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Topic: Pupillary reflex

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	Spinal Reflexes
		A reflex is an involuntary neural response to a specific sensory stimulus that threatens the survival or homeostatic state of an organism.
		Examples are the gag reflex that occurs when objects touch the sides or the back of the throat, and the carotid sinus reflex that restores blood pressure to normal when baroreceptors detect an increase in blood pressure.
		Examples of reflexes with protective and diagnostic importance are the flexor withdrawal reflex, the corneal (blink) reflex, and the accommodation reflex.
	virtual.yosemite.cc.ca.us /dward/physo101/f05_pages/s5_cns/sup_spinal_stretch_reflexes.htm (550 words)

	Dorlands Medical Dictionary
		The presence of this reflex indicates integrity of the first lumbar nerve segment of the spinal cord or its root; absence indicates damage of the first lumbar nerve segment or its root or lesion of the corticospinal tract.
		reflex vomiting caused by irritation of the fauces, cf.
		a reflex in the female corresponding to the cremasteric reflex in the male; i.e., on stroking of the inner anterior aspect of the upper thigh there is a contraction of the muscular fibers at the upper edge of Poupart's ligament; cf.
	www.mercksource.com /pp/us/cns/cns_hl_dorlands.jspzQzpgzEzzSzppdocszSzuszSzcommonzSzdorlandszSzdorlandzSzdmd_r_06zPzhtm (4360 words)

	Reflex action - Wikipedia, the free encyclopedia
		A reflex action is a stereotyped (involuntary) motor response elicited by a defined stimulus.
		A reflex action or reflex is a biological control system linking stimulus to response and mediated by a reflex arc.
		For a reflex, reaction time or latency is the time from the onset of a stimulus until the organism responds.
	en.wikipedia.org /wiki/Reflex_action (208 words)

	Chapter 8: Reflex evaluation
		Reflexes are the most objective part of the neurologic examination and they are very helpful in helping to determine the level of damage to the nervous system.
		Reflexes are graded at the bedside in a semiquantitative manner.
		This is actually a superficial reflex that is elicited in the same manner as the plantar response (i.e., scratching along the lateral aspect of the sole of the foot and then across the ball of the foot toward the great toe).
	www.dartmouth.edu /~dons/part_1/chapter_8.html (3103 words)

	Reflex action Summary
		A reflex is considered a "stereotypical" response, in that it is a mechanical response brought about by the stimulation of a particular neuron, resulting in a particular action which is not varied through the voluntary control of the individual.
		An example is the escape reflex (e.g., the sudden withdrawal of a hand in response to a pain stimulus), or the patellar reflex (the jerking of a leg when the kneecap is tapped).
		Within the spine a reflex arc switches the signals straight back to the muscles of the body (in this case the arm or the leg) (effectors) via an intermediate nerve cell and then a motor nerve cell; contraction of the leg occurs, and the muscle contracts (the arm or leg jerks upwards).
	www.bookrags.com /Reflex_action (2194 words)

	Ophthalmic Hyperguide. Neuro-ophthalmology: The Pupil
		Axons of ganglion cells that subserve the pupillary reflex, similar to ganglion cells that subserve vision, undergo a hemidecussation in the optic chiasm (Slide 1).
		Lesions of the dorsal midbrain often produce pupillary light-near dissociation, with impairment of the light reflex and relative sparing of the near response.
		The pupillary fibers of the third nerve arise from the Edinger-Westphal subnucleus, a midline structure that innervates both pupils (Slide 1).
	www.ophthalmic.hyperguides.com /tutorials/neuro/pupil/tutorial.asp (7045 words)

	[No title]
		Stretch reflexes tend to be hypoactive or absent in cases of peripheral nerve damage, and hyperactive in corticospinal tract lesions.
		This reflex is mediated through the cranial nerve V. The absence of this reflex is an ominous sign because it often indicates damage to the brain stem resulting from compression of the brain or other trauma.
		Absence of the normal pupillary reflex is generally a late indication of severe trauma or deterioration of the vital brain stem tissue.
	frcc.cc.co.us /docs/cms/reflex_physiology.doc (1026 words)

	Pupil constriction -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-11-06)
		In (The branches of medical science that deal with nonsurgical techniques) medicine, pupil constriction (also known as the pupillary reflex) is reduction of (Contractile aperture in the iris of the eye) pupil size.
		Emergency room physicians often assess the pupillary reflex because it is useful for gauging (The part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus) brain stem function.
		The oculomotor nerve is responsible for the (additional info and facts about efferent) efferent limb of the pupillary reflex; in other words, it drives the muscles that constrict the pupil.
	www.absoluteastronomy.com /encyclopedia/p/pu/pupil_constriction.htm (433 words)

	Pupillary Abnormalities
		The pupillary light reflex is a four neuron arc.
		This occurs because the light seems dimmer to the affected eye and because the consensual response from the normal eye is brisk causing the defective eyes pupil to be smaller when you swing the light over to the affected eye and less light is allowed to enter.
		The abnormal eyes pupillary reaction is more sluggish than the normal eye, therefore, when the light stimulus is brought from the normal eye to the abnormal eye the affected pupil dilates instead of constrict.
	www.opt.indiana.edu /riley/HomePage/Pupil_Abnormal/1_Saint_Pupil_Abnormal.html (1891 words)

	Lab 15: Reflex Physiology
		To describe the components of reflex arcs involved in patellar reflex, and pupillary light reflex), and to explain the functional importance of each.
		Illicit the reflex by tapping the ligament with a reflex hammer at the level of the knee joint, using a short, smart wrist action, note the response.
		Conduct the reflex test in an area where the lighting is dim.
	frcc.cc.co.us /docs/cms/Lab_15.htm (527 words)

	The Effect of Antiemetics on Pupillary Reflex Dilation During Epidural/General Anesthesia -- Larson 97 (6): 1652 -- ...
		The Effect of Antiemetics on Pupillary Reflex Dilation During Epidural/General Anesthesia -- Larson 97 (6): 1652 -- Anesthesia & Analgesia
		The Effect of Antiemetics on Pupillary Reflex Dilation During Epidural/General Anesthesia
		Reflex dilation was induced by intermittent noxious stimulation
	www.anesthesia-analgesia.org /cgi/content/abstract/97/6/1652 (386 words)

	Motor lab protocol for PHSL 410b (Site not responding. Last check: 2007-11-06)
		Reflex action is initiated by an input stimulus and results in an output response.
		Reflex activity ranges from the simple reflex, which are mediated by neuronal connections within the spinal cord to the complex reflexes in which higher brain centers are involved.
		Door jam Reflex- This exercise is designed to demonstrate the activity of the muscle spindle by having the subject stand in the doorway and extend both arms to the side, pressing against the door jam.
	www.siumed.edu /~bkinney/cnsprotocol3.html (2880 words)

	Human Biology Final Year Project (Site not responding. Last check: 2007-11-06)
		The effects of iris pigmentation on the human pupillary light reflex was studied using 55 subjects (aged 18-60, of either sex), who were separated into 5 groups according to iris colour.
		Pupillary light reflex was measured by an electronic infra-red scanning pupillometer.
		Measurement of the pupil's reflex response to the light was assessed over a period of three seconds by the pupillometer's infra-red scanner that operated at a frequency of 20 scans per second and which measured the pupillary area.
	www.lboro.ac.uk /departments/hu/projects/abstracts/91hb0170.htm (417 words)

	ScienceDaily: Pupillary reflex (Site not responding. Last check: 2007-11-06)
		In medicine, the pupillary reflex or pupillary light reflex, is the reduction of pupil size in response to light.
		Optic Nerve Disease May Cause Sleep Disorders (February 3, 2004) -- Young people with eye diseases that damage the inner part of the retina and optic nerve are significantly more likely to have sleep disorders than those with other types of eye disease or those with...
		Pupillary reflex -- In medicine, the pupillary reflex or pupillary light reflex, is the reduction of pupil size in response to light.
	www.sciencedaily.com /encyclopedia/Pupillary_reflex (1369 words)

	Lab Guide 11 (Site not responding. Last check: 2007-11-06)
		Spinal reflexes involve neural sensory input (afferent) from the peripheral nervous system (PNS) that is integrated at the level of the spinal cord, resulting in neural motor output (efferent) from the spinal cord to effectors of the body via motor neurons.
		A reflex is an involuntary, rapid, and predictable response to a specific stimulus.
		This demonstrates the reflex mediated by the parasympathetic innervation of the circular muscle of the iris.
	www.apsu.edu /~taylorc/BIOL2010/LabGuides/labguide11.htm (845 words)

	GC1135 LAB: Human Reflexes (Site not responding. Last check: 2007-11-06)
		The pupillary reflexes can be elicited by covering one eye and shining a light into the other.
		The patellar tendon reflex ("knee-jerk" reflex) is a monosynaptic stretch reflex that assesses the nervous tissue between (and including) the L2 and L4 segments.
		The plantar reflex is a superficial spinal reflex that depends both on functional upper-level motor pathways and on the cord-level reflex arc.
	www.gen.umn.edu /courses/1135/lab/reflexlab/reflexlab.html (1320 words)

	Oculomotor Nerve (Cr N III)
		Pupillary constriction and convergence of the eye accompany accomodation to near vision.
		The mechanism by which this phenomenon occurs is thought to be by a reduction in the number of fibers subserving the light reflex on the affected side.
		This pupillary response is frequently seen with tertiary syphilis, pinealomas, diabetes, and brain stem encephalitis.
	www.ucsf.edu /nreview/02.2-Anatomy-CranialNerves/CN03-oculomotor.html (1470 words)

	Science News: Retina transplant restores rat reflex. @ HighBeam Research (Site not responding. Last check: 2007-11-06)
		For the first time, researchers have evoked reflex responses in laboratory rats with midbrain neural transplants, demonstrating that such transplants are capable of transmitting specific information in response to natural stimuli.
		In that reflex, information is transmitted from the light-detecting retina to the brain via the optic nerve.
		If a pupillary response is necessary, a command is transmitted from the brain to the pupil along a separate, oculomotor nerve.
	www.highbeam.com /library/doc0.asp?DOCID=1G1:6065021&refid=ip_encyclopedia_hf (759 words)

	Yale- Cranial Nerve 3, pg. 16
		As a result of this damage, signals carried by CN II from the retina are not relayed via the pretectal nucleus on the affected side to the Edinger-Westphal nuclei.
		This results in a loss of both the direct and consensual pupillary light reflex when light is shined in the eye on the affected side.
		Because the accommodation reflex pathway is distinct from the pupillary light reflex pathway the accommodation reflex is unaffected.
	info.med.yale.edu /caim/cnerves/cn3/cn3_16.html (87 words)

	headinjury&neuroophthalmology
		The light reflex in particular is an excellent index of midbrain function, assuming that the afferent arc is intact.
		A unilateral contracted pupil with the retention of the light reflex may be due to interruption of the sympathetic pathways in the brainstem, cervical spinal cord, or neck.
		The consensual pupillary reflex in the opposite eye, with light is thrown in the affected eye, is brisk.
	www.thamburaj.com /optic_nerve_injuries.htm (7256 words)

	REFLEX (Site not responding. Last check: 2007-11-06)
		This reflex counteracts the stimulus that triggered it.
		The sensory receptor, which is tuned to the reflex's adequate (specific triggering) stimulus (salivary reflex is triggered by taste in mouth; eye blink reflex is triggered by air puff to eye, etc.).
		Other reflexes adjust blood pressure, heart rate, and other vital functions in response in increased or decreased demand for oxygenated blood, make eyes jump left or riight as you turn your head, increase or decrease actions of gut depending on food content, etc.
	www.indiana.edu /~p1013447/dictionary/reflex.htm (431 words)

	[No title]
		Pupillary light reflex: When a concentrated bright light is shone into one eye, the pupil of that same eye will constrict (the direct pupillary light reflex), as well as the pupil of the other eye (consensual pupillary light reflex).
		The easiest way to test this reflex is by moving a hand or other object quickly toward the eye; however, the air currents created by such a movement can also cause a blink reflex.
		Visual placing reflex: When a dog is picked up and carried toward a surface (such as a raised table), it will naturally reach forward with its front legs and try to place them on that surface, guided by sight.
	www.eyevet.info /coile2.html (3881 words)

	Re: Why do we sneeze when we look at the sun?
		A sneeze is a reflex triggered by sensory stimulation of the membranes in the nose, resulting in a coordinated and forceful expulsion of air through the mouth and nose.
		A "reflex" means that some type of stimulation of your body causes you to react in a way that is NOT under your control, in other words you do it automatically without thinking and you can’t even stop it.
		In the pupillary light reflex, shining a light in the eye causes nerve signals to go from the eye to the brain and then back the eye again, telling the pupil to constrict.
	www.madsci.org /posts/archives/aug97/865380242.Me.r.html (1002 words)

	CiteULike: Autonomic pupillary reflex activity during early infancy and its relation to social and nonsocial visual ... (Site not responding. Last check: 2007-11-06)
		Autonomic pupillary reflex activity during early infancy and its relation to social and nonsocial visual stimuli
		Pupillary activity to five visual stimuli--the subject's mother's face, a female stranger's face, a 4-square checkerboard pattern, a 144-square checkerboard pattern, and a triangle--was studied in 1-, 2-, and 4-monthold infants.
		Greater pupillary dilation accompanied the presentation of social stimuli than to nonsocial stimuli in 1- and 4-month-old infants.
	www.citeulike.org /user/chchatham/article/458361 (352 words)

	AccessMedicine - Adams and Victor's Neurology: The Pupils
		Essential, of course, is the proper interpretation of the pupillary reactions, and this requires some knowledge of their underlying neural mechanisms.
		The most common stimulus for pupillary constriction is exposure of the retina to light.
		Reflex pupillary constriction is also part of the act of convergence and accommodation for near objects (near-synkinesis).
	www.accessmedicine.com /content.aspx?aID=969111 (349 words)

	Characteristics of the Pupillary Light Reflex in the Macaque Monkey: Discharge Patterns of Pretectal Neurons -- Pong ...
		Dineen JT, and Hendrickson A. Overlap of retinal and prestriate cortical pathways in the primate pretectum.
		Luminance neurons in the pretectal olivary nucleus mediate the pupillary light reflex in the rhesus monkey.
		Cells in the pretectal olivary nucleus are in the pathway for the direct light reflex of the pupil in the rat.
	jn.physiology.org /cgi/content/full/84/2/964 (7970 words)

	Physical Exam (Site not responding. Last check: 2007-11-06)
		The concept behind this test is that shining a light in one eye causes both pupils to constrict equally as a result of pupillomotor fibers crossing at the optic chiasm and at the midbrain tectum.
		The consensual reflex is the pupillary reaction in the non-illuminated eye.
		A direct ophthalmoscope is used to detect opacities of the ocular media in the red reflex and examine the optic disc, retinal vessels, and macula.
	hubnet.buffalo.edu /ophthalmology/site/Home/Physical_Exam/physical_exam.html (2088 words)

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