Chapter14 Flashcards
Route of Sound Waves
- Sound waves vibrate the tympanic membrane
- Auditory ossicles vibrate. Pressure amplified
- pressure waves created by stapes pushing on the oval window move through fluid in the scala vestibuli
4a. Sounds w Frequencies belowing hearing travel through helicotrema and don’t excite hair cells
4b. vibrate basilar membrane and deflecting hairs on inner hair cells.
Parts of Vascular Layer
Choroid Region - Supplies blood to all layers of eyeball, brown pigment absorbs light to prevent light scattering. Ciliary body - Smooth Ciliary muscles control lens shape, capillaries of ciliary processes secrete fluid.
Iris - Colored part of eye
Ascending Pathways
First-Order Neuron: Conducts impulses from cutaneous receptors;
Second-order Neuron: Interneuron. Cell Body in dorsal horn of spinal cord or medulla Axons to thalamus or cerebellum.
Third-order Neuron: Interneuron
Lacrimal Apparatus and What are lacrimal secretions
Saline, mucus, antibodies, lysozyme (TEARS), will drain to nasal cavity
A Small Subset of ganglion cells in retina contain
Melanopsin (circadian pigment) which project to pretectal nuclei and suprachiasmatic nucleus
Tract to brain
Olfactory receptor cells synapse with mitral cells in olfactory bulbs then via olfactory tracts to piriform lobe of olfactory cortex, some to frontal lobe, hypothalamus, amygdala, and regions of limbic sys
Taste Buds
Gustatory Epithelial cells: taste cells, microvilli are receptors. Basal Epithelial cells: dynamic stem cells that divide every 7-10 days. 10,000 taste buds on tongue, few on soft palate, cheeks, pharynx, epiglottis
Taste bud responses
Sweet: Sugars, saccharin, alcohol, some amino acids, some lead salts. Sour: Hydrogen ions in solution. Salty: metal ions (inorganic salts). Bitter: Alkaloids (quinine, nicotine, aspirin). Umami: Glutamate, aspartate
Otitis Media
Middle ear inflammation, especially in children, who have shorter more horizontal pharynogotympanic tubes, most frequent cause of hearing loss, treated with antibiotics or myringotomy (tubes)
Exteroreceptors
Respond to stimuli outside body (touch, pressure, pain, temp)
Interoreceptors
Respond to stimuli arising in internal viscera (chemical changes, tissue stretch, temp changes)
Propprioreceptors
Respond to stretch
Mechanoreceptors
Touch, pressure, vibration and stretch
Thermoreceptors
Changes in temperature, Cold (10-40) Superficial dermis, Hot (32-48) Deeper Dermis, outside ranges, notifiy nociceptors activated for pain
Photoreceptors
Light energy (retina)
Chemoreceptors
Chemicals (smell, taste, changes in blood chemistry)
Nociceptors
pain-causing stimuli for extreme heat/cold, Ion channel opened by heat, low pH, chemicals, capsaicin (hot peppers), chemicals from damaged tissue
Nonencapsulated
Free Nerve Ending - In epithelia and connective tissues, respond to temp, and pain, pressure induced tissue movement, itch
Tacticle Corpuscles
Encapsulated dendritic Endings (meissner’s) Discriminitive touch, differentiate between quantities i.e. 2 popsicle sticks
Lamellar Corpuscles
Encapsulated dendritic Endings (Pacinian) Deep pressure and vibration
Bulbous Corpuscles
Encapsulated dendritic Endings (ruffini endings) Deep continuous pressure
Muscle Spindles
Encapsulated dendritic Endings Muscle stretch (deep)
Tendon Organs
Encapsulated dendritic Endings Stretch in tendons
Joint Kinesthetic Receptors
Encapsulated dendritic Endings joint position and motion
Steps of Sensation Production
- Receptor level: Sensory reception and transmission to CNS 2. Circuit Level: processing in ascending pathways 3. Perceptual Level: processing in cortical processing
Generator Potential
A graded potential in afferent neuron summated to produce action potential - stimuli
Receptor Potentail
A graded potential in receptor cell that affects amount of neurotransmitter released, then neurotransmitters generate graded potentials in sensory neuron
Phasic Receptors
Signal the beginning or end of stimuli (pressure, touch smell) clothes on in the morning, you don’t notice them all day
Tonic Receptors
adapt slowly or not at all (nociceptors and most proprioceptors)
Phantom Limb Pain
Felt in limb not present, now use epidural anesthesia to reduce, create a memory of pain with or without the limb in place
Hyperalgesia
Pain amplification, Chronic pain, long-lasting/intense pain
Olfactory Epithelium
contains bipolar neurons with radiating olfactory cilia, bundles of nonmyelinated axons of olfactory receptor cells from olfactory nerve
Olfactory Neurons
Thin dendrite terminates in knob with long, olfactory cilia, covered by mucus (solvent for odorants) olfactory stem cells replace them
Smell Genes”“Smell Genes”"”mell Genes”“Smel”ell Ge
400 active in nose, each encodes unique receptor protein, each odor binds to different receptors and pain and temp also
Role of Taste
Triggers reflexes involved indigestion, increase secretion of saliva into mouth and gastric juice into stomach, protective reaction, gagging, vomiting
Synesthesia
stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway (colors of sounds)
Middle Ear
Small, air-filled, mucosa-lined cavity flanked medially by bony wall containing oval and round windows
Pharyngotympanic (auditory) tube
Equalizes pressure in middle ear
Ossicles
Malleus, incus, stapes; small bones that transmit vibratory motion of eardrum to oval window
Two Major Divisions of Internal Ear
Bony Labyrinth, vestibule, semicircular canals, cochlea - filled with perilymph & Membranous labyrinth
Membranous Labyrinth
Membranous sacs and ducts. Filled with K+-rich Endolymph
Cochlea
Snail shell shaped - spiral, conical, bony chamber - Contains cochlear duct, which houses spiral organ and ends at cochlear apex
3 Chambers of Chochlea
Scala Vestibuili: to oval window, perilymph. Scala Media: (cochlear duct) endolymph. Scala Tympani: to round window; perilymph
Amplitude
Height of Crests (loudness) Normal range is 0-120 decibels (dB) hearing loss with exposure above 90 dB
Frequency
of waves in a given time
Wavelength
Distance between two crests (shorter wavelength = higher frequency)
Pitch
Perception of different frequencies ; higher frequency = higher pitch
Cochlear hair cells
One row of inner hair cells, three rows of outer hair cells, that move back and forth for sound
Stereocilia
Of the hair cells, protrude into endolymph, longest enmeshed in gel-like tectorial membrane
Tip Link
A fiber on end of stereocilia that connects it to the next tallest (kinocilium) which as it moves opens or closed mechanically gated ion channels
Vestibule
2 Membranous sacs - Saccule: static equilibrium in an up and down motion, Utricle: static equilibrium in a side to side motion
Sensory Receptors in Vestibule
Maculae - continuously release neurotransmitters but modified amounts depending on movement of head
Cilia embedded in Otolith Membrane
Stereocilia and kinocilia and studded with otoliths(calcium carbonate stones), works with gravity
Semicircular Canals
Lie in 3 planes
Ampulla
Of each semicircular canal houses equilibirum receptor region called the crista ampullaris. The receptors respond to angular rotational movement of the head
Bending of haris in cristae
Depolarization
Bending of hairs in opposite direction
hyperpolarization
Vestibular Nystagmus
As rotation begins eyes drift in direction opposite to rotation, then CNS compensation causes rapid jump toward direction of rotation
