Reflex Arcs Flashcards
What happens in a reflex arc?
a sensory neuron picks up a stimulus and transmits it to the CNS, which then communicates to motor neurons to affect muscles or glands
What is a reflex?
an automatic response to stimuli within or outside of the body
What do reflexes do?
they maintain homeostasis by controlling many involuntary processes such as heart rate, breathing rate, blood pressure, sneezing. coughing, and vomiting
What is withdrawal reflex?
the autonomic response to move your body away from something that causes pain as quickly as possible
What are some examples of withdrawal reflex?
moving your hand away after touching something hot, not putting pressure on your foot after stepping on something sharp
What are the 5 types of receptors?
chemoreceptors, pain receptors, thermoreceptors, mechanoreceptors, and photoreceptors
What stimulates a chemoreceptor?
a change in chemical concentration
What’s an example of a chemoreceptor?
your tastebuds
What stimulates a pain receptor?
tissue damage
What’s an example of a pain receptor?
the nervous system
What stimulates a thermoreceptor?
change in temperature
What’s an example of a thermoreceptor?
your skin
What stimulates a mechanoreceptor?
changes in pressure and movement
What’s an example of a mechanoreceptor?
muscles and joints
What stimulates a photoreceptor?
light energy
What’s an example of a photoreceptor?
your eyes
When does sensation occur?
when the brain becomes aware of sensory impulses
When does perception occur?
when the brain interprets the sensory impulses
What happens during projection?
when a sensation forms, the cerebral cortex causes the feeling to seem to come from the stimulated receptors - the brain projects the sensation back to its apparent source
What does projection allow people to do?
pinpoint the region of stimulation (eyes see, ears hear)
What is sensory adaptation?
the ability to tune out unimportant stimuli
Where are free nerve endings found?
in epithelial cells
What are free nerve endings responsible for?
itching sensations
Where are tactile corpuscles found?
hairlines, lips, palms, soles, nipples, and genitals
What are tactile corpuscles responsible for?
interpreting things that lightly touch the skin
Where are lamellated corpuscles found?
dermal tissue, tendons, and ligaments
What are lamellated corpuscles responsible for?
responding to heavy/deep pressure
What can temperature senses be broken down into?
warm receptors and cold receptors
What temperatures are warm receptors most sensitive to?
temperatures above 77°F
What temperatures cause warm receptors to become unresponsive?
temperatures above 113°F
What temperatures are cold receptors most sensitive to?
temperatures between 50°F and 68°F
What temperatures make cold receptors send out pain responses?
temperatures below 10°F
Where is the sense of pain distributed?
throughout the skin and internal tissues
How do pain receptors protect the body?
they cause us to act and avoid the dangerous activity that causes pain
What are acute pain fibers?
myelinated nerve fibers that transmit pain stimuli rapidly and are associated with sharp pain
What are chronic nerve fibers?
unmyelinated nerve fibers that transmit pain stimuli slowly and are associated with dull, aching pain
