Notes in 2. Physiology

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Published	02/10/2024	Hearing Mechanism in CochleaFootplate of stapes moves in and out of {{c1::oval window}} creating a travelling wave in the {{c2::scala vestibuli}}&nbsp…
Published	02/10/2024	For every frequency there is a specific place on the basilar membrane where the hair cells are maximally sensitive to that frequency. This is known as…
Published	02/10/2024	The two otolith organs of the ear are the {{c1::utricle}} and {{c1::saccule}}, they contain a sensory epithelium called the macula
Published	02/10/2024	The {{c1::ampullae}} are the expanded areas at each end of the semicircular canals.
Published	02/10/2024	The ampullae contain the sensory organ – the {{c1::crista}} which stimulates the {{c2::vestibulo-ocular}} reflex when it moves.
Published	02/10/2024	The {{c1::vestibulo-ocular}} reflex stabilises gaze by moving eyes in order to compensate for head and body movement.→ This fixes image on retina for …
Published	02/10/2024	Systems regulating body balance are {{c1::visual}} inputs i.e. vision, {{c1::vestibular}} inputs i.e. rotation and gravity, and {{c1::proprioceptive}}…
Published	02/10/2024	{{c1::Refraction}} is {{c2::bending of light when it passes from one optical medium to another}}.
Published	02/10/2024	Within the eye, there are two mediums that bend light, they are the {{c1::cornea}} and the {{c1::lens}}
Published	02/10/2024	Bending of light waves is known as {{c1::refraction}}
Published	02/10/2024	Cornea is the most powerful {{c1::“bender"}} of light but the lens has the capacity to change its {{c1::“bending power"}} via attachment of zonul…
Published	02/10/2024	When objects are {{c1::distant (>6m)}} then only {{c2::parallel}} rays from the object reach the eye
Published	02/10/2024	When objects are {{c1::up close (<6m)}} then {{c2::divergent}} rays from the object reach the eye and they need to be bent to be foc…
Published	02/10/2024	When an object comes closer, the eye needs more bending power to focus on it → the lens becomes {{c1::thicker}} & hence more {{c1::powerful}}…
Published	02/10/2024	{{c1::Accommodation}} is the {{c2::eye's capacity to change focus from distant objects (infinity) to close objects (20cm)}}
Published	02/10/2024	The changes to the eye that comprise accommodation are:[1] {{c1::Change of the shape of lens}}[2] {{c1::Pupil constriction}}[3] {{c1::Eye convergence}…
Published	02/10/2024	The ciliary body is innervated {{c1::parasympathetically}} by {{c2::oculomotor (CN III)}} nerve
Published	02/10/2024	During accommodation, the lens become {{c1::thicker}} and more {{c1::spherical}} via {{c2::contraction}} of ciliary body
Published	02/10/2024	During accommodation, the pupil {{c1::constricts}} via action of {{c2::sphincter pupillae}} muscle.
Published	02/10/2024	The sphincter pupillae muscle is innervated {{c1::parasympathetically}} via {{c2::oculomotor (CN III)}} nerve
Published	02/10/2024	During accommodation, our eyes {{c1::converge}} due to action of {{c2::medial rectus}} muscles
Published	02/10/2024	Refractive errors[1] {{c1::Myopia}} ‒ short-sightedness (not able to see far objects well)[2] {{c1::Hyperopia}} ‒ long-sightedness (not able to see cl…
Published	02/10/2024	An {{c1::emmetrope}} is a person that has perfect vision.
Published	02/10/2024	The most common cause of {{c2::Myopia}} is structural i.e. the eyeballs are too {{c1::long}}, or more {{c1::curved}} cornea or lens, this leads to sho…
Published	02/10/2024	Correction of Myopia is by {{c1::decreasing}} the bending power of cornea and lens via usage of {{c2::biconcave}} lens
Published	02/10/2024	In Myopia, the cornea + lens bend rays of light, they make the image form {{c1::IN FRONT OF}} the retina.
Published	02/10/2024	In Hyperopia, the cornea + lens bend rays of light, they make the image form {{c1::BEHIND}} the retina.
Published	02/10/2024	The most common cause of {{c2::Hyperopia}} is structural i.e. the eyeballs are too {{c1::short}}, or more {{c1::flat}} cornea or lens, this leads…
Published	02/10/2024	Correction of Hyperopia is by {{c1::resting}} the accommodative power of cornea and lens via usage of {{c2::biconvex}} lens
Published	02/10/2024	In Astigmatism, the cornea + lens bend rays of light, they make more than one image form {{c1::randomly}} around the retina.
Published	02/10/2024	Treatment of Astigmatism is via {{c1::cylindrical}} glasses that have a certain {{c1::lens power}} with a specific {{c1::meridian}}
Published	02/10/2024	{{c1::Presbyopia}} is longsightedness that occurs due to old age because the lens become less mobile/elastic→ So when the ciliary muscle contracts, it…
Published	02/10/2024	{{c1::Bitot's spots}} in the conjunctiva are sometimes the first indication of {{c2::Vitamin A}} deficiency
Published	02/10/2024	Visible light is a part of the {{c1::electromagnetic}} spectrum
Published	02/10/2024	Visible light activates the rods and cons that contain lamellae with integral proteins known as {{c1::opsins}}
Published	02/10/2024	Opsins contain vitamin A compounds that react to visible light and isomerises from {{c1::11-cis retinal}} to {{c1::all-trans retinal}} causing a break…
Published	02/10/2024	The type of Opsin that breaks down, whether a rod or a cone, depends on the {{c1::spectrum}} of light that falls on it.
Published	02/10/2024	When light falls on the Opsin it causes the visual pigment to {{c1::bleach}} which leads to a cascade that forms an {{c2::action potential}} in the op…
Published	02/10/2024	{{c1::All trans-retinal}} is converted to {{c1::All-trans retinol}} and is picked up by retinal pigment epithelial cell (RPE), which uses up Vitamin A…
Published	02/10/2024	The cascade of reactions that occur within the rod/cone causing {{c1::hyperpolarization}} to generate an action potential in the optic nerve cells.
Published	02/10/2024	The {{c1::Visual field}} is everything you see with one eye (including in the periphery) that focuses on the fovea.
Published	02/10/2024	This test is known as a {{c1::visual acuity}} test
Published	02/10/2024	This test is known as an {{c1::automated perimetry}} test
Published	02/10/2024	Visual pathwayOptic {{c1::nerve}} → Optic {{c1::chiasma}} → Optic {{c1::tract}} → synapses at {{c1::Lateral Geniculate Body (LGB)}} → Optic {{c1::radi…
Published	02/10/2024	Optic {{c1::chiasma}} is found {{c1::superior}} to the {{c2::pituitary (hypophysial) fossa}}
Published	02/10/2024	Images formed on the retina in both eyes from the {{c1::left}} visual field go to the {{c2::right}} occipital lobeImages formed on the retina in both …
Published	02/10/2024	Orientation of images formed on the retina is {{c1::upside down}}
Published	02/10/2024	{{c1::Nasal}} nerve fibres cross while {{c1::Temporal}} nerve fibres do not cross→ Causes the fibres on one side of the brain to see the visual field …
Published	02/10/2024	{{c1::Bitemporal hemianopia}} is usually caused due to a pituitary tumour where the optic chiasm is disrupted in the middle.
Published	02/10/2024	If the {{c1::outer}} half of retina is affected → {{c2::Inner}} part of vision is blindIf the {{c1::inner}} half of retina is affected → {{c2::Outer}}…
Published	02/10/2024	Describe this eye condition{{c1::Bitemporal hemianopia ‒ occurs due to pituitary tumour that disrupts the optic chiasmaIf the inner half of retina is …
Published	02/10/2024	Describe this eye condition{{c1::contralateral homonymous hemianopia ‒ due to right optic tract or optic radiation damageIf the outer half of retina i…
Published	02/10/2024	Describe the eye movement {{c1::Elevation}}
Published	02/10/2024	Describe the eye movement {{c1::Depression}}
Published	02/10/2024	Describe the eye movement {{c1::Abduction}}
Published	02/10/2024	Describe the eye movement {{c1::Adduction}}
Published	02/10/2024	Describe the eye movement {{c1::Elevation}}
Published	02/10/2024	Describe the eye movement {{c1::Depression}}
Published	02/10/2024	Describe the eye movement {{c1::Dextroversion}}
Published	02/10/2024	Describe the eye movement {{c1::Levoversion}}
Published	02/10/2024	Describe the eye movement {{c1::Levoelevation}}
Published	02/10/2024	Describe the eye movement {{c1::Levodepression}}
Published	02/10/2024	Describe the eye movement {{c1::Dextroelevation}}
Published	02/10/2024	Describe the eye movement {{c1::Dextrodepression}}
Published	02/10/2024	Describe the eye movement when the top of the eyeball rotates towards the nose {{c1::Intorsion}}
Published	02/10/2024	Describe the eye movement when the top of the eyeball rotates away from the nose {{c1::Extorsion}}
Published	02/10/2024	Actions of individual EOMs can be remembered via the mneumonic {{c1::RADSIN (Recti ADductors, Superiors INtortors)}}
Published	02/10/2024	Primary, Secondary, Tertiary action of medial rectus {{c1::}}
Published	02/10/2024	Primary, Secondary, Tertiary action of lateral rectus {{c1::}}
Published	02/10/2024	Primary, Secondary, Tertiary action of superior rectus {{c1::}}
Published	02/10/2024	Primary, Secondary, Tertiary action of inferior rectus {{c1::}}
Published	02/10/2024	Primary, Secondary, Tertiary action of superior oblique{{c1::}}
Published	02/10/2024	Primary, Secondary, Tertiary action of inferior oblique{{c1::}}
Published	02/10/2024	Action of individual extrinsic ocular muscles is influenced by two factors:[1] {{c1::The muscles are attached along the orbital axis and not the optic…
Published	02/10/2024	The movement of the {{c3::oblique}} muscles is {{c1::elevation}} or {{c1::depression}} when the eye is {{c2::adducted}}
Published	02/10/2024	The movement of the {{c3::recti (SR & IR)}} muscles is {{c1::elevation}} or {{c1::depression}} when the eye is {{c2::abducted}}
Published	02/10/2024	{{c1::Strabismus (Squint)}} is a condition where there is misalignment of the eyes
Published	02/10/2024	Functional consequences of squint[1] {{c1::Amblyopia (lazy eye)}} ‒ brain suppresses the image of one eye leading to poor vision [2] {{c1::Diplop…
Published	02/10/2024	Pen torch in front of one eye → check for both pupils constricting (direct and consensual reflex)Swing light to other side → should remain b…
Published	02/10/2024	Explain the pathway of the light reflex[1] Afferent limb {{c1::(Visual pathway ‒ Optic nerve → Optic chiasma → Optic tract)}}[2] Center {{c1::(Optic t…
Published	02/10/2024	Presentation of patient with Oculomotor (CN III) nerve palsy with absence of pupillary reflex suggests a {{c1::cerebral artery aneurysm}}
Published	02/10/2024	{{c1::Horner's syndrome}} occurs due to damage to the sympathetic innervation to the pupil, which causes a classic triad of symptoms that include…
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