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P1 PHAR 7456
Physiology - Neurophysiology Exam 04 Part 03
| Question | Answer |
|---|---|
| 2 classes of neuronal receptors | nerve endings and receptor cells |
| these can be actual bare terminals of nerve fibers, or specialized endings | nerve endings |
| these are specialized cells that sense the environment, and then secrete neurotransmitters to excite nerve endings that are closely associated with the receptor cell. | receptor cells |
| examples are photoreceptors (rods and cones) of the retina and hair cells of the cochlea and semicircular canals | receptor cells |
| potential caused by a stimulus to a nerve ending | generator potentials |
| potential caused by a stimulus to a receptor cell | receptor potential |
| a peripheral afferent neuron is commonly termed? because it is the first neuron in the sensory pathway | primary afferent |
| primary afferents have their cell bodies in the? | dorsal root ganglia |
| typical 3 neuron pathway | 1. primary afferent 2.secondary neuron in spinal cord or brainstem which projects to thalamus 3. tertiary neuron in thalamus which projects to cortex |
| AB(beta) | touch -skin, myelinated |
| C | skin, unmyelinated skin |
| A delta | pain, skin, myelinated |
| enhanced sensation of pain at the site of tissue | primary hyperalgesia |
| enhanced sensation of pain in the undamaged area surrounding the damaged area | secondary hyperalgesia |
| sensed by high threshold receptor on (most commonly) bare nerve endings | nociceptors |
| tough, outermost layer of the eye | sclera |
| transparent external surface, major refractive component, continuous with sclera | cornea |
| opening that controls the amount of light reaching the retina | pupil |
| consists of 2 muscles, an inner circular and outer radial; pupillary diameter depends on activity of these muscles. eye color is based on this | iris |
| fine-tunes refraction for focusing light on retina(accommodation) | lens |
| spincter-like circular muscle; controls thickness of lens during accommodation | ciliary muscle |
| connect lens to ciliary muscle. with relaxation of ciliary muscle, tension on these fibers is high, and lens is flat; vice versa for contraction of ciliary muscle | zonular fibers |
| highly vascularized, b/w retina and sclera | choroid |
| anterior chamber | aqueous humor |
| posterior chamber | vitreous humor |
| photoreceptive area of eye | retina |
| center area (1mm2) of retina; site on retina where light falls if one looks straight | macula |
| center of macula, only cones found, region of the greatest density | fovea centralis |
| entrance of the optic nerve (blind spot) | optic disc |
| normal vision | emmetropia |
| far sightedness | hyperopia |
| near sightedness | myopia |
| with age, the lens becomes stiffer which prevents it from being able to assume a more round configuration. this reduces accommodation | presbyopia |
| this is due to an uneven curvature of the cornea , which has the effect of focusing an object at 2 seperate places on the retina, producing blurry vision | astigmatism |
| very sensitive to low levels of light, low acuity | rods |
| less sensitive to light, high acuity, color vision | cones |
| all photopigments consist of a light-absorbing molecule called? | retinal |
| all photopigments consist of this protein | opsin |
| an object up close requires more refraction to focus on the retina than an object far away, this is done by? | accommmodation |
| image is focused behind the retina | hyperopia |
| image is focused in front of the retina | myopia |
| to correct defects that require reduced refraction you use a? | concave lens |
| to correct defects that require increased refraction use a? | convex lens |
| increased refraction | hyperopia |
| reduced refraction | myopia |
| a cylindrical lens is used to correct? | astimatism |
| high cGMP opens Na channels so what happens? | dark current- cell deporlarizes |
| dorsal pathway from the primary visual cortex is the? | "where" pathway b/c helps in detecting where things are in space and detection of motion of objects |
| Ventral pathway from the primary visual cortex is the? | "what" pathway b/c involved in identification of objects |
| lesions in the ventral pathway can lead to loss of color perception called? | achromatopsia |
| lesions in the ventral pathway can lead to loss of the ability to name objects called? | anomia |
| lesions in the ventral pathway can lead to inability to recognize familiar faces called? | prosopagnosia |
| bilateral lesions to the this pathway makes it impossible to perceive a moving object | dorsal pathway |
Created by:
oupharm2012
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