Senses Flashcards
Depends on sensory receptors.
Sense receptors
Respond to various stimuli. What is this?
What triggers an impulse in a receptor?
What travels to cerebral cortex are processed and interpreted?
- Sense receptors
- Stimulus
- Action potentials
Receptors are widely distributed in the body; pain, touch, pressure, proprioception
General senses
Receptors are localized in a particular area; smell, hearing, sight
Special senses
Stimulus of this sense receptor changes in chemical concentration of substances. What is this? What is an example of this? (2)
Chemoreceptors
- taste and smell
Stimulus of this sense receptors cause changes in pressure or movement in fluids. Examples are proprioceptors in joints, receptors for hearing and equilibrium.
Mechanoreceptors
Stimulus of this sense receptor causes tissue damage. Example of this are pain receptors
Nociceptors
Stimulus of these sense receptors causes changes in temperature. Examples are heat and cold.
Thermoreceptors
Stimulus of these sense receptors are light energy and an example is vision.
Photoreceptors
Steps involved in sensory perception:
- Stimulus
- Receptor detects the stimulus and creates an action potential
- Action potential (impulse) is conducted to the CNS
- Within the CNS, the impulse is translated into information
- Information is interpreted in the CNS into an awareness or perception of the stimulus
A decreased sensitivity to a continued stimulus. Triggers impulses only if strength of stimulus is increased. Some sense receptors are most sensitive to changes in stimulus. They become tolerant to continuous stimuli of the same strength.
Sensory adaptation
Found throughout the body. Associated with visceral organs, skin, muscles, joints. Include touch, pressure, proprioception, temperature, and pain.
General senses (Somatic Senses)
Receptors for touch and pressure. Sensitive to forces that deform or displace tissues. Widely distributed in the skin.
Mechanoreceptors
Mechanoreceptors involved in touch and pressure. Have no connective tissue covering. Interspersed in epithelial tissue. Sens objects that are in continuous contact with the skin (e.g. clothing)
Free nerve endings
Mechanoreceptors involved in touch and pressure. Located in dermal papillae (just beneath epidermis). Sense light discriminative touch stimuli
Meissner’s corpuscles
Mechanoreceptors involved in touch and pressure. Located in deeper dermis and subcutaneous tissues, tendons, ligaments, because several layers of connective tissue surrounded the nerve endings. Stimulated by heavy pressure.
Pacinian corpuscles (lamellated corpuscles)
Sense of position or orientation. Allows an individual to sense the location and rate of movement of on body pat relative to another.
Proprioception
Important Mechanoreceptors for proprioception. Location is junction of a tendon with a muscle. Muscles spindles (located in skeletal muscle).
Golgi tendon organs
Located immediately under skin. Temperature receptors help the human being avoid damage to the skin from excessive heat or cold. Widely distributed throughout the body:
- Most numerous: Lips
- Least numerous: Broad surfaces of trunk
Thermoreceptors
Thermoreceptors has up to how many times more cold receptors in a given areas than heat receptors?
Thermoreceptors extremes in temperature simulate pain receptors is below how many degrees Celsius? Pain receptors produce a freezing sensation.
- 10 times
- Below 10 degrees Celsius
As temperature increases above how many degrees Celsius and Fahrenheit cause pain impulse to cease and cold receptors behind to be stimulated?
10 degrees Celsius and 50F
At temperatures about how many degrees Celsius and Fahrenheit does heat receptors begin to be stimulated and cold receptors fade out?
25 degrees C and 77F
As temperatures approach how many degrees Celsius and Fahrenheit does heat receptors fade out and pain receptors are stimulated; producing a burning sensation?
45 degrees Celsius and 113 F
Extreme cold and extreme heat feels almost the same. Both are painful and pain receptors are being stimulated. What is exhibited by thermoreceptors causing thermoreceptors are strongly stimulated by abrupt changes in temperature. Then fade after a few seconds or minutes; for example, a heating pad no longer feels warm?
Sensory adaptation
Initiate the sense of pain. Consists of free nerve endings. Stimulated by tissue damage. Widely distributed throughout the skin and in tissues of internal organs. Usually do not adapt and may continue to send signals after the stimulus is removed
Nociceptors
No pain receptors in the what tissue of the brain? other tissues in the brain have an abundant supply.
What are 2 examples?
- Nerve tissue
- Meninges and blood vessels
What is the function of pain receptors?
They signal to locate and remove source of tissue damage.
Protection
Also known as taste. Are also chemoreceptors. Sensitive to chemicals in food. What is this?
What are the organs of taste? Located on the surface of the tongue.
- Gustatory Sense
- Taste buds
Taste buds lie along the walls of projections called what?
Taste cells also known as what cells are specialized epithelial cells? Lie within the taste bud. Interspersed with supporting cells and nerve fibers.
- Papillae
- gustatory cells
Opening of the taste bud opens to the surface.
Taste pore
Project from taste cells through the taste pore. What is this? What do the function as?
Taste hairs
- function as the chemoreceptors
What are the four types of taste receptors that control taste sensations? Each one is concentrated in a specific region on the tongue.
- Salty
- Sour
- Sweet
- Bitter
Taste hair chemoreceptors are stimulated by chemicals in food. Causes an impulse to be triggered on a nerve fiber.
Interpretation of taste sensations
Impulses from the anterior two thirds of tongue.
Facial nerve
Impulses from posterior one third of tongue.
Glossopharyngeal nerve
The impulses are interpreted in the sensory cortex on what lobe of the cerebrum, near the lateral sulcus?
What type of nerves carry taste impulses?
- parietal lobe
- cranial nerves, a type of peripheral nerves
Sense of smell. Are chemoreceptors. Stimulated by chemicals dissolved in liquids. Consists of olfactory neurons in the nasal cavity.
Long cilia extend to the surface. Project into nasal cavity. Function as the chemoreceptors.
Olfaction (olfactory receptors)
Airborne molecules responsible for odors. Dissolve in fluid on the surface of the olfactory epithelium. Then bind to cilia chemoreceptors and triggers impulses. Impulses travel along olfactory neurons to the olfactory bulb. Synapse with association neurons. Impulse is conducted through the olfactory tract to the brain. Impulse travels to olfactory cortex in what lobe for interpretation?
Where in the brain do the impulses first arrive?
Interpretation of smell sensations
- temporal lobe
- olfactory bulb
Organs of vision. Protected by a bony socket. Assisted by accessory structures that protect and move them.
Eyes
What portions of the eyes are visible?
Where is the part of the eye that cannot be seen externally?
- Only a small portion
- in the eye socket or or orbit
Surrounds most of eye. Made up of seven cranial bones. Formed by portions of the frontal, lacrimal, ethmoid, maxilla zygomatic, sphenoid, and palatine bones.
Bony orbit
Keeps perspiration out of eye because perspiration can irritate the eye.
Eyebrows
Open and close the eye. Keeps foreign objects from entering the eye.
Eyelids
Closes the eye
Orbicularis oculi
Opens the eye
Levator palpebrae superioris
Mucous membrane. Lines the eyelid and covers the anterior portion of eyeball, except for cornea.
Conjunctiva
What from the conjunctiva keeps eye from drying out?
What are composed of skin, connective tissue, muscle, and conjunctiva, a thin, clear, moist membrane that coats the inner eyelid and the outer surface of the eye.
- Mucous
- Eyelids
What traps foreign particles?
Eyelashes
Associated with eyelashes. Secrete an oily fluid, lubricate the region
Sebaceous glands
Inflammation of a sebaceous gland of the eye
Stye
Produces and transports tears.
Lacrimal apparatus
Produces tears. Located superior and latter region of orbit
Lacrimal gland
Transports tears from lacrimal gland to surface of eye.
Lacrimal ducts
Cary tears from surface of eye toward nasal cavity
Lacrimal canals
What moisten, lubricate, and cleans anterior surface of the eye; contain lysozyme (enzyme) that destroys bacteria and prevents infection?
Tears
Also known as bulbus oculi. 2-3 cm in diameter
Eyeball
What are the 3 layers of the eye?
What is the innermost tunic found only in the posterior of the eye?
- Fibrous tunic
- Vascular tunic
- Nervous tunic (retina) (innermost tunic)
What two things does the fibrous tunic include?
What 3 things are included in vascular tunic?
What 2 things is included in nervous tunic?
- Sclera and cornea
- Choroid, ciliary body, iris
- Retina, optic disk
White part of the eye. Covers 5/6 of the eye. Consists of white tough connective tissue.
Fibrous tunic
Transparent anterior “window” of the eye
Cornea
Highly vascular, brown pigmented middle layer. Loosely attached to the retina. Also loosely lines the sclera. What is this?
What absorbs excess light rays that might interfere with vision?
What nourish interior of the eye?
- Choroid
- Pigment
- Blood vessels
Contains fingerlike ciliary processes that secrete aqueous humor. Also contains the ciliary muscle.
Ciliary body
This is what the ciliary body secretes. A fluid located in the anterior portion of the eye. Maintains shape of anterior part of eye; nourishes the structures in that region; maintains internal pressure of the eye.
aqueous humor
Connect ciliary body to lens of the eye. What is this?
When the ciliary muscles contract it causes what to relax?
Suspensory ligaments
Colored portion of the eye. Composed of two groups of smooth muscles that help regulate the amount of light entering the eye. What is this?
When the radial muscles contract, what happens to the pupil?
When the circular muscles contract, what happens to the pupil?
- Iris
- Dilates
- Constricts
Doughnut-shaped diaphragm with a central aperture
Pupil
Deeply pigmented and firmly attached to choroid.
Outer layer of retina
Have layer containing rods and cones, the photoreceptor cells. Have layer of neurons and ganglion cells that have axons of ganglion cells that form the optic nerve.
Retina
White spot where the optic nerve leaves the eye. Does not have photoreceptor cells. Known as the “blind spot”
Optic disk
The optic disk can be seen as a white spot when the physician looks into the eye with an ophthalmoscope. Blood vessels can also be seen.
Why the optic disk is known as the “blind spot”
Yellow spot located near center of retina.
Macula lutea
Depression located in the center of the macula. The region of the retina that produces the sharpest image.
Fovea centralis
The eye is divided into 2 cavities by what parts of the eye? (3)
Lens, suspensory ligaments, and ciliary body
Space between the cornea and lens
Anterior cavity
Space between lens and retina.
What is this?
Filled with a colorless, transparent, gel-like fluid called what? Presses the retina firmly against wall of eye; supports internal parts of the eye; and maintains shape of the eye.
- Posterior cavity
- Vitreous humor
The bending of light rays. These surfaces in the eye bend the light rays so that they focus on the retina. Image is upside down and backward, the brain interprets the image in the correct position.
Refraction
With an object that is at least 20 feet away, the eye is normal and relaxed and is able to focus the image on the retina.
What occurs to the following:
- ciliary muscle
- suspensory ligaments
- lens
- Ciliary muscle: is relaxed
- Suspensory ligaments: are taut
- Lens: is flat
If a person is nearsighted, what happens to the normal focal distance?
If a person is farsighted, what happens to the normal focal distance?
- Shorter
- Longer
When the object is closer than 20 feet, the eye must make adjustments to focus the image.
What happens to the following parts of the eye?
- Ciliary muscle
- Suspensory ligaments
- Lens
- Ciliary muscle: contracts
- Suspensory ligaments: become loose and relaxed
- Lens: bulges or becomes more convex
Changing shape of lens
Accommodation
The closer the object, the more the light rays have to bend to focus and the greater the curvature of what part of the eye?
lens
Thin cells with slender, rodlike projections. Much more NUMEROUS than cones. Sensitive to dim light.
Rods
Visual purple. Contained in rods. Very light sensitive and allows the eye to adapt to dim light. ABSENT in the fovea centralis. Increase as distance from fovea centralis is increased. Vision with this lacks fine detail.
Rhodopsin
Receptors for color vision and visual acuity. Located primarily in fovea centralis. Thicker cells with short, blunt projections. Vision with this provide sharp images and fine detail. There are three different types, each with a different type of pigment. One type responds best to green light, one to blue light, and a third to red light.
Cones
Visual impulses generated in the rods and cones leave the eyes in the axons that form what nerves?
- Optic nerves
Axons from the medial portion of each retina cross over. Enter the optic tract on the opposite side.
Optic chiasma
What contains fibers from the lateral portion of the right eye and the medial portion of the left eye?
What contains the fibers from the lateral portion of the left eye and the medial portion of the right eye?
As a result, the left side of the brain interprets visual information from the front and right area of vision, and the right side of the brain interprets visual information from the front and left area of vision.
- Right optic tract
- Left optic tract
- Optic tracts lead to the thalamus
- Synapse with neurons
- Impulse travels to visual cortex of occipital lobes for interpretation because some fibers cross over in optic chiasma, allows for three-dimensional vision
Visual Pathway
Organ for hearing. Auditory or acoustic organ. Organ for equilibrium. Sound vibrations also are responsible for initiating impulses that are interpreted as sound.
Ear
What is between auricle and tympanic membrane?
What begins at tympanic membrane and ends at oval and round windows?
What are interconnecting chambers in the temporal lobe?
- External Ear
- Middle ear
- Inner ear
Fleshy part of external ear. Visible on side of head. Surrounds opening into external auditory canal. Coleects sound waves and directs them toward auditory canal.
Auricle (pinna)
S-shaped tube. 2.5 cm long. Extends from auricle to tympanic membrane. Contains numerous hairs and ceruminous glands that secrete a waxy substance called cerumen.
External auditory canal
What 2 things help prevent foreign substances from reaching the eardrum?
Hair and cerumen
Consists of an air-filled cavity. Contains the auditory ossicles and has an opening into the eustachian tube.
What is this?
What is a thin membrane that separates the external ear from the middle ear? It can be seen clearly through an otoscope. Sound waves cause this to vibrate.
- Tympanic cavity
- tympanic membrane (eardrum)
Located in medial wall of middle ear. Connect middle ear with inner ear.
Oval window and round window
Connects middle ear with throat. Equalizes pressure between outside air and middle ear. Necessary for normal hearing. Throat infections may spread to middle ear through this.
Auditory tube (eustachian tube)
When tympanic membrane vibrates, this transmit vibrations. What is this?
What are the three tiny bones that this contains?
Auditory ossicles
- Malleus (hammer)
- Incus (anvil)
- Stapes (stirrup)
When the bones of the ear do not move freely, what interferes with sound transmission?
Otosclerosis
Series of interconnecting chambers in the temporal bone.
Bony labyrinth
Membranous tubes located inside bony labyrinth. What is this?
What is clear fluid that fills membranous labyrinth?
What is fluid that fills space between bony and membranous labyrinths?
Membranous labyrinth
- Endolymph
- Perilymph
What 2 things in the inner ear function in equilibrium?
What part of the inner ear is the coiled portion of bony labyrinth and functions in hearing?
- vestibule and semicircular canals
- cochlea
Membranous labyrinth inside bony labyrinth. Contains endolymph. What is this?
What is located within cochlear duct, contains receptors for sound, and the receptors on this are hair cells with hair-like projections?
- Cochlear duct
- Organ of Corti
What pitched tones create low- frequency waves? What pitched tones create high-frequency waves?
What frequency sounds have shorter wavelength (high frequency or low frequency)?
- Low-pitched tones
- High-pitched tones
- High frequency sounds (shorter)
Individual with normal hearing should be able o hear frequencies of normal speech. What is the range of vibrations per second? Hearing is most accurate between what vibrations per second?
- 300-4000
- 2000-3000
Initiation of Impulses:
- Sound waves enter external auditory canal
- Travel through external ear
- Vibrations reach tympanic membrane and cause it to vibrate
- Vibrations transferred to malleus, incus, and stapes
- Vibrations transferred to oval window membrane
- Interference with hearing may occur when there is excessive fluid in the middle ear or when the auditory ossicles do not move properly.
- Movement of the oval window membrane transfers the motion to the fluids in the inner ear
- Causes bending of the hairs on the hair cells in the organ of Corti
- Bending of the hairs stimulates formation of impulses
- Impulses transmitted to the auditory cortex of the temporal lobe for interpretation
- By the cochlear branch of cranial nerve VIII (vestibulocochlear nerve)
What nerve causes impulses to be transmitted to the auditory cortex of the temporal lobe for interpretation?
cochlear branch of cranial nerve VIII (vestibulocochlear nerve)
Detected by portion of the organ of Corti that vibrates in response to the sound and sensitivity of hair cells.
Pitch
Determined by intensity of sound waves
Loudness
Evaluating position of head relative to gravity. Occurs when head is motionless or moving in a straight line.
Static equilibrium
Occurs when head is moving in a rotational or angular direction
Dynamic equilibrium
Contains organs of static equilibrium. What is this?
What is this divided into? (2)
What small structure do each of these saclike structures contain?
Vestibule
- Utricle
- Saccule
- a macula
Consists of sensory hair cells and supporting cells. What is this?
What is embedded in a gelatinous mass that covers the macula?
What is embedded on the surface of gelatinous mass and consists of grains of calcium carbonate?
When the head is in upright position, hairs are straight. When the head tilts or bends forward, what 2 things move in response to gravity?
- Macula
- Projections (hairs) of hair cells
- Otoliths
- Both otoliths and gelatinous mass
What part of the ear contains sense organs for dynamic equilibrium? How many semicircular canals are positioned at right angles to each other in different planes?
- Semicircular canals
- 3
Each membranous canal is surrounded by what? Contains what? And has what that is located at the base of each canal that contains sensory organs known as crista ampullaris?
- Surrounded by perilymph
- Endolymph
- Ampulla
When head turns rapidly, what happens to the following:
- Semicircular canals
- Endolymph
- Fluid pushes against what when tilted to one side and as it tilts, it bends some hairs on hair cells?
- Move the head
- remain stationary
- cupula
When head turns rapidly, it triggers a sensory impulse and how many canals are in different planes, so cristae are stimulated differently by same motion? Due to this, it creates a mosaic of impulses.
Impulses are transmitted to the CNS on vestibular branch of vestibulocochlear nerve. CNS interprets information. Initiates appropriate response to maintain and achieve what?
- 3
- balance
Happens du to aging. Farsightedness. Most common age-related dysfunction of the eye.
Presbyopia
Aging of the Senses:
- Presbyopia
- Cataracts
- Increase astigmatism
- Require more light to see (muscle atrophy in iris reduces pupil’s ability to dilate)
- Rhodopsin becomes slower
Cornea becomes more translucent and less spherical
Astigmatism
In the eye, what 2 things happens to the lens, which makes it less able to change shape to accommodate for near vision due to aging?
What percentage of people over 70 have some degree of cataract formation?
- becomes thicker and less elastic
- 90%
Does external and middle ear changes have little effect on hearing when aging?
Is it true that buildup of cerumen may cause hearing loss in low-frequency range and joints between auditory ossicles becomes less moveable?
Most hearing loss is due to degeneration of receptor cells in the what?
- Decrease in nerve fibers occurs in what nerve?
- Decrease in vestibular fibers affects what 2 things?
- Yes, has little effect
- Yes, its true
- organ of Corti
- vestibulocochlear nerve
- affects balance and equilibrium
Does taste and smell show a decline with age and people aging find food unappetizing, is this true? Does anyone know why?
- True, no one knows why
- May be due to degeneration of receptor cells
- May be changes in the way the impulses are process in the brain
- Likely due to a combination of several factors
