Transcript Senses power point

Special Senses
General Senses
• Widely distributed throughout the body
– Examples
• Touch
• Pain
• Proprioception (provides information
about the position of the body)
Special Senses
• Produced by highly localized sensory
organs
– Examples
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Smell
Taste
Sight
Hearing
Model of the human nose
The Inner Ear
Structures of the outer and middle
ear
• Outer ear
– Pinna- collects and focuses sound waves
– External auditory canal- passage way that leads to the
ear drum
– Ear drum- also called tympanic membrane. It vibrates
with sound waves.
• Middle ear
– hammer, anvil, and stirrup- bones that transmit
vibrations
– Oval and round windows- two openings that connect the
middle ear to inner ear
– Auditory tube- angles air pressure to be equalized
How We Hear
• Sound waves are collected by the auricle and conducted
through external auditory meatus toward the tympanic
membrane which causes vibrations
• The vibrations of the stirrup produce waves in the
perilymph of the cochlea. This makes the perilymph move
and this pushes against the membrane of the round
window
• This causes the vestibular membrane to vibrate. It creates
waves in the indolymph and the basilar membrane
• Cochlear nerves (located in the cochlar ganglion), send
axons to the cochlar nueculas in the brain stream
• Neurons project to other areas of the brain stream to
inferior collicuculus thalamus auditory cortex of the
cererum.
Olfactory - nose
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Smell- Olfactory
• Molecules in the air enter the nasal cavity
and dissolve in the mucus lining of the
uppermost shelf of the nose
(chemoreceptors – cilia)
• The olfactory neurons of the molecules
contact the olfactory receptors who send
impulses to the axons.
• The olfactory bulbs send this to the brain
which interprets each scent.
Taste - tongue
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Taste
• Saliva breaks down the food into fluid.
The chemicals in the fluid attach to the
taste cells.
• Nerve fibers send impulses to the facial
nerves, which send impulses to taste
cortex of parietal lobe for interpretation.
Structures of the eye pictures
Accessory structures of the eye
• Eyebrows-protect eyes by preventing perspiration
from running down the forehead.
• Eyelids- protect the eyes from foreign objects
• Conjunctiva- covers inner surface of the eyelids
• Lacrimal Apparatus- produces tears
• Extrinsic Eye Muscles- help movement of the eye
Eye structures
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Sclera – outermost, white, hard, layer
Cornea – transparent part of sclera, light in
Choroid – 2nd layer, black, absorbs light
Retina – innermost layer, bipolar cells: rodsnight vision and cones- color vision
• Ciliary body – holds the lens in place
• Iris – colored part of eye, regulates light
• Fovea Centralis – area producing sharpest
vision
Chambers of the eye
• Anterior compartment- between the lens and cornea,
divided into anterior chamber and posterior chamber
– Filled with aqueous humor
• Helps maintain pressure in the eye
• Bends light
• Provides nutrients to inner eye
• Circulates around the cornea
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Posterior compartment
– Filled with a transparent jellylike substance called the vitreous
humor
• Holds the retina in place
• Has many similar functions to the aqueous humor
• Unlike aqueous humor, it does not circulate
Path of sight input
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The rods / cones synapse
bipolar sensory cells
to the optic nerve
reaches the thalamus of brain
Visual cortex of occipital lobe of cerebrum
Eye Disorders
• Conjunctivitis- also called pink eye, an infection of the
conjunctiva
• Chalazion- a small lump in the eyelid caused by
obstruction of an oil producing gland
• Cataract- clouding of the natural lens
• Glaucoma- malformation or malfunction of the eye’s
drainage structures
• Myopia- nearsightedness
• Presbyopia- an eye in which the natural lens can no
longer accommodate
• Stye- same as chalazion