Chapter 15 the special senses
When taste stimulus reaches a gustatory cell, it must be transduced into a electrical signal in these 3 steps
-Changes in ion movements depolarize the gustatory cells plasma membrane. -Depolarization of the membrane opens voltage gated Ca2+ channels, and Ca2+ enter a cell -The Ca2+ trigger the release of neurotransmitters, which produce an action potential in the axon of the sensory neuron.
The ability of the lens to change its shape from flattened to round is known as ___?
Accommodation
What are the roles of basal and supporting cells?
Basal cells - are stem cells that differentiate into new gustatory cells, life span 10-14days. or support lifelong renewal of the olfactory epithelium Supporting cells - surround the gustatory cells, providing support
The loudness of sound is determined by the vibration of the ____?
Basilar membrane
The vascular layer of the eye contains the ____?
Choroid, Ciliary body, Iris
The sclera is continuous with a transparent layer over the anterior eye known as the _____?
Cornea
In the dark "absence of a stimulus, the photo receptors are ____?
Depolarized
The three layers of the eyeball from outer to inner are ____?
Fibrous, Vascular, Neural layers
What are the functions of the tarsal glands and conjunctivae?
Functions of the tarsal glands are: secreting oil to prevent eyelid from sticking together. also called "modified sebaceous gland" Function of the Conjunctiva : cover the anterior surface of the lucent, which permits you to see tiny blood vessels beneath it. or provides protection and lubrication of the eye by the production of mucus and tears.
What involves chemotherapy that responds to chemicals?
Gustation
How does a gustatory cell transduce a chemical taste into an action potential?
Gustatory cells release a variety of neurotransmitters onto associated sensory axons, including serotonin, glutamate, acetylcholine and GABA.
In which layer of the eyeball are the photo receptors found?
Neural layer
Neural sensory signals are relayed to the thalamus, except for the sensation of __________.
Olfaction
Five special sense are
Olfaction, Gustation, Vision, Equilibrium, Hearing
What type of cells make up the olfactory epithelium?
Olfactory neuron, Basal cells, olfactory gland,
A nurse administer pilocarpine eye drops. The nurse instructs the patient to press on the nasolacrimal duct for 30 seconds because the medication can have some systemic side effects if absorbed into the blood circulation through the nasal mucosa. Determine how pressing on the nasolacrimal duct prevents passage of pilocarpine to the nasal mucosa?
Pressing on the nasolacrimal duct prevents the passage of pilocerpine into the inferior nasal meatus.
What type of chemicals produce each of the five taste sensation?
Sweet - Ethylene Glycol Sour - Hydrogen ion Salty - sodium and potassium ions Bitter - alkaloids Umami - glutamate
What gland secretes oil to prevent the eyelids from sticking together?
Tarsal gland
Where does the conscious awareness of sound begin, along with the analysis of its pitch, location, and loudness?
Temporal lobe
Where are olfactory stimuli sent for conscious perception and interpretation?
The axons of olfactory neurons carry olfactory stimuli to the olfactory bulb in the CNS. An olfactory stimuli travels from the olfactory bulb to the primary olfactory cortex in the temporal lobe. "located in temporal lobe for identification"
What are the functions of each component of the vascular layer of the eyeball?
The functions of the "Choroid" is to supply oxygen and nutrients to the neutral layer of the eyeball. The function of the "Ciliary Body" contains smooth muscle helps contract the size and shape of the lens to obtain a sharp image. The function of the "Iris" to control the light from passing through the pupil.
What is the function of the lens?
The lens focuses light on the retina
As sound waves travel into the ear, they pass from the auditory canal to the:
Tympanic membrane, auditory ossicles, oval window, perilymph, scala vestibuli of the cochlea
Which cranial nerve transmits taste sensation to the CNS?
Vagus nerve X Glossopharyngeal IX Facial nerve VII
olfactory epithelium
a thin layer of tissue, within the nasal cavity, that contains the receptors for smell
What happens in an olfactory neuron when an odorant binds to its receptors?
activates G-Protein. The activated g-protein triggers the enzymes adenylate cyclase to convert ATP into cycle AMP(cAMP). cAMP opens ion channels that allow sodium and calcium ions to enter the cell.
How many humans detect such a variety of odors with a limited number of olfactory receptors?
all humans or over a trillion
accessory structures of the eye
eyebrows, eyelids"palpebrae", conjunctiva, lacrimal apparatus, extrinsic eye muscles
Layers of the eyeball
fibrous , vascular , retina"Neurl layer"
Where does Olfaction begin?
olfactory epithelium
olfactory epithelium consist of
olfactory receptors, supporting cells, basal cells and secretion of the olfactory glands coat the surface of the olfactory organ.
olfactory organs
organs at the top of the nasal cavity containing olfactory receptors. Provides smell
Which part of the brain is responsible for identifying a particular taste?
primary gustatory cortex
The three types of cones are designated ____?
red, green, and blue.
What taste sensation results when sodium ions enter gustatory cells through sodium ion channel receptors, and the cell depolarizes?
salty
The fibrous layer of the eye contains the _______.
sclera and cornea
Olfaction
sense of smell
Gustation
sense of taste
Olfaction is the sense of __________.
smell
Which two extrinsic eye muscles move the eyeball superiorly?
superior rectus muscle and superior oblique
Gustation is the sense of
taste
Vision
the perception of light reflected by various objects.
How does a gustatory cell stimulate a sensory neuron?
they release neurotransmitters onto the dendrites of sensory neurons.
What is not part of the inner ear?
tympanic membrane
Where are the taste buds located?
typically located om the lateral surface of the papillae. Contains: Gustatory "taste" cells, basal cells, supporting cells.
