Sensory System Chapter 1 Flashcards
A ______________ is able to convert a signal from the environment, called a stimulus, into a nerve impulse. This signal is transmitted to the CNS for integration
Sensory receptor
Type of sensory receptor that responds to chemical substances
Taste, smell
Chemoreceptors
Type of sensory receptors that respond to light energy
Seeing color
Photoreceptor
Type of sensory receptor that is stimulated by forces, pressure
Hearing, touch
mechanoreceptors
Type of sensory receptor that is stimulated by temperature changes
Touch (skin)
Thermoreceptors
Absorbs stray light, extensive blood supply
Chorioid
Contains mostly cones for acute vision
Fovea
Contains photoreceptors for sight, located at the back of the eye
Retina
Protects and supports the eye, white outer layer of the eye
Scelera
Admits light into the eye, hole in the center of the eye
Pupil
Transmit light rays and support the eye, located in front of and behind lens
Humors
Refracts light rays, window of the eye
Cornea
Regulates light entrance into the eye, regulates size of pupil
Iris
Refracts and focuses light rays, divides the eye into compartments
Lens
Transmits impulses to the visual cortex
Optic Nerve
The photoreceptors
Rods contain _____
Cones contain_______
rhodospin
Photopin
disks that contain visual pigments
membrane of each disk contains Rhodopsin (when it absorbs light energy splits and releases retinal causing plasma membrane to close so nerve signals go to the brain) which has a deep purple pigment
Rods
Located in fovea and activated by bright light that helps us detect fine detail and color
Cones
3 layers of neuron
Inner layer of the eye
Rod and cone cells are at the back of it
As signals pass to bipolar cells and ganglian cells, integration occurs
Retna
Shows no rods and cones where optic nerves exit the retina
No vission possible in this area
In different spot in eye so you have complete vision
Blind spot
Lens of eye is cloudy
less light reaches retina causing vision loss
cataract
Build up of fluid pressure inside eye may lead to decreases in vision or blindness
Glaucoma
Uneven cornea means that the rays do not focus evenly
Uneven lens allows subject to see objects clearly
Astigmatism
Long eye; rays focus in front of retina when viewing distant objects
Concave lens allows subject to see distant objects
nearsighted
Short eye; rays focus behind retina when viewing close objects
Convex lens allows subject to see close objects
farsighted
