Special Senses

Special Sensory Reception Olfaction

Olfactory tract Olfactory bulb Nasal conchae Route of inhaled air Olfactory epithelium Olfactory nerve fibers

Mitral cell (output cell) Olfactory gland Olfactory tract Olfactory epithelium Filaments of olfactory nerve Cribriform plate of ethmoid bone Lamina propria connective tissue Basal cell Supporting cell Dendrite Olfactory cilia Olfactory bulb Glomeruli Axon Olfactory receptor cell Mucus Route of inhaled air containing odor molecules

Special Sensory Reception Gustation

Fungiform papillae Foliate papillae Umami

Taste bud Circumvallate papilla

Taste fibers of cranial nerve Gustatory (taste) cells Taste pore Gustatory Hair (microvilli) Stratified squamous epithelium of tongue Basal cells

Special Sensory Reception Vision

Copyright © 2010 Pearson Education, Inc. Eyelashes Sclera (covered by conjunctiva) Site where conjunctiva merges with cornea Lateral canthus Iris Medial canthus Lacrimal caruncle Eyelid Eyebrow Pupil Palpebral fissure

Copyright © 2010 Pearson Education, Inc. Figure 15.2 Lacrimal gland Excretory ducts of lacrimal glands Lacrimal punctum Lacrimal canaliculus Nasolacrimal duct Inferior meatus of nasal cavity Nostril Lacrimal sac

Copyright © 2010 Pearson Education, Inc. Levator palpebrae superioris muscle Orbicularis oculi muscle Eyebrow Tarsal plate Palpebral conjunctiva Tarsal glands Cornea Palpebral fissure Eyelashes Bulbar conjunctiva Conjunctival sac Orbicularis oculi muscle

Copyright © 2010 Pearson Education, Inc. Central artery and vein of the retina Optic disc (blind spot) Optic nerve Posterior pole Fovea centralis Macula lutea Retina Choroid Sclera Ora serrata Ciliary body Ciliary zonule Cornea Iris Anterior pole Pupil Anterior segment (contains aqueous humor) Lens Scleral venous sinus Posterior cavity (contains vitreous humor)

Copyright © 2010 Pearson Education, Inc. Iris (two muscles) Sphincter pupillae Dilator pupillae Sphincter pupillae muscle contraction decreases pupil size. Dilator pupillae muscle contraction increases pupil size. Sympathetic +Parasympathetic +

Copyright © 2010 Pearson Education, Inc. Neural layer of retina Pigmented layer of retina Central artery and vein of retina Optic nerve Sclera Choroid Optic disc Pathway of light

Copyright © 2010 Pearson Education, Inc. Pigmented layer of retina Pathway of light Pathway of signal output Amacrine cell Horizontal cell Rod Photoreceptors Cone Bipolar cells Ganglion cells

Point sources (a) Focusing of two points of light. (b) The image is inverted—upside down and reversed. Focal points

Process of bipolar cell Outer fiber Apical microvillus Discs containing visual pigments Melanin granules Discs being phagocytized Pigment cell nucleus Inner fibers Rod cell body Cone cell body Synaptic terminals Rod cell body Nuclei Mitochondria Connecting cilia Basal lamina (border with choroid) The outer segments of rods and cones are embedded in the pigmented layer of the retina. Pigmented layer Outer segment Inner segment

Pretectal nucleus Right eyeLeft eye Fixation point Optic radiation Optic tract Optic chiasma Uncrossed (ipsilateral) fiber Crossed (contralateral) fiber Optic nerve Lateral geniculate nucleus of thalamus Superior colliculus Occipital lobe (primary visual cortex) The visual fields of the two eyes overlap considerably. Note that fibers from the lateral portion of each retinal field do not cross at the optic chiasma. Suprachiasmatic nucleus

Special Sensory Reception Equilibrium (balance) and Hearing

External acoustic meatus Auricle (pinna) Helix Lobule Pharyngotympanic (auditory) tube Tympanic membrane External ear Middle ear Internal ear (labyrinth)

Pharyngotympanic (auditory) tube Auditory ossicles Entrance to mastoid antrum in the epitympanic recess Tympanic membrane Semicircular canals Cochlea Cochlear nerve Vestibular nerve Oval window (deep to stapes) Round window Incus (anvil) Malleus (hammer) Stapes (stirrup) Vestibule

Anterior Semicircular ducts in semicircular canals Posterior Lateral Cristae ampullares in the membranous ampullae Utricle in vestibule Saccule in vestibule Stapes in oval window Temporal bone Facial nerve Vestibular nerve Superior vestibular ganglion Inferior vestibular ganglion Cochlear nerve Maculae Spiral organ (of Corti) Cochlear duct in cochlea Round window