Chapter 9

Choroid

contains blood vessels that provide nutrients to the retina

Anterior Cavity:

contains the aqueous humor that supplies oxygen and nutrients to the lens and cornea

Posterior Cavity

contains the vitreous humor that maintain the shape of the eye and keeps the retina attached to the choroid

Retina

converts light into action potentials

Phasic

fast adapting and react when the stimulus is first applied and cease to respond while stimulus is maintained.

nociceptors

respond to painful stimuli resulting from physical or chemical damage to tissues

Ciliary body:

responsible for secreting aqueous humor

Pain information goes through the ​________, __________, __________​ without passing through the thalamus.

reticular formation​, ​limbic system​, ​hypothalamus

The ​______​​ is the middle part of the bony labyrinth in the vestibule and consists of two sacs called the ​______​​ and the ​________

vestibule, utricle, saccule

What does acuity mean?

Acuity is sharpness of perception—the ability to precisely locate and distinguish one stimulus from another.

What is an electrode?

An electrode is a device that conducts electrical charges.

What are the three main regions of the ear? What are their functions?

External ear- collects sound waves and channels them inward Middle ear - conveys vibrations to the oval window Inner ear - houses receptors for hearing and equilibrium

Pupil

Hole in the center of the iris by which light enters the posterior cavity of the eyeball.

__________ ​are sensory receptors that respond to internal stimuli, while ​________​ are sensory receptors that detect stimuli from the external environment.

Interoceptors, Exteroceptors

_______ _____ ​ is when input from sensory receptors on the border of the stimulus is inhibited compared to input from sensory receptors on the center of the stimulus.

Lateral​ ​inhibition

______ _________ are touch receptors located on upper part of dermis.

Meissner Corpuscles​

__________ and​ _________ ​ are two types of slowly adapting touch receptors.

Merkel Discs​ , Ruffini corpuscles

What are the five primary tastes?

Sweet, salty, sour, bitter, umami

What do the eyes detect?

The eyes detect visible light, light with wavelengths ranging from 400 to 700 nm.

Where in the eye is visual acuity the highest?

The fovea of the retina has the highest visual acuity.

What part of the eye is responsible for converting light into action potentials?

The retina.

Define referred pain. Give an example.

When pain is felt in another area of the body, than it's actual sources

Sensory information is converted to ​________ ________ ​before it is sent to the CNS for integration.

action​ ​potentials

Tonic

adapt slowly and continue to produce significant response a slong as the stimulus is present.

Lens

an elastic structure that refracts light rays

thermoreceptors

detect changes in temperature

chemoreceptors

detect chemicals in the mouth, nose and body fluids

photoreceptors

detect light that strikes the retina of the eye

Canal of Schlemm

drains the aqueous humor from the anterior cavity. From here, it reenters the blood

Stimulus modality:

each unique sensation, encoded by the sensory receptors and neural pathways that are activated when stimulus is applied

Stimulus Duration

encoded by duration of action potentials in sensory neurons.

Stimulus Location:

encoded by the location of the activated receptive field.

Stimulus Intensity:

encoded by two main factors, frequency of action potentials generated in response to stimulus, and number of sensory receptors activated by stimulus

The ​______ ​​is a curved tube that conveys sound waves from the pinna to the tympanic membrane

external auditory canal

The ​______​ and ​______​ hair cells have different roles. The​ _________ are the receptors for hearing, while the ​_____ ​hair cells are ​_______​ the sensitivity of the _______

inner, outer, inner hair cells​, outer, increasing, ​inner hair cells

The presence of overlapping receptive fields improves stimulus​ ___________.

localization

The inner ear consists of two main sections: an ​___________ that encloses an​________

outer bony labyrinth​​ , ​​inner membranous labyrinth

Within the partition separating the middle and inner ears are two membrane-covered openings: an upper ​________​​ and a lower ​_______

oval window, round window

Feeling​ ______ ​protects the body from stimuli that can cause tissue damage.

pain

Iris

part of the eye responsible for color of the eye. Not detection of color.

Receptive field

particular region of sensory space in where the stimulus would make that neuron fire. This varies depending on the stimulus Examples : Skin - region of skin where sensory neurons are located ; olfactory - odorants (chemicals in odor) to which the olfactory receptor cells can respond ; auditory - particular set of sound frequencies that elicits response in auditory neuron ; gustatory - specific type of tastants (chemicals in food) that cause response in taste neuron.

The ​_______ ​​collects and directs sound waves into the external auditory canal.

pinna

Mechanoreceptors

sensitive to mechanical stimuli such as the deformation, stretching, or bending of cells. Provide sensations of touch, pressure, vibration, proprioception (muscle and joint position), and hearing and equilibrium. They also monitor the stretching of blood vessels and internal organs

Fovea

small depression in the macula lutea which is the highest area of visual acuity

Zonular fibers/suspensory ligaments:

suspensory ligaments that attach to the lens

Pain information that arrives in the primary somatosensory cortex first passes through the _________​.

thalamus

Sclera

the "white" of the eye. It is a tough coat of connective tissue that covers the entire eyeball except the cornea

Optic disc:

the site where the optic nerve (II) exits the eyeball. Contains no photoreceptors

Cornea

transparent structure that admits and refracts incoming light rays into the eye

Sensory coding

use of organizational and functional features of the nervous system to represent specific details about a stimulus.

The main function of the​ _________ is to transmit and amplify vibrations to the__________

​​auditory ossicles​​, ​oval window

The middle ear is connected to the pharynx by the​ __________​​, also known as the ________

​​eustachian tube, auditory tube