Special Senses And Nervous System Key Words Flashcards
Chemoreceptors
Respond to chemicals dissolved in solution
Nocioreceptors
help sense pain. Alerted by chemicals that indicate damage
Thermoreceptors
Respond to temperature changes
Mechanoreceptors
Modified dendrites that detect changes in pressure, flex or flexion
Photoreceptors
Specialized receptor cell that responds to light energy, rods and cones
Retina
Inner layer of eyeball,
Contains photoreceptors, rods and cones
Golgi receptor organs
Proprioceptors (sense organ that gets info from inside body) senses tension. If too much tension, will inhibit muscle from creating more force through a reflex arc. Will protect you from injuring yourself. Relax tendons
Muscle spindle fiber
Senses stretch and speed of stretch. Sends message to stop stretching when you reach the endpoint of spindle stretch. Protects you from overstretching or hurting yourself
Sensation
Perception of a stimulus through one of the special senses
Sensation
Awareness of internal and external stimuli
Perception
Conscious interpretation of internal and external stimuli
Sensory adaptation
Change in sensitivity and nerve impulse generation in response to a constant stimulus. For example, photoreceptors adapt to bright light
Sensory conflict (ex. Motion sickness)
Confusion of sensory inputs. Being in ship during storm. Visual input looks like stationary, but rough movement cause vestibular apparatus to detect motion sickness
Free nerve endings
Sense pain, cold and warmth.
Uncapsulated dendrite of a sensory neuron. Modified dendrites that collect information. Change information to stimulus
Most common nerve endings in skin
Free nerve endings,
Extend to middle of epidermis
Which nerve endings are less sensitive to to abrupt changes in stimulation?
Free nerve endings
Where are Meissner’s corpuscules found?
Papillary layer of dermis
Meissner’s corpuscules
Tactile corpuscules
Touch receptors
Light pressure receptors, at junction of dermis and epidermis
Sense textural differences
Pacinian corpuscules
Lamellar corpuscules
Deep pressure receptors in dermis and subcutaneous tissue. Respond only when pressure is first applied
Deep vibration
Visceral pain
Pain emanating from the internal organs ,
Vague, dull aching sensation can be caused by extreme stretching of tissue, irritating chemicals, muscle spasms
Causes of visceral pain
Extreme stretching of tissue,
Ischemia (low blood flow),
Irritating chemicals,
Muscle spasms
Ischemia
Low blood flow
Referred pain
Pain stimuli arising from one part of the body are perceived as coming from another part
Cause of referred pain?
Same segments of spinal cord innervate multiple parts. T1-T5 innervate heart and arm
Olfaction
Sense of smell
Olfactory receptor cells
Located in roof of nasal cavity under mucosa. Respond to chemicals dissolved in solution
In superior nasal cochae
Olfactory bulbs
Receive information from sensory neurons that are triggered by olfactory receptors.
Two small structures at front of brain above nasal cavity
Olfactory tracts
pair of nerve pathways that connect olfactory bulbs to brain. after the olfactory bulbs process the information about different smells, the olfactory tracts send this information to higher brain regions for further processing and interpretation. travel to brain and reach olfactory cortex which controls conscious awareness
Gustation
Sense of taste
Taste buds
Sensory receptor organs, house gustatory epithelial cells, respond to dissolved food chemicals
Where do you find taste buds?
Anterior and posterior of tongue and palate
Papillae
Hold some of the taste buds, small raised projections
Taste cells
Gustatory epithelial cells, receptor cells for taste
Taste pore
Holds gustatory hair
Gustatory hair
Sensitive portions of gustatory epithelial cells. Bathed in saliva to dissolve chemicals
Basal epithelial cells
Stem cells,
Divide and differentiate into new gustatory epithelial cells. Replaced every seven to 10 days
Causes of sweet taste
Sugar, saccharin, alcohols, aminoacids, lead salts
Sour taste causes
Acids H+ ions in solution
Salty taste causes
Metal ions (inorganic salts);NaCl tastes the saltiest
Bitter taste causes
Alkaloids, quinine, nicotine, caffeine,morphine, and non alkaloids like aspirin
Umami
Delicious
Beef taste of steak,
Auricle
Visible portion of outer ear.
Funnels sound waves into external acoustic meatus
External acoustic meatus
Short tube from auricle to eardrum. Lined with cerumenous glands to trap foreign bodies and repel insects. Guides sound to tympanic membrane
Middle ear parts
Ear drum
Ossicles
Eustachian tube
Auditory ossicles
Malleus, incus, stapes
Allow sound wave transmission. Connect tympanic membrane to inner ear
membrane covered opening that separates the middle ear from the inner ear. located at end of stapes.
Oval window
Round window
Inferior to oval window.
Equalizes pressure changes. Dissipate pressure created by sound waves entering the inner ear.
Tympanic reflex
protective mechanism in response to loud sounds. muscles in middle ear contract to dampen sound vibrations. the stapedius and tensor tympani muscles contract and stiffen the ossicles. Reduce transmission of sound vibrations to inner ear.
Auditory tube
Connects the middle ear an pharynx. Aka eustachian tube
Bony labyrinth
Makes up internal ear
Membranous labyrinth is suspended in this.
Membranous labyrinth
Continuous series of membranous sacs and ducts contained within the bony labyrinth more or less following its contours.
Perilymph
Fluid similar to CSF and continuous to CSF
Bony labyrinth parts
Vestibule, Semicircular canals and cochlea
Vestibule
Egg shaped cavity of bony labyrinth. Posterior to cochlea. Anterior to Semicircular canals flanks middle ear medially.
Perilymph
Fluid that helps transmit sound vibrations within cochlea
Endolymph
potassium rich fluid that helps transmit electrical signals related to hearing and balance within inner ear
Baroreceptors
Monitor changes in volume and pressure.
Important in cardiovascular system
Sensory nerve ending in wall of carotid sinus or aortic arch sensitive to vessel stretching.
General senses location
All over body
Special senses location
Mostly cephalic or found in the head
Free nerve endings are part of which kind of neuron
Unipolar sensory neurons
General flow of information in the nervous system
Sensory neurons connect to motor neurons or interneurons. Tracts take sensory and motor information up and down the spinal cord.
After sensory information enters the spinal cord it goes up to the brain for processing, integration and decision-making
Highly modified sensory neurons
Encapsulated nerve ending.
Mechanoreceptors, include tactile corpuscules, lamellar corpuscules, bulbous corpuscules and muscle spindles
Three levels of sensory integration
- Receptor (sensory receptors)
- Circuit (ascending pathway)
- Perceptual levels (cerebral cortex)
Transduction
Conversion of stimulus energy via receptor or generator potentials into action potentials.
Frequent stimuli are stronger or weaker?
Stronger
Adaptation
Decreased response to a continuous or unchanging stimulus
Adaptation occurs in
All general receptors except pain and proprioceptors
Modified epithelial cells
Act like sensory neurons
Send depolarization signal to a neuron> neuron sends along to nervous system
Example of modified epithelial cells
Taste buds
Modified epithelial cells that have microvilli
Taste buds
Provide information that gets interpreted as sense of taste
Taste buds
Rod
Photoreceptors found in retina.
Have continuous discs
Respond to dim light, night vision and peripheral vision
Respond to dim light, night vision and peripheral vision
Rods
Need bright light for activation
Cones , low sensitivity
Pigments in cones
One of three different pigments that create vividly colored view of world.
Pigment in rods
Single visual pigment. Only perceive grey tones
Converging pathway
Impulses from several neurons come together in one neuron
Wiring of rods
As many as 100 rods feed into each ganglion cell. Rod effects are summated and considered collectively.
Why is vision produced by rods fuzzy and indistinct.
Visual cortex doesn’t know which rods of the large number influencing a ganglion are activated
Proprioceptors
Give information about muscle position on the body. Info goes back to cerebellum.
Merkel discs
Respond to touch, in epidermal layer of skin
Connected to neurons
Krause end bulbs
Respond to touch
Root hair plexus
Responds to touch
Nerve fibers associated with hair follicle. Cause pain when pulling hair out
Ruffini endings
Detect pressure
Two examples of general sensors that help with proprioception or location of different muscles in the body
Golgi tendon organ
Muscle spindle
Reflex arc of muscle spindle
Stretch of muscle spindle causes reflex contraction. No interneuron
Golgi tendon organ reflex
Has interneuron
Which cranial nerves are involved with taste
Facial vii (anterior 2/3)
Glossopharyngeal IX (posterior 1/3 of tongue)
And vagus X (taste info around epiglottis)
Types of papilla on tongue
Fungiform,
Filiform,
Folliate
Circumvallate papilla
Fungiform papilla
Middle of tongue
Filiform papilla
Tip of tongue
Follate papilla
Side of tongue
Do all papillae hold taste buds?
No
Papilla with no taste buds
Filiform papilla
Which papilla have taste buds?
Foliate and circumvallate papilla
Special collections of modified epithelial cells behaving like sensory neurons. Detect flavor
Taste buds
Basal cell of taste buds
Stem cells that regenerate gustatory cells
Taste pore
Opening in papilla where gustatory cells are exposed
Function of gustatory hairs
Microvilli that grab onto molecules and dissolve them in saliva as you chew