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