VISION part I Flashcards
an instrument used by eye specialists to visualize the retina & the blood vessels in it thru the pupil
OPHTHALMOSCOPE
the study of the structure, functions & diseases of the eyes
OPHTHALMOLOGY
a physician who specializes in the diagnosis & treatment of eye disorders
OPHTHALMOLOGIST
licensed specialist who examines & tests the eyes for visual defects
OPTOMETRIST
a technician who fits/adjusts lenses with the prescription of an
optometrist/ophthalmologist
OPTICIAN
is the means by which the brain receives information from the ‘outside world’
SENSES
anything from the inside or outside the body that can cause a response in a nerve, muscle,
gland or other tissue
STIMULUS
the conscious awareness of stimuli received
SENSATION or PERCEPTION
is a peripheral ending of the functional dendrites of afferent neurons
RECEPTORS
is a group of structures which convert the energy of a stimulus into sensation
SENSORY ASSEMBLAGE
3 COMPONENTS OF SENSORY ASSEMBLAGE
- RECEPTOR
- PATHWAY TO THE BRAIN
- SENSORY AREA
transforms the energy of the stimulus to an electrical form
RECEPTOR
these are peripheral nerves thru which impulses can be conducted
PATHWAY TO THE BRAIN
in the cerebral cortex is where nerve impulses give rise to sensation
SENSORY AREA
refer to both somatic senses and visceral senses. It is more widely
distributed throughout the body. It involves the sense of touch, pain, pressure,
temperature, vibration and proprioception.
GENERAL SENSES
y) include tactile sensations (touch, pressure,
vibration, itch, and tickle), thermal sensations (warm and cold), pain sensations,
and proprioceptive sensations. Proprioceptive sensations allow perception of
both the static (nonmoving) positions of limbs and body parts (joint and muscle
position sense) and movements of the limbs and head
SOMATIC SENSES
provide information about conditions within internal organs.
Example: pressure, stretch, chemicals, nausea, hunger, and temperature
VISCERAL SENSES
It includes the sensory modalities of smell, taste, vision, hearing, and equilibrium or balance
SPECIAL SENSES
PROCESS OF SENSATION
- STIMULATION OF THE SENSORY RECEPTORS
- TRANSDUCTION OF STIMULUS
- GENERATION OF AN IMPULSE
- INTEGRATION OF SENSORY INPUT
The stimulus must occur within the receptive
field of the sensory receptors. This receptive field is that part of the sensory receptor
that is capable of responding to stimulus
STIMULATION OF THE SENSORY RECEPTORS
When a sensory receptor is stimulated, it converts
a stimulus into a graded potential=a small deviation/change from the membrane
potential that makes the membrane either more polarized (more-) or less
polarized (less-) each type of sensory receptor can convert only 1 kind of
stimulus.
TRANSDUCTION OF STIMULUS
After a sensory receptor has converted a certain
stimulus, an impulse is generated. Thus when a graded potential in a sensory
neuron reaches a threshold, it triggers one or more nerve impulses, which then
propagate toward the CNS
GENERATION OF AN IMPULSE
Upon an impulse has reached the brain, integration
of sensory input happens
INTEGRATION OF SENSORY INPUT
It is located on the medial surface of the occipital
lobe and it receives impulses that convey visual info like shape, color, and movement
PRIMARY VISUAL AREA
It receives sensory impulses from the
primary visual area & the thalamus. As an association area, it relates present
& past visual experiences, thus is essential in recognizing & evaluating what
is seen (Ex: having seen Vigan)
VISUAL ASSOCIATION AREA
It is located superior part of the temporal lobe
PRIMARY AUDITORY AREA
It is located inferior & posterior to the
primary auditory area. It ascertains whether a sound is speech, music or noise.
AUDITORY ASSOCIATION AREA
Primarily located at medial aspect of the
temporal lobe. It receives impulses for smell.
PRIMARY OLFACTORY AREA
It located at the base of the post central
Gyrus, superior to the lateral cerebral sulcus and receives impulses for taste.
PRIMARY GUSTATORY AREA
It located at or near the external surface of the body. It is sensitive to stimuli from outside the body.
EXTERORECEPTORS
It is responsible in monitoring the internal environment.
Primarily located in blood vessels, visceral organs, nervous system
ENTERORECEPTORS
It is responsible in monitoring the internal environment. Primarily located in blood vessels, visceral organs, nervous system
ENTERORECEPTORS
They respond to stimuli that are far from the body. It include exteroceptors located in the eyes, nose & ears
TELECEPTORS
These are free nerve endings found in every tissue of the body except the brain. They respond to all stimuli producing pain sensation
NOCIRECEPTORS
They detect chemicals in the mouth (they help in detecting what kind of taste the food has); nose (smell); body fluids (respond to
changes in the chemical composition of the body fluids: ex: increase in pH,
electrolyte level.
CHEMORECEPTORS
They detect change in temp.
THERMORECEPTORS
They detect mechanical stimuli; provide sensations of touch, pressure, vibration, proprioception, and hearing and equilibrium; also
monitor stretching of blood vessels and internal organs.
MECHANORECEPTORS
they detect light that strikes the retina
PHOTORECEPTORS
They respond to changes in BP
BARORECEPTORS
CHARACTERISTICS OF SENSATION
- PROJECTION
- AFTER-IMAGE
- ADAPTATION
- LOCALIZATION
- MASKING
- AFFECT/FEELING TONE
- MODALITY/INTENSITY
What is sensed at a certain part of the body thru the sensory receptors, is directed/projected to the brain thru the transmission of impulses
& the brain then sends back what info it has processed to the part or source
of stimulation
PROJECTION
It is the ability to perpetuate sensation
despite cessation of stimulation
AFTER IMAGE
It is the absence of sensation despite
the continuous stimulation.
ADAPTATION
It is the ability to recognize the point of stimulation.
LOCALIZATION
It is the ability to camouflage sensation.
MASKING
It is the effects of sensation, whether pleasant or
not
AFFECT/FEELING TONE
It refers to the sensory receptors for the different
sense organs are specific
MODALITY/INTENSITY
