Senses! Flashcards
(36 cards)
Name the types of chemoreceptors
Olfactory neurons, gustatory cells, other
Describe general, mechanism of senses
1) Stimulus opens Channels (directly: Ligand gated or mech gated or indirectly: enzymatic pathway)
2) depolarization (more positive) produces graded potential which is converted into AP for relaying
3) Projection where AP passes through specific neutron pathways to area of cortex
4) Brain decodes- type of stimulus, location of stimulus and strength
What are tonic receptors
Always on, slow or no adaptation: Muscle receptors for pain and balance
What are phasic receptors
adapt, fire @ beginning and end of stimulus. Eg. Meisner corpuscle or hearing
What does the utricle detect
horizontal movement (acceleration)
what does the saccule detect
vertical movement (jumping, elevator)
Semicircular ducts
detect changes in rate of rotation
When the stereocillia bend toward the kinocillium causes…
depolarization
when the stereocillia bend away from the kinocillium causes…
hyper polarization
where are hair cells for balance found
In the semicircular ducts, embedded in the ampulla where a cupola sways when the endolymph moves
How is hearing similar to balance
- Both have hair cells
- both happen in ear
- both have hair cells in endolymph
- both use vestibulocochlear nerve
Difference between balance and hearing
Location of receptor: Scala media & semicircular ducts.
Structure of receptor: Balance has a kino cilliim
Mechanism: Fluid waves in scala vestiboli cause waves in the scala media, where the hair cell will brush against the tectorial plate and depolarize as mechanical gated K+ channels are opened.
where as balance: when head moves, sterocilia will bend toward the kinocillium which will open K+ ch causing depolarization or hyperpolarazation. Synapse with the afferent neutron and vestibulocochlear nerve
Explain what is happening in distance vision.
What the Lens and cornea are doing:
The lens is flat (think flat, far away) it reflects light
the cornea does not change shape
Explain what is happening in distance vision.
what neurons are involved?
Sympathetic neurons
Explain what is happening in distance vision.
What are the cilliary muscles doing?
they are relaxed/dilated
Explain what is happening in distance vision.
what are the suspensory ligaments doing?
pulled taut
Explain what is happening in distance vision.
What is the binocular vision doing?
Parallel rays can land on fovea when yes are forward.
Explain what is happening in distance vision.
What are the pupils doing?
Dilated. (large)
Pupillary dilator muscles contract and constrictor muscles relax, pulled open
Explain what is happening in close vision.
What is the lens doing
accommodates to become round.
Reading & relaxed = round
Explain what is happening in close vision.
What are the neurons involved
Parasympathetic
Explain what is happening in close vision.
What are the ciliary muscles doing
Contracted
Explain what is happening in close vision.
What are the suspensory ligaments doing
loose relaxed
Explain what is happening in close vision.
what are the binocular vision doing
Requires convergence, extrinsic eye muscles rotate medially so divergent rays land on fovea
Explain what is happening in close vision.
What are the pupils doing
Constricted.
