Download The Endocrine System

BIOL 2401
Fundamentals of Anatomy and Physiology
Mrs. Willie Grant
[email protected]
(210)486-2780
© 2012 Pearson Education, Inc.
17
The Special Senses
PowerPoint® Lecture Presentations prepared by
Jason LaPres
Lone Star College—North Harris
© 2012 Pearson Education, Inc.
18
The Endocrine System
PowerPoint® Lecture Presentations prepared by
Jason LaPres
Lone Star College—North Harris
© 2012 Pearson Education, Inc.
An Introduction to the Special Senses
Learning Outcomes
17-1 Describe the sensory organs of smell, trace the olfactory
pathways to their destinations in the brain, and explain the
physiological basis of olfactory discrimination.
17-2 Describe the sensory organs of taste, trace the gustatory
pathways to their destinations in the brain, and explain the
physiological basis of gustatory discrimination.
17-3 Identify the internal and accessory structures of the eye, and
explain the functions of each.
17-4 Explain color and depth perception, describe how light
stimulates the production of nerve impulses, and trace the visual
pathways to their destinations in the brain.
17-5 Describe the structures of the external, middle, and internal ear,
explain their roles in equilibrium and hearing, and trace the
pathways for equilibrium and hearing to their destinations in the
brain.
© 2012 Pearson Education, Inc.
An Introduction to the Endocrine System
Learning Outcomes
18-1 Explain the importance of intercellular communication, describe the
mechanisms involved, and compare the modes of intercellular communication
that occur in the endocrine and nervous systems.
18-2 Compare the cellular components of the endocrine system with those of other
systems, contrast the major structural classes of hormones, and explain the
general mechanisms of hormonal action on target organs.
18-3 Describe the location, hormones, and functions of the pituitary gland, and
discuss the effects of abnormal pituitary hormone production.
18-4 Describe the location, hormones, and functions of the thyroid gland, and
discuss the effects of abnormal thyroid hormone production.
18-5 Describe the location, hormone, and functions of the parathyroid glands, and
discuss the effects of abnormal parathyroid hormone production.
18-6 Describe the location, structure, hormones, and general functions of the
adrenal glands, and discuss the effects of abnormal adrenal
hormone production.
18-7 Describe the location of the pineal gland, and discuss the functions of the
hormone it produces.
18-8 Describe the location, structure, hormones, and functions of the pancreas, and
discuss the effects of abnormal pancreatic hormone production.
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An Introduction to the Special Senses
Five Special Senses
Olfaction
Gustation
Vision
Equilibrium
Hearing
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17-2 Taste (Gustation)
Taste Receptors (Gustatory Receptors)
Are distributed on tongue and portions of pharynx and larynx; clustered into taste buds
Taste Buds
Associated with epithelial projections (lingual papillae) on superior surface of tongue
Three Types of Lingual Papillae
Filiform papillae
Provide friction
Do not contain taste buds
Fungiform papillae
Contain five taste buds each
Circumvallate papillae
Contain 100 taste buds each
Monitored by cranial nerves that synapse within solitary nucleus of medulla oblongata
Then on to thalamus and primary sensory cortex
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Beef, chicken
broth, Parmesan
cheese
1 What is umami?
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17-3 Accessory Structures of the Eye
Vision
Accessory Structures of the Eye
Provide protection, lubrication, and support
Include:
The palpebrae (eyelids)
The superficial epithelium of eye
The lacrimal apparatus
Eyelids (Palpebrae)
Continuation of skin
Blinking keeps surface of eye lubricated, free of dust and debris
Eyelashes
Robust hairs that prevent foreign matter from reaching surface of eye
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2 What is lacrimal fluid?
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17-3 The Eye
Three Layers of the Eye
Outer fibrous layer
Intermediate vascular layer
Deep inner layer
Eyeball
Is hollow
Is divided into two cavities
Large posterior cavity
Smaller anterior cavity
3 What are the components of the fibrous tunic and vascular tunic?
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Light Refraction
Bending of light by cornea and lens
Focal point
Specific point of intersection on retina
Focal distance is determined by two factors (a and b).
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17-3 The Eye
Light Refraction of Lens
Accommodation—the shape of the lens changes to focus image on retina
Astigmatism
Condition where light passing through cornea and lens is not refracted properly and the
visual image is distorted.
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Light Refraction of Lens
Image reversal
Visual acuity
Clarity of vision
“Normal” rating
is 20/20
4 What is presbyopia?
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Figure 17-20 The Visual Pathways
Combined Visual Field
Left side
The Visual Pathways. The
crossover of some nerve fibers
occurs at the optic chiasm. As a
result, each hemisphere receives
visual information from the medial
half of the field of vision of the eye
on that side, and from the lateral
half of the field of vision of the eye
on the opposite side. Visual
association areas integrate this
information to develop a
composite picture of the entire
field of vision.
Left eye
only
Right side
Binocular vision
Right eye
only
The Visual
Pathway
Photoreceptors
in retina
Retina
Optic disc
Optic nerve
(N II)
Optic chiasm
Optic tract
Lateral
geniculate
nucleus
Diencephalon
and
brain stem
Suprachiasmatic
nucleus
Projection fibers
(optic radiation)
Visual cortex
of cerebral
hemispheres
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Left cerebral
hemisphere
Superior
colliculus
Right cerebral
hemisphere
17-5 The Ear
Hearing
The External Ear
Auricle
Surrounds entrance to external acoustic meatus
Protects opening of canal
Provides directional sensitivity
External acoustic meatus
Ends at tympanic membrane (eardrum)
Tympanic membrane
Is a thin, semitransparent sheet
Separates external ear from middle ear
Ceruminous glands
Integumentary glands along external acoustic meatus
Secrete waxy material (cerumen)
Keeps foreign objects out of tympanic membrane
Slows growth of microorganisms in external acoustic meatus
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Figure 17-21 The Anatomy of the Ear
Middle Ear
External Ear
Elastic cartilages
Internal Ear
Auditory ossicles
Oval
window
Semicircular canals
Petrous part of
temporal bone
Auricle
Facial nerve (N VII)
Vestibulocochlear
nerve (N VIII)
Bony labyrinth
of internal ear
Cochlea
Tympanic
cavity
Auditory tube
To
nasopharynx
External acoustic
meatus
Tympanic
membrane
Round Vestibule
window
5 To which structure of the external ear does the malleus of the middle ear attach?
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6 What are the names
of the two sacs that lie in
the membranous labyrinth of
the vestibule?
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Figure 17-26 Pathways for Equilibrium Sensations
To superior colliculus and
relay to cerebral cortex
Red nucleus
N III
Vestibular
ganglion
N IV
Vestibular
branch
Semicircular
canals
Vestibular nucleus
N VI
To
cerebellum
Vestibule
Cochlear
branch
N XI
Vestibulocochlear nerve
(N VIII)
7 What is dynamic equilibrium?
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Vestibulospinal
tracts
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18
The Endocrine System
PowerPoint® Lecture Presentations prepared by
Jason LaPres
Lone Star College—North Harris
© 2012 Pearson Education, Inc.
An Introduction to the Endocrine System
The Endocrine System
Regulates long-term processes
Growth
Development
Reproduction
Uses chemical messengers to relay information and instructions between
cells
8 What is the basic difference between endocrine glands and exocrine glands?
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Table 18-1 Mechanisms of Intercellular Communication
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18-1 Homeostasis and Intercellular Communication
Direct Communication
Exchange of ions and molecules between adjacent cells across gap junctions
Occurs between two cells of same type and is highly specialized and rare
Paracrine Communication
Uses chemical signals to transfer information from cell to cell within single tissue
Most common form of intercellular communication
Target Cells
Are specific cells that possess receptors needed to bind and “read” hormonal messages
Hormones
Stimulate synthesis of enzymes or structural proteins
Increase or decrease rate of synthesis
Turn existing enzyme or membrane channel “on” or “off”
Synaptic Communication
Ideal for crisis management
Occurs across synaptic clefts
Chemical message is “neurotransmitter”
Limited to a very specific area
9 What is the difference between an autocrine and a paracrine hormone?
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10 Is the pancreas an
endocrine or an exocrine gland?
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Figure 18-20 The General Adaptation Syndrome
ALARM
Alarm Phase (“Fight or Flight”)
During the alarm phase, an immediate
response to the stress occurs. The
sympathetic division of the
autonomic nervous system
directs this response. In the
alarm phase, (1) energy
reserves are mobilized,
mainly in the form of
glucose, and (2) the body
prepares to deal with the
stress-causing factor by “fight
or flight” responses. Epinephrine
is the dominant hormone of the
alarm phase. Its secretion is part of a
generalized sympathetic activation.
Immediate Short-Term
Responses to Crises
Brain
General
sympathetic
activation
Adrenal medulla
Sympathetic
stimulation
Epinephrine,
norepinephrine
RESISTANCE
Resistance Phase
If a stress lasts longer than a few
hours, the individual enters the
resistance phase of the
GAS. Glucocorticoids are
the dominant hormones of
the resistance phase. Epinephrine, GH, and thyroid
Sympathetic
stimulation
hormones are also involved.
Energy demands in the resistance phase
remain higher than normal, due to the combined
effects of these hormones. Neural tissue has a
high demand for energy, and requires a reliable
supply of glucose. If blood glucose levels fall
too far, neural function deteriorates. Glycogen
reserves can meet neural demand during the
Kidney
alarm phase, but become depleted after
several hours. Hormones of the resistance
phase mobilize metabolic reserves and shift
tissue metabolism away from glucose, thus
increasing its availability to neural tissue.
Exhaustion Phase
Growth hormone
Pancreas
Glucagon
ACTH Adrenal cortex
Glucocorticoids
Mineralocorticoids
(with ADH)
Long-Term Metabolic
Adjustments
• Mobilization of remaining
energy reserves: Lipids are
released by adipose tissue;
amino acids are released by
skeletal muscle
• Conservation of glucose:
Peripheral tissues (except
neural) break down lipids to
obtain energy
• Elevation of blood glucose
concentrations: Liver
synthesizes glucose from
other carbohydrates, amino
acids, and lipids
• Conservation of salts and
water, loss of K+ and H+
Renin-angiotensin
system
EXHAUSTION
The body’s lipid reserves are sufficient to maintain the
resistance phase for weeks or even months. But when the
resistance phase ends, homeostatic regulation breaks
down and the exhaustion phase begins. Unless
corrective actions are taken almost immediately, the failure
of one or more organ systems will prove fatal. The
production of aldosterone throughout the resistance phase
results in a conservation of Na+ at the expense of K+. As the body’s K+ content declines, a
variety of cells begin to malfunction. The underlying problem of the exhaustion phase is the
body’s inability to sustain the endocrine and metabolic adjustments of the resistance phase.
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• Increased mental alertness
• Increased energy use by
all cells
• Mobilization of glycogen and
lipid reserves
• Changes in circulation
• Reduction in digestive activity
and urine production
• Increased sweat gland
secretion
• Increased heart rate and
respiratory rate
Collapse of Vital Systems
• Exhaustion of lipid reserves
• Cumulative structural or
functional damage to vital
organs
• Inability to produce
glucocorticoids
• Failure of electrolyte balance
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