Ch 43 Flashcards
What is involved in the sensation process?
sensory receptors transmit coded signals, the brain then interprets the signals
What is sensory adaptation?
it is a decrease in frequency of action potentials in a sensory neuron, it ocurs even when the stimulus is maintained, and it decreases the body’s response to the stimulus, it’s when we recieve a sensory signal over and over again and our bodies become accustomed to the signal, example: we aren’t constantly aware that we’re wearing clothes
sensory receptors
detect information about changes in the external and internal environment, these receptors consist of specialized neuron endings or specialized cells in close contact with neurons; sensory receptors, along with other types of cells, make up complex sense organs, such as eyes, ears, nose, and taste buds
accesory cells
support, connect, and integrate sensory receptors and neurons
mechanoreceptors
respond to deformation, mechano=touch&hearing, examples of mechanoreceptors: hair follicle receptor, pacinian corpuscle, merkel disc, meissner corpuscle, free nerve endings, Ruffini corpuscle (be able to recognize these as mechanoreceptors), balance, acceleration, and hearing are all mechano-
photoreceptors
respond to light
chemoreceptors
respond to concentration changes of chemical stimuli, ex: taste buds
nociceptors
respond to painful stimuli
thermoreceptors
respond to heat and cold
vestibular apparatus
responds to acceleration
proprioceptors
respond to muscle and joint position, being able to recognize where your body is based on joint position, a sense of where you are
electroreceptors
respond to electric currents or magnetic fields
interoceptors
respond to internal pH, salt, and gas
lateral lines
respond to water currents (found in fish, not humans), this is how fish ‘hear’ underwater, senses vibrations and water movement, the lateral line organ is a canal that extends the length of the body, the canal has numerous groupings of hair cells and openings to the outside environment, the receptor cells are hair cells, each hair cell has steriocilia and a kinocilium that are covered with a gelatinous cupula, the hair cells respond to waves, currents, and other disturbances in the water
statocysts
respond to gravity (hair cells that respond to gravity), a sense of where you’re going, similar to vestibular apparatus
vestibular apparatus
helps with balance, in human’s ears there is the ‘jello’ like hill or cupula with otoliths (little stones) on top. when you tilt your head the stones move the cupula and give you a sense of where your body is
organ of corti
in the inner ear, helps us hear, there are hair cells and certain pitches activate different rows of the hair cells, this is in the cochlea
what do vertebrate hair cells do?
detect movement, ther are found in lateral line of fishes, vestibular apparatus, cochlea, and skin
How does taste work? what are the 4 taste receptors?
the nose and tongue work together and interact with smell, texture, and temperature to form the taste, the taste receptors are salt, sweet, sour, and bitter
How does the chemical process of taste work?
1) chemical contact, 2-5) membrane proteins activate second messengers, 6) second messengers close K+ channels, 7) sensory receptor cell membrane depolarizes releasing the neurotransmitter, 8) action potential induced in neighboring sensory neurons; potassium channels are normally open in taste receptors, so K+ is always leaking out, the way the cell depolarizes is by closing the K+ channels
What is the chemical process of smell?
1) chemical contact, 2-4) membrane proteins activate second messengers, 5) second messengers open Na+ membrane channels, 6) sensory receptor cell membrane depolarizes, releasing neurotransmitter, 7) action potential induced in neighboring sensory neurons; very similar to taste, how to tell them apart? you taste a banana which has potassium (K+), if someone gets knocked out you use smelling salts (Na+)
sight
absorbs light energy, transduces it into electrical energy, produces receptor potentials, which produce polarizations or depolarizations of the membrane or graded responses
What are ocelli?
ocelli are eyespots, the are found in cnidarians and flatworms, they detect only light, do not form images
Ommatidia of insects and crustaceans
insects such as flies have visual units called ommatidia that produce a mosaic image
How do human eyes work?
light enters through the cornea, light is focused by the lens, the image is produced on the retina, the iris regulates the amount of light
What are the photoreceptor cells in the retina?
rods and cones
What are the steps of the human vision process?
1) absorb light energy, 2) internal membrane proteins activate second messengers, 3) second messengers close Na+ membrane channels, 4) rod cells signal to bipolar cells via reduced neurotransmitter, 5) bipolar cells signal to ganglion cells; at rest, sodium channels are open and the photoreceptor is depolarized
Human vision process: take 2
light strikes the rhodopsin, the rhodopsin signals to close the Na+ channels, the rod cell (photoreceptor) depolarizes, bipolar cell depolarizes, ganglion cell depolarizes
