Chapter 7 (part 3) Sensory Physiology Flashcards
based on the physics of sound and the physiology of the ear, the nerves, and the brain regions involved in processing acoustic info
Hearing
energy that is transmitted through vibration of the medium’s molecules
Sound energy
When there are no molecules, as in a vacuum, there can be no sound
true
Sound Transmission in the Ear
tymapnic membrane deflects
middle ear bone moves
membrane in oval window moves
basilar membrane movment
membrane in round window moves
Vestibular information is used to:
- To control eye movement
- To maintain posture and balance
- To provide awareness of body position and acceleration
Neural Pathways in Hearing
- Cochlear nerve fibers synapse with interneurons in the brainstem.
- From the brainstem a multineuron pathway transmits information through the thalamus to the auditory cortex in the temporal lobe.
Vestibular information is integrated with information from __________
proprioceptors
fibers used to transmit information through the brainstem and thalamus to the vestibular centers in the parietal lobe.
Vestibular nerve fibers
Chemicals binding to specific chemoreceptors are responsible for the detection of taste and smell.
Chemical Senses
other term for taste
gustation
groups of cells arranged around a hollow pore
on the tongue
Taste buds
increase the surface area, and contain membrane proteins that transduce a chemical into a receptor potential on tongue
Microvilli
divide and differentiate to continually replace taste receptor cells damaged in the harsh environment
Basal cells (of taste buds)
To enter the pores of the taste buds, food molecules must be dissolved in liquid
true
Types of Taste Receptors
Salt taste
sodium ions
Types of Taste Receptors
Sour taste
hydrogen ions
Types of Taste Receptors
Sweet taste
glucose
Types of Taste Receptors
associated with poisonous substances, especially plant alkaloids
Bitter flavor
Types of Taste Receptors
depolarize via a G protein-coupled receptor mechanism
associated with the taste of glutamate and is sometimes described as savory or flavorful
Umami receptor
- lie in the olfactory epithelium in the upper part of the nasal cavity
- last for only about two months, so they are constantly replaced by new cells produced from stem cells in the olfactory epithelium
Olfactory Receptors
Olfactory Receptors have ___________, contain the receptor proteins that provide the binding sites for odor molecules.
cilia
Axons of the neurons form the olfactory nerve which is what number cranial nerve
(cranial nerve l)
- Proteins in the mucus interact with the odorant molecules, transport them to the receptors, and facilitate their binding to the receptors.
Smell
in smell, Stimulated odorant receptors activate a
_______________ that increases cAMP, which in turn opens nonselective cation channels and depolarizes the cell.
G protein-mediated pathway
Some are born with genetic defects resulting in lack of the ability to smell
(anosmia)
Factors that Affect the Sense of Smell
- Attentiveness
- Hunger (greater in hungry subjects)
- Gender (women have keener olfactory sensitivities)
- Smoking (decreased sensitivity)
- Age (decreases with age)
- State of the olfactory mucosa (decreases when the mucosa is congested, as in a head cold)
What changes take place in neurotransmitter release from the rods or cones when they are exposed to light?
When exposed to light, rods and cones in the retina decrease their neurotransmitter release due to a process called hyperpolarization, meaning they become more negatively charged, which in turn reduces the amount of glutamate released at the synapse; essentially, the more light, the less neurotransmitter is released.
What is the relationship between head movement and cupula movement in a semicircular canal?
When the head moves, the fluid (endolymph) inside the semicircular canal lags behind due to inertia, causing the cupula to bend in the opposite direction of the head movement,
In what ways are the sensory systems for taste and olfaction similar? In what ways are they different?
Both odors and tastes involve molecules that stimulate specific chemoreceptors. Although humans commonly distinguish taste as one sense and smell as another, they work together to create the perception of flavor. A person’s perception of flavor is reduced if he or she has congested nasal passages.
However, they differ in their mechanisms and the range of sensory information they provide.
When we chew food or sip wine, chemicals are vaporized into air passages that connect the mouth and the back of the nose, stimulating olfactory receptors and allowing us to realize the subtleties of flavor. Other aspects of the taste experience, such as food texture and temperature, engage additional senses.
