lab 7 Flashcards
(32 cards)
receptors that detect sensations such as pressure and touch
mechanoreceptors
receptors that detect temperature
receptors that detect pain
receptors that detect pH
thermoreceptors are for temp
nociceptors are for pain
pH =chemoreceptors
areas with higher receptors have small receptive fields… what are some parts of the body with small receptive feels (more pain is felt in these areas)
parts of the body with higher receptive fields?
more pain is felt in lips, fingertips, face
back of neck, back of calf
how do the densities of the warm and cold receptors correspond to that of the touch receptors in the area tested?
there are more touch receptors on the ventral side of the forearm. the touch receptors were able to discriminate the probe from warm and cold. cold receptors had less density than warm receptors.
referred pain.. what is it , what is an example
sensory experience in which pain is perceived as a risingg in one area of the body when in fact another, remote area is receiving the painful stimulus.
ex: heart attack being felt in lett arm
what are proprioception and how does proprioceptors work?
the sensation of your body’s positioning and movement, works with inner ear to maintain balance, proprioceptor s supply data to the brain that are used to discriminate forces, weights, and sizes.
what sensation might a subject whose nociceptors are firing a large number of successive action potentials be experiencing?
nociceptors+ pain
alert us to potentially damaged stimuli at the skin by detecting extreme in temp and pressure and injury related chemicals
what is the weber fechner principle?
the intensity of a sensation is proportional to the stimulus causing it . can’t tell the difference between 8 sugar cubes and 9 sugar cubes
what kind of receptors are taste receptors, and what are the 5 categories?
chemoreceptors, sweet, bitter, salty, sour, umami
mechanism for salty stimuli
Na+ ions directly enter the taste receptor. this depolarizes call and leads to APs in associated afferent neuron
mechanism for sour stimuli
detect H+ of acids, H+ ions block the leak k+ channels, leads to depolarization
mechanism for sweet stimuli
sugars such as glucose bind to these receptors and activate G - Protein coupled receptors, stimulates a second messenger pathway that blocks K+, depolarizing the cell
mechanism for bitter stimuli
associated with a variety of poisons such as plant alkaloids, bitter compounds activate a G-protein toppled receptors but mechanism of transaction is unknown
mechanism for umami stimuli
translation for japanese word for delicious, receptors are stimulated by glutamates, which are found in savory foods. Glutamate binds to G protein coupled receptors, second messenger pathway leads to depolarization of the taste receptor.
explain the process that occurs in the eye when changing from bright sunlight to a dimly lit room. be sure to include which muscles are relaxing/contracting?
pupil in normal/bright light = 2–> 4 mm
dark light = 4–>8mm
circular muscles contract in bright light
visceral muscles relax in bright light
when do pupils constrict?
pupils constrict to direct illumination (direct response) and to illumination of the opposite eye (consensual response). the pupils also constrict when the eye is focused on a near object (accommodation to distance.)
four types of photoreceptors and what do they do
rods can detect objects in dim light, but they cannot determinate color of the object (just black and white, or shades of grey).. three types of cones, with peak sensitive to red, green, and blue colors respectively, are used to provide color vision.
have more rods than cones so it is easier to detect black and white more
what happens in the eye to cause the image to “snap” into focus (accommodation to distance)
the cornea and the lens help to focus the light rays onto the back of the eye (retina). cells in retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve –> brian (like a camera)
what is the process of seeing light (accommodation to distance)
light reflects enters via pupil directed to retina ( in back) forms upside down image. Rods and cones transform image into electrical impulses, which are transmitted to brain by the optic nerve. muscles in iris do the contracting and relaxing. circular muscles contract in bright light, visceral muscles relax in bright light
general senses (somatic/visceral)
temp, pain, touch, pressure, vibration, proprioception, (body position), receptor structure is typically more simple
special senses
smell (olfaction), taste (gustation), balance (vestibular system) , hearing/vision
receptor of afferent pathway much more complex
afferent vs efferent
afferent convey info from tissues and organs to CNS
efferent convey info from tissues and organs away from CNS to effector cells like the muscle
cold stimulus uses
free nerve ending (common in papillary layer , unencapsulated, no complex sensory structure.. most common nerve ending, found mostly in skin)
pressure stimulus uses
encapsulated nerve ending
