Chapter 16
The eye is spherical, measuring about 5 centimeters in diameter, and most of it is receded into the orbit of the skull
False
______ occurs when impulses from an organ are perceived as originating from the skin
Referred pain
General Function of Sensory Receptors
Sensory Receptors are specialized cells that monitor the external and internal environment. When they are stimulated by a specific change in conditions, they generate action potentials that travel along axons of sensory neurons towards the CNS. The stimulus can light energy, sound energy, mechanical energy, etc, this is dependent on the type of sensory receptor being activated. The change of the original stimulus type to an electrical stimulus is called transduction. Because the sensory receptors can covert the origninal stimulus energy to electrical energy they are referred to as transducers. Two features of sensory receptors that transduction are: resting membrane potential and modality gated channels.
lacrimal puncta
The lacrimal lake is drained by two holes
palpebral conjunctiva
The portion covering the inner surfaces of the palpebrae
palpebral fissure
The superior palpebra (upper eyelid) and inferior palpebra (lower eyelid) are separated by the
lacrimal caruncle
a gland that produces thick secretions
Which cavity of the eyeball is divided into an anterior and posterior chamber?
anterior cavity
gustatory cells are found in taste
buds
Receptors initiate sensory input to the ______
central nervous system
gustatory cells are
chemoreceptors
What is the largest structure of the vascular tunic?
choroid
What structure is filled with pigment from melanocytes?
choroid
Which structure of the eye absorbs light to prevent it from scattering within the eye?
choroid
The iris is continuous with the ______.
ciliary body
The limbus is the junction between the sclera and the ______
cornea
What are parts of the fibrous tunic
cornea and sclera
eyelashes
covers the margins of the palpebrae and help to sweep away foreign compounds, including insects, before they enter and damage the eye.
Adaptation
decrease in sensitivity to a continuous stimulus
The outermost layer of the eye is called the_________-
fibrous tunic
Modality
form of a stimulus, chemical, mechanical, electrical, light, sound
Lacrimal ducts
from the lacrimal gland travel to the superolateral surface of the eye and release the tears
Tonic receptor
in response to constant stimulus, these receptors continuously generate nerve signals and onl y slowly decrease the number relayed to the CNS
Phasic receptor
in response to constant stimulus, these receptors exhibit rapid adaptation. These receptors generate nerve signals only in response to a new or changing stimulus and quickly decrease the number of nerve signals relayed to CNS
medial canthus
inner corner of eye
What structure is the dividing line between the anterior and posterior chambers?
iris
Structures of Vascular Tunic in order
iris ciliary body choroid
inferior palpebra
lower eyelid
The fat surrounding the eye is called
orbital or periorbital
lateral canthus
outer corner of eye
Olfactory receptors ______.
perceive odors
lacrimal apparatus
produces, distributes, and removes tears
Most of the eye is ______ the orbit of the skull
receded into
phasic
receptor that can undergo adaption
What structure is the "white" of the eye
sclera
Which part of the eye is an attachment site for extrinsic eye muscles?
sclera
Gustation
sense of taste
Olfaction is the sense of ___________
smell
We use the sense of ...................to sample our environment for information about the food we will eat, the presence of other individuals in the room, or potential danger.
smell
Sensation
stimulus that we are consciously aware of
Optic tracts extend to which structures after they leave the optic chiasm?
superior colliculi the lateral geniculate nucleus of the thalamus
Mechanoreceptors located in the skin and mucous membranes are called ______ receptors
tactile
What is a feature common to all receptors
the ability to respond to a stimulus
The cornea is
transparent
Which are the characteristics of the cornea?
transparent/avascular
superior palpebra
upper eyelid
The vascular tunic of the eye is also called the ______.
uvea