Download 1. Taste

RECEPTORS
GENERAL RECEPTORS
•Receptors for touch, pressure, pain & temperature
•Located throughout the body
•Found in the Dermis layer of the skin
-- pain receptors also called NOCICEPTORS
SPECIAL RECEPTORS
•Photoreceptors for Vision (sight) -- On the Retina
1. RODS -- dim light & motion
2. CONES -- color
•Mechanoreceptors --for Hearing, Position, & Balance
1. Hearing -- located in the Cochlea of the inner ear
2. Baroreceptors -- monitoring of Blood Pressure
--located in the arch of the Aorta & in the carotid sinuses
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 hypothalamus
2. Monitor for changes in the concentration
of body fluids (Electrolytes)
•Chemoreceptors -- for Taste, Smell, O2 & CO2 levels
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 the
Aorta & carotid sinuses
DEFINITIONS
ADAPTATION
-- Receptors adjust themselves so that they no
longer respond to the stimulus as they did in the
beginning.
REFERRED PAIN
-- Some neuron connect impulses from the skin &
the viscera to send to the brain
-- The brain cannot differentiate,
so assign pain to the skin
Gallbladder pain may
be felt in in the shoulder
Kidney pain may be felt
in the lumbar (flank)region
EYE
Clear, transparent, anterior
coat of the eye
Part that is replaced in a
corneal transplant
Cornea Lens
Watery fluid & helps
maintain curve of cornea
& carries nutrients
to the cornea & lens
thickness is adjusted
Aqueous
to focus light
humor
-- lens thins or flattens out
for distance
Ciliary Suspensory -- lens thickens or
body
ligament
rounds up for near
-- hold Lens in place &
vision
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 changes
to enable us to focus on
on objects
Jelly-like substance that give the
Vitreous eye shape & aids in refraction
humor
If lost cannot be replaced causing
blindness as retina falls forward
Cornea
Removal of the eyeball is
called Enucleation
absorbs stray light
Retina rays & nourishes
Choroid the retina
opaque back portion of
Sclera
the Cornea
Rods -- functions in dim light & senses motion
Cones -- functions in bright light & is sensitive to
3 colors
Red Green
Light blue
Fovea
centralis
Retinal
artery & vein
Optic
nerve
Optic
disc
-- Cranial Nerve II carries visual impulses from the rods
& cones to the Occipital Lobe
Papilledema --swelling & inflammation of the optic
nerve
(Blind Spot) -- area in which there is no rods or cones
Area where the vascular bed can be directly examined
-- area that contains a large amount of cones, so it is
the point of most acute vision
Muscles of the Eye
Intrinsic muscles
-- inside the eye
Lens
Iris
Colored portion of the
eye
Pupil
-- regulates amount of light
entering the eye
-- rounds up or flattens to view objects
Myopia -- nearsightedness
Hyperopia -- far-sightedness
Astigmatism -- distortion of the
curvature of the cornea
Presbyopia -- old-sightedness
Extrinsic Muscles
6 muscles attach to the skull bones & the
sclera to allow for coordinated movement
Nerves for the Extrinsic Muscles
Trochlear
& -- supplies one extrinsic muscle each
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)
Produces tears
Lacrimal Conjunctiva
Tears film across the eye
gland
in the direction of the nose
Lacrimal
ducts
Keeps the eyeball moist
Lines the eyelid & cornea
Destroys pathogens
EAR
External Structures
Also called the Auricle
Pinna
Made of cartilage
Helps collect sound waves
Not necessary for hearing
which captures foreign material
& protects the ear
Sound vibrations are first
picked up here
In small children, it is chiefly
made of cartilage
Tympanic
Membrane
External
Auditory
Canal
Middle Ear
It’s a cavity filled with air
Incus
& containing Ossicles
Connects middle ear to the throat
Stapes
Equalizes pressure
Malleus
Easy route for infection
Lies between the tympanic
membrane & Incus
Shaped like a hammer
Shaped like an anvil & lies between
Eustachian
Tube
the Malleus & Stapes
Attaches to the Oval window, which is the dividing line
between Middle & Inner ear
These bones are joined in such a way that sound waves are
amplified 20x by the time they reach the oval window
Inner Ear
Osseous Labyrinth
Semicircular
canal
-- vibrations enter here
Vestibulocochlear
through the Oval window
nerve
Functions in hearing
Contains Organ of Corti,
the site for the sensory receptor
cells (Hair Cells)
Vestibule
Cochlea
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
Within the Bony Labyrinth is a Membranous Labyrinth
Membranous
Labyrinth
The inner ear contain fluid
Between the Bony labyrinth
and the Membranous
labyrinth is a fluid called: Perilymph
Endolymph -- is the fluid inside the Membranous
Labyrinth
bone
membrane
perilymph
endolymph
Balance & Equilibrium
Senses eye
movement & head
position
Also send impulses to
Vestibulocochlear nerve
& then to the Cerebellum
Organ of Corti
Endolymph
Hair Cells
Basilar
Membrane
Tectorial
Membrane
Sound Waves
Vibration of the
Tympanic Membrane
Vibration of
Middle Ear bones
Vibration
of Oval Window
Fluid Movement
within Cochlea
Vibration of the
Basilar Membrane
Bending of Hairs of
Receptor Cells of
Organ of Corti starts
the Electrical
Stimuli
Vibration of
Round Window
Dissipation
of Energy
Electrical Stimulus
picked up by the
Vestibulocochlear
Nerve
Impulse sent to
the Temporal Lobe
of the Cerebral
Cortex
HEARING LOSS
Conductive Deficit
--Causes:
Cerumen (ear wax)
Foreign bodies
Perforation of the tympanic membrane
Otitis Media -- inflammation or infection of the
middle ear
Otosclerosis -- immobility of an ossicle
usually the stapes
Treatment 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 away
is the most frequent cause of nerve deafness