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73 Cards in this Set
- Front
- Back
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What do "sensations" involve?
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the conversion of stimulus energy into a change in the membrane potential of sensory receptors
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What are "Sensations" and how do they reach the brain?
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Sensations are action potentials that reach the brain via sensory neurons
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Do sensory receptors contain axons, dendrites or neurons?
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dendrites
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Describe how the sensory receptor acts as a transducer
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They translate chemical mechanical or electromagnetic stimuli into electrical energy
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What are the tips os some sensory nerve fibres associated with?
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tissues that amplify thee stimulus and thereby increase the sensitivity of the receptor
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What is a sensory organ?
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a sensory nerve fibre with its associated tissues
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What are the two main types of sensory organs? Define both
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Special sensory organs: associated with specialized cells
General sensory organs: concerned with the sensation of touch, temperature |
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What are the three types of sensory receptors found in general sensory organs?
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Free sensory receptors: free nerve endings
Encapsulated sensory receptors: nerve endings enclosed in a specialized structure Associated sensory receptors |
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Define proprioception
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sense of the relative position of neighbouring body parts or the body and strength
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Nerves associated with specialized _______ are responsible for maintaining muscle tone and posture
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muscle fibers or muscle spindles
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T/F
When posture changes or load is added to the bod muscle spindles are stretched which generates action potential that causes the muscle to contract |
T
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Name the 4 types of special sensory organs
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-chemical stimuli (chemoreceptors)
-Radiation stimuli (radiation receptions) -Mechanical stimuli (mechanoreceptors -Electrical stimuli (Electroreceptors) |
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In terrestrila vertebrates chemosensory system, the gustation (taste) is dependent on? What is the olfaction (smell) dependent on?
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the detection of chemicals called testants by chemoreceptors in the mouth.
dependent on the detection on odorant molecules in the air by the chemoreceptors in the nose. |
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In terrestrial insects the taste chemoreceptors are ______ and located on the _______ and on the _______ parts
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sensory hairs; feet; mouth parts
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Where are the smell chemoreceptors located on terrestrial insects
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antennae
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Where are the taste and smell chemosensory receptors located on a fish?
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No distinction between the 2
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In fish, where are the olfactory sensory receptors located? How does it work?
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in nasal sacs, water moves in and out of the sacs as the fish swims
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What is the Vomoronasal organ?
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its in amphibians and it is an area of specialized sensory cells that is present in the nasal sac
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Define vomerofaction
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The process of using the vomeronasal organ to detect chemicals
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T/F
Vomerfaction is well developed in lizards and snakes |
TRUE HOMIE
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T/F
The vomoronasal organ is present in all mammals and birds |
FALSE
Present in SOME mammals and ABSENT in birds and crocodiles |
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What are chemoreceptors in the mouth called?
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taste buds
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In amphibians and reptiles, where are taste buds located?
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In the mouth an pharynx
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Where are the taste buds located in mammals?
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in the mouth and throat, but predominantly on the papillae of the tongue
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Radiations travel in waves. What are short waves called, and what are long waves called?
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Gamma radiation
radio waves |
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What wavelengths can humans perceive?
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between 380-760nm
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Some birds and reptiles can perceive _______radiation and some reptiles can perceive ______ raidaiton
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UV;IR
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In most animals, where are the photoreceptors located?
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eyes
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Photoreceptors are though to be ________among species
a. analogous b. homologous |
b. homologous
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What is the ocellus? And where is is located?
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the light-detecting organ in planarians (flatworms)
located in the head region |
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What is another name for flatworms?
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planarians
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Do ocellus form images?
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no, they can just detect light
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Planarians are _____________; they move from an area of high light intensity to an area of lower light intensity
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photonegative
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What is the compound eye and which species is it found in?
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an image forming organ. Found in insects and crustaceans (Arthropoda) and in some polychaete worms (annelids)
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What are the light detectors in a compound eye called?
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ommatidia
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Yes/ No
-The ommatidia share a lens that detects light -ommatidium is sensitive to visible light (colour) and UV light -Compound eye forms mosaic images, good at detecting movements |
no --> each has its own lens
--> yes --> yes |
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What is so special about single-lens eye?
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can form images and can focu on objects ar different distances
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Where are single-lens eyes found?
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invertebrates
in spiders, molluscs and some polychaete worms |
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Who eye is the most complex?
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vertebrates image-forming eye
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What kind of light does the vertebrate eye detect?
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visible light and colour
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How are incoming light rays focused on the retina?
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lens and cornea bends the incoming light
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What two types of photoreceptors does the vertebrate retina contain?
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rods and cones
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What happens when the pigments absorb light photons?
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retinal changes shape which excties the neuron
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Do nocturnal animals and diurnal animals have the same amount of rods and cones?
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NO
nocturnal animals: few to no cones diurnal animals: have both rods and cones |
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Where are rods concentrated around?
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the periphery of the retina (NOT at the fovea)
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What visual pigment do rods contain?
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rhodopsin, which changes shape when absorbing light
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Are cones less or more abundant than rods?
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less abundant
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Can rods and cones both distinguish colours?
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no only cones can
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Where are cones concentrated?
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in the fovea (the centre of the visual field)
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What are the three types of cones and what is the visual pigment they all contain?
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red, green, blue
photopsin |
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What is the range of colour that can be perceived dependent on?
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he number of different types of cone cells they have
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Which vertebrate lacks cones altogether?
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sharks
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What is tetrachromatic vision? and who was it found in?
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4 types of cones
found in fish, turtles, lizards and birds |
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Who has 3 types of cones, and what is is called?
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amphibians
trichromatic vision |
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How many cones to humans and apes have?
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trichromatic vision (3)
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How many cones do mammals have and what is is called?
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2
dichromatic vision |
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What do pigmented epithelium cells do?
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protect the photoreceptors from light
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What do bipolar cells do?
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receive neural impulses from rods and cones
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What to horizontal and amacrine cells do?
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function in neural pathways that integrate visual information before it is sent to the brain
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What to ganglion cells do?
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synapse with bipolar cells and send action potentials to the brain
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In diurnal animals, where do single cones tend to synapse?
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with single bipolar cells that synapse single ganglion cells that project to the CNS
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In diurnal animals, is the configurations increased or decreased to the resolution of the retina?
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increased
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In nocturnal animals, who do the photoreceptor cells converge with?
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a small number of interneurons
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In nocturnal animals, is the configurations increased or decreased to the resolution of the retina?
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decreased
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What do optic nerves do?
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carry axons from the retina
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What is optic chiasm?
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the crossing over of the optic nerves
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What is lateral gesticulate nuclei (LGN)?
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integration centres located in the thalamus
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What does the visual cortex do?
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integrates neural info and formulates what the animals sees (images)
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What is noncular vision?
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animals with eyes on the sides of their head. wide visual field (rabbits)
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What is binocular vision?
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animals with eyes in front of their head, wide area of overlap in the field of view
-enhances depth perception and visual acuity (owls, humans) |
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what is parallax mean?
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the slightly different view one gets of distant objects from different points of view.
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Why are infrared receptors also called thermoreceptors?
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because they have warming effects on objects
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Who has specialized thermoreceptors?
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snakes, boas, pit vipers...they are sensitive to temperature changes
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