The General Senses
These corpuscles are also called Type II tactile disks
ruffini corpuscles
The ___ interprets the sensory information entirely on the basis over which line it arrives
CNS
Along the inner margin of the eyeball are _______ ____ which secrete a lipid-rich substance which prevents the eyeballs from sticking together.
Meibomian Glands
These corpuscles are abundant in the eyelids, lips, fingertips, nipples, and external genitalia and provide fine touch and pressure, and low frequency vibration sensations
Meissner's corpuscles
are sensory dendrites which are highly coiled and interwoven. They are surrounded by modified Schwann cells and fibrous capsule surrounds the entire complex and anchors it within the dermis.
Meissner's corpuscles
Also called Type 1 tactile discs
Merkel's discs
are specialized epithelial cells found in skin surfaces that lack hair. They are sensitive to touch when compressed or disturbed.
Merkel's discs or Type 1 tactile discs
This is known as the tympanic cavity.
Middle Ear
This type of adaptation occurs when the receptor of sensory neurons alter their levels of activity. In this situation, the receptors respond rapidly at first and then their activity decreases. These receptors are also called fast acting receptors.
Peripheral Adaptation
Where are the receptors for taste located?
The receptors are located in taste buds which are on the tongue, the soft palate, and the throat.
What are tears composed of chemically?
The secretions are watery, slightly alkaline, and contain the enzyme lysozyme- burst bacterial cell walls.
are free nerve endings which detect changes in temperature.
Thermalreceptor
carry sensations of slow pain or burning and aching pain
Unmyelinated Type C Fibers
monitor changes in pressure in the walls of blood vessels (aorta, carotid arteries, lungs, and vena cava), the digestive tract, urinary tract, and reproductive tract
barroreceptors
probably produce new olfactory cells
basal cells
produces new gustatory and supporting cells
basal cells
The rods and cones synapse with approximately six million ____ cells which in turn synapse with a layer of ____ cells. The axons of these cells exit the back of the eye to form the optic nerve.
bipolar, ganglion
The breakdown of rhodopsin into retinal and opsin is called?
bleaching
The area where the axons exit the eyeball and lacks photoreceptors for vision is called?
blindspot
A thin membrane called the ______ covers the inner surface of the eyelids and the anterior surface of the sclera up to the margin of the cornea.
conjunctiva
the inflammation of conjunctiva membrane due to trauma or pathogenic infection
conjunctivitis
By binding to presynaptic membrane, endorphins are preventing the release of substance P. Thus, they are reducing the ______ perception of pain, although the painful stimulus remains.
conscious
medial rotation of eyes as object approaches you
convergence
It contains many free nerve endings which make it very sensitive to chemicals, touch, and drying.
cornea
_____ is clear and transparent, a vascular continuation of the scera.
cornea
is a transparent surface on the front of the eyeball
cornea
The greatest amount of refraction occurs when light passes from the air into the ____ tissues which have a density close to that of water.
corneal
taste buds are monitored by which cranial nerves
cranial nerve seven (facial), cranial nerve nine (glossopharyngeal) and cranial nerve ten (vagus)
Where are receptors for temperature found?
dermis of the skin, skeletal muscle, hypothalamus, and liver
The distance between the center of the lens and the focal point is called?
focal distance
Refraction takes place when light passes from the aqueous humor into the relatively dens lens. The lens provides the extra refraction needed to focus the light rays from an object towards a specific _____ ____.
focal point
The primary function of the lens is to _____ an ____ on the surface of the retina. In order to do this, it must be continually reshaped. there is a capsule around the lens to which the suspensory ligaments attach.
focus, image
A pocket called the ____ is formed where the palpebral conjunctiva meets the ocular conjunctiva.
fornix
how many opsin are there?
four
a shallow depression called the _____ can be found on the posterior surface of the eye
fovea centralis
The simplest receptors are what?
free dendrites of sensory neurons
are sensitive to touch and pressure; are found between adjacent epidermal cells and on the corneal surface of the eye
free nerve endings
These papilllae are located on the tip and sides of tongue
fungiform papillae
knob like or mushroom shaped papillae are called
fungiform papillae
What is the word that describes excessive intraocular pressure which causes degeneration of the retina and blindness.
glaucoma
the sense of taste
gustation
There are forty to fifty of these cells per taste bud.
gustatory cells
The greater the number of receptors being affected by the stimulus, the ____ it is to localize a stimulus.
harder
allows us to perceive and interpret sound waves
hearing
"farsightedness" This results if the eyeball is too short or the lens is too flat, the image of a distant object will focus behind the retina.
hyperopia
The neural retina's primary function is _____ ____.
image formation
The area responsible for equilibrium and hearing
inner ear
These are also called visceroceptors
interoceptors
monitor conditions inside the body
interoceptors
What pressure is produced by the aqueous humor?
intraocular
This layer of the eyeball includes the ____, ____ , and ____.
iris, ciliary body, and choroid coat.
The neural link between the receptor and cortical region is called a
labeled line
This apparatus produces, distributes, and removes tears.
lacrimal apparatus
These punctum drain the tears into the superior and inferior ____ ___.
lacrimal canal
is a fleshy pad which contains glands which produce thick secretions which lubricate the eyeball
lacrimal caruncle
The ____ ____ are located on the superior- lateral aspect of the eyeball and produce about 1 ml of lacrimal fluid or tears per day.
lacrimal glands
The canals deliver the tears into the ______ ___ which channels tears into the nasal lacrimal duct which empties into the inferior meatus of the nasal cavity.
lacrimal sac
"nearsighted" This results if the eyeball is too deep or the resting curvature of the lens is too great, the image of a distant object will focus in front of the retina
myopia
In this vision, the ciliary muscle contracts and the tension on the suspensory ligametns is lessened resulting in the lens beingallowed to become more convex.
near vision
This is also called the retina
neural tunic
detect pain due to temperature and physical or chemical damage to the tissues.
nociceptors
emmytropia
normal vision
Visual sensations arrive at the visual region of the cortex called _____ ___.
occipital lobe
This conjunctiva covers the anterior surface of the sclera up to the margin of the cornea.
ocular conjunctiva
the sense of smell
olfaction
These cells are bipolar neurons. The distal end has up to twenty free dendrites or olfactory cilia which extend into the surface layers of mucous where dissolved chemicals interact with receptors on the membrane surface; the cell body lies between supporting cells; the axons of these bipolar neurons form cranial nerve I, olfactory nerve. These axons pass through the olfactory foramina of the cribriform plate of the ethmoid bone and synapse with neurons in the olfactory bulb. Axons leaving the olfactory bulb travel along the olfactory tract to reach the olfactory cortex, hypothalamus, and portions of the limbic system.
olfactory cells
what is another name or blind spot
optic disc
are composed of a single dendritic fiber surrounded by concentric cellular layers. They are scattered throughout the integument as well as superficial and deep fascia, joint capsules, the mesenteries, and the wall of the urinary bladder. They are sensitive to pulsing or high frequency vibrating stimuli
pacinian corpuscles
Blinking sweeps tears over the surfaces of the eyeball towards the lacrimal ____, two small openings in the upper and lower eyelids at the medial canthus.
punctum
Visual pigments are composed of a compound called ____. This compound contains a protein called ______ which is bound by a pigment called _____ which is synthesized form vitamen A
rhodopsin, opsin, retinal
The ___ are responsible for white and black vision
rods
somewhat cylindrically shaped
rods
the rhodopsin of ____ breaks down quickly in the presence of bright light and reforms slowly
rods
The innermost zone contains photoreceptor cells called _____ and ______.
rods and cones
These receptors are modified ends of dendrites
rods and cones (photoreceptors)
400-700 nanometers
rods and cones vision
are the nerve endings which wrap around the follicle of the hair; when the hair is displaced, the movement of the follicle distorts the sensory dendrites and produces action potentials which may be interpreted as movement or pain.
root hair plexus
function in color vision
cones
somewhat conicaly shaped
cones
There are about ____ rods around the periphery of the retina.
125 million
These are neuromodulators whose release inhibits activity along pain pathways in the brain.
Endorphins/ Enkephlins
carry sensations of fast pain or prickling pain. An injection or deep cut produces this type of pain.
Myelinated Type A Fibers
This is the area being monitored by the receptor
Receptor Field
Each receptor has a characteristic sensitivity. This is called what?
Receptor Specificity
What is an example of a complex receptor?
Rods and Cones of the retina
These are specialized cell that provide the CNS with information about conditions inside or outside the body.
Sensory Receptors
Rods and Cones, complex receptors are protected by what?
accessory cells and layers of CT
these structures offer support and protect the eyeballs
accessory structures
The process of reshaping the lens to compensate for near and far vision
accomidation
is a reduction in the sensitivity of a receptor in the presence of a constant stimulus
adaptation
The handle of the malleus attaches to the tampanic membrane and the head connects to the incus. The incus in turn attaches to the stapes which fits its oval surface into the oval window of the inner ear. An auditory tube leads from the pharynx to the middle ear and functions in equilization of ambient ____ in the middle ear.
air pressure
The fluid called ___ ___ is secreted by the epithelium of ciliary processes
aqueous humor
This fluid helps to nourish the lens and cornea
aqueous humor
If a lens has minor imperfections or irregularities, it will not be able to uniformly refract the light entering the eye and therfore the image on the retina will not be uniformly focused. This issue is called
astigmatism
This type of adaptation occurs in the central nervous system as a result of inhibition of sensory nuclei along neural pathways.
central adaptation
Bacterial infections of the meibomian glands produces a small lump called
chalazion
are receptors which respond to water-soluble and lipid-soluble substances dissolved in the surrounding fluids
chemoreceptors
The _____ ___ is a heavily pigmented layer which seperates the fibrous and neural tunics.
choroid coat
This layer contains many capillaries that supply the retina with oxygen and nutrients and remove waste products
choroid coat
begins at the junction of the sclera and cornea and extends posteriorly to the ora serrata
ciliary body
circular, doughnut shaped papillae arranged in an inverted V on the posterior portion of the tongue.
circumvallate papillae
___ require more light in order to function in comparision to the other photoreceptor
cones
informs us to our position relative to gravity as well as our movement through space
equilibrium
How quickly is aqueous humor being replaced?
every ninety minutes
consists of the external pinna or auricle which captures sound waves and channels them into the external auditory canal. This canal is lined with ceruminous glands which produce a waxy secretion to trap dust and debris. It also acts as a bacteriacidal agent and short hairs which keep larger debris and insects out of ear. the sound waves eventually cause the thin concave membrane called the tympanic membrane or eardrum to vibrate back and forth.
external ear
provide information about the external environment
exteroceptors (smell, hearing, vision, taste, temperature, pain)
They are located in the two orbits of the skull, are about one inch in diameter and share the orbit with the extrinsic eye muscles, fat for padding and insulation, the lacrimal gland, blood vessels, and several cranial nerves.
eye
the visual organs which contain the receptors for vision
eye
These are short stiff hairs embedded in the outer margins of the eyelids. They prevent dust and debris from falling into the eye and will cause a blink reflex to occur if touched.
eyelashes
Also called palpebrae
eyelid
a skin flap which slides over the eyes periodically. It shades the eyeball, spreads fluid over the surface of the eye, and protects the eyeball from debris and drying out
eyelid
In this vision, the ciliary muscle relaxes and the tension on the suspensory ligaments increases resulting in the lens being pulled which reshapes the lens into a lesser biconvex shape.
far vision
They give a friction surface to move food around in your mouth
fibriform papillae
slender, thread-like pointed projections which cover the anterior 2/3 of the tongue
fibriform papillae
the outermost layer of the eyeball which consists of the sclera and cornea
fibrous tunic
a layer of loose CT which holds the nasal epithelium to bone. It also contains nerves and blood vessels which bring oxygen and nutrients to the epithelium and remove carbon dioxide and waste products
lamina propria
Radial muscle fibers (pupillary dialator muscle) make pupils smaller or larger
larger
____ and ____ ___ divide the interior of the eye into anterior and posterior cavities.
lens and ciliary body
Where are endorphins found?
limbic system, hypothalamus, and reticular formation
The junction between the sclera and cornea is called ?
limbus
The fewer the number of receptors being affected by the stimulus, the greater the ability to _____ a stimulus.
localize
The identity of the active labeled line indicates the ___ and ___ of the stimulus
location and nature
When sensory information arrives at the CNS, it is routed according to the _____ and ____ of the stimulus.
location and nature
Critical vision occurs at the __.
macula lutea
The visual axis is always focused on the _____ _____.
macula lutea
There is an area of the retina which covers the fovea called the ___ which is composed mostly of cones.
macula lutea
detect physical stimuli which result from the physical distortion of a cell's membranes. These membranes contain mechanically gated ion channels whose gates open and close in response to stretching, compression, twisting, vibrations or other distortions
mechanoceptors
The two eyelids join at the corners of the eye. these areas are called the
medial and lateral canthus
What are the general senses?
pain, pressure, proprioception, touch, temperature, and vibration
This conjunctiva covers the inner surface of the eyelids.
palpebral conjunctiva
the opening between the upper and lower eyelids
palpebral fissure
Touch, pressure, pain, temperature, and taste sensations arrive at the primary sensory cortex called _____ ___.
parietal lobe
What are the two types of adaptation?
peripheral and central adaptation
What type of receptor are thermoreceptors? are the phasic or tonic
phasic (since they are temporarily inactive)
These receptors are normally inactive. They become temporarily active when there is a change in the condition they are monitoring.
phasic receptors
a loss of the elasticity of the lens which usually occurs in the older individuals and results in hyperopia.
presbyopia
Endorphins bind to the _____ ______ and prevent the release of substance P
presynaptic membrane
receive information concerning body position and movement
proprioceptor
These corpuscles are located deep in the skin and are sensitive to pressure and distortion. They consist of a capsule, which contains interwoven dendrites surrounded by collagen fibers.
ruffini corpuscles or Type II tactile disks
The fluid used to suspend or dissolve a food source so it may be tasted, soften to swallow, and begin carbonate digestion via amylase- breaks down carbohydrates to glucose in mouth
saliva
______ is a dense white fibrous coat (contains collagen and elastic fibers) which is tough enough to prevent puncturing, maintains the shape of the eyeball, and is a point of insertion for the six extrinsic eye muscles
sclera
provides information about the strength, duration, variation, and movement of the stimulus
sensory coding
There are about ____ cones on the posterior retinal surface.
six million
Circular muscle fibers (pupillary constrictor muscle) make the pupil smaller or larger
smaller
What are special senses?
smell (olfaction), taste (gustation), balance (equilibrium), hearing, and sight (vision)
Which of the following are not a general sense? pain, temperature, touch, pressure, smell, hearing, vibrations and proprioception
smell, hearing
To taste something, the material must be in a _____.
solution
The Ciliary Muscle is a _____ muscle which lays under the finger-like epithelial folds called ciliary processes
sphincter
An infection of a sebaceous gland of the eyelashes, a Meibomian gland, or sweat gland of the eye produces a painful localized swelling called a ___
sty
What is the neurotransmitter in the limbic system, hypothalamus, and reticular formation called?
substance P
a specialized epithelium which forms the capsule of a taste bud and supports the olfactory cells
supporting cells
columnar epithelial cells of the mucous membrane; some of these columnar cells have differentiated into goblet cells
supporting cells
The _______ _______ of the lens extend from a capsule covering the lens to the ciliary processes
suspensory ligaments
These ____ help to hold the lens behind the iris and centered with the pupil.
suspensory ligaments
monitor touch, pressure, and vibrations. Can be free nerve endings to specialized structures
tactile receptors
Which of the following is not a general sense? pain, pressure, proprioception, taste, touch, temperature, and vibrations
taste
Each hair-like process called microvilli or taste hair will project out of the taste bud by way of a ____
taste pore
auditory and olfactory sensations arrive at their receptive regions of the cortex called
temporal lobe
The lateral portion of the superior fornix receives____ to ____ ducts from the lacrimal gland.
ten to twelve
This area contains blood vessels, the intrinsic eye muscles, and lymphatics.
vascular tunic
Why are corneal transplants possible?
they are possible due to the fact that there are no blood vessels to carry white blood cells to this area to attack the foreign tissue
There are____ zones of neurons in the neural retina
three
What is the job of tears?
to reduce friction, remove debris, prevent bacteria infection, and provide nutrients/oxygen to conjunctiva.
These receptors are always active. When the stimulus increases or decreases, the rate of their action potentials change accordingly.
tonic receptors
The translation of a stimulus into an action potential is called?
transduction
This consists of an inner neural retina which contains photoreceptor for _____ and an outer pigmented layer
vision
the ability to detect light and form detailed images
vision
The posterior cavity contains a thick, jelly-like fluid called ____ humor.
vitreous
This fluid helps to prevent the eyeball from collapsing and holds the retina flush against the interior of the eyeball. It is crystal clear and not replaced quickly by the body.
vitreous humor
