Special Senses Flashcards
Sensory receptors are at the interface between the environment and the brain. Name the term that describes their overall action and define this term (3)
Transduction. Convert one form of energy (e.g. photic, mechanical) to electrical energy.
Outline the physiological mechanism which inhibits transmission of somatosensory information to the somatosensory cortex while the child is asleep (2)
Activation of the reticular nucleus which releases GABA and inhibits activity of other thalamic nuclei
Compare the spectral selectivity of the rods and cones of the retina (2)
Rods do not responds to colour, cones (trichromatic) show differential spectral sensitivity in the red blue and green parts of the colour spectrum
Draw a schematic diagram to show the layers of the retina (4)
Need to show relative layers (with correct orientation): choroid, photoreceptor layer, outer nuclear, outer plexiform, inner nuclear, inner plexiform and innermost ganglion cell layers
State the specific nucleus and its location in the brain to which visual information is transmitted from the retina and where it is processed before being transmitted to the visual cortex (1)
Lateral geniculate nucleus of the thalamus
Draw a schematic diagram to show the pathway of information flow from the left retina to the primary visual cortex (5)
Diagram to show origin of left optic tract/nerve (nasal, temporal hemi-retinae), optic chiasm, optic tract, lateral geniculate nucleus, and primary visual cortex in occipital lobes
Explain why hair cells involved in hearing and equilibrium have morphological polarity (3)
Hair cells have one very long kinocilium relative to the other cilia which are arranged in descending order of length. When the other cilia are bent in the direction towards the kinocilium, the hair cell depolarizes and when it is bent in a direction away from the kinocilium the hair cell hyperpolarizes, causing respectively, increased and decreased firing of action potential in the afferent fibre.
