the senses chapter 35. 5 senses --- touch, taste, smell, sight & hearing touch the skin is the...
TRANSCRIPT
The Senses
Chapter 35
5 senses --- touch , taste, smell, sight & hearing TOUCHThe skin is the organ of touchTouch is a combination of pain, pressure, hot & cold TASTEThe tongue is the organ of tasteReceptors for taste are located in the taste budsSweet--- tip of tongueSalt--- sides of tongue near frontSour--- sides of tongue near backBitter--- across back of tongue
•SMELL
The nose is the organ of smell
The Olfactory neurons in the nose detect smell
•SIGHT
The eye is the organ for sight
The EyePART FUNCTION
conjunctiva protection
sclera Lets no light throughHolds the eye in shape
cornea Lets light into the eye
choroid Nourishes eye & prevents reflection of light with in eye
Fovea (yellow spot) Contains cones only– region of sharpest vision
Blind spot Where optic nerve leaves the eye
Optic nerve Carries impulses from the eye to the brain
Lens Changes shape to focus light on the retina
Ciliary muscle Cause the lens to change shape
Iris (coloured part) Controls the amount of light entering the eye
Pupil Lets light into the eye
Aqueous Humour Holds the front of the eye in shape
Retina Contains rods & cones (the light receptors)Rods for black & white vision & work in dim lightCones for colour vision & work in bright light
Vitreous Humour Holds the back of the eye in shape
Long Sightedness--Hypermetropia Person with long sight can see distant
objects clearly, but cannot see near objects
Cause: eyeball is too short To Fix: use CONVEX lens
Short sightedness--- Myopia Person can see near objects clearly, but
cannot see distant objects Cause: the eyeball is too long To Fix: use CONCAVE lens
Accommodation Is the ability of the eye to focus light from
objects at different distances by altering the focal length of the retina
Response of Iris to light BRIGHT LIGHT
the circular muscles contractthe size of the pupil decreasesLess light enters the eye
DIM LIGHT
The circular muscles relaxThe size of the pupil increasesMore light enters the eye
Hearing The function of the ear is hearing and
balance There are 3 sections to the ear1. Outer ear2. Middle ear3. Inner ear
The Ear
PART FUNCTION
Auditory canal Collects vibrations & carries vibration to eardrum
Eardrum Carries vibration to the middle ear
Ossicles– hammer, anvil, stirrup
Increases the vibrations & passes them to the oval window
Eustachian tube Connects the middle ear & pharynxEqualises pressure between the middle & outer ear
Cochlea Hearing– contain receptors which are stimulated by pressure waves in lymph. Receptors cause electrical impulses to be sent to the brain along the auditory nerve which interprets them as sound
Organ of Corti Contains receptors for hearing
Pinna Collect and channel vibration into the auditory canal
Vestibular apparatus Balance
How we hear Sound waves enter the ear Eardrum vibrates Three bones amplify the sound Oval window vibrates Liquid in cochlea moves hair cells stimulated Auditory nerve carries impulses to the
brain Brain interprets the sound
Glue Ear Is a hearing disorder Caused: by too much sticky fluid in the
middle ear Corrected: by decongestants or grommets(
small tubes inserted into the eardrum)