Senses and vision Flashcards
Sensation is the capacity to ____ a particular ____ or ____ stimulus.
Involves ____ organs and ____ nerves.
detect, physical, chemical sensory, afferent
Perception is the ____ experience and ____ of ____ information. Involves ____ in the ____ nervous system.
conscious, interpretation, sensory
neurons, central
A stimulus is a thing or ____ that evokes a specific ____ reaction in an ____ or ____
event
functional
organ
tissue
What is transduction?
Each sensory organ deploys a specific mechanism to transform chemical or physical attributes of stimuli to neuronal activity
Each sensory organ deploys a specific mechanism to transform chemical or physical attributes of stimuli to what?
Neuronal activity. This is called stimulus transduction
Give some examples of physical and chemical stimuli
Physical = sound visible light, heat, magnetic field, UV light
Chemical = taste, odour, pheromones
Weakly electric fishes produce and detect small current flows around them. What is this called? What is this called when used to communicate with conspecifics?
Electrolocation
Electrocommunication
What is the purpose of cockeyed squid having asymmetrical eyes?
Large eye looking upward to detect predators against dim sunlight
Small eye looking downward to detect prey bioluminescent signals
Sensory receptors are cells that specialise in ____ ____ stimuli (physical or chemical) into ____ (electical) ____
converting, external, neural, activity
What do the following detect, and what activity are they linked to?
1. Photoreceptors
2. Mechanoreceptors
3. Chemoreceptors
4. Nociceptors
- Detect light | vision
- Detect movement | sound, texture, blood pressure, muscle stretch
- Detect chemical compounds | smell, taste
- Detect tissue damage | pain
A receptor threshold is the ____ stimulus ____ that is ____.
minimum, intensity, detected
What are three things that can affect how we perceive the same sensory experience?
Context, emotional state, memories
What is meant by “visual light”?
Section of the electromagnetic spectrum that the human eye can detect
Describe the role of the following in the eye…
1. Iris - o____ and c____ to allow more or less l____ through the p____
2. Cornea and lens - f____ the light into the r____, where the image is r____
3. Optic disc - allows v____ going in and out, and the optic n____ to carry visual information to the b____
- Opens and closes to allow more or less light through the pupil
- Focus the light into the retina, where the image is recreated
- Allows vessels going in. and out, and the optic nerve to carry visual information to the brain
The fovea is mainly covered by d____ p____ c____
Densely packed cones (acute vision during daylight)
The periphery is covered by r____, which are more s____ to l____ than c____.
Rods, which are more sensitive to light than cones (sense very dim light)
What are the three types of cones?
1. B____
2. G____
3. R____
Each type is s____ to a specific w____ b____
Blue, green and red
Each type is sensitive to a specific wavelength band
Photoreceptors are depolarised in the dark, releasing what?
Glutamate
Light makes them hyper polarise, reducing glutamate release
What are the three cell layers in the eye?
1. G____ cell layer
2. B____ cell layer
3. P____ layer
- Ganglion cell layer
- Bipolar cell layer
- Photoreceptor layer
Photoreceptors and bipolar cells do not fire action potentials. Instead they do what to affect the probability of neurotransmitter release?
C____ their m____ p____
Change their membrane potential
In vertebrate retinas, what are the two types of bipolar cells?
O____ and o____
ON and OFF
How many photoreceptors are the bipolar cells connected to in the fovea and the peripheral retina?
Fovea - one bipolar cell connected to one photoreceptor
Peripheral retina - one bipolar cell connects with several photoreceptors
Both eyes collect light from both sides of the visual field. Where does visual information coming from each side of the visual field get conveyed to?
The visual information coming from the right side of the visual field is conveyed into the left hemisphere.
The one from the left side of the visual field is analysed in the right hemisphere
What are the three neural routes to the visual brain?
1. R _ _ _ _ _ h _ _ _ t _ _ _ _ _ _ tract
2. G _ _ _ c _ _ _ s _ _ _ _ _ _ pathway
3. T _ _ _ _ p _ _ _ _ _ _ _ pathway
- Retinohypotalamic tract
- Geniculostriate pathway
- Tectopulvinar pathway
Discuss the retinohypotalamic tract
Around __% of g____ cells express a p____.
These neurons are not connected to ____ and project to the s______ nucleus of the h______.
Involved in regulating the c____ rhythm and controlling p____ reflex that expands or contracts the pupil to c____ the amount of l____ reaching the r____.
Not involved in visual p____.
1, ganglion, pigment
photoreceptors, suprachiasmatic nucleus, hypothalamus.
circadian, pupillary, control, light, retina.
perception
Discuss the geniculostriate pathway
Upon reaching the ____ cortex, neural information diverges into:
1. D____ stream - analyses the ____, guides ____ relative to objects
2. V____ stream - analyses the ____, object ____ (colour, shape, size, texture).
Necessary for the ____ experience of vision.
visual
Dorsal, how, movement
Ventral, what, identification
conscious
Discuss the tectopulvinar pathways
The only pathway present in f____, a____ and r____.
Information through ____ cells from the ____ periphery, with no ____ information.
Analyses ____ information of objects.
Explains the ____ ability of patients with ____.
fish, amphibians and reptiles ganglion, retina, color
spatial
visual, blindsight
What are the two major functions of the brain?
1. Controls m____ of m____, producing u____ behaviours
2. R____ body’s i____ e____
- Controls movement of muscles, producing useful behaviours
- Regulates body’s internal environment
What is rhodopsin?
Photopigment that reacts with light
