Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_27_библиотеки_им_акад_М_И_Перельмана
.pdf
1. Monochromatic light. A single spike at 500 nanometers, rising to a relative
intensity of 2.5.
2. Incandescent bulb. Starting at 0.5 intensity at 400 nanometers, and rising
gradually to reach 4.5 intensity at 700 nanometers.
3. Sunlight. Starting at 1.5 intensity at 400 nanometers and rising to around 3
intensity at 500 nanometers. The line remains at 3 intensity until around 650
nanometers and then drops to 2 intensity.
4. Fluorescent bulb. The line for fluorescent bulb is more erratic. It starts at 1.2
intensity at 400 nanometers and rises sharply to 5.5 at 420 nanometers. It then
drops sharply to return to 1.2 at 430 nanometers. It rises very slowly to reach 1.5
intensity at 500 nanometers. It continues to rise to 2 intensity at 520 nanometers
and then rises sharply again to reach 5.5 at 530. It then drops sharply to reach
2.5 intensity at 540. It then rises to 4 intensity at 550 nanometers. At this point
the line falls gradually, reaching 2 intensity at 600 nanometers and stabilizing at
around 1.2 at 700 nanometers.
Back to Figure
An author introduction reads as follows. In section A, the major parts of the eye
are shown. In section B, the major pathway of visual information is shown, including
from the photoreceptor to bipolar cells to ganglion cells. Note how the connections to
the cones fan out away from the fovea, making the cones there more accessible to
light.
Section A. Refraction of light onto the lens.
The diagram illustrates the anatomy of a human eye and the concept of refraction.
The eye is viewed in cross-section. The eye can be divided into 2 segments:
anterior and posterior. The components of the 2 segments are as follows.
Anterior Segment (front third of the eye).
Cornea. The outer layer of the eye is controlled by muscles.
Pupil. The pupil is the aperture or hole in the center of the iris.
Iris. The iris surrounds the pupil.
Lens. The lens is an ellipsoid structure that sits behind the pupil and iris and
refracts light into the retina. Muscles control the adjustment of the lens.
Posterior Segment (rear two thirds of the eye).
Cavity. A cavity containing a clear gel.
Retina. The retina is the innermost layer of the eye and connects directly to
the optic nerve.
Fovea. The fovea is a small depression or pit within the retinal surface.
Optic disk or Blind spot. The optic disk is the point of exit for ganglion cell
axons leaving the eye. The retinal area does not contain photo receptors, and
this creates a blind spot.
Optic Nerve. The Optic nerve runs from the back of the eye to the brain.
The diagram illustrates how the retina interprets an image as upside down and
backwards. In the example a letter G is used to illustrate this concept. It is positioned
at a fixation point and when processed by the eye, it appears upside down and
backwards on the retina. This is the concept of refraction, where the cornea has
refracted the light onto the retina.
Section B. Focusing of light in the fovea.
A diagram enlarges on the fovea region of Section B and represents the
specialized cells of the retina and the fovea. A cross-section of the human eye shows
light entering the eye. A detailed cross-section of the retina is shown. The retina is
formed of 3 main connected layers.
Ganglion Cells. The ganglion cells are a type of neuron located near the inner
surface of the retina of the eye
1. Bipolar Cells. Bipolar cells exist between photoreceptors, rod cells and cone
cells, and ganglion cells. They signals from the photoreceptors to the ganglion
cells.
2. Photoreceptors, including Cones and Rods.
The 3 stages of the process are as follows:
1. Light entering the eye, and focusing on the fovea, triggers a photochemical
reaction in rods and cones at the back of the retina.
2. A chemical reaction in turn activates the bipolar cells by a neural impulse.
3. The ganglion cells transmit this information to the optic nerve and on to the
visual cortex via the thalamus.
Back to Figure
https://t.me/medicina_free
An author introduction reads as follows. In Figure 3.5 A, note the location of the
retina relative to other anatomical structures in the eye. As you can see, the foveal
region looks like a pit, as the top layers of the retina are swept aside so that there is
no scatter of light reaching the receptor cells, that is, the cones. In Figure 3.5 B, note
a schematic of what the retina would look like if it were stretched out to reveal the
layers. Oddly, the rods and cones form the back layer of the retina, even though they
are the light-sensitive portion of the retina. The horizontal, amacrine, and bipolar cells
serve as a middle layer and connect the photoreceptors to the retinal ganglion cells,
which exit the retina and bring visual information to the brain.
Section A. A cross-section of a human eye is annotated to highlight the fovea at
the back of the eye on the retina. The fovea is a small depression or pit within the
retinal surface. It is composed of closely packed cones and plays a central role in
sharp central vision which is essential for reading and driving.
A second diagram, positioned to the right, displays the layers of the retina. These
are as follows.
1. Ganglion cell layer. Contains nuclei of ganglion cells, the axons of which
become the optic nerve fibers.
2. Inner synaptic layer. Contains the synapse between the bipolar cell axons
and the dendrites of the ganglion and amacrine cells
3. Inner nuclear layer. Contains the nuclei and surrounding cell bodies of the
amacrine cells, bipolar cells, and horizontal cells.
4. Outer synaptic layer. Projections of rods and cones ending in the rod
spherule and cone pedicle.
5. Outer nuclear layer. Cell bodies of rods and cones.
6. Inner and outer segments of photoreceptors. The outer segments contain a
highly specialized light-sensing apparatus.
7. Pigment epithelium. A single layer of cuboidal epithelial cells. This layer is
closest to the choroid and provides nourishment and supportive functions to the
neural retina.
8. Choroid. The choroid is the vascular layer of the eye, containing connective
tissues, and lying between the retina and the sclera.
Section B features a detailed illustration of the structure of the retina. From left to
right, the 10 regions of the Retina are as follows.
1. Vitreous chamber. The large space behind the lens contains a thick, gel-like
fluid called vitreous humor or vitreous gel.
2. Axons of the optic nerve.
3. Retinal ganglion cell. A retinal ganglion cell is a type of neuron located near
the inner surface, the ganglion cell layer, of the retina of the eye. It receives
visual information from photoreceptors via two intermediate neuron types: bipolar
cells and retina amacrine cells.
4. Amacrine cell. Amacrine cells are interneurons in the retina.
5. Bipolar cell. Bipolar cells exist between photoreceptors, rod cells and cone
cells, and ganglion cells. They act, directly or indirectly, to transmit signals from
the photoreceptors to the ganglion cells.
6. Horizontal cell. Horizontal cells are the laterally interconnecting neurons
having cell bodies in the inner nuclear layer of the retina of vertebrate eyes.
7. Cone. Cone cells, or cones, are photoreceptor cells in the retina.
8. Rod. Rod cells are photoreceptor cells in the retina of the eye that can
function in lower light better than the other type of visual photoreceptor, cone
cells.
9. Pigment Epithelium. A single layer of cuboidal epithelial cells.
10. Choroid. The choroid is the vascular layer of the eye.
Back to Figure
An author’s introduction reads as follows. Close your right eye and hold the book
or your electronic device at arm’s length. Slowly move the book or device toward you
while looking at the orange circle with your left eye. At some point, the plus sign will
disappear. The plus sign disappears when its image lands on the optic disc, where
there are no receptor cells.
The diagram consists of a blue plus sign positioned on the left. On the right is an
orange dot. Above the orange dot is a blue vertical line. Below the orange dot is a
second blue vertical line.
Back to Figure
An author’s introduction reads as follows. From both eyes, the optic nerves meet
at the optic chiasm, where the signals cross to the opposite half of the brain. The
https://t.me/medicina_free
nerve fibers travel in two tracks through the thalamus, where they are directed to the
visual cortex.
The diagram contains an illustration of the ventral view, or underside, of the brain
and eyes.
The eyes view 2 objects, A on the right and B on the left. The image of object A is
represented by a thick blue line that tapers to a thin line as it enters the right and left
eyes and ends at the rear wall of the retina. The image of object B is represented by
a thick red line that again tapers to a thin line as it enters the right and left eyes and
ends at the rear wall of the retina.
The optic nerve carries the visual signal from the eyes to the Optic Chiasm. The
signals are again represented by blue and red. The optic chiasm is the part of the
brain where the optic nerves cross. It is located at the bottom of the brain immediately
inferior to the hypothalamus.
The partial crossing over of optic nerve fibers at the optic chiasm allows the visual
cortex to receive the same hemispheric visual field from both eyes. The result is that
the right cerebral hemisphere processes the left visual hemifield, and the left cerebral
hemisphere processes the right visual hemifield.
Beyond the optic chiasm the optic nerves are called optic tracts. They branch off
to the lateral geniculate body of the thalamus, in turn giving them to the occipital
cortex of the cerebrum.
The illustration shows the visual cortex located in the occipital lobe at the back of
the brain. Object A, positioned on the right, is being processed on the left side of the
brain. Object B, positioned on the left, is being processed on the right side of the
brain.
Back to Figure
An author introduction reads as follows. Hubel and Wiesel implanted
microelectrodes in a cat’s visual cortex, projected visual stimuli, and measured singlecell activity. These signals were amplified and displayed on an oscilloscope.The
illustration contains 4 stages as follows.
1. Stimulus projected on screen.
2. Microelectrode is connected to the cat’s visual cortex.
3. The microelectrode is attached to an amplifier which presents the information
audibly.
4. A digitized oscilloscope presents the information visually.
Hubel and Wiesel demonstrated that some neurons were only responsive to
information that came from a single eye, a phenomenon they referred to as ocular
dominance. The work won Hubel and Wiesel a Nobel Prize for Physiology in 1981.
Back to Figure
An author introduction reads as follows. As shown, any color can be produced by
mixing blue, green, and red light waves. When all three colors are combined, white is
produced.
The diagram features 3 projectors. A green projector on the left, a red projector in
the center, and a blue projector on the right. The projectors are positioned to focus on
a single point in front of them. The interactions between the 3 colors creates a series
of different colors in the style of a Venn diagram. The Venn diagram features 3
circles, and the color interactions are as follows.
1. The upper circle is red.
2. The lower right-hand circle is blue.
3. The lower left-hand circle is green.
4. The intersection between the red circle and the blue circle creates a purple
section.
5. The intersection between the blue circle and the green circle creates a
turquoise section.
6. The intersection between the green circle and the red circle creates a yellow
section.
7. The intersection between the green, blue, and red circles at the center of the
Venn diagram, creates a white section.
Back to Figure
An author introduction reads as follows. Colors opposite each other are
complementary. That is, equal amounts of light in those colors cancel each other out,
producing a neutral gray.
The color wheel contains 16 colors. The complementary pairs and their positions
are as follows, in a clockwise direction.
1. Red and 8. Green.
https://t.me/medicina_free
2. Orange and 9. Dark Green.
3. Light Orange and 10. Green-Blue.
4. Dark Yellow and 11. Blue.
5. Yellow and 12. Dark Blue.
6. Lime Green and 13. Dark Purple.
7. Light Green and 14. Purple.
8. Mid Green and 15. Pink.
Back to Figure
The list of common sounds, and their decibel level, are listed as follows, from
quietest to loudest. There are 13 entries as follows.
1. Zero decibels. Sound threshold of a normal young adult.
2. 20 decibels. Empty theater, whispered conversation.
3. 40 decibels. Usually sufficient sound to awaken a sleeping person.
4. 50 decibels. Quiet office level. Normal refrigerator sound level.
5. 60 decibels. Normal conversation.
6. 80 decibels. Flushing toilet.
7. Anything over this point is highlighted in yellow. This indicates that prolonged
exposure above 85 decibels can cause noise-induced hearing loss.
8. 90 decibels. Very loud. Sustained sound at this level can cause damage.
9. 100 decibels. Lawn mower at close range. Stereo level of many listeners.
10. 120 decibels. Sound induces pain. Even short-term exposure can cause
permanent damage.
11. 130 decibels. Immediate and permanent hearing loss.
12. 160 decibels. Handgun firing.
13. 180 decibels. Jet airplane at takeoff. Deafening if no protection.
Back to Figure
An author introduction reads as follows. The process of hearing begins in the
three-part, outer, middle, and inner, structure of the ear. From the auditory nerve,
signals are relayed to the auditory cortex.
The human ear detects and analyzes sound by the process of transduction which
involves the conversion of sound waves into electrochemical impulses, and maintains
the sense of balance, known as equilibrium.
Anatomically, the ear has 3 main distinguishable parts as follows.
1. The outer ear
2. The middle ear.
3. The inner ear.
Part 1. The Outer Ear.
The outer ear consists of the visible portion called the auricle, or pinna, which
projects from the side of the head, and the short external auditory canal, the inner
end of which is closed by the tympanic membrane, commonly called the eardrum.
The function of the outer ear is to collect sound waves and guide them to the
tympanic membrane.
The thin semi-transparent tympanic membrane, or eardrum, which forms the
boundary between the outer ear and the middle ear, is stretched across the end of
the external canal. Its diameter is around 10 millimeters and it is shaped like a
flattened cone with its apex directed inward.
The entire tympanic membrane consists of three layers.
1. The outer layer of skin is continuous with the external canal.
2. The inner layer of mucous membrane is continuous with the lining of the
tympanic cavity of the middle ear.
3. Between these layers is a layer of fibrous tissue made up of circular and
radial fibers that give the membrane its stiffness and tension. The membrane is
well supplied with blood vessels and sensory nerve fibers that make it acutely
sensitive to pain.
Part 2. The Middle Ear.
The middle ear is a narrow air-filled cavity in the temporal bone.
The middle ear cavity is a narrow air-filled space. A slight constriction divides it
into an upper and a lower chamber, the tympanum, or tympanic cavity, below and the
epitympanum positioned above. These chambers are also referred to as the atrium
and the attic, respectively.
The middle-ear cavity space roughly resembles a rectangular room with four
walls, a floor, and a ceiling, as follows.
1. The outer wall of the middle-ear space is formed by the tympanic membrane.
https://t.me/medicina_free
2. The ceiling is formed by a thin plate of bone that separates the middle-ear
cavity from the cranial cavity and brain above.
3. The floor is a thin bony plate which separates the middle-ear cavity from the
jugular vein and the carotid artery below.
4. The back wall partly separates the middle-ear cavity from another cavity, the
mastoid antrum, but an opening in this wall leads to the antrum and to the small
air cells of the mastoid process, which is the roughened, slightly bulging portion
of the temporal bone just behind the external auditory canal and the auricle.
5. In the front wall is the opening of the eustachian tube, also known as the
auditory tube, which connects the middle ear with the nasopharynx.
6. The inner wall separates the middle ear from the inner ear, also known as the
labyrinth. It has two small openings, known as fenestrae, one above the other.
The upper one is the oval window, which is closed by the footplate of the stapes.
The lower one is the round window, which is covered by a thin membrane.
The middle ear is spanned by a chain of three tiny bones, collectively referred to
as the auditory ossicles, as follows.
1. The malleus, which is also known as the hammer. The malleus more closely
resembles a club than a hammer.
2. The incus, which is also known as the anvil. The incus looks more like a
premolar tooth with uneven roots than an anvil.
3. The stapes, which is also known as the stirrup. The stapes is the smallest
bone in the body. It is about 3 millimeters long and weighs only 3 mg. It lies at
right angles to the incus and it is free to vibrate in transmitting sound to the
labyrinth.
This ossicular chain conducts sound from the tympanic membrane to the inner
ear, which is known as the labyrinth. The labyrinth is a complicated system of fluidfilled passages and cavities located deep within the rock-hard petrous portion of the
temporal bone.
The Eustachian tube is a canal that links the middle ear with the back of the nose.
The eustachian tube helps to equalize the pressure in the middle ear which facilitates
the transfer of sound waves. The eustachian tube is lined with mucous.
Part 3. The Inner Ear.
The inner ear consists of 2 functional units as follows.
1. The vestibular apparatus, consisting of the vestibule and semicircular canals,
which contains the sensory receptors for maintaining equilibrium.
2. The snail-shell-like cochlea, which contains the sensory organ of hearing.
These sensory organs are highly specialized endings of the eighth cranial nerve,
also called the vestibulocochlear nerve.
The following 5-step process outlines how the ear works.
1. Sound is transmitted as sound waves from the environment. The sound
waves are collected by the outer ear and travel along the ear canal to the
eardrum.
2. The sound waves cause the eardrum to vibrate, which sets the malleus,
incus, and stapes in the middle ear into motion.
3. The motion of these bones causes the fluid in the inner ear or cochlea to
move.
4. The movement of the inner ear fluid causes the hair cells within the cochlea
to bend. The hair cells transform the movement into electrical pluses.
5. These electrical impulses are transmitted to the auditory nerve and up to the
primary auditory cortex in brain, where they are interpreted as sound.
Back to image
To recap, the 3 main regions of the ear are follows.
1. The outer ear, including the pinna, or earlobe, and the external auditory canal
which connects to the tympanic membrane, known as the eardrum.
2. The middle ear, including the middle-ear cavity and the malleus, incus, and
anvil.
3. The inner ear, including the vestibule, the semicircular canals, and the
cochlea.
A more detailed description of the anatomy of the ear is available in the
description for Figure 3.13.
Back to Figure
An author’s introduction reads as follows.
The brain is able to detect small differences in the timing and intensity of sound
between the two ears and can use these differences to localize the source.
https://t.me/medicina_free
The diagram consists of 2 people shown from above. The person at the bottom of
the image is looking forward. When they speak they project a sound, and this sounds
widens as it gets further away from the speaker. The second person stands at a 45
degree angle to the sound. The ears of the listener are therefore at a different
distance from the speaker, one closer and one further away. This difference is known
as interaural time difference and intensity difference. The head and body of the
listener also interrupt the sound. The area behind the listener, sheltered from the
speaker by the listener’s body, is known as the sound shadow.
Back to Figure
An author introduction reads as follows. Once in the nose, odorant molecules are
trapped by olfactory receptors. These receptors send signals through the olfactory
nerve to the olfactory bulb, which communicates with various parts of the brain.
Olfactory system, the bodily structures that serve the sense of smell. The system
consists of the nose and the nasal cavities. The upper parts support the olfactory
mucous membrane for the perception of smell and in the lower parts act as
respiratory passages.
The bony framework of the nose is part of the skull, but the outer nose is
supported only by bone above. Below that, its shape is maintained by cartilaginous
plates. The expanded lower part of the side of the nose, the ala, is formed only of
skin, both externally and internally, with fibrofatty tissue between the layers.
The olfactory system includes the following structures.
1. Nose. The nose is an opening containing nasal passages that allow outside
air to flow into the nasal cavity. The nose is also a component of the respiratory
system, and it acts as a filter and warms the air inside the nose.
2. Nasal cavity. The nasal cavity is divided by the nasal septum into left and
right passages. It is lined with mucous membrane.
3. Olfactory epithelium. This is a specialized type of epithelial tissue in nasal
cavities that contains olfactory nerve cells and receptor nerve cells. These cells
send impulses to the olfactory bulb.
4. Cribriform plate. This plate is a porous extension of the ethmoid bone, which
separates the nasal cavity from the brain. Olfactory nerve fibers extend through
the holes in the cribriform to reach the olfactory bulbs.
5. Olfactory nerve. The olfactory nerve, also known as the first cranial nerve, is
involved in olfaction, the sense of smell. Olfactory nerve fibers extend from the
mucous membrane, through the cribriform plate, to the olfactory bulbs.
6. Olfactory bulbs. The olfactory bulbs are bulb-shaped structures in the
forebrain where olfactory nerves end, and the olfactory tract begins.
7. Olfactory tract. The olfactory tract is formed from a band of nerve fibers that
extend from each olfactory bulb to the olfactory cortex of the brain.
8. Olfactory cilia. Olfactory Cilia are located along the upper surface of the
inside of the nasal passages. These hair-like receptor cells respond to chemical
stimuli that have dissolved in the nasal mucus.
9. Olfactory cortex. The olfactory cortex is an area of the cerebral cortex that
processes information about odors and receives nerve signals from the olfactory
bulbs.
The process of smell.
Our sense of smell works by the detection of odors. Olfactory epithelium located
in the nose contains millions of chemical receptors that detect odors. When we sniff,
chemicals in the air are dissolved in mucus. Odor receptor neurons in olfactory
epithelium detect these odors and send the signals on to the olfactory bulbs.
The cutaway section of the diagram visualizes the process from the olfactory cilia
to the receptor cells, to the neuron axons, and on to the olfactory bulb.
These signals are then sent along olfactory tracts to the olfactory cortex of the
brain through sensory transduction.
The olfactory cortex is vital for the processing and perception of odor. It is located
in the temporal lobe of the brain, which is involved in organizing sensory input. The
olfactory cortex is also a component of the limbic system. This system is an integral
part of the processing of our emotions, survival instincts, and memory formation.
The olfactory cortex connects with other limbic system structures such as the
amygdala, hippocampus, and hypothalamus. The amygdala is involved in forming
emotional responses and memories, the hippocampus indexes and stores memories,
and the hypothalamus regulates emotional responses. It is the limbic system that
connects senses, such as odors, to our memories and emotions.
Back to Figure
https://t.me/medicina_free
The taste bud is a small organ located on the tongue and plays a key role in the
perception of taste.
Taste receptor cells occur on the tongue in groups of 50 to 150. Each of these
groups forms a taste bud, which is grouped together with other taste buds into taste
papillae. The taste buds are embedded in the epithelium of the tongue and contact
the outside environment through a taste pore.
The receptor cells interact with incoming chemicals from food and other sources.
Slender processes known as microvilli extend from the outer ends of the receptor
cells through the taste pore, where the processes are covered by the mucus that
lines the oral cavity. At their inner ends the taste receptor cells connect, with afferent
sensory neurons, and these nerve cells that conduct information to the brain. Each
receptor cell synapses with several afferent sensory neurons, and each afferent
neuron branches to several taste papillae, where each branch contacts many
receptor cells. The afferent sensory neurons occur in three different nerves running to
the brain. These are the facial nerve, the glossopharyngeal nerve, and the vagus
nerve. Taste receptor cells of vertebrates are continually renewed throughout the life
of the organism. The human tongue has between 2,000 and 8,000 taste buds and the
positioning of the taste buds may be very different depending on the individual.
Back to Figure
An author introduction reads as follows. When people use only a single hand to
touch both cold and warm temperatures at once, the resulting sensation is very hot
and painful. The apparatus used to create this sensation is called a thermal grill.
Scientists have conducted thermal grill studies for decades, but they remained baffled
by the phenomenon until now. Lindstedt and colleagues in 2011 built their own
thermal grill, much like the one you see here, and tested 20 participants’ response to
the grill while in an f, M, R, I scanner. The result was that the study participants had
busy activity in the thalamus and the brain’s pain matrix.
The illustration shows a woman pressing her hand onto the thermal grill. The grill
sits flat on the table and contains horizontal bars which are alternate temperatures.
One hot, one cold, and so on. A thought bubble is emanating from the woman that
contains a blue flame. Her expression is one of experiencing pain and shock.
Back to Figure
An author introduction reads as follows. Each drawing has two different
interpretations. Most people report seeing one interpretation and then the other but
never both simultaneously.
The 3 drawings are as follows.
Drawing 1 features a transparent cube that appears in one interpretation to be
facing in a southwesterly direction and in another to be facing a northeasterly
direction.
Drawing 2 features a line drawing that appears in one interpretation as a rabbit
and another as a seagull, with the rabbit’s ears forming the bill of the seagull.
Drawing 3 features a drawing that appears in one interpretation as an elegant
chalice or goblet in black, and in another as 2 faces in profile facing each other, as if
almost kissing.
Back to Figure
An author introduction reads as follows. Depending on whether the white or
orange areas are seen as figural, this drawing may be perceived as a vase or as two
people facing each other.
The image features a drawing that appears in one interpretation as an elegant
chalice or goblet in orange, and in another as 2 faces in profile facing each other, as if
almost kissing.
Figure ground organization is a type of perceptual grouping that is a vital
necessity for recognizing objects through vision. In Gestalt psychology it is known as
identifying a figure against a different colored background.
Back to Figure
An author note reads as follows. The law of good continuation. You will see a
zigzag line with a curved line running through it, so that each line continues in the
same direction it was going prior to intersection. Notice that you do not see the
figures as being composed of the two elements below.
The zig zag has been split into 2 parts. The upper half of the curved line is now
attached to the end of the left-hand part of the zig zag. The lower half of the curved
line is now attached to the end of the right-hand part of the zig-zag. This version of
the figure suggests that it was always 2 joined parts, rather than a separate zig zag
and a curved line.
https://t.me/medicina_free
The author continues as follows.
Look out the window at the branches of a tree and focus on two branches that
form a cross. You clearly perceive two straight lines, rather than two right angles
touching each other.
Back to Figure
According to Biederman, people perceive objects by breaking them down into
simple, three-dimensional component shapes called geons. Examples of geons are
shown in section A.
Section A. There are 6 examples of 3 dimensional shapes.
1. A long cylinder.
2. A rectangular pyramid.
3. A short cylinder.
4. A square prism.
5. A curved cylinder.
6. A cone.
Just as letters of an alphabet can be combined to produce a large number of
words, combinations of geons create thousands of different objects. Examples of
these objects are shown in section B.
Section B. There are 5 examples of objects constructed from 3 dimensional
shapes.
1. A goblet. Constructed from a wide cylinder, a narrow cylinder, and a circular
base.
2. A cone constructed from a cone.
3. A flashlight constructed from a long cylinder and a short cylinder.
4. A cup constructed from a cylinder and a curved cylinder.
5. A watering can constructed from a wide cylinder, a curved cylinder, and a
narrow cylinder.
Back to Figure
In the example the baby crawls to the edge of the visual cliff and stops. She looks
over the edge but does not go any further even though her father is encouraging her
by reaching out to her.
The visual cliff consists of a sheet of Plexiglas that covers a cloth with a high-
contrast checkerboard pattern. On one side, the cloth is placed immediately beneath
the Plexiglas, and on the other it is dropped about four feet below to create the
illusion of a cliff edge. The apparatus measures depth perception in babies.
Back to Figure
An author’s note reads as follows. What someone sees in the middle drawings
depends on the order in which they look at the pictures. Subjects who start at the far
left see the drawings in the middle as a man’s face; those who start at the far right
see a woman’s figure.
The 8 drawings are positioned in 2 rows of 4 drawings. The upper left image
appears to feature a face of a man. The lower right image appears to feature a
kneeling young woman. The 6 images in between these images are transitional
images, each image from left to right transforming slightly and developing into the
goal image. If you start with the image of the man and move to the right, then you can
see image change and develop into the kneeling young woman. If you start with the
image of the young woman and move to the left, then you can see the image of the
man developing.
Perceptual set theory stresses the idea of perception as an active process
involving selection, inference and interpretation. Gordon Allport described it as, a
perceptual bias or predisposition or readiness to perceive particular features of a
stimulus.
Back to Figure
An author introduction reads as follows. Indicating the effects of context on
perception, people see the middle item as B or 13 depending on whether it is
surrounded by letters or numbers.
The diagram features a pale yellow square. At the center of the square is the
number 13. At the 12 o’clock position is the number 12. At the 3 o’clock position is the
letter C. At the 6 o’clock position is the number 14. At the 9 o’clock position is the
letter A.
Back to Figure
The diagram depicts a checkerboard with light and dark squares, partly shadowed
by a ball which has been placed on the board. The optical illusion is that the area
https://t.me/medicina_free
labeled X1 appears to be a darker color than the area labeled X2, which is in the
shadow of the ball.
However, within the context of the two-dimensional image, the 2 squares are of
identical brightness.
Back to Figure
On the left are 2 examples of a line. The first vertical line has arrow fins at each
end which are pointed inwards. Essentially it looks like a double-headed arrow. The
second vertical line has arrow fins at each end which are pointed outwards. The
vertical lines are exactly the same length but the positioning of the arrow fins, inwards
or outwards, causes the eye to perceive the line with the outward fins as longer.
On the right are 2 illustrations of real-life examples of this phenomenon. The first
illustration features a view of a corridor. The edge of the wall is highlighted to form the
vertical line and the inward facing arrows at the junction between the wall and the
floor. The second illustration features a different view of the corridor. The corner of the
corridor is highlighted to form the vertical line and the outward facing arrows at the
junction between the wall and the floor.
Back to Figure
An author’s note reads as follows. Viewed low over the Tampa, Florida, skyline,
the moon seems larger than when it is seen higher in the sky above the city of Abu
Dhabi, in the United Arab Emirates.
The Tampa photograph shows the Moon hanging over the city, closer to the
horizon. The Moon is much higher in the sky over Abu Dhabi. The Moon illusion is an
optical illusion which causes the Moon to appear larger near the horizon than it does
when viewed higher up in the sky.
https://t.me/medicina_free
4 CONSCIOUSNESS
iStock.com/RomoloTavani
Learning Objectives
Describe the nature of consciousness and the selectivity of what we
attend to and are aware of in our environment.
Explain why sleep is a necessary function for many mammals,
including humans.
Explain the phenomenon of hypnosis and how it is used in therapy.
Identify psychoactive and addictive drugs and the effects of drug use
on consciousness and long-term health.
WHAT’S YOUR PREDICTION: DO SUBLIMINAL
SELF-HELP RECORDINGS WORK?
The Situation
You saw a social media ad seeking volunteers for a study of subliminal (outside of
conscious awareness) videos, and you could not resist. No money is offered for
participating, but you’ve heard about the power of subliminal messages, so you sign
up. During your first session, an experimenter plays for you an audio recording
created by a company that specializes in subliminal materials. He asks you to listen
to the recording once a day, every day, for five weeks. But first, you fill out some
questionnaires, including some self-esteem scales and memory tests. When you’ve
finished, you are handed a recording labeled either “Subliminal Building Self-Esteem”
or “Subliminal Memory Improvement.”
With the recording in hand, you go home and try it. All you can hear is classical
music, but you know that the recording contains faint messages you cannot
consciously detect, such as “I have high self-worth” or “My ability to remember is
increasing daily.” The recording is now part of your daily routine, and after five weeks,
you return to the lab for testing. As before, you fill out some self-esteem scales and
memory tests. Then depending on the group you’re in, the experimenter asks, “Do
you feel that the recording has improved your self-esteem (memory)?”
The procedure in this study is simple. Participants are exposed to positive
subliminal messages concerning their self-esteem and memory. After five weeks, the
experimenter measures both actual improvement on objective tests and self-rated
improvement. There’s just one hitch. Although half the participants are randomly
assigned to receive recordings that are correctly labeled, the other half have
recordings with the labels reversed (the self-esteem recordings have the memory
label, and vice versa).
What’s Your Prediction?
So what do you think happens? Let’s focus on the potential for improvement in
memory. To some extent, scores on objective tests should increase across the board
simply because participants had practice taking such tests in the first session. But
what about the added benefit to those who listened to the recording? In the first row
of the table below, put an X in the box if you think the recording produced an actual
https://t.me/medicina_free
Соседние файлы в папке Библиотека им академика М.И. Перельмана