chapter 10 the senses Flashcards
anatomy of the eye: retina
contains photoreceptors: sensory cells of the eye
anatomy of the eye: Lens
focus light onto retina
anatomy of the eye: Cornea
helps focus image on retina
anatomy of the eye: optic nerve
- coming from each eye
- collects the light, sends it to the retina, and the light is converted into action potentials which can be sent down to neurons
rods
respond to low levels of light
cones
respond to bright light signals (red, blue, green)
neural pathways of vision
- Light signals are converted into action potentials through the interaction of photoreceptors w/ bipolar cells & ganglion cells.
- ->Glutamate is neurotransmitter released
- Photoreceptor and bipolar cells only undergo graded responses, they lack the voltage-gated channels that mediate action potentials
- Ganglion cells are the first cells in the pathway where action potentials can be initiated.
from the back of the retina to front
-effective light traps, bipolar cells, ganglion cells
photoreceptors cells-in the retina
Contain Photopigments arranged for effective light trap
Metabotropic receptor eye
: initiates formation of second messengers when bound with ligand (neurotransmitter), found in neurons
Ionotropic receptor eye
binding of neurotransmitter controls the protein for the ion to move through
neural pathways in the brain
- Optic nerve (cranial 2) from each eye meet at the optic chiasm, project to many areas mainly the thalamus
- Other inputs come in from brainstem & visual cortex
- Some visual pathway neurons project to areas other than visual cortex, like hypothalamus
- Information is coded in spatial and temporal electrical activity-we perceive it all as a visual image consisting of lines, colors, contrast and movement
ear: tympanic membrane
- air molecules push against it at same frequency as sound wave
- Pressures and movement of the membrane indicate pitch and volume
ear: 3 bones
- malleus, incus, stapes
- Transduce sound by amplifying it through middle ear to the oval window
ear: Cochlea
- Waves of pressure are created against the scala vestibuli- transmits sound to cochlear duct
- Cochlear duct to cochlea
ear: Organ of corti
contains ears receptor cells
ear: receptor cells
- Receptor cells called Hair cells(mechanoreceptors)
- The hairs on the cell called Stereocilia (!) are bent back and forth as sound waves vibrate
- K+ channels open, Bursts of neurotransmitters are then released onto afferent neurons
- Glutamate (neurotransmitter) binds and causes action potentials in neurons making up the vestibulocochlear nerve
fluid in the cochlea is highly ___(+/-)
+
more K, K moves down gradient in (??)
neural pathways in hearing
- Cochlear nerve fibers synapse with interneurons in the brainstem.
- Different arrival times from each ear and intensity help determine sound source also the shape of the outer ear and head movements
-vestibulocochlear nerve–>brainstem (medulla oblongata)–>thalamus–>auditory cortex
steps for neural pathway
vestibulocochlear nerve–>brainstem (medulla oblongata)–>thalamus–>auditory cortex
Chemicals binding to specific ______ are responsible for the detection of taste and smell.
chemoreceptors
taste responds to chemicals ……
dissolved in food and drink
smell responds to chemical……
molecules from the air
taste buds located in bumps on the lounge called _____
papillae
what does microvilli do
increase the surface area of taste receptor cells. Microvilli come into contact with chemicals.
To enter the pores of the taste buds and come into contact with taste-receptor cells, food molecules must be …
dissolved in liquid, either ingested or provided by secretions of the salivary glands.
salt taste
sodium ions
sour taste
high acid content (H+ ions)
sweet taste
glucose
bitter flavor
quinine
umani
amino acid glutamate
pathway for taste
Pathways for taste go from glossopharyngeal nerve->medulla->thalamus->gustatory cortex (also prefrontal cortex) in the brain
true or false: All areas of the tongue are able to respond to all five categories
true
Independent coded pathways lead from the receptors, afferent neurons, to the CNS
This means a particular taste cell is sensitive to only one category
ok??
Olfactory receptors
-The olfactory receptor neurons lie
in the olfactory epithelium, in the
upper part of the nasal cavity.
- Each odorant is determined by the activation of a certain combination of receptors (affinity is higher for some receptors than others)
- Axons of these cells synapse in the olfactory bulb of the cerebra cortex then onto the olfactory cortex & interconnects with the amygdala, hippocampus, and limbic system
