GENERAL RECEPTORS

SPECIAL RECEPTORS-- On the Retina

2. CONES -- color

RECEPTORSRECEPTORS

•Mechanoreceptors1. Hearing -- located in the Cochlea of the inner ear2. Baroreceptors -- monitoring of Blood Pressure --located in the arch of the Aorta & in the carotid sinuses

--for Hearing, Position, & Balance

•Photoreceptors for Vision (sight)

•Located throughout the body•Found in the Dermis layer of the skin

•Receptors for touch, pressure, pain & temperature

-- pain receptors also called NOCICEPTORS

1. RODS -- dim light & motion

3. Proprioceptors --Located in muscles, tendons, joints

& the semicircular canals of the inner ear--Provide information on position, balance

& movement of limbs•Osmoreceptors 1. Located in the digestive tract & in

the hypothalamus2. Monitor for changes in the concentration

of body fluids (Electrolytes)

1. Taste --taste buds located on the tongue fissures--4 types (Bitter, Sour, Salty, & Sweet)

2. Smell --olfactory cells located in roof of the nasal cavity

3. Receptors for O2 & CO2 located in arch of theAorta & carotid sinuses

•Chemoreceptors -- for Taste, Smell, O2 & CO2 levels

DEFINITIONSADAPTATION-- Receptors adjust themselves so that they no

longer respond to the stimulus as they did in the beginning.

REFERRED PAIN

Gallbladder pain maybe felt in in the shoulder

Kidney pain may be feltin the lumbar (flank)region

-- Some neuron connect impulses from the skin &the viscera to send to the brain

-- The brain cannot differentiate,so assign pain to the skin

EYEEYE

Cornea

Aqueoushumor

Ciliarybody

Suspensoryligament

Lens

Clear, transparent, anteriorcoat of the eye

Part that is replaced in acorneal transplant

Watery fluid & helpsmaintain curve of cornea

& carries nutrientsto the cornea & lens

thickness is adjustedto focus light

-- lens thins or flattens out for distance

-- lens thickens orrounds up for near vision-- hold Lens in place &

help it to change shape

Refraction -- the change of direction of a light ray as it passes from one medium to another (bending)

Accommodation -- coordinated eye changesto enable us to focus on

on objects

RetinaChoroid

Sclera

Vitreoushumor

Jelly-like substance that give the eye shape & aids in refraction

If lost cannot be replaced causing blindness as retina falls forward

Removal of the eyeball iscalled Enucleation

opaque back portion ofthe Cornea

Cornea

absorbs stray lightrays & nourishesthe retina

Rods

-- functions in dim light & senses motionCones-- functions in bright light & is sensitive to

3 colors Red Green Light blue

Foveacentralis

Opticnerve

Retinalartery & vein

Opticdisc

-- Cranial Nerve II carries visual impulses from the rods& cones to the Occipital Lobe

(Blind Spot) -- area in which there is no rods or conesArea where the vascular bed can be directly examined

--swelling & inflammation of the optic nerve

Papilledema

-- area that contains a large amount of cones, so it isthe point of most acute vision

Lens

Pupil

Iris

Muscles of the EyeIntrinsic muscles -- inside the eye

Colored portion of the eye

-- regulates amount of lightentering the eye

-- rounds up or flattens to view objects

Myopia -- nearsightedness

Hyperopia -- far-sightedness

Presbyopia -- old-sightedness

Astigmatism -- distortion of thecurvature of the cornea

Extrinsic Muscles

6 muscles attach to the skull bones & the sclera to allow for coordinated movementNerves for the Extrinsic Muscles

-- supplies one extrinsic muscle eachTrochlear Abducens&

Oculomotor-- supplies 4 extrinsic muscles

Protection of the Eye-- Skull bones-- Eyelid & eyelashes

--eyelashes sense particles-- sebaceous glands help lubricate the eye

(Sty -- inflammation of one of these glands)

Lines the eyelid & corneaDestroys pathogens

ConjunctivaLacrimal gland

Lacrimalducts

Produces tears

Tears film across the eyein the direction of the nose

Keeps the eyeball moist

EAREARExternal Structures

Pinna

ExternalAuditoryCanal

TympanicMembrane

Also called the Auricle

Helps collect sound wavesNot necessary for hearing

Made of cartilage

which captures foreign material & protects the earSound vibrations are first picked up here

In small children, it is chiefly made of cartilage

EustachianTube

Malleus

Incus

Stapes

Middle EarIt’s a cavity filled with air& containing OssiclesConnects middle ear to the throatEqualizes pressureEasy route for infection

Lies between the tympanic membrane & IncusShaped like a hammer

Shaped like an anvil & lies between the Malleus & StapesAttaches to the Oval window, which is the dividing line between Middle & Inner earThese bones are joined in such a way that sound waves are amplified 20x by the time they reach the oval window

Vestibule

Semicircularcanal

Osseous Labyrinth

Cochlea

Functions in hearingContains Organ of Corti,the site for the sensory receptor cells (Hair Cells)

Vestibulocochlearnerve

Impulses are picked up here and sent to the 8th Cranial nerve Vestibulocochlear

Base of the canal contains 2 sacs with hair cells that deal with head position & equilibrium

Inner Ear

-- vibrations enter herethrough the Oval window

Within the Bony Labyrinth is a Membranous Labyrinth

MembranousLabyrinth

The inner ear contain fluid

Between the Bony labyrinth and the Membranous labyrinth is a fluid called: Perilymph

Endolymph -- is the fluid inside the MembranousLabyrinth

bonemembrane

perilymphendolymph

Balance & Equilibrium

Senses eye movement & head position

Also send impulses to Vestibulocochlear nerve & then to the Cerebellum

Organ of CortiOrgan of Corti

Hair CellsBasilar

Membrane

TectorialMembrane

Endolymph

Impulse sent tothe Temporal Lobeof the CerebralCortex

Electrical Stimuluspicked up by theVestibulocochlearNerve

Bending of Hairs ofReceptor Cells ofOrgan of Corti startsthe ElectricalStimuli

Vibration of theBasilar Membrane

Fluid Movementwithin Cochlea

Sound Waves

Vibration of theTympanic Membrane

Vibrationof OvalWindow

Dissipationof Energy

Vibration ofRound Window

Middle Ear bonesVibration of

HEARING LOSS

Conductive Deficit

--Causes:

Cerumen (ear wax)

Foreign bodies

Perforation of the tympanic membrane

Otitis Media -- inflammation or infection of themiddle ear

Otosclerosis -- immobility of an ossicleusually the stapesTreatment is a Stapendectomy

Treat underlying cause

Nerve Deficit-- Damage to the 8th Cranial Nerve

--Causes:

Prolonged exposure to loud noises

Drugs like Streptomycin; Neomycin

Cochlear atrophy

German measles in the first trimester

Mumps

Cilia (hair cells) on the receptors have worn awayis the most frequent cause of nerve deafness