Senses Flashcards
What is the sequence of events for taste?
Dissolved molecules interact with receptors, the membrane depolarises and an action potential is fired, intracellular calcium intake increases, NT is realised, excitation or afferent nerve fibres.
Give the pathway light takes to the eye?
Detected and focused by the lens, through pupil, focused to fovea, centred to optic nerve then leaves
Explain the structure of cortical modules?
2 mm squared, blobs to interpret colour, orientation columns both left and right, ocular dominance columns and inter blob regions
Give the sequence of events for smell?
Odourants bind to receptors on cilia and G-proteins are activated. cAMP is produced and binds to calcium and sodium channels. Channels open and chloride ions channels open which causes depolarisation.
Give the three types of papillae in order of small to large?
Fungiform, foliate and circumvallate
Where are photoreceptors rods and cones found?
In the fovea and the back of the retinal in the black pigment epithelial cells.
Give the four types of cells in the retina?
Photoreceptors, bipolar, horizontal and retinal ganglion.
Give the pathway of smell from receptors to target?
Olfactory receptors to olfactory bulb to olfactory tracts to target in the cortex.
What are the three classes of somatosensory receptors?
Tactile- mechanoreceptors
Temp. hot and cold- thermal
Nociceptors-all three
Give three steps to turn sound into nerve impulses?
- Stereocilia are disturbed to give mechanoelectrical transduction.
- The scala media endolymph is high in potassium, opening of channels causes depolarisation.
- Calcium causes NT release to auditory complex on superior temporal gyrus.
What are the sensory receptors on the ear?
The inner hair cells of the scala media in the cochlea
Is conduction velocity positively of negatively associated with axon diameter?
Positively
What does NOT cause pain?
The over stimulation of receptors responsible for touch
What is the response of substance P being locally release?
Increased inflammatory response
What’s the different between thermoreceptors and nociceptors?
Both detect heat but thermoreceptors are just for warm and mild temp and nociceptors work at extreme temperatures.
What is a contralateral pathway in pain?
Where the sensory impute cross at the level of the spinal cord and ascend on opposite sides.
What cells are involved in the direct pathways of light?
Photoreceptors, to bipolar cells, to retinal and ganglion cells.
What happens to NT transmission in the dark?
cGMP is converted to GMP, sodium channels close and no NT is released
What are the two parts is the retina divided into?
Nasal and temporal
How is full vision in the brain ensured?
The nasal signals cross at the optic chiasm and the temporal continues on its own side
What is another name for the primary visual cortex?
The striate cortex
Give the parts of the outer ear?
Pinna and auditory canal
Give the parts of the middle ear?
Tympanic membrane and ossicles
Give the parts of the inner ear?
Cochlea and semi circular canals
What are the three senses associated with the nose and mouth?
Olfactory, gustatory and chemical trigemnal
What contributes to taste?
Tongue, pharynx, palate, food odor and texture/appearance
What is the macula in the retina for?
Central vision
What is the optic disc of the retina?
The origin of blood vessels and where the optic nerve axons exit the eye- blind spot.
What do photoreceptors do?
Convert light energy into neural activity
What do bipolar cells create?
Direct pathways from photoreceptors to ganglion cells.
What is sound?
A series of changes in air pressure which form a wave
