Transcript Chapter 6 The Integumentary System and Body Membranes - USA-AP

CHAPTER 10
AFTER YOU HAVE COMPLETED THIS CHAPTER, YOU SHOULD BE ABLE TO:
1.
Classify sense organs as special or general and explain
tne basic differences between the two groups.
2.
3.
4.
5.
Discuss how a stimulus is converted into a sensation.
Discuss the general sense organs and their functions.
List the major senses.
Describe the structure of the sys and the functions of its
components.
6. Name and describe the major visual disorders.
7. Discuss the anatomy of the ear and its sensory function
in nearing and equilibrium.
8. Name and describe the major forms of nearing
impairment.
9. Discuss the chemical receptors and their functions.
In this presentation we will discuss the following:
A. CLASSIFICATION OF SENSE ORGANS
B. CONVERTING A STIMULUS INTO A SENSATION
C. GENERAL SENSE ORGANS
D. SPECIAL SENSE ORGANS
 The Eye
 Visual Disorders
 The Ear
 Hearing Disorders
 The Taste Receptors
 The Smell Receptors
CLASSIFICATION OF
THE SENSE ORGANS
A. General sense organs (Table 10-1)
1. Often exist as individual cells or receptor
units
2. Widely distributed throughout the body
Page(s) 311-315
Page(s) 312
Page(s) 313
Page(s) 315
CLASSIFICATION OF
THE SENSE ORGANS
B. Special Sense Organs (Table 10-2)
1. Large and complex organs
2. Localized grouping of specialized receptors
Page(s) 311-314
CLASSIFICATION OF
THE SENSE ORGANS
C. Classification by presence or absence of
covering capsule
1. Encapsulated
2. Unencapsulated
(“free” or
“naked”)
Page(s) 312, 315
CLASSIFICATION OF
THE SENSE ORGANS
D. Classification by type of stimuli required to
activated receptors
1.
2.
3.
4.
5.
Photoreceptors (light)
Chemoreceptors (chemicals)
Pain receptors (injury)
Thermoreceptors (temperature change)
Mechanoreceptors (movement or
deforming of capsule)
6. Proprioceptors (position of body parts or
changes in muscle length or tension)
Page(s) 312
CONVERTING A STIMULUS
INTO A SENSATION
A. All sense organs have common functional
characteristics
1. All are able to detect a particular stimulus
2. A stimulus is converted into a nerve
impulse
3. A nerve impulse is perceived as a sensation
in the CNS
Page(s) 314
GENERAL SENSE ORGANS
(TABLE 10-1)
A. Distribution is widespread; Single-celled
receptors are common
Page(s) 314
Page(s) 312
Page(s) 313
GENERAL SENSE ORGANS
(TABLE 10-1)
B. Examples (Figure 10-1, Table 10-1)
1.
Free nerve
endings—pain,
crude touch, and
temperature
2. Meissner’s
corpuscles—fine
touch and vibration
3. Ruffini’s
corpuscles—touch
and pressure
4. Pacinian
corpuscles—
pressure and
vibration
Page(s) 314-315
GENERAL SENSE ORGANS
(TABLE 10-1)
A. Examples (Figure 10-1, Table 10-1)
5. Krause’s End
bulbs—touch
6. Golgi tendon
receptors—
proprioception
7. Muscle
spindles—
proprioception
Page(s) 314-315
SPECIAL SENSE ORGANS
A. The Eye (Figure 10-2, 10-3)
1. Layers of eyeball
a.
Sclera—tough outer coat; “white” of eye; cornea is
transparent part of sclera over iris
Page(s) 315-316
SPECIAL SENSE ORGANS
A. The Eye
1. Layers of eyeball
b.
Choroid—
Pigmented
vascular layer
prevents
scattering of
light; front part
of this layer
made of ciliary
muscle and iris,
the colored part
of the eye; pupil
is the hole in the
center of the
iris; contraction
of iris muscle
dilates or
constricts pupil
Page(s) 315-317
SPECIAL SENSE ORGANS
A. The Eye
1. Layers of eyeball
b. Retina—innermost
layer of the eye;
contains rods
(receptors for night
vision) and cones
(receptors for day
vision and color vision)
(Figure 10-5)
Page(s) 315-318
SPECIAL SENSE ORGANS
A. The Eye
1. Layers of eyeball
b.
Retina—
innermost
layer of the
eye; contains
rods
(receptors for
night vision)
and cones
(receptors for
day vision and
color vision)
(Figure 10-5)
Page(s) 315-319
Page(s) 317
SPECIAL SENSE ORGANS
A. The Eye
2. Conjunctiva—
3.
mucous
membrane
covering the
front surface of
the sclera and
lining the eyelids
Lens—
transparent
body behind the
pupil; focuses
light rays on the
retina
Page(s) 316-317
SPECIAL SENSE ORGANS
A. The Eye
4. Eye fluids
a.
b.
Aqueous
humor—in
the anterior
cavity in front
of the lens
Vitreous
humor—in
the posterior
cavity behind
the lens
Page(s) 317-318
SPECIAL SENSE ORGANS
A. The Eye
5. Visual Pathway
a.
b.
Innermost layer
of retina contains
rods and cones
Impulse travels
from the rods and
cones through the
bipolar and
ganglionic layers
of retina (Figure
10-5)
Page(s) 318-319
SPECIAL SENSE ORGANS
A. The Eye
5. Visual Pathway
c. Nerve impulse
leaves the eye
through the optic
nerve; the point of
exit is free of
receptors and is
therefore called a
blind spot
d. Visual
interpretation
occurs in the visual
cortex of the
cerebrum
Page(s) 318-320
SPECIAL SENSE ORGANS
B. Visual Disorders
1. Refraction Disorders (Figure 10-7)
a. Myopia(nearsightedness) is often caused
by elongation of the eyeball
b. Hyperopia (farsightedness) is often
caused by a shortened eyeball
c. Astigmatism is distortion caused by an
irregularity of the cornea or lens
Page(s) 320-321
Page(s) 321
SPECIAL SENSE ORGANS
B.
Visual Disorders
d. Conjunctivitis
(inflammation of the
conjunctiva) can
interfere with refraction
1)
Trachoma—chronic
chlamydial infection
2) Acute bacterial
conjunctivitis—
highly contagious
infection that
produces a
discharge of
mucous pus (Figure
10-8)
3) Conjunctivitis can
be caused by
allergies
Page(s) 322
SPECIAL SENSE ORGANS
B. Visual Disorders
e. Strabismus—
improper
alignment of eyes
(Figure 10-8)
1) Eyes can
converge
(cross) or
diverge
2) If not
corrected, can
cause
blindness
Page(s) 322
SPECIAL SENSE ORGANS
B. Visual Disorders
2. Disorders of the retina
a) Retinal Detachment can be a
complication of aging, eye tumors, or
head trauma
b) Diabetic retinopathy—damage to retina
from hemorrhages and growth of
abnormal vessels associated with
diabetes mellitus
c) Glaucoma—increased intraocular
pressure—decreases blood flow in retina
and thus causes retinal degenereation
Page(s) 323-324
SPECIAL SENSE ORGANS
B. Visual Disorders
d) Nyctalopia (night blindness) or inability to see in
dim light is caused by retinal degeneration or
lack of vitamin A
e) Macular degeneration—progressive
degeneration of central part of retina; leading
cause of permanent blindness in elderly
f) Red-green colorblindness is an X-linked genetic
condition in which certain colors are not seen
properly; It is caused by an abnormality in the
cones’ photopigments
Page(s) 324-325
Page(s) 326
SPECIAL SENSE ORGANS
B. Visual Disorders
3. Disorders of the visual pathway
a) Degeneration of the optic nerve resulting
from diabetes, glaucoma, and other
causes can impair vision
b) Scotoma is the loss of only the central
visual field when only certain nerve
pathways are damaged
c) Cerebrovascular accidents (CVAs) can
damage visual processing centers;
example is acquired cortical color
blindness
Page(s) 325-326
SPECIAL SENSE ORGANS
C. The Ear
1. The ear functions in
hearing and in
equilibrium and
balance
a. Receptors for
hearing and
equilibrium are
mechanoreceptors
Page(s) 326
Page(s) 327
SPECIAL SENSE ORGANS
C. The Ear
2. Divisions of the ear (Figure 10-12)
a. External ear
1) Auricle (pinna)
2) External auditory canal
a) Curving canal 2.5 cm (1 inch) in length
b) Contains ceruminous glands
c) Ends at the tympanic membrane
Page(s) 326-327
Page(s) 328
SPECIAL SENSE ORGANS
C. The Ear
2. Divisions of the ear
b. Middle ear
1) Houses ear ossicles—Malleus, incus,
and stapes (hammer, anvil, and stirrup)
2) Ends in the oval window
3) The auditory (eustachian) tube
connects the middle ear to the throat
4) Inflammation called otitis media
Page(s) 328-329
Page(s) 328
SPECIAL SENSE ORGANS
C. The Ear
2. Divisions of the ear
c. Inner ear (Figure 10-13)
1) Bony labyrinth filled with perilymph
2) Subdivided into the vestible,
semicircular canals, and cochlea
3) Membranous labyrinth filled with
endolymph
Page(s) 329-331
Page(s) 330
SPECIAL SENSE ORGANS
C. The Ear
4) The receptors for balance in the
semicircular canals are called crista
ampullaris
5) Specialized hair cells on the organ of
Corti respond when bent by the
movement of surrounding endolymph
set in motion by sound waives (Figure 1014)
Page(s) 329-330
Page(s) 331
SPECIAL SENSE ORGANS
D. Hearing Disorders
1. Conductions Impairments
a. Can be caused by blockage of the
external or middle ear (for example,
cerumen and tumors)
b. Otoschlerosis—inherited bone disorder
involving irregularity of the stapes; it
first appears as tinnitus (ringing) then
progresses to hearing loss
c. Otitis—ear inflammation caused by
infection; can produce swelling and fluids
that block sound conduction
Page(s) 331-332
SPECIAL SENSE ORGANS
D. Hearing Disorders
2. Nerve impairment
a. Presbycusis—progressive nerve deafness
associated with aging
b. Progressive nerve deafness also can
result from chroinic exposure to loud
noise
c. Meniere’s disease—chroinic inner ear
disorder characterized by tinnitus, nerve
deafness, and vertigo
Page(s) 332
SPECIAL SENSE ORGANS
E. The taste receptors (Figure 10-15)
1. Receptors are chemoreceptors called taste
buds
2. Cranial nerves VII and IX carry gustatory
impulses
3. Most physiologists list only four kinds of
primary taste sensations—sweet, sour,
bitter, salty (umami and metallic tastes are
sometimes included as primary taste
sensations)
4. Gustatory and olfactory senses work
together
Page(s) 332
Page(s) 333
SPECIAL SENSE ORGANS
F. The smell receptors (Figure 10-16)
1. Receptors for fibers of olfactory (cranial
nerve I) lie in olfactory mucosa of nasal
cavity
2. Olfactory receptors are extremely
sensitive but easily fatigued
3. Odor-causing chemicals initiate a nerveous
signal that is interpreted as a specific odor
by the brain
Page(s) 332-334
Page(s) 333
CREDITS
A. All photos and references are taken from:
Thibodeau, Gary, & Patton, Kevin. (2005).
The Human body in health & disease.
Mosby.
ISBN: 0-323-03161-7