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Olfactory information is first received by which part of the brain?
- - primary afferents synapse in the olfactory bulb
- - information flows to the olfactory cortex, hypothalamus, and limbic system
- - they are the only sensory pathways to reach the forebrain without first synapsing in the thalamus
- - they exhibit a considerable amount of convergence
A normal, relaxed inhalation carries about ____ of the inhaled air to the olfactory organs.
Olfactory receptors send axons through the cribriform plate. They synapse on neurons in the:
Gustatory receptors are located:
on the surface of the tongue
What lingual papillae has the largest number of taste buds?
Stimulation of nociceptive receptors within the trigeminal nerve might produce a perception of:
What structure changes the shape of the lens for far and near vision?
The palpebrae are connected at the:
lateral and medial canthus
The neural tunic of the eye:
- - contains the photoreceptor cells
- - is the deepest layer of the eyeball
- - contains ganglion cells
- - contains bipolar cells
A structure that is located at the medial canthus and contains glands that contribute to a gritty deposit is the:
The _____ covers most of the exposed surface of the eye.
The opening in the iris through which light passes is the:
What are the functions of tears?
- - lubricate the eye
- - wash away debris
- - nourish the cornea and conjunctiva
- - provide oxygen
A ray of light entering the eye will encounter these structures in which order?
conjunctiva --> cornea --> aqueous humor --> lens --> vitreous body --> retina --> choroid
Pupillary muscle groups are controlled by the ANS. Parasympathetic activation causes pupillary _____, and sympathetic activation causes _____.
Why must accommodation occur to view objects closer than 20 feet from the eye?
the light rays are divergent instead of parallel and require more refraction
The optic disc is a blind spot because:
there are no photoreceptors in that area
When a rod is stimulated by light:
- - cGMP decreases and sodium channels close
- - the plasma membrane becomes hyperpolarized
- - the retinal changes from the 11-cis to the 11-trans form
- - less neurotransmitter is released
An elongate outer segment containing membranous discs and a narrow connecting stalk that attaches the outer segment to the inner segment describes:
The first step in the process of photoreception is:
absorption of a photon by a visual pigment
The steps that occur in rods when they are excited by photons of light:
- 1. Retinal changes from the 11-cis form to the 11-trans form
- 2. Opsin activation occurs
- 3. Opsin activates transducin
- 4. Increased phosphodiesterase breaks down cGMP
- 5. Membrane sodium channels close
- 6. The membrane hyperpolarizes and the rate of neurotransmitter release declines
Where are the visual pigments located in the rods and cones?
inside membrane discs stacked in the outer segment
A loud noise causes:
- - an alerting reaction leading to sympathetic activation
- - reflex contractions of middle ear muscles
- - a large movement of the tympanic membrane
- - a big pressure pulse entering the cochlear duct at that oval window
The ____ ear collects sounds waves and transmits them to the _____ ear, which contains auditory ossicles
The frequency of a perceived sound depends on:
which part of the cochlear duct is stimulated
An infection that damages the vestibular nerve could result in a loss of:
The structure attached to the oval window that transmits vibrations from the tympanic membrane to the inner ear is the:
The superficial hard part of the inner ear is called the ____ and contains _____.
bony labyrinth; perilymph
The sensory receptors of the semicircular canals are located in the:
The structure that supports the organ of Corti is the:
The vibrations received by the tympanic membrane are transferred to the oval window by the:
seals the oval window