2nd Sem M2 Flashcards
What are the muscles of the Auricle innervated by?
Facial Nerve
Solar Elastosis
Damage to skin Dermis by UV causing black-stained masses of disorganized fibers
Blood supply of Auricle
- Supf. Temporal A
- Ant. Auricular A
- Post. Auricular A
(ECA)
Innervation of External acoustic canal
- Auriculotemporal N
- Facial N
- Glossopharyngeal N
- Auricular Br. of Vagus
(GAFAX)
Subdivisions of Tympanic Cavity
1) Epitympanum
2) Mesotympanum
3) Hypotympanum
Posterior wall of Tympanic Cavity
Mastoid Wall
- Aditus to mastoid antrum
- Pyramidal Eminence (stapedius)
- Canaliculus for Chorda Tympani
- Fossa Incudis
- Lat. semicircular canal
Inferior wall of Tympanic Cavity
Jugular Wall
- Opening of Tympanic Canaliculus
- Tympanic N. of CN9 to medial wall
Superior wall of Tympanic Cavity
Tegmental Wall
- Tegmen Tympani
- Groove for Lesser Petrosal N.
Anterior wall of Tympanic Cavity
Carotid Wall
- Caroticotympanic canaliculi
- Caroticotympanic nn. (symp.)
- Tympanic branches of ICA
- Musculotubarian canal
- Chochleariform Process
Medial wall of Tympanic Cavity
Labyrinthine Wall
- Promontory
- Tympanic Plexus
- Fenestra Vestibuli
- Fenestra Cochleae
- Prominence of Facial Canal
Lateral wall of Tympanic Cavity
Membranous Wall
- Anterior/Posterior Malleolar Folds
- Pars flaccida & Pars tensa
What makes up the Tympanic Plexus
- Tympanic N. (CN 9)
- Caroticotympanic nn. (symp.)
- Communicating Br. of Facial N.
What forms the Lesser Petrosal nerves
Secretomotor Fibers
- Out: Foramen ovale
- To: Otic ggl.
(auriculotemp. n. to parotid gland)
Ossicular Chain
1) Malleus
2) Incus
3) Stapes
Ligaments of Ossicles
- Malleus = 3 Ligaments
- Incus & Stapes = 1 Ligament each
Which Ligament connects to Fossa Incudis
Posterior Ligament of Incus
What Ligament Borders Prussak’s Space
Lateral Malleolar Ligament
Annular Ligament
Attaches the foot/base of Stapes to the Fenestra Vestibuli (Oval window)
1st Ossicular Articulation
Incudomalleolar Joint
- Head of Malleus
- Body of Incus
- Saddle-shaped
2nd Ossicular Articulation
Incudostapedial Joint
- Lenticular process of Incus
- Head of Stapes
Specifics of Ossicular articulations
- Covered by articular (Hyalin) Cartilage
- Synovial membrane Capsules
Tensor Tympani Muscle
- Tenses Tympanic Membrane
- Pushes Stapes footplate into Oval window
- Inn: Mandibular N.
- From cartilaginous part of tube to handle of Malleus
Stapedius Muscle
- Helps damp down excessive sound vibration
- Opposes action of Tensor Tympani
- Stapedial N. of CN8
- From Pyramidal eminence to neck of stapes
Chorda Tympani Path
1) Enters tympanic cavity through posterior canaliculus
2) Crosses over upper part of handle of Malleus
3) Exits through anterior canaliculus
4) Exits skull at petrotympanic fissure
Chorda Tympani Sensation
- Parasympathetic fibers to Submandibular and Sublingual glands (via submandibular ggl.)
- Taste fibers from anterior 2/3 of Tongue
Blood Supply of Tympanic Cavity
- Caroticotympanic A. (ICA)
- Stylomastoid A. (post. auric.)
- Inf. Tympanic A. (asc. pharyng)
- Post. Tympanic A. (stylomastoid)
- Ant. Tympanic A. (maxillary)
- Sup. Tympanic A. (mid. mening)
- Deep Auricular A. (maxillary)
Recesses in Vestibule
- Elliptic Recess (Utricle)
- Spheric Recess (Saccule)
- Cochlear Recess
What duct is found in the Utricle/Elliptic recess
Endolymphatic Duct / Vestibular Aqueduct
What connects the Cochlear duct to Saccule?
Ductus Reuniens
Perilymph
- Fills bony labyrinth around the membranous labyrinth
- Mechanical Protection
- Produced by Periosteum Vessels
- Interstitial fluid
Endolymph
- Fills membranous labyrinth
- Produced by Stria Vascularis (cochlea)
- Intracellular Fluid
Cells of Stria Vascularis
- Marginal Cells (Darker)
- Basal Cells
What covers the basilar membrane?
Layer of squamous perilymphatic cells
Vestibular/Reissner’s membrane composition
2 Layers of squamous epithelium separated by a basal lamina (may contain collagen fibers)
Blood Supply of Labyrinth
1) Labyrinthine A.
2) - Common Cochlear A
- Ant. Vestibular A
3) CCA –> - Spiral A
Vestibulocochlear A
Cochlea Specialized Neuroepithelia
Corti-Organ
Saccula/Utricle Specialized Neuroepithelia
Static Receptors
Semicircular ducts Specialized Neuroepithelia
Kinetic Receptors
Functions of Vestibular System
- Perception of movement and orientation in space
- To maintain equilibrium
Ampullary Crest
- In Semicircular ducts
- Angular acceleration (rotation)
- Kinetic receptors
Macula
- In Saccule & Utricle
- Perpendicular to each other
- Linear acceleration (gravity)
- Static receptors
Types of sensory cells in Macula
Vestibular sensory cells
- Type 1: Bottle-shaped
- Type 2: Cylindrical
Cilia arrangement in Macula
Opposite arrangement of Kinocilia on 2 sides of Striola
- Utricle: Kinocilia towards striola
- Saccule: Kinocilia away from striola
What types of Neurons in Spiral ggl
Bipolar Neurons
- Organ of Corti
- Cochlear N
Modiolus Canals
- Longitudinal canals
- Spiral Canals
Vestibular membrane function
Squamous cells with Tight junctions to preserve ionic gradient bw Perilymph and Endolymph
Stria Vascularis function
Stratified epithelium responsible for production and maintenance of Endolymph.
Encloses capillary network pumping fluid and K+ as endolymph.
Spiral limbus function
Covered by Interdental cells that produce the tectorial membrane
Stereocilia of Hair cells
- Inner hair cell stereocilia float freely
- Outer hair cell sterocilia embedded in tectorial membrane
Other name for Outer phalangeal cells (Corti)
Deiters
What causes activation of Hair cells?
Mechanosensitive K+ Channels
Where is 95% of acoustic information transduced from
Inner hair cells (true sensory)
OHC are to amplify signal
What makes up Cilia of Hair cells in Macula
1 Kinocilia
40-100 Stereocilia
Maculae Cribrosae
- Sup. Macula cribrosa: Utricular n, ant/lat ampullary n
- Medial Macula cribrosa: Saccular n
- Inf. Macula cribrosa: Post. Ampullary n
Superior Oblique inn.
CN4
Lat. Rectus Inn
CN6
What does CN3 innervate?
- Levator palpebrae sup.
- Sup/Med/Inf Rectus
- Inf. oblique
Walls of the eye
1) External Fibrous coat
2) Middle Vascular coat
3) Inner Nervous coat
Layers of the Tunica Fibrosa Sclera
1) Stratum Episclerale
2) Substantia propria (Tenon)
3) Lamina suprachoroidea
Layers of the Tunica Fibrosa Cornea
1) Epithelium Corneae (ant.)
2) Ant. limiting membrane (Bowman’s) - UV protection
3) Substantia propria (stroma)
4) Post. limiting membrane (Descemet’s) - mech protection
5) Endothelium of ant. chamber
AVASCULAR
What cells are found in T. Fibrosa bw collagen lamellae?
Keratocytes
(Parallel or Perpendicular)
What collagen type in Cornea Stroma
Type I
Layers of the Tunica Vascularis Choroid
1) Suprachoroid layer (Haller’s Space)
2-3) Lamina Vascularis
4) Choriocapillary Layer
5) Vitreal layer (Bruch’s)
Layers of the Tunica Vascularis Ciliary Body
1) Supraciliary Layer
2) Ciliary muscle (oculomotor n)
3) Vascular layer
4) Ciliary epithelium (ciliary part of retina)
Layers of the Tunica Vascularis Iris
1) Endothelium of ant chamber
2) Stroma (mm, melanocytes)
3) Stratum pigmenti iridis
Types of muscle Fibers in Ciliary Body
- Meridional fibres (Brūcke)
-Circular fibers (Müller)
What produces aqueous humor?
Ciliary processes to the posterior chamber
What drains aqueous humor?
Fontana’s space to Schlemm’s canal
In corneo-scleral Limbus
Layers of the Lens
1) Lens capsule
2) Anterior epithelium
3) Cortex of Lens
4) Lens Nucleus
What holds lens?
Zonular Fibers from ciliary body
What type of cells in Lens?
Simple cuboidal epithelium ONLY Anteriorly
(Basal membrane layer capsule above)
Glial cells in Retina
- Horizontal cells
- Amacrine cells
- Müller cells (Supporting)
Retina Layers how many?
10 Layers
Retina Layer names
1) Pigmented Epithelium
2) Cones & Rods
3) Ext. Limiting membrane
4) Ext. nuclear layer
5) Ext. Synaptic Layer (Plexiform)
6) Int. Nuclear Layer
7) Int. Synaptic Layer (Plexiform)
8) Ganglion Cell Layer
9) Optic N fibers
10) Int. Limiting membrane
Border between sensitive and non sensitive parts of Retina?
Ora Serrata
What is the name of area where optic fibers leave eye?
Area Cribrosa
What Vessels can be seen Near optic nerve on slide?
- Central Retinal A (with nerve)
- Ciliary A br of Opthalmic (further)
What connects the Pituitary to the Hypothalamus?
Infundibulum
Blood Supply of the Pituitary gland
- Sup. Hypophyseal A. (ICA)
- Inf. Hypophyseal A. (Circle of Willis)
Divisions of Pituitary
- Neurohypophysis
- Adenohypophysis
Neurohypophysis
- Posterior Pituitary
- No hormone production
- Neuronal Tissue
Adenohypophysis
- Anterior Pituitary
- Hormone Production
- Glandular Tissue
Magnocellular Cells
- In Paraventricular & Supraoptic Nuclei
- Axons sent through Pituitary stalk to Neurohypophysis
- Hypothalamo-Hypophysial Tract
Expressed Hormones in Magnocellular Neurons
- Vasopressin (ADH)
- Oxytocin
What Carries Hormones of Magnocellular Neurons?
- Neurophysin 1 = Oxytocin
- Neurophysin 2 = Vasopressin
Where are Hormones stored before release?
Herring Bodies
What do Herring Bodies store?
Oxytocin and ADH produced by Hypothalamus
Parvocellular System Nuclei
- Periventricular
- Paraventricular
- Preoptic
- Arcuate Nuceli
Parvocellular System
Cellular release of Hormones into the Portal Circulation
Flow of Blood with Hormones in Pituitary
1) Primary Capillary system established by sup/inf hypophyseal arteries
2) Secondary capillary bed forms to anterior pituitary through portal veins
3) Blood carying hormones exits via Hypophyseal Vein
Chromophobes
- Dont stain
- Dont produce Hormone now
- Already secreted hormone
Acidophils
- Somatotroph (GH releasing)
-Lactotroph (Prolactin secretion)
Basophils
- Thyrotrophs (TSH)
- Gonadotrophs (LH & FSH)
- Corticotropes (ACTH)
Where is the Sole source of Cholinergic Innervation of Cortex?
Nucleus Basalis of Meynert
Parts of the Adenohypophysis
- Pars Distalis
- Pars Tuberalis
- Pars Intermediata
Meyer’s Loop
Inferior Retinal fibers from LGB
(Temporal)
Barum’s Loop
Superior Retinal fibers from LGB
(Parietal)
What does Neurohypophysis develop from?
Floor of the Diencephalon
What makes up 25% of Neurohypophysis?
Pituicytes
(type of astrocyte)
What does Adenohypophysis develop from?
Hypophyseal placodes
Spongiosa scelae
- Iridocorneal angle
- Trabeculae
- Fontana’s spaces
