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Name special senses
- Touch(General)
- Eyes/seeing(special)
- Ears/hearing(special)-equilibrium(sound/balance)
- Taste/gustatory(special)
- Smell(special)
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What are the accessory eye structures?
- Eyelids-shade eyes during sleep, spread eye lubrication over eye ball, protect from excessive light and foreign objects
- Eylashes-protect from border of eyelid and protect eyeballs
- Lacrimal gland-drains lacrimal fluid/tears
- Eyebrows-protect eyeballs from foreign objects and direct sun
- Extrinsic eye muscles-control eye movement
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Flow of tears
- Lacrimal Gland
- Duct
- Superior or inferior canal
- Lacrimal sac
- Nasolacrimal duct
- Nasal Cavity
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Describe the structured functions of the eye include tunics
1. Fibrous tunic-dense connective tissue, outside of eye; contains cornea and sclera, for protection and transparent for light
- 2. Vascular Tunic-Supply other layers with blood contains melanin, absorbs light
- Choroid-absorb scattered light waves
- Iris-Ring of smooth muscle control size of pupil
- Cilliary Body- Control change shape of lens (smooth muscle) and (accommodation)
- 3. Nervous Tunic/Retina-(inner tunic) sensory neurons that respond to light
- -Pigmented layer-Epithelial cells(rods and cones) all store pigments from veggies. Light causes nerve impulses
- -Bipolar cells
- -Ganglion cells-group of cell bodies lying outside the CNS
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Visual Pathway
- Optic nerve
- Optic Chiasm
- Optic tract
- Thalamus
- Optic radiations
- Primary Visual area of cortex in occipital lobe
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What are the Chambers of the eye?
All filled with aqueous humor fluid
- Anterior chamber-
- Posterior Chamber-
- Vitreous Chamber-
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What is accommodation, Papillary constriction, and Convergence?
Accommodation- increase in the curvature of the lens for near vision
Papillary Constriction-narrowing of hole where light enters eye, iris muscles contract
Convergence-medial movement of two eyeballs, both are directed to object being viewed. Ex: pencil moving towards eye
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What are Optic discs and Fovea centralis?
Optic discs-site where optic nerve exits the eyeball
Fovea centralis-small depression at center of posterior portion of retina at visual axis of eye
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What are the major divisions of the ear?
External ear-collects sound waves and channels them inward
Middle ear-conveys sound vibrations to oval window
Internal ear-houses receptors for hearing and equilibrium
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What are Olfactory receptors?
First order of neurons of the olfactory pathway, bipolar neurons with exposed dendrites and axon; respond to inhaled chemicals
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Explain Olfactory Pathway
- Olfactory nerves
- Olfactory bulbs
- Olfactory tract
- Olfactory cortex
Impulses go to Limbic system
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What are tastebuds?
An oval body consisting of three kinds of epithelial cells: supporting cells, gustatory receptor cells and basal cells. Found on tongue called papillae
Supporting cells-surround the gustatory receptor cells
Gustatory receptor cells-
Basal cells-replace receptor cells
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Explain Gustatory Pathway
- Tastebud
- Thalamus
- Gustatory Cortex
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What is contained in the Olfactory Epithelium
Smell ties to emotions
Supporting cells-surround olfactory receptors
Olfactory receptor cells-
Basal cells-replace olfactory cells
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What are the two main functions of the ear
sound and balance=equilibrium
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What is Rhodopsin?
photopigment in rods
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What is contained in the Outer ear, middle ear, and inner ear?
- Outer-Pinna/Oracle(cartilage, help direct sound waves into ear), External auditory canal, tympanic membrane(eardrum, vibrate when soundwaves hit it), exocrine glands(make earwax)
- Middle-Malleous, Incus and stape, nasopharynx(auditory tube)
- Inner-Cochlea(auditory receptors), saccule and uticle make up vestibule
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What are the difference between rods and cones?
Rods are stimulated by by low light and allow dim vision
Cones are stimulated by right light and produce color vision
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Explain the sound waves path
- enter external auditory canal
- vibrations of tympanic membrane
- ossicles vibrate, strike oval window
- setup waves in perilymph
- strike vestibular membrane and scala tympani
- setup waves in endolymph
- vibrate vasilar membrane
- stimulate hair cells on spiral organ
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What receptors are involved in hearing and equilibrium(sound and balance)
vestibule(saccule and utricle)
semicircular ducts
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