The Sense Organs
Taste Smell Vision Hearing Balance Special Senses
Mechanoreceptors Chemoreceptors Thermoreceptors Photoreceptors Nociceptors (Pain Receptors) Types of Receptors
Taste respond to chemicals in an aqueous solution food dissolved in saliva airborne chemicals dissolved in mucous membrane Taste and smell are involved with specific receptor cells called chemoreceptors
The Tongue The Tongue
Taste Buds Circumvallate Papilla Filiform papilla Fungiform papilla Connective tissue Tongue epithelium
Taste Buds taste buds papilla taste pores
Taste Buds
Five Basic Tastes Salty- metallic ions Sweet- sugar Umami Sour- H + Bitter- alkaloid Why are they important?
Dry tongue with a paper towel and place a little sugar on surface. What do you taste?
Taste triggers reflex involved in digestion; causes an increase of saliva in mouth (amylase) and gastric juice in stomach acids cause strong salivary reflex bad tasting food causes gagging or reflexive vomiting taste can change over time taste is 80% smell Mouth also contains: Thermoreceptors Mechanoreceptors Nociceptors- sensitive nerve fibers that are aware of painful stimuli
Olfaction olfactory hairs olfactory receptor cell bone olfactory bulb Nasal conchae
Smell not as good as animals; however, some people are wine tasters, perfumers If you smell a particular odor all day, you won’t recognize its presence, you become accustomed, ex. garbage men Old people lose sense of smell- lots of perfume Humans can distinguish 10,000 or so chemicals What we really smell is pain: ex. chili, ammonia, menthol (cold) Specific chemicals cause specific patterns of neurons to fire Olfaction
sclera iris pupil tear drainage canal cornea
The Eye optic nerve extrinsic eye muscles
sclera cornea iris choroid retina pupil optic nerve lens aqueous humour vitreous humour
corneairislenspupilsuspensory ligament canal of Schlemm ciliary body aqueous humour
Coarse Fixed Focusing Cornea Shape Cornea Shape Accommodation- adjust configuration of Lens Shape Lens Shape Pupil Size Pupil Size
refraction
Focusing on a Near Object
Focusing on a Far Object
The Retina blind spot macula
Details of the Retina light photoreceptive cells Choroid Schlera Ganglion Amacrine Bipolar neuron Horizontal cells
Photoreceptive Cells of the Retina cone rod
Effect: Subjective or illusory contours
Geometrical illusions
Cushion Illusion: This drawing consists solely of rectangles and squares, set straight and true; the curvature is all in your mind.
Luminance & Contrast
The scintillating grid illusion
No, these are a bunch of independent circles It’s a spiral right?
Effect: Illusory visual motion
Successive contrast : afterimages... what do you see? fixate the black dot in the center for 60 seconds... … and then look at a the black dot in the right panel !
external auditory canal tympanic membrane Auditory tube malleus incus stapes round window oval window
The Inner Ear
The Cochlea Unwound
The Cochlea
The Organ of Corti hair cells tectorial membrane basilar membrane Sensory & motor neurons in the cochlear branch of the vestibulocochle ar (VII) nerve Supporting cells
Scala tympani Cochlear duct Basilar membrane MalleusIncus Auditory ossicles Stapes Oval window Scala vestibuli Helicotrema Cochlear nerve Round window Tympanic membrane (a) Route of sound waves through the ear
Static Balance – utricle and sacule Dynamic Balance- semicircular canals
(semicircular canal)
cupula hair cells Endolymph fluid Vestibular nerve fibers (semicircular canal)
The effect of gravitational pull on the macula receptor cell in the utricle
Hearing loss- due to disease (ex. meningitis), damage, or age related Conduction deafness- prevention or blocking sounds from entering inner ear. Sensoneural deafness- damage to the neural structures
IDENTIFY Hearing Animation:
1.Wher are merkel cells located? 2.What do proprioceptors sense? 3.What type of stimulus triggers a response in nociceptors? 4.Two senses that detect chemical concentrations are____. 5.A person with defective otolith sensory receptors may have difficulty ______. 6.Which eye muscle moves the eye to look medially? 7.Name the three bones in the middle ear. 8.What is the blind spot in the eye called? 9.Where are the highest concentration of cones located?