
Name what this process is in terms of a spinal reflex:
- stretch reflex excites Motorneurons from agonists
- but inhibits antagonists
- Ia inhibitory interneurons
- disynaptic inhibitory pathway
Reciprocal Inhibition.
What is reciprocal inhibition?
The process of muscles on one side of a joint relaxing to accommodate contraction on the other side of that joint.
When a muscle spindle is stretched and the ____ _________is activated, the opposing muscle group must be ____ to prevent it from working against the resulting contraction of the homonymous muscle.
Stretch, reflex, inhibited.
What does Ib Afferent Inhibition prevent skeletal muscle from?
- Developing too much tension
- Tearing or breaking tendons
What causes Ib afferent inhibition to arise?
Activation of Golgi Tendon Organ.
Ib afferent inhibition acts via ___ _______ _______.
Ib inhibitory interneurone.
When does Ib afferent inhibition operate?
Only operates in posture, not during walking.
What is the name for the spinal reflex known as a tendon reflex?
Polysynaptic Reflex.
What spinal reflex has a complicated response?
Polysynaptic Reflex.
In a polysynaptic reflex:
- Interneurons control more than one _____ group
- Produce either ____ or ______
- Can influence many _____ segments.
Muscle, EPSPs, IPSPs, Spinal.
Name an example of a Polysynaptic Reflex.
Withdrawal reflex.
A type of polysynaptic reflex is a withdrawal reflex, what is a withdrawal reflex?
Move body part away from stimulus (pain/pressure).
Name this:
Action to move part of the body away from painful or harmful stimulus.
Flexion Withdrawal Reflex.
The stretch, tendon and withdrawal reflexes are ______ reflex arcs.
Ipsilateral.
Define what is meant by an Ipsilateral Reflex Arc.
The sensory stimulus and motor response occur on the same side of the body.
The crossed extensor reflex is a _____ reflex arc. This means the motor response is on the opposite side from the stimulus.
Contralateral.
-The flexor reflex causes the leg to pull up.
What does the crossed extensor reflex then do?
It straightens the other leg to stop person falling over.
General characteristics of polysynaptic reflexes:
- Involve pools of _______
- Are _________ in distribution
- Involve ________ inhibition
- Can be ____ lasting
- Several _____ cooperate to produce a _____, control response.
Interneurons, Intersegmental, Reciprocal, Long, reflexes, coordinated.
Reflexes can adapt to what?
Existing conditions.
Reflexes can be modified by the _____ input at the _____ cord level.
Sensory, Spinal.
Reflex motor behaviours occur what?
Occur automatically.
What do reflex motor behaviour not need?
They don’t need instruction from the higher centres.
What can have a profound effect on the performance of a reflex?
Higher Centres.
What can higher centres do to a reflex based in the spinal cord?
They can facilitate or inhibit reflex motor patterns based in the spinal cord.
What do altered spinal reflexes indicate?
Neurological Damage.
Name this reflex:
- Normal in children, may indicate CNS damage in adults
- Toes fan out in response to external stimulation.
Babinski Reflex
What leads to spasticity?
Hyperactive stretch reflex.
Spasticity is often a result of stroke, SCI, MS and CP, what is spasticity?
Long lasting uncontrolled muscle contractions.
Lokomat training helps people to ____.
Walk.
The brain can alter ____ reflexes.
Spinal.
Automatic reflexes can be activated by the _____ as needed.
Brain.
Higher centre of brain incorporate ____, reflexive ____ patterns.
Lower, Motor.
The brain uses few ___ _____ to control complex ____ functions, such as _________.
Nerve impulses, Motor, Walking.
