sensory neurons and reflexes Flashcards
which parts of the reflex arc are in the CNS
the end feet of the sensory neuron, the interneuron and the body of the motor neuron
name the parts of the reflex arc in order from stimulus to reaction
receptor > sensory neuron > interneuron > motor neuron > effector organ
which part of the reflex arc carries out the response?
the effector organ or cell (like an SMF)
what happens to the neurons to cause your skin to “get used to” a sensation like warmth or a ring on a finger?
the neurons stop firing as quickly
if a sound is made on one side of the body, that side receives the sound (more/less) quickly and (more/less) intensely and what does this cause
more quickly
more intensely
causes the brain to be able to decipher which side of the body the sound was made on
if a sound is equidistant from both ears, it is harder to determine the location of origin of the noise because ears receive the stimulus…
at the same intensity and at the same time
the optic nerve is one of
12 pairs of cranial nerves
what type of receptor causes the swallowing reflex?
touch receptor
what type of sensory receptor causes the knee-jerk reflex?
stretch receptor
what is a basic unit of the nervous system
the reflex arc
how does the AP travel in a reflex arc?
sensory receptor > sensory neuron > interneuron > motor neuron > effector cell (effector organ)
define reflex
autonomic response to a stimulus
what produces a reflex?
a reflex arc
how much conscious thought does a reflex require?
none
what are the types of reflexes?
autonomic
somatic
name some examples of autonomic reflexes?
BP
TCO2
name some examples of somatic reflexes?
withdrawal reflex (from pain) golgi tendon reflex (prevents over-stretching tendons) stretch reflex
what is the simplest type of reflex?
stretch reflex
define stretch reflex?
muscle cntx in response to a stretching force applied to it
what type of specialized SMF is the sensory receptor of the stretch reflex
muscle spindle
if the stretch reflex overactive in the knee-jerk reflex
the CNS neurons are overactive
the sensory neurons of the knee-jerk reflex may be depressed if
the reflex is decreased
no knee-jerk reflex may indicate
that the reflex pathway may not be intact
what type of color blindness is most common?
red-green
why is red-green color blindness more common in men?
it is on the X chromosome (men only have one X chromosome)
what is the frequency of occurrence of colorblindness in men and women?
7% occurrence in men, 8x more likely than in women
what regulates the amount of light entering the eye
pupil diameter
how does the lens of the eye change to focus on a near object? what is this process known as?
it must become more spherical (thicker)
accommodation
define the near point of vision
the point at which the eye is no longer able to “accommodate” enough to focus on an object being brought closer
where does the eye focus an image?
on the retina
what causes double vision?
an image is NOT focused on corresponding points of the two eyes
define convergence reflex
the reflex adjustment made by the eyes that allows an image to continue to be focused on corresponding areas of the retinas of the two eyes
the cones of the eye are responsible for what type of perception?
color
the rods are responsible for allowing the perception of
light and objects
when looking directly at an object, the object being viewed is formed on what part of the retina?
fovea centralis of the retina
what type of vision does the fovea centralis of the retina allow for and how?
allows for particularly acute vision with a concentration of cone cells
where do nerve fibers from the eye exit and form the optic nerve?
the optic disk
what part of the retina lacks rods and cones
optic disk
the optic disk is what is responsible for
the blind spot
what happens when you shine a light into the eyes? and why?
the pupils contract – photopupil reflex – the pupil regulates the amount of light entering the eye and strong light can be harmful to cells in the retina
how do the eye drops at the eye doctors work?
they inhibit the photopupil reflex
