Olfactory & Visual Systems Flashcards
Human can detect about ___ different odorants.
10,000
The olfactory system is has a ___ (central/peripheral) origin.
peripheral
Where is the patch of olfactory epithelium located?
bilaterally, in the roof of the nasal cavity
The olfactory epithelium contains 3 million receptor cells. supporting cells, Bowman’s gland ducts, and sensory endings from CN ___.
V
The olfactory receptor is a small ___ neuron.
bipolar
The olfactory ___ ends in olfactory ___, from which 10-30 ___ spread over the surface in a layer of mucus secreted by ___ glands to stimulate chemosensitive cilia.
dendrite; vesicle; cilia; Bowman’s
T/F. Axons from olfactory receptors are among the thickest and fastest.
False, Axons from olfactory receptors, among thinnest and slowest.
The olfactory receptors collect into a series of bundles (only about 20) called ___ ___, pass thru holes in ___ plate of ethmoid bone and end in the ___ ___.
olfactory fila; cribiform; olfactory bulb
What makes up CN I?
Olfactory fila make up cranial nerve I
T/F. The Olfactory bulb develops as an outgrowth of diencephalon and reaches the contralateral hemisphere through the thalamus.
False, the olfactory bulb develops as an outgrowth of TELencephalon and reaches IPSILATERAL hemisphere with NO relay in thalamus.
The bulb also has interneurons made up of ___ cells (T) and ___ cells (G).
tufted; granule
T/F. Axons from the 100s of olfactory receptor neurons (go) that express a given odorant receptor converge on 1 or 2 glomeruli.
True
Mitral cells have axons that collect and join the olfactory tract but what does its dendrites form?
its dendrites form glomeruli.
T/F. Even though cells are intermingled in the olfactory epithelium, each type of olfactory receptor sends an axon to one glomerulus of a mitral cell.
True.
Axons from what cells are found in the olfactory tract?
axons of mitral and tufted cells
What is detected by collaterals to the anterior olfactory nucleus?
they regulate sensitivity of the olfactory bulb
T/F. The olfactory bulbs project to the olfactory cortex. Fibers project to both bulbs after crossing in the anterior commissure.
True.
Some fibers in tract end in olfactory ___ but most turn laterally and end in the ___ ___ ___, which is the main central projection for olfaction.
tubercle; lateral olfactory pathway
What are the two general areas that olfactory bulb projections end?
primary olfactory cortex and amygdala
What are the areas of the primary olfactory cortex that the olfactory bulb projections end in?
Cortex near lateral olfactory tract, a.k.a. piriform cortex
Cortex covering amygdala, periamygdaloid cortex
Small part of parahippocampal gyrus
What is another name for the cortex near the lateral olfactory tract where olfactory bulb projections end near?
piriform cortex
What two structures focus an image on the retina?
the cornea and lens
What does focus require?
the refraction of light
The lens accounts for about a ___ of the eye’s refractive power and plays a major role in adjusting ___ for near/ far objects.
third; focus
Where does most refraction occur?
Most refraction is in air-water interface at corneal surface.
T/F. All waves bend when they pass from a medium that allows fast propagation to one that only allows slower propagation.
True.
What structure affects the brightness and quality of an image focused on the retina?
iris
How is pupil size controlled?
by 2 smooth muscles in the iris:
pupillary sphincter and pupillary dilator
Which smooth muscle encircles the pupil and is stronger?
pupillary sphincter
T/F. A smaller pupil worsens ocular performance.
False, A smaller pupil improves ocular performance
What smooth muscle is arranged in radiating spokes from the pupil?
pupillary dilator