A&P - Chapter 18 (Part 4) Flashcards
What is another name for nerve impulses?
Action potentials
What are nerve impulses constantly being conducted from over neuron pathways? (2)
- Receptors
2. Effectors
Reflex arch
Is a specialized neuron pathway that results in a rapid involuntary or autonomic response to a stimulus
What is an automatic response to a stimulus called?
A reflex
What are 2 types of reflex responses?
- Contraction by a muscle
2. Secretion by a gland
What are the 5 components to a reflex arch?
- A receptor
- Sensory/afferent neuron
- CNS
- Motor/efferent neuron
- Effector
What does a receptor do? (2)
- Detects change
2. Generates nerve impulses
Where are interneurons located?
In the CNS
What is the effector?
Its a muscle that performs the action and manifests the effect
What is the difference between a 2 and 3 neuron arch? (2)
- 2 neuron arch only has a sensory and motor neuron
2. 3 neuron arch has many neuron connections
What is another name for a 2 neuron arch?
Monosynaptic
What is another name for a 3 neuron arch?
Poly-synaptic
What does a two neuron arch consist of?
Sensory neurons synapsing in the spinal cord with motor neurons
- simplest reflex arch
What does two neuron arches not have?
Interneurons
What does a three neuron arch consist of?
Sensory neurons synapsing in the spinal cord with interneurons that synapse with motor neurons
Where are interneurons located?
Entirely within the gray matter of the brain or spinal cord
What happens if the sensory information is more threatening?
The information is more likely to get sent to the brain for more complex processing and integration
Where are receptor/sensory neurons located?
In the dorsal root ganglion and ends in the posterior horn of the gray matter
- dendrite –> cell body –> axon
Synapse
Microscopic space between neurons where neurotransmitters are release in order to promote the nerve impulse onto the next neuron
Where is the motor neuron?
In the ventral root
- synapse at neuromuscular or neuroglandular junctions
Are 2 neuron relex arcs learned or unlearned?
Unlearned
- true reflexes
What do 3 neuron arcs respond to?
Injury or pain
- withdrawal reflex
What do 3 neuron arcs provide?
An automatic reaction that occurs quickly to ensure survival
Can reflexes occur before you are even conscious of the stimulus/pain?
Yes
