Reflexes Flashcards
reflux
- Rapid automatic response to the stimuli
- Through spinal cord (without the involvement of brain)
Examples:
Blinking
sneezing/coughing
salivation
reflex arc
*Neural pathway that mediates in a reflex action
- Sensory neurons pass through the spinal cord to activate spinal motor neurons without delay of steering signals through the brain
components of reflex arc
- Sensory receptor
- Sensory nerve (afferent neuron)
- Interneuron (synapse)
- Motor nerve (efferent neuron)
- Target organ (muscle or gland)
sensory receptor
receives informations and generates impulses
Primary: neuron with specialized region for stimulus transduction
Secondary: non-neuronal cell specialized for stimulus transduction, stimulates neuronal cell through neurotransmitter
on the basis of development
- Innate reflexes connection of the neurons that form during normal development, genetically determined
Include: withdrawal from pain, blinking, and sucking - Acquired reflexes are rapid, and automatic but are
learned responses
Include: salivation when smelling food
motor responses
- Somatic reflexes: control activities of the muscular system
- Visceral reflexes: autonomic involuntary reflexes, control the actions of smooth and cardiac muscles and glands
processing site
Spinal reflexes: control the activities of the muscular system
Cranial reflexes: processed in the brain
complexity of the circuit
Monosynaptic reflexes: sensory neuron synapses directly with the motor neuron.
Little delay between sensory input and motor
output.
*Control the most rapid reflexes
polysynaptic refelxes
- At least one neuron between sensory afferent and motor efferent
- Longer delay between stimulus and response
- Length of delay = # of synapses involved
- Can produce far more complicated responses that monosynaptic reflexes as the interneurons can control several muscle groups
unconditioned reflexes
inborn reflex, inherited and shown from birth onward, and present in all individuals and animals
Example: withdrawal from pain
conditioned reflexes
not inherited, learn by doing the same act several times
Example: salivation when smelling food
muscle spindles
- Sensory receptors within the belly of a muscle
- Primarily detects change in the length of this muscle
- measure stretch of the muscle
- stimulate alpha motor neurons to contract and stretch
*Sensory receptors within the belly of a muscle
Primarily detects change in the length of this muscle
Stretch reflex (myotatic reflex)
- extrafusal fibers
- intrafusal fibers
- golgi tendon organ
extrafusal fibers vs intrafusal fibers
extrafusal fibers: regular contractile tissue, innervated by alpha motor neurons, stimulates contraction
intrafusal fibers: (sense organs within muscle fibers). Innervated by gamma motor neurons
golgi tendon organ
senses stretch in tendons- feeds back on a alpha motor neurons (similar to stretch receptors but in the tendons)
*proprioceptor