Sensation & Perception Flashcards
Sensation
Transduction - conversion of information from our internal and external environment to electrical signals in the nervous system
Perception
Processing to make sense of sensations, interpret them and their significance
Sensory Receptors
Respond to stimuli and trigger electrical signals
Ganglia
Transmit data from receptors to the Central Nervous System
Photoreceptors
Detect electromagnetic waves (vision)
Hair Cells
Fluid in inner ear responsible for hearing, linear and rotational acceleration
Nocioreceptors
For painful or Noxious stimuli
Thermoreceptors
Detect changes in temperature
Osmoreceptors
Detect the osmolarity of blood; responsible for water homeostasis
Olfactory Receptors
Detect volatile compounds through smell
Taste Receptors
Detect dissolved compounds through taste
Threshold
Minimum amount of stimuli resulting in perception of difference
Absolute Threshold
Minimum stimuli needed to stimulate / activate a sensory system where the stimulus is converted into action potentials; It is the amount of stimulus that an individual can perceive
Conscious Perception
Evoke action potentials long enough to be noticed
Difference Threshold
Minimum difference between 2 stimuli necessary to be perceived by the organism
Weber’s Law
Constant ratio between stimuli to produce a just noticeable difference
change in Intensity of Stimuli (a jnd)
_____________________________ x 100 = K
Intensity of original stimuli
Signal Detection Theory
Changes in our perception of the same stimuli depending on nonsensory internal factors (memories, motive, experiences, expectations etc…) and external (environmental) context
Adaptation
Physiological (sensory) component and psychological (perceptual) component changes our detection of stimuli over time
Cornea
Clear dome-like window in the front of eye
*Gathers and focuses incoming light
Pupil
Hole in the iris
*Allows passage of light from anterior to posterior chamber; contracts in bright light and expands in dim light
Iris
Colored part of the eye
*Controls the size of the pupil thus the amount of light entering the eye
Ciliary Body
Provides aqueous humor (clear liquid in the front of the eye between the lens and the cornea)
Canal of Schlemm
Drains the aqueous humor (clear liquid in the front of the eye between the lens and the cornea)
Lens
Lies right behind the Iris
*Refracts and Controls the curvature of light coming in and can focus near or distant objects on the retina
Retina
In the back of the eye
*Detects images through rods and cones
Sclera
Structural Support
Visual Pathway
Cornea Lens Vitreous Retina (rods and cones) Bipolar Cells Ganglion Cells Optic Nerve Optic Chiasm Optic Tract Lateral geniculate nucleus (LGN) of thalamus Radiation through temporal and parietal lobes Visual cortex (occiptal lobe)
Rods
Are responsible for Night Vision (active at low levels of light): Light and dark
- Increase in number toward the edge (periphary) of the eye
Cones
Are responsible for color detection and fine details (active at higher levels of light)
- Centered in the fovea
Duplicity Theory of Vision
Rods (dim light) and cones (bright light) both create vision
- Light passes through intermediate sensory neurons before reaching and stimulating photoreceptors
Fovea
Middle section of the Retina
Center of eye; only cones (best in daylight vision)
Optic Nerve
Contains no photocepetors; formed bu groups of ganglion cells
Ganglion Cells
Grouped together to form the Optic Nerve
*Receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and retina amacrine cells.
Bipolar Cells
Highlight gradients between adjacent rods and cones
Horizontal Cells (Amacrine)
Important for edge detection and perception of contrasts
Parallel Processing
Simultaneously analyze and combine information regarding
- color (cones)
- shape (parvocellular cells)
- motion (magnocellular cells)
Parvocellular Cells
Responsible for shape; see fine detail in stationary or slow moving objects
Magnocellular cells
Responsible for motion; blurry but moving image
Pinna (Auricle)
Cartilage (fleshy part of the outer ear) that channels sound waves into the external auditory canal
Tympanic Membrane (Eardrum)
- Divides outer ear from middle ear
- Vibrates in phase with the incoming sound wave
Ossicles
3 Smallest bones in the middle ear that transmit and amplify vibrations to the inner ear
- Malleus (hammer)
- Incus (anvil)
- Stapes (stirrup)
Eustacian Tube
Equalizes pressure between middle ear and environment
Endolymph
K+ rich fluid that fills the membranous labyrinth of the ear
Perilymph
Transmits vibrations via fluid from outside world and cushions the inner ear
Organ of Corti
Actual hearing apparatus; hair cells (receptors of hearing) bending is converted from physical stimulus into an electrical signal carried along the nerve fiber connecting to the auditory nerve and the Central Nervous System
Vestibule
Composed of the Utricle and Saccule; sensitive to linear acceleration, balance, determines ones orientation; hair cells resist the motion
Semicircular Canals
Sensitive to rotational acceleration; endolymph resists the motion
Auditory Pathway
Pinna External Auditory Canal Tympanic Membrane Malleus Inca Stapes Oval Window Perilymph Coclea Basilar Membrane Hair cells Vestbulocochlear Nerve Brainstem Medial geniculate nucleus (MGN) of thalamus Auditory Cortex (Temporal Lobe)
Tonotopically
Organization of the cochlea (basilar membrane and apex) allows hair cells to vibrate
Basilar Membrane
High frequency base of the cochlea
Apex
Low Frequency top of the cochlea
Smell
Olfactory chemoreceptors respond to volatile or aerolized compounds
Pheremones
Secreted by an organism to compel another organism to behave a certain way
Olfactory Pathway
Nostril Nasal Cavity Olfactory Chemoreceptors Olfactory bulb Olfactory tract Higher order brain regions (Limbic system)
Tastes
- Sweet
- Salty
- Sour
- Bitter
- Umami (savory)
Somatosensation
Sensitive to pressure, vibration, pain and temperature