Biology Questions and Answers
of the pupils. These movements depend
upon the muscles of the iris.
- Which is the part of the
human visual system where
the receptors that sense light,
i.e., the photoreceptor cells,
are located? How do those
cells work?
The photoreceptor ca lamina that covers thells form the internale retina,
posterior rphotosensitiveegion of the eyeball. The cells of the retina ar (^) e
divided into two types: the cone cells
and the rod cells. These cells havepigments that sense specific light wave (^)
ranges (frequencies) and trigger action
potentials conducted nerves to the visual area of the brain.by the optical
- Since the visual images are
projected in an inverted
manner on the retina why
don't we see things upside
down?
Since the crystalline lens is a convex
spherical leon the retina (evns it forms invery converging lenserted imag es
forms inverted images). The inverted
information nerves until thfollows throe occipitalugh the optical cerebral cortex (^)
that contains the visual area of the
brain. In the brain the interpretation othe image takes place and the invertedf (^)
information is reverted.
- What type of structure is
the crystalline lens? What is
its function?
The crystallinelens. This natural le is a cons has the functionnverging spherical
to project images oretina. f objects onto the - What is visual
accommodation?
Visual accommodation phenomenon of varying the curvaturis the (^) e of
the crystallinevariation of its refractivity lens to make p to adjust theossible the
images of objects exactly onto the
retina. Thaccomplishee visual accommod by the action odation isf the ciliary (^)
muscles.
The nitid vision depends on the visual
accommodationot projected onto the retina n since, if the images arbut in e
front or behind it, they will appear
blurred. The closer athe ciliary muscles must compress then object is more (^)
crystalline lens (increasing its
curvaturis more the ciliarye); the more distant an object muscles must relax.
- What are the near point
and the far point of the vision?
The near point is the closestbetween an object and the eye that distance
makes possible focused, i.e., it is the point in the formed image which thto bee (^)
ciliary muscles are in their maximum
contraction.distant point from th The far point is the moste eye in which an (^)
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