Explain Reflex Activity And Spinal Reflexes Flashcards
How is a reflex defined?
Reflex is defined as a fast, automatic response to a specific stimulus.
What can reflex activity be in the human body?
It can be inborn or intrinsic. It can also be Learned or acquired.
What is inborn or intrinsic reflex?
It is a rapid and predictive motor response to stimuli formed between neurons during human development.
What do inborn or intrinsic reflexes do?
They are involuntary reflexes that subconsciously maintain body posture, help to avoid pain and control visceral activities.
Give examples of inborn or intrinsic reflexes?
An example would be a response to pain is triggered by an inborn spinal reflex that operates without assistance from the brain.
In terms of an inborn or intrinsic reflex what are the regulates the visceral response?
Many visceral reflexes are regulated by the brainstem and spinal cord.
How is learned or acquired reflexes defined?
These reflexes are developed over time, because of repeated reactions to stimuli.
Is it similar to inborn reflexes?
No, whilst being more complex than inborn reflexes, learned or acquired reflexes can be altered by learning and conscious efforts.
What is the reflex arc?
The reflex arc may or may not use interneurons. Sensory impulses from receptors can reach their effectors without being processed by the brain.
What are the five basic components of the reflex arc?
- Receptor
- Sensory Neuron
- An integration Centre
- A motor Neuron
- An Effector.
What is a receptor?
This is the site of the stimulus action.
What is a sensory neuron?
A sensory neuron transmits afferent impulses to the CNS.
There are two types of sensory neurons what are they?
They are a monosynaptic or a polysynaptic reflex.
When dealing with a sensory neuron. What is a monosynaptic reflex?
A single synapse is located between sensory neuron and a motor neuron and is referred to as a monosynaptic reflex.
When dealing with sensory neurons, what is a polysynaptic reflex?
This is a more complex reflex arc relying on multiple synapses. There are chains of interneurons are involved. Polysynaptic reflexes are slower than monosynaptic reflexes.
Where is the integration centre?
The integration centre lies within the the central nervous system
What does a motor neuron do?
A motor neuron conducts efferent impulses from the integration centre to an effector organ.
What is an effector?
An effector is defined as a muscle fibre or gland cell that responds to an impulse by contracting or secreting.
What is the most complicated spinal reflex?
The most complicated spinal reflexes are intersegmental reflex arcs. They have many segments working together and produce coordinated motor responses that are extremely variable.
What is a somatic reflex?
A somatic reflex activates skeletal muscles.
What does a somatic reflex allow?
The somatic reflex allows for involuntary muscle control.
Give an example of a somatic reflex?
Examples of a somatic reflex would include superficial stretch and patellar reflexes.
What are somatic reflexes also known as?
They are also known as deep tendon or myotonic reflexes.
What is an autonomic reflex?
It is also known as a visceral reflex.
What makes up a visceral reflex?
Every visceral arc includes a receptor, a sensory neuron and one or more interneurons.
What are the lengths of a visceral reflex?
They can be either long or short.
Are somatic reflexes controlled by the spinal cord?
The spinal cord only controls some of the common somatic reflexes. These are called spinal reflexes.
Are the spinal reflexes directly involved with the higher functions of the brain?
No, they will often occur without direct involvement of the higher centres of the brain, but the brain can intercede on spinal reflexes due to them being monitored.
What may occur if the spine is transected?
When the spine is transected spinal shock may occur.
