Special Sense Organs Flashcards
Label the following structures of the ear:
External, middle, and internal (labyrinth) ears, Auricle (pinna), Helix, Lobule, External acoustic meatus, Tympanic Membrane, Pharyngotympanic (auditory or eustachian) tube
What is cerumen and what is its function?
Ceruminous and sebaceous secretions from the auditory canal mixed with dead skin cells; earwax
Function: coats guard hairs, making them more effective in blocking foreign particles from entering the auditory canal; deterrent to insects, ticks, and other pests
Label the following structures of the middle and inner ears:
Tympanic membrane, Oval window, Eustachian tube, Auditory ossicles (malleus, incus, and stapes), Vestibular and cochlear nerves, Semicircular canals, Cochlea
What are the functions of the anterior, posterior, and lateral semicircular canals?
Detect head rotation in X, Y, and Z planes
What is the function of the cochlear duct (scala media)?
Hearing sensory organ within the cochlea; contains the spiral organ of Corti and is lined with stereocilia; associated with CN VIII; sits between the scala tympani and scala vestibuli
What is this structure of the inner ear?
Scala vestibuli; contains perilymph (specialized CSF); lies next to the cochlear duct, which are separated by Reissner’s membrane
What is this structure of the inner ear?
Scala tympani; lies next to the cochlear duct, which are separated by the basilar membrane; contains perilymph (specialized CSF)
Label the following structures of the cochlea:
Vestibular membrane, Stria vasicularis, Cochlear duct, Spiral limbus, Organ of Corti, Spiral ligament, Basilar membrane, Osseous spiral lamina, Scala vestibuli, Scala media, Scala tympani, Spiral ganglion
Label the following structures of the Organ of Corti:
Tectorial membrane, Hair cells, Interdentate cells, Basilar membrane, Spiral limbus, Auditory nerve fibers, Vestibular membrane, Stria vasicularis, Boney spiral lamina, Modiolus, Spiral ligament
What are the similarities and differences between the saccule and utricle?
Both: contain macula (2x3 mm patch of hair cells and supporting cells); detect static equilibrium; linear acceleration
Saccule: lies vertically
Utricle: lies horizontally
Describe otoliths. Structure? Function?
Structure: weighted granules on the ends of stereocilia composed of calcium carbonate and protein
Function: adds to the density and inertia of the otolithic membrane, which enhances the sense of gravity and motion
What is the crista ampullaris?
Stereocilia embedded in a gelatinous cupula in the semicircular ducts; serve to convert movement senses into nerve signals
Label the parts of the lacrimal apparatus:
Lacrimal gland, Lacrimal ducts, Lacrimal sac, Lacrimal punctum, Lacrimal canaliculus, Nasolacrimal duct, Inferior meatus of nasal cavity
What are the components of the fibrous tunic of the eye?
Sclera: white
Cornea: transparent, anterior
What are the components of the vascular tunic (uvea) of the eye?
Choroid: pigmented layer behind the retina
Ciliary body: ring of smooth muscle around the lens
Iris: pigmented diaphragm controlling pupil diameter (contains concentric smooth muscle as constrictor and spoke-like myoepithelium as dilator)
What are the optical components of the eye? (3)
Aqueous humor: posterior chamber (lens to iris) and anterior chamber (iris to cornea)
Vitreous humor: vitreous chamber behind the lens
Lens: suspensory ligament; bends light and projects it onto the retina
Label the following components of the eye:
Cornea
Iris
Lens
Anterior chamber
Posterior chamber
Ciliary body
What are the neural components of the eye? (3)
Retina: contains rods and cones; sends visual information to the optic nerve; ora serrata = anterior margin (thins out)
Optic disc: area on the retina where the optic nerve exits; blind spot
Macula lutea: central patch for detailed vision; contains the fovea centralis (pit within the macula)
What are the four major cell types that make up the retina and what are their functions?
Rods: night vision (scotopic); monochromatic; pigment = rhodopsin
Cones: day vision (photopic); trichromatic; pigment = photopsins (3 pigments)
Bipolar cells: interneurons that receive input from rods and cones
Ganglion cells: Receive input from bipolar cells; axons form optic nerve
Label the following components of the retina:
Inner nuclear layer, Outer plexiform layer, Inner limiting membrane, ganglion cell layer, nerve fiber layer, Inner plexiform layer, Outer nuclear layer, Pigment epithelium layer, Nuclei of rods and cones, Outer limiting layer, Photoreceptor layer
