Chapter 9 Flashcards
What do sensory receptor neurons do?
they transduce (convert) environmental energy (like light) into neural activity.
For vision, the ____________ in the _____Convert light energy into chemical energy.
Photoreceptors; retina
In the auditory system, ___ ________ ______ are first converted into mechanical energy, which activates the _________ receptors that produce action potentials.
Air pressure waves; auditory
In the somatosensory system, mechanical energy activates receptors sensitive to ______, __________, or ______
Touch; pressure; pain
For taste and olfaction, various chemical molecules in the ____ or in _____ fit themselves into receptors of various ______ to activate action potentials in the respective receptor neurons
Air; food. shapes
Every sensory receptor organ and cell has a “receptive field,” what is this?
A specific part of the world to which it responds.
- each photoreceptor cell in the eye points in a slightly different direction (each has a unique receptive field)
Color photoreceptors are _________ and __________ packed. Receptors for black-white vision are _________ and are more ________.
small; densely
larger; scattered
vision passes through the _______, to the _________, and then to the _________ ________
retina, thalamus, cerebral cortex
Auditory receptors (sounds) pass through the ear, then to the _______, then to the __________, then the _________, and then finally to the ________ _________-
Hindbrain, midbrain, thalamus, cerebral cortex
Somatosensory receptors (touch) goes first to the ________ _______, then the __________, then the thalamus, and then the cerebral cortex.
Spinal chord, brainstem
If a person “hears” the speech syllable ba, but sees someone articulating the syllable ga, what do they hear?
They hear a hybrid sound (like da)
How do action potentials encode different sensations?
the receptors of a stimulus can be encoded by an increase or decrease in a neurons discharge rate
What is Synthesis?
The mixing of senses
eg. shivering when hearing a certain sound
In most mammals, the _________ represents the sensory field of each modality (vision hearing, touch, smell, taste)
Neocortex
all mammans have at least one primary cortical area for each sensory system. What are additional areas called?
Secondary
What is Perception?
interpretation of sensations
Light energy travels from the outside world through the _______ and into the eye, where it strikes a light-sensitive surface, the ________, at the back of the eye.
From this stimulation of ______________ cells on the retina, we begin to construct a visual world.
Pupil; Retina
Photoreceptor
What exactly do photoreceptor cells and the retina do?
They translate light into action potentials, discriminate wavelengths so we can distinguish color, and work in a range of light intensities (bright to dim)
How does the brain initially perceive objects
upside down and backwards
our vision is better in the center of the visual field than at the margins, or periphery, why?
because photoreceptors are more densely packed at the centre of the retina, a region known as the Fovea
What is a Blind Spot?
A small area of the retina called the Optic Disc. This is an area where blood vessels enter/exit the eye, and where fibres are located (there are no photoreceptors)
Why dont we usually have a problem with the Optic Disc?
because there are at different locations one each eye.
What is Papilledma?
The swelling of the optic disc
What are two causes for Papilledma?
1) Inter cranial pressure wither from a. tumor or infection
2) inflammation of the optic nerve itself (also called optic neuritis)
