HS&F 2 - 1 (15) Special Senses
130 flashcards · Other · by John Mark Webb
In general, how do all sensory receptors work? neurons are stimulated info is sent to brain cerebral cortex integrates info forms perception
What is the difference between sensation and perception? sensation awareness of the stimuli perception interpreting the stimuli
How do we form perceptions? neurons are stimulated info is sent to brain cerebral cortex integrates info forms perception
What is the largest sense organ of the body? skin
What do we mean by a threshold? Do receptors respond to only one stimulus? with enough stimulation the nerve fires receptors can respond to multiple stimuli
What are exteroceptive senses? respond to stimuli arising outside the body
What are interoceptive senses? respond to stimuli arising in internal viscera and blood vessels
What are proprioceptive senses? respond to stretch in skeletal muscles, tendons, joints, ligaments, and connective tissue coverings of bones and muscles informs brain of one's movement
What do we mean when we speak of simple receptors? modified dendritic endings of sensory neurons found throughout body monitor most types of general sensory info
Is the cerebral cortex the only place where information is processed? no
How is information processed? Three levels: receptor level (sensory receptors) circuit level (processing in ascending pathways) perceptual level (processing in cortical sensory areas)
What is meant by a graded potential or receptor potential? graded potential a ligand opens a ligand-gated channel in the dendrites, allowing ions to enter (or exit) the cell receptor (generator) potential a type of graded potential, is the transmembrane potential difference produced by activation of a sensory receptor
What is transduction? the conversion of a sensory stimulus from one form to another physical stimulus is converted into an action potential
What are generator potentials? stationary depolarization of a receptor that occurs in response to a stimulus graded according to its intensity and that results in an action potential when the appropriate threshold is reached
What is sensory adaptation? reduction in sensitivity to a stimulus after constant exposure to it
What is the difference between phasic and tonic receptors? phasic receptors fast adapting (mainly to report changes) tonic receptors sustained response w/ little or no adaptation
How is information processed at the perceptual level? information is processed in cerebral cortex
What is frequency encoding? means by which the central nervous system, limited by the all-or-none properties of nerve impulse conduction, is able to convey information about varying intensity of signals
What sense organs help us feel touch and pressure? What are their receptor cells? skin mechanoreceptors
How do we sense different temperatures? thermoreceptors in skin
What are the receptors for pain? What stimuli can cause pain? nociceptors detect damage from mechanical, electrical, thermal, or chemical energy
What is substance P? neurotransmitter involved in the synaptic transmission of pain and other nerve impulses
Do pain receptors adapt? Why is this good? pain receptors adapt little, if at all if adapted, protection from pain would be lost and would become useless
What is the difference between pain threshold and pain tolerance? all people have the same threshold (perceived pain at the same stimulus intensity) not all people have the same tolerance (how well you handle pain)
What can change a person’s pain tolerance? age chronic pain cultural factors psychological factors
What sensations do we get from our viscera? pain receptors (nociceptors) are the only receptors in the viscera that produce sensations
What is referred pain? pain that feels like it is coming from somewhere else in the body
What is phantom pain? pain that comes from a limb that has been amputated
What are the two types of pain fibers and how do they differ? acute pain fibers thin myelinated conducts up to 30 m/s sharp/localized pain seldom continues after stimulus stops chronic pain fibers thin unmyelinated conducts up to 2 m/s dull/aching/widespread pain may continue after stimulus stops
Hope do ascending and descending fibers modulate pain or cause analgesia? ascending fibers block pain transmission in spinal cord descending fibers release norepinephrine or serotonin, which suppress pain or activate enkephalin releasing neurons
Hope does aspirin function in pain relief? inhibits the synthesis of prostaglandins
What do muscle spindles sense? What reflexes do they cause? sense of stretching of the muscle cause contraction to maintain position
What do Golgi tendon organs sense? What reflexes do they cause? sense of change in muscle tension inhibits relaxation and prevents damage to the tendon
What do nociceptors detect? respond to damage from mechanical, electrical, thermal, or chemical energy
What do thermoreceptors detect? respond to changes in temperature
What do mechanorecptors detect? respond to mechanical forces (fluid movement or pressure)
What do photoreceptors detect? respond to light
What do chemoreceptors detect? respond to chemical concentration of various substances
What do osmoreceptors detect? detects changes in osmotic pressure
Which one of the types of receptors functions in the sense of taste? chemoreceptors (same as smell)
Which one of the types of receptors functions in the sense of smell? chemoreceptors (same as taste)
Which one of the types of receptors functions in the sense of hearing and equilibrium? mechanoreceptors
Which one of the types of receptors functions in the sense of vision? photoreceptors
The senses of smell and taste have nerve fibers that run through the limbic system. What effect does this have? taste is 80% smell smell and taste have an emotion attached to them
Of the four types of body tissues, which type of cells form the receptors for the sense of smell? Where are these receptors located? bipolar neurons olfactory epithelium is found in the superior nasal concha and nasal septum
Describe the olfactory mucosa. located in upper region of nasal cavity mucus protects the olfactory epithelium and allows odors to dissolve so that can be detected contains sensory fibers (trigeminal nerve) which play a role in initiation of reflexes like sneezing
What role does the mucus play in the sense of smell? Where does it come from? chemicals are dissolved in mucus to stimulate the receptors epithelial supporting cells produce the mucus
How do we recognize thousands of different odors? a combination of primary scents allow us to recognize thousands of different odors they bind do different receptor proteins
Are olfactory receptors replaced during a person’s lifetime? Why is this unusual? How long do these receptors live? receptors last 30-60 days (they are replaced) unusual bc they are neurons and neurons are not usually replaced
What happens to our sense of smell as we get older? due to a gradual loss of receptors, sense of smell declines because receptors are replaced more slowly as we age
What bony structure do the olfactory fibers pass through on their way to the olfactory bulb? cribriform plate
How quickly does the sense of smell adapt? olfactory cells adapt very rapidly
What can you tell me about the threshold for the sense of smell? it is a very low threshold, especially to certain odors
What are the five primary taste sensations? Which has the lowest threshold? Why is this protective? sweet, sour, bitter, salty, umami bitter is lowest threshold
If we can only detect five tastes, why do foods taste so different from each other? a combination of smell and taste changes the way we perceive tastes
Where are the receptors for taste located? mostly on the tongue some located on soft palate, cheeks, pharynx, epiglottis
Of the four types of tissues, which of the type of cells form the receptors for the sense of taste? gustatory epithelial cells
Describe the structure of a taste bud. Are the gustatory receptors primary or secondary receptors? on top of fungiform papillae, can have receptors for all primary tastes secondary receptors
How does each of the five tastes cause depolarization of the receptors? salty Na+ influx (direct depolarization) sour H+ (by opening cation channels) sweet, bitter, and umami coupled to unique G-protein gustducin
What cranial nerves transmit our sense of taste? facial (XII) and glossopharyngeal (IX) taste buds to medulla vagus (X) pharynx and epiglottis to medulla
What are the three main divisions of the ear? outer middle inner
What structures make up the outer ear? What glands do we find here? auricle pinna lobule helix glands sebaceous and ceruminous make earwax
What is the primary function of the outer ear? auricle funnels sound to auditory canal so that sound can pass through to the eardrum
What is the structure of the tympanic membrane? What does it do? thin, translucent connective tissue membrane detects sound waves vibrates to middle ear bones
What structures make up the middle ear? tympanic antrum auditory tube auditory ossicles two muscles
Besides the eardrum and oval window, to what other structures (areas) does the middle ear connect? Why are these important? mastoid antrum allows it to communicate with the cells of the mastoid bone
What is the function of the middle ear? Name the 3 ossicles in order. transform sound waves into mechanical vibrations that stimulates the inner ear malleus, incus, stapes
What do we call an infection of the middle ear? otitis media (middle ear infection)
What are the muscles found in the middle ear and what is their function? tensor tympani stapedius muscle function: they contract and pull the bones together to dampen loud noises (aka: tympanic reflex)
Describe the bony and membranous labyrinths of the inner ear. bony labyrinth channels worming through the bones of the inner ear filled with perilymph membranous labyrinth series of membranous sacs and ducts within the bony labyrinth and following its contours filled with endolymph
What are the three main divisions of the labyrinths? Which is involved in hearing? vestibule semicircular canals cochlea (involved in hearing)
What labyrinth is involved in static equilibrium? Dynamic equilibrium? Static vestibule Dynamic semicircular canals
Describe the structure of the cochlea. Where do we find perilymph? Endolymph? snail shaped with 3 compartments: scala vestibuli scala tympani scala media perilymph scala vestibuli scala tympani endolymph scala media
What type of tissue makes up the receptors found in the organ of Corti? epithelial tissue
Trace the path of sound waves from the outer ear to the cochlear branch of crucial nerve VIII and describe how transduction takes place in the organ of Corti. canal to tympanic membrane incus and stapes transmit vibrations to oval window vibrations travel through perilymph to scala vestibuli to scala tympani in cochlea creating waves in fluid basilar membrane moves causing Organ of Corti to transmit movement to tectorial membrane outer hairs bend stimulating Organ of Corti to send message throu…
Why does which way the hair cells are bent make a difference? hair cells bent toward kinocilium = increase frequency of APs hair cells bent away kinocilium = decrease frequency of APs
Some fibers from each ear cross over to the opposite cerebral hemisphere. Why? spatial correlation between cells in the sensory organ and specific locations in the primary auditory cortex hearing in stereo
What is the function of the round window? allow movement of fluid into the cochlea leading to the movement of hair cells which helps us hear acts as a pressure valve
How do we hear high sounds differently from low sounds? Soft and loud? specific hair cells that vibrate and bend give us sense of pitch number of hair cells that bend give us sense of loud and soft
What is the range of human hearing? 20–20,000 hertz
How do otoliths help maintain static equilibrium? Where are they located? motions of the head cause the otoliths to pull on the hair cells, stimulating the vestibular nerve, which signals the position of the head with respect to the rest of the body
How do the maculae of the utricle and saccule function? maculae of utricle sensitive to horizontal acceleration maculae of saccule sensitive to vertical acceleration (both otoliths in them, they pull on hair cells)
What part of the inner ear helps sense dynamic equilibrium? How does it function? semicircular canals help sense dynamic equilibrium when your head moves around, the liquid inside the semicircular canals sloshes around and moves the tiny hairs that line each canal
What is nystagmus and why does it occur after we spin a chair? strange, uncontrollable eye movements occurring during and/or after rotation fluid in semicircular canal continues to move after spinning causing eyes to track movement
What are the four layers of the eyelid? What two muscles are found here? layers skin muscle connective tissue conjunctiva muscles orbicularis oculi levator palpebrae superioris
What are eyelashes and eyebrows for? eyebrows shade eyes from light protects from sweat eyelashes shade from light very good dust catchers (camels have longest eyelashes)
Where is the lacrimal gland and what does it do? releases saline solution called lacrimal secretion (tears)
Where do tears go when they leave your eyes? lacrimal puncta lacrimal canaliculi lacrimal sac nasolacrimal duct inferior nasal meatus
Would the activation of the sympathetic or parasympathetic nervous system produce tears? parasympathetic nervous system
What are the six extrinsic eyes muscles and how does each one move the eyeball? lateral rectus: outward medial rectus: inward superior rectus: upward inferior rectus: downward superior oblique: downward and medially inferior oblique: upward and laterally
What cranial nerve innervate which extrinsic eye muscle? lateral rectus is innervated by the abducens nerve superior oblique is innervated by the trochlear nerve the rest are innervated by oculomotor nerve
What is strabismus? What is phoria? strabismus cross-eyed eye rotates medially and/or laterally phoria weakness of eye muscles
What are the three layers of the eyeball? What structures are in each layer? fibrous tunic cornea sclera vascular tunic choroid ciliary body iris nervous tunic retina
Do you find blood vessels in the fibrous tunic? nope it is avascular
Why is the cornea clear? so light can pass through it to the retina
What are the two main functions of the ciliary body? make aqueous humor accommodation of the eye
How do muscles of the ciliary body and the lens work together to allow you to see close objects? ciliary body contracts, shortening fibers, causing lens to become rounder
How and where is aqueous humor produced? produced in the ciliary body and drains continuously produced by the epithelium of the ciliary body
Where does aqueous humor drain? into the scleral venous sinus
What happens if too much aqueous humor is produced or if too little drains? glaucoma