Chemosensory and Visual Adaptations Flashcards
What is the most universal sensory modality?
Chemoreception
What two receptors make up chemoreception?
gustatory-taste and olfactory-smell
Did the chemosensory systems evolve dependently or independently in many groups?
independently
What is olfaction?
sense of smell
What types of neurons are involved in olfaction?
bipolar neurons
How many different odors can mammals discern?
Well over 10,000
How are air-born molecules sensed?
The molecules are collected in the nasal concha and dissolved in a fluid in order to bind to receptors and produce a signal
What does it mean that the binding to the sir born molecules for olfaction is reversal?
The receptor can bind to the molecule and then after sometime it is released so we do not constantly recognize the smell
What are sencilia?
the combination of the words sensory and cilia; they are processes long enough to fall over and sit below the mucopolysaccharide fluid that collects the airborn molecules
What are the sententacular cells in olfaction?
Non-neuronal cells that support the cells physically and also help bind molecules and pass them across to the sensory cells
What is the primary odor hypothesis?
We do not have 10,000 receptors for the 10,000 different smells we can smell. Instead there are a finite number of specific receptor types and then differential activation of these types to greater or lesser degrees and the combinations of them have unique signature that the brain interprets as a specific sound.
What are the primary odors?
musky floral pepperminty camphoraceous-vicks vapor rub ethereal-gas pungent putrid
What do organisms use olfaction for?
- foraging feeding
- location or navigation
- reproduction and development
- protection
How much greater do dogs have olfaction senses than humans do?
40 times
What part of the brain do all the olfaction senses get interpreted by animals lower than mammals?
The midbrain which is the most primitive part of the brain
For humans where is olfaction sensation interpreted and processed? Why does this make smelling different to us than other senses we have?
Mostly interpreted in the higher center in the cerebral cortex region a fair amount is processed in the midbrain. This is unusual bc most senses are passed up really quickly to higher brain centers. This makes olfaction different from other senses, a certain smell will often bring up memories and emotional images
What are three examples of how organisms use chemoreception-olfaction?
- Parasites: every species has its own species of roundworm, when entering the intestine the worms look for chemical cues to start development, dog roundworms in humans do not receive the right chemical sensations and go looking for them to begin development and can end up in bad places such as the brain etc.
- Insects gypsy moths: male moths more showy frilly antennas and females less showy and sometimes flightless. Males use big antennas more surface area and females release pheromones. We isolate pheromones into bug zapers and control population of males.
- Cnidarians release sperm and eggs into water. Eggs release chemical that attracts the sperm
- Barnacles: They are sessile organisms but reproduce by internal fertilization so barnacles have enormously long penises and the barnacle colonies release chemicals and the larval form of barnacles which is the only motile form will swim towards chemical and attach near colony no further than one penis length away.
How do mammals use gustatory responses?
We have taste buds that occur in groups (40-60)
What type of cells are taste buds?
secondary epithelial sense cells
How do vertebrates taste?
molecules come in dissolve in salvia and fluid in mouth settle on taste hairs and initiate action potential sent to brain
Are taste buds hair cells?
yes they are modified hair cells that are no longer sensitive to sheer or torque forces but to chemical stimuli
Why are taste buds kept below the epithelial tissue?
For protection. They are less likely to be damaged there. Taste buds are expensive to make and this is a way to limit their exposure to damaging substances.
What are the four classic tastes and the 2 non-traditional tastes?
sour salty sweet bitter
water umami
Can humans taste water? Can fish taste water?
We taste the ions in water the dissolved amino acids but we can not describe the taste of water. Fish can taste water they can tell saltwater from fresh water and lack salty taste buds
Where are the remnants of the system that can taste water in humans?
In the brain and help determine thirst
What does the taste bud umami pick up?
amino acids gultamic acid meat
Why do humans have a predisposition for sweet tastes?
sweet tastes often corresponds to things high in calories and less toxic and in the old days when humans scavenged for food sweet things were safe to eat
How are the taste buds in vertebrates distributed?
irregularly
In birds how good is their sense of smell and tastes?
No sense of taste decent sense of smell. For example vulture have no taste but fairly good sense of smell
How do salmon use magneto reception and chemoreception?
They find the coastline using magneto reception. They follow the coastline up using the sense of smell then taste to taste the freshwater of stream.
What is another name for the Vomoronasal organ?
Jacobson’s organ
Gustation in reptiles and amphibians using the Jacobson’s organ is a ______ sense?
Chemotaxic sense it gives them the direction to go in based on the number of molecules present
What is the role of the forked tongue?
for directionality to tract prey it sticks the tongue out into the air and then sticks it into the roof of the mouth and it senses if more molecules on right than left the prey went right
What mammals have the Jacobson’s organ?
cats
jacobson’s organ picks up senses using what but is actually a what sense?
using the tongue but is an olfactory sense
What sense gives more detailed information about and near and distant environment than any other sense?
Vision/photoreception
True or false. Vision is instantaneous?
True.
What types of information can vision supply?
- intensity/contrast-distance
- wavelength-color
- plane of polarization-used for distance and direction like a sextant
WHat is dermal light sense? and what is another name for this type of sense?
It is the sense of light on the skin’s surface. Occurs in nearly all animal phyla. Another name for it would be diffuse photosensitivity
How does the dermal light sense work?
The mechanism is not entirely clear. Photosensitive nerve endings? No
Heat sensors? NO
What types of information is the dermal light sense important for?
- Nocturnal animals with the ability to tell light from dark but not with eyesight
- Time certain events such as daylight or breeding times
- Out and about and the environment changes for example if your small and a shadow passes over you you may want to take cover so you are not eaten
