what are the 2 types of awareness
Conscious and unconscious
sensory receptors respond to changes in what?
thier enviroment (stimulus)
Activation of sensory receptors results in what?
graded potentials that trigger nerve impulses
awarness of stimulus
interpretation of the meaning of the stimulus
sensation and preception occur where?
receptors are classified based on what 3 things?
- stimulus type
- structural complexity
what are the 5 stimulus "type" classifications?
which receptor responds to touch,pressure, vibration?
which receptor responds to changes in temprature?
which receptors respond to light energy?
Wich receptors respond the chemicals (like smell,taste and changes in blood chemistry)?
Which receptors are sensitive to pain stimulus?
what are the 3 stimulus "location" classifications?
exterorecptors respond to stimulus occuring where?
outside the body
where are exteroreceptors found?
- skin (touch, pressure, pain, temp)
- most special senses organs
what are the 2 classifications of receptors based on structural complexity?
- complex receptors
- simple receptors
what does the complex receptors handle?
special sense organs (taste, vision, hearing, equlibrium, smell)
what does the simple receptors handle?
- general senses
- tactile sensations
- encapsulated or unencapsulated (free) dendritic endings
what 3 receptors are classified with unencapsulated dendritic endings
- Thermoreceptors - cold (10-40 C) / heat (32-48 C)
- Nocireceptors - respond to pinching, chemicals from damaged tissue, temps outside the range of thermoreceptors
- Light touch receptors - tactile (merkel) discs
which receptor is the only to be classified with encapsulated dendritic ending?
what are the encapsulated dendritic ending mechanoreceptors? (6)
- meissners (tactile) corpuscles
- pacinian (lamenatted) corpuscles
- ruffini endings
- muscle spindles
- golgi tendon organs
- joint kinesthetic receptors
meissners corpuscle is responsable for what ?
descriminative touch (2 point descrimination)
is meissners corpuscle shallow or deep?
what is Pecinian corpuscles resonsable for?
deep pressure and vibration (think P for PRESSURE)
is pecinian deep or shallow
Ruffini Endings sense what?
deep continous pressure
muscle spindles respond to what
what do golgi tendon organs sense
stretch in tendons
what do joint kinetic receptors sense
stretch in articular capsuls
what is the adaptation of sensory receptors
adaptation is a change in sensitivity in the presence of a constant stimulus
what happens in adaptation
- receptor membranes beacome less responsive
- receptor potentials decline or stop
what does sensory adaptation allow the CNS to do?
concentrate on the important stimuli and ignore noncritical ones to maintain homeostasis
which receptors adapt to continuing stimuli
light, touch, pressure, and smell
which receptors do not adapt
pain, joint, and muscle monitoring receptors
which percentage of sensory receptors are found in the eye?
most of the eye is protected by what ?
cusion of fat and boney orbit
what do the assesory structures of the eye do?
protect the eye and aid in eye function
what are the 5 accesory structures of the eye?
- eyebrows - sweat
- eyelids (palpebrae)
- lacrimal apparatus
- extrinsic eye muscles
eyebrows - location, function
- overlie the superorbital margins
- funtions in shading the eyes and preventing persperation from reaching the eye
eyelids are also known by what name
what is the function of the eyelids
protect the eye anteriorly
what are the two parts of the eyelid and thier funtions
- palpebral fissure - seperate the eyelids
- lacrimal - caruncle - the elevation at medial commisure contain oil and sweat glands
eyelashes have nerve endings which initaite what
transparent membrane over eye
what are the two types of conjunctiva
- palpebral conjunctiva - lines the eyelid
- bulbar conjunctiva - covers the whites of the eyes
- produces lubricating mucus secreation
what makes up the lacrimal apperatus?
Lacrimal gland and the ducts that connect to the nasal cavity
what are lacrimal secretions (tears) made of
dilute saline solution containing mucus, antibodies, and lysozyme
blinking spreads tears toward what structure?
tears drain into what
how many extrinsic eye muscles are there?
where do the extrinsic eye muscles originate
from the boney orbit
what are the functions of the extrinsic eye muscles
- enable eye to follow an object
- maintain the shape of the eye
extrinsic eye muscle are made up of what to types of muscles
how many rectus muscles are there and where do they originate
- originate from the common tendonious ring
how many oblique eye muscles are there and what is their function
- move the eye in a verticle plane and rotate the eyeball
name the 4 rectus muscles of the eye
what is the action of the lateral rectus muscle of the eye
moves the eye laterally
what is the action of the medail rectus muscle of the eye
moves the eye medially
what is the controlling cranial nerve of the lateral rectus muscle of the eye
what is the controlling cranial nerve of the medial rectus muscle of the eye
what is the controlling cranial nerve of the superior rectus muscle of the eye?
what is the controlling cranial nerve of the inferior rectus of the eye?
what is the controlling cranial nerve of the inferior oblique muscle of the eye?
what is the controlling cranial nerve of the superior oblique muscle of the eye?
whats another name for a layer in the eye
the wall of the eyeball contains 3 layers, name them.
the internal cavity of the eye is filled with fluid called...
the lens seperates the internal cavity of the eye into what to cavities or chambers
- anterior chamber
- posterioir chamber
what is the outermost layer of the eye?
the fiberous layer consists of ....
dense avascular connective tissue
what are the two regions of the fiberous layer
what is the sclera and its functions
- opaque posterior region
- protects the eye shape
- anchors extrinsic eye muscles
what is the cornea and what are its functions
- transparent anterior 1/6 of fiberous layer
- bends light as it enters the eye
- numerous pain receptors contribute to blinking and tearing reflexes
what are the 3 parts of the vascular layer or tunic of the eye
- choroid region
- ciliary body
what is the function of the choroid region
supplies blood to all layers of the eyeball
what is the ciliary body
ring of tissue surrounding the lens
ciliary body is made up of two structures name them
- smooth muscle bundles (ciliary muscles)
- ciliary zonules (suspensory ligaments)
what is the function of the smooth muscle bundles of the ciliary body?
controls lens shape
what is the function of the ciliary zonules
holds lens in position
which part of the is the iris
what is the central opening of the iris that controls the amount of light that enters the eye called?>
what are the 2 muscles that make up the iris and control the size of the pupil
- sphincter pupallae
- dilator pupallae
of the two muscles in the iris which would be sympathetic and which would be parasympathetic
- sphincter - parasympathetic
- dilator - sympathetic
the retina is made up of
delicate two layer membrane
what are the 2 layers of the retina
- pigmented layer
- neural layer
what is the function of the pigmented layer of the retina
- absorbes light and prevents its scattering
- absorbs vitamen A
what is the functions of the neural layer of the retina
its the photoreceptor - transduces light energy
why is the optic disc a blind spot?
there are no photorecptors there
ganglion cell axons of the the retina are located where in the retina
run along the innersurface of the retina
what do the ganglion cell axons of the retina leave the eye as?
the optic nerve
what is the optic disc
site where optic nerve leaves the eye
what are the 2 types of photoreceptors
what condition do rods preform in and what type of vision do they provide
- operate in dim light
- provide indistinct, fuzzy, non color peripheral vision
what conditions do cones operate in and what typoe of vision do they provide
- operate in bright light
- provide high acuity color vision
what does the posterior segment of the eye contain
what are the functions of the vitreous humor
- transmit light
- support the posterior surface of the lens
- hold the neural retina firmly against the pigmented layer
- contributes to interoccular pressure
anterior segment consists of what two segments
- anterior chamber
- posterior chamber
what type of "humor" does the anterior segment hold
what are the properties of the lens
what does the lens allow?
precise focusing of light on the retina
what transparent protein are lens fibers filled with
what happens to the lens with age?
becomes denser, more convex, and less elestic
what is the pathway of light entering the eye?
- aqueous humor
- vitreous humor
- neural layer of retina
the outer layer of both rods and cones contain visual pigments. what is a visual pigment?
molecules that change shape as they absorb light
what are the chemical senses
taste and smell
what is the origin of smell
olfsactory epithelium in the roof of the nasal cavity
what are olfactory receptor cells
bipolor neurons with radiating olfasctory cilia
what are the receptor organs of taste and where are they found
what are the 5 primary taste sensations
what is the gustatory pathway
- CN's VII and IX carry impulses from taste buds to solitary nucleus of the medulla
- impulses then travel to the thalamus from there fibers branch to the; gustatory cortex in the insula and then hypothalamus and limbic system
what are the influence of other sensations on taste?
- taste is 80% smell
- thermoreceptors, mechanoreceptors, nocirecptors in mouth influence taste
- temp and texture enhance or detract from taste