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Anatomy 3 final (practical and oral part) > C16 - The eyeball: tunics and its accessory organs > Flashcards

C16 - The eyeball: tunics and its accessory organs Flashcards

1
Q

What does the visual organ consists of?

A
  • Eyeball
  • N. opticus
  • Accessory organs
    • Corpus adiposum orbitae
    • Fascia bulbi
      • Preorbita
      • Fascia muscularis superficialis
      • Fascia muscularis profunda
    • Muscles of the eyeball
    • Eyelids (palpebrae)
      • Superior
      • Inferior
    • Gl. lacrimalis
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2
Q

Define orbit

General knowledge

A
  • The orbit is a cavity on the lateral surface of the skull
  • Contains the eyeball
  • Continous with fossa temporalis and fossa peterygopalatina
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3
Q

Give the division of the interior of the eyeball

General knowledge, not directly linked to the topic

A
  • The interior of the eyeball is divided into 3 chambers (camera bulbi):
    • Camera anteror (anterior chamber)
      • Between cornea and iris
      • Filled with aqueous humor
    • Camera posterior (posterior chamber)
      • ​Between iris, ciliary body and lens
      • Filled with aqueous humo
    • Camera viteria (viterous body)
      • Largest of the 3 chambers
      • Behind the lens
      • Surrounded by retina
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4
Q

The eyeball

Give the tunics of the eyeball

A
  • The wall of the eyeball is formed by 3 layers (tunicae), which enclose the interior of the eyeball
  1. Tunica externa/fibrosa
    • ​Role: gives form and protects the eyeball
    • The only complete tunic
    • Consists of:
      • Sclera
      • Cornea
  2. Tunica media/vasculosa
    • ​Consists of blood vessels and smooth muscles
    • Role:
      • Nutrition of the eyeball
      • Regulation of the shape of the lens and size of the pupil
    • Consists of:
      • Choroidea
      • Ciliary body
      • Iris
  3. Tunica interna/nervosa
    • ​Consists of nervous tissue
    • Role: the layer most directly concerned with vision
      • Translation of visual stimuli into nerve impulses form interpretation by the brain
    • Consists of:
      • Nonvisual retina (pars caeca retina)
      • Optic part of retina (pars optica retinae)
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5
Q

Tunics

Tunica externa/fibrosa

A
  • Made up of very dense collagenous tissue
    • ​Resisting the internal pressure and gives the eye shape and stifness
  • Consists of sclera and cornea which meet at the limbus

Sclera:

  • Outer layer (together with cornea)
  • “white of the eye”
  • Pars perforata: ventral to the posterior pole, passes the fibers of n. opticus
  • It gives attachment to the tendons of the ocular muscles anterior to the equator
  • Vagina bulbi: posteriorly, except for the area taken up by the m. retractor bulbi, it is covered by a thin membrane that separates the corpus adiposum orbitae
  • Near the limbus the sclera is covered by conjuctiva, which furnishes connection to the inside of the lids
  • Limbus cornea: the edge of the cornea where it is continous witht the sclera

Cornea: ​​

  • Outer layer (together with sclera)
  • Avascular
  • Layers:
    • Epithelium
    • Lamina limitans anterior (acellular)
    • Substantia propria
    • Lamina limitans posterior (acellular)
    • Endothelium camerae anterioris
  • Cornea lack blood vessels
    • Nourished by diffusion from the interior of the eye
    • Nutrition: vessels of limbus → lacrimal fluid
  • Corneal reflex: free nerve endings from the n. ciliaris longus (of n. opthalmici); eye lids close when touching the cornea
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6
Q

Tunics

Tunica media/vascularis

A
  • Tunica vasculosa = uvea
  • Interposed between sclera and retina
  • Functions:
    • Blood supply
    • Suspension and regulation of shape of the lens
    • Regulation of the size of the pupil
    • Production of aqueous humor
  • 3 zones in poterioanteroior sequence
    1. Choroidea
    2. Corpus cileare
    3. Iris
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7
Q

Tunics

Tunica media/vascularis: choroidea

A
  • ​​Vascular layer
  • Envelopes the posterior part of the eyeball
  • Tapedium lucidum:
    • Dorsal to optic papilla, in a half-moon shaped area
    • Has an additional reflective layer between the vascular and choroideocapillary layer
    • Avascular layer (ø sus)
    • Cellular (ca)
    • Fibrous (ru, eq)
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8
Q

Tunics

Tunica media/vascularis: corpus ciliaris

A
  • Thickened middle segment of tunica vascularis
  • Between choridea and iris
  • forms lateral borders of the posterior chamber
  • Outer surface is covered by sclera
  • Inner surface is covered by nonvisual part of retina
  • Corpus ciliaris can be subdivided into:
    • Ciliary ring
    • Crown of ciliary body
      • ​Most prominant anterior portion
      • Contains processus ciliaris
  • Lens is fixed in position by ciliary zonule
  • M. ciliaris:
    • ​Smooth muscle
    • Action: accommodation
      • Enables the lens to change its shape to focus on near or distant objects
    • Innervation:
      • Parasympathetic from ggl. ciliaris (muscle contract)
      • Sympathetic innervation from plexus caroticus interna (muscle relaxes)
      • Sensory: V1 → n. nasociliares → n. ciliare
  • ​​Oculomotorius ??
  • 1 motor nuclei ??
  • Parasympathetic nuclei ??
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9
Q

Tunics

Tunica media/vascularis: iris

A
  • Thin ring of vascular tissue
  • Suspended between the cornea and lens
  • Attached at the periphery of the sclera (by ligg. pectinati) and corpus ciliaris
  • Color of the iris determines the color of the eyes, depending on the number of pigmented cells present in the stroma
  • Size of pupil: amount of light reaching the retina are regulated by the smooth muscles
    • M. sphincter pupillae
      • ​Close to pupillary margin
      • Parasympathetic fibers
    • M. dilator pupillae
      • ​Contraction → enlarges pupil
      • Sympathetic fibers
  • Divides the space between the lens and cornea into:
    • Anterior chamber
    • Posterior chamber
  • Both chambers are filed with aqueous humor
    • Circulation:
      1. Pupil
      2. Angulus iridocornealis
      3. Space of fontana
      4. Channels of schlemm
      5. Episcleral veins
  • Consists of 3 layers:
    • Anterior epithelial layer
    • Middle layer
    • Posterior epithelial layer
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10
Q

Tunics

Tunica interna/nervosa

A

Retina:

  • ​Contains light-sensitive receptor cells
  • No blood vessels
  • Connected by n. opticus
  • Outgrowth of diencephalon
  • The retina can be divided into:
    • Non-visual retina (pars caeca retinae)
      • ​Ciliary part of retina (pars ciliaris retinae)
      • Iridial part of retina (pars iridica retinae)
    • Optic part of retina (pars optica retinae)
  • Ora serrata: marks the border between non-visual retina and optic part of retina
  • Discus n. optici: ​Blind spot where n. opticus enters
  • Macula: Area of maximum optical resolution
  • Non- visual retina: (optic part)
    • Pars ciliaris
    • Pars iridialis

Pars ceca retinae:

  • ​Anterior part of eye

Pars optica retinae:

  • ​Posterior to ora serrata
  • Divided into:
    • Outer pigmented layer
    • Inner neural layer
  • Layers:
    • Pigmented cells
    • Receptor cells:
      • ​Rods (black/white vision, night)
      • Cones (color vision, day)
    • Bipolar ganglion cells
    • Multipolar ganglion calles
  • Transduction of stimulus: (tertiary receptor type)
    • Cell 1: rods and cones (sensing stimuli)
    • Cell 2: bipolar cells (transduction and transformation)
    • Cell 3: gangilon cells (affterent nerve)
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11
Q

N. opticus

Ekstra informasjon, egentlig topic C17

A
  • N. opticus is actually a tract of the brain/CNS
  • Pathway:
    • Enters the skull through for. opticum and canalis opticus
    • Cross to the contralateral side at optic chiasm
    • Continue at the optic tract and pass to the lateral geniculate nucleus and thaalmus
    • Projects onto the visual area of the cerebral cortex
    • Terminate in the supraoptic and paraventricular nucleus of hypothalamus
      *
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12
Q

Accessory organs

List the accessory organs of the eyeball

A
  1. Corpus adiposum orbitae
  2. Fascia bulbi
  3. Muscles of the eyeball
  4. Palpebrae (eyelids)
  5. Lacrimal apparatus (with gl. lacrimalis)
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13
Q

Accessory organs

Corpus adiposum orbitae

A

Supports the eyeball

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14
Q

Accessory organs

Fascia bulbi

A
  • Capsule of tendon
  • Thin membrane which envelops the eyeball from n. opticus → limbus
  • Periorbita (external)
    • Splits at orbit margin
  • Fascia muscularis superficialis (middle)
    • Envelops m. palpebrae superioris and gl. lacrimalis
  • Fascia muscularis profunda (internal)
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15
Q

Accessory organs

Muscles of the eyeball

A
  • ​M. rectus bulbi
    • ​M. rectus bulbi dorsalis
      • O: around for. opticum
      • I: anterior to equator
      • ​A: eyeball up
      • Innervation: III. n. oculomotorius
    • M. rectus bulbi ventralis
      • O: around for. opticum​​
      • I: anterior to equator
      • A: eyeball down
      • Innervation: III. n. oculomotorius
    • M. rectus bulbi lateralis
      • O: around for. opticum​​
      • I: anterior to equator
      • A: eyeball lateral
      • Innervation: VI. n. abducens
    • M. rectus bulbi medialis
      • O: around for. opticum
      • I: anterior to equator
      • ​​A: eyeball medial
      • Innervation: III. n. oculomotorius
  • M. obliquus bulbi
    • ​M. obliquus dorsalis
      • O: around canalis opticus
      • I: deep to m. rectus dorsalis
      • A: rotate eyeball
      • Innervation: IV. n. trochlearis
    • M. obliquus ventralis
      • ​O: medial wall of orbit
      • I: eyeball posterior to equator
      • A: pull eyeball into orbit
      • Innervation: III. n. oculomotorius
  • M. retractor bulbi
    • ​O: around canalis opticus (Car: fissura orbitalis)
    • I: Eyeball posterior to equator
    • A: pull eyeball into orbit
    • M. retractor bulbi lateralis
      • ​Innervation: VI. n. abducent
    • M. retractor bulbi medialis​
      • ​Innervation: III. n. oculomotorius
  • M. levator palpebralis
    • A: suspension
    • Innervation: III. n. oculomotorius
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16
Q

Accessory organs

Eyelids (palpebrae)

A
  • Eyelids:
    • Upper lid (most mobile one)
    • Lower lid
    • Third li
      • ​Semilunar fold of cojuctiva
      • Lymph nodes are found within the third eyelid
      • Base of the cartilage is surrouded by superficial gland of the third eyelid
  • Rima palpebralis: opening between upper and lower lids
  • Margo palpebralis: free margins of upper and lower lid
  • Caruncula lacrimalis: nasal angle of the eye
    • Ca: gl. lacrimalis beneath
  • Conjuctival sac: space between lower lid and eyeball, contains mucous and tears
  • M. orbicularis oculi: levator muscle of the upper eyelid, extends from for. ethmoidale → upper eyelid
17
Q

Accessory organs

Lacrimal apparatus

A
  • The lacrimal apparatus includes structures that are responsible for production, dispersal and disposal of tears:
    • Gl. lacrimalis
      • ​Location: between eyeball and dorsotemporal wall of the orbit
    • Gl. palpebrae tertiae
    • Canaliculi lacrimalis
    • Saccus lacrimalis
      • ​Marks the beginning of ducuts nasolacrimalis
    • Ductus nasolacrimalis
      • ​Goes through os lacrimale and maxilla
18
Q

Accessory organs

Glands

A
  • Sabecous gland (opens into follicles of cilia)
  • Ciliary gland (coiled, tubular, sweat gland)
  • Tarsal gland (oily, superficial layer of the tear film)
  • Lacrimal gland (between eyeball → wall of orbit)
19
Q

Blood supply of the eye

A
  • A. maxillaris → a. opthalmichi externa → rr. ciliares + palpebralis externa → a. malaris → a. lacrimalis
  • A. cerebri rostralis → a. opthalmichi interna

​

  • Veins are parallel to arteries, but:
    • Vv. vorticosae → v. opthalmichi externa
20
Q

Innervation of the eye

A
  • N. oculomotorius (III):
    • Sympathetic
    • Parasympathetic
    • Supporting ciliary system
  • N. opticus (II):
    • ​Sensory
    • _​_Visual perspective
    • No myelinated sheath
    • Actually a tract of the brain
  • N. opthalmichi (V1)
    • Principla sensory innervation of eye and orbit
    • → N. frontalis innervates upper lid
    • → N. lacrimalis innervates gl. lacrimalis and temporal canthus
    • → N. nasociliaris → n. infratrochlearis innervates conjuctiva and third lid
  • N. maxillaris (V2)
    • N. zygomaticus give sensoryinnervation to lower eyelids
  • Controls movement of eyeball:
    • N. oculomotorius (III)
    • N. trochlearis (IV)
    • N. abducent (VI)

Anatomy 3 final (practical and oral part) (128 decks)

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