Transcript Document

PowerPoint® Lecture Slides
prepared by
Barbara Heard,
Atlantic Cape Community
College
CHAPTER
1
The Human Body:
Modified by Dr.
Par
Mohammadian
© Annie Leibovitz/Contact Press Images
© 2013 Pearson Education, Inc.
About This Chapter
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Definition
Organizational levels: Systems
Homeostasis & Control systems
The science of physiology
Overview of Anatomy and Physiology
Physiology: Study of the functions of a living
organism and its components, including all
chemical and physical processes.
Derived from scientific experiments
Anatomy: Study of structure, with much less
emphasis on function.
Pathophysiology: Study of body function in a
disease state (pathos: suffering)
Levels of Structural Organization
Atoms
Organelle
Smooth muscle cell
Molecule
Chemical level
Atoms combine to
form molecules.
Cellular level
Cells are made up
of molecules.
Cardiovascular
system
Heart
Blood
vessels
Smooth muscle tissue
Tissue level
Tissues consist of
similar types of cells.
Blood vessel (organ)
Smooth muscle tissue
Connective tissue
Epithelial
tissue
Organ level
Organs are made up of different types
of tissues.
Organ system level
Organismal level
The human organism is made Organ systems consist of different
organs that work together closely.
up of many organ systems.
Slide 1
Figure 1.3a The body’s organ systems and their major functions.
Hair
Skin
Nails
Integumentary System
Forms the external body covering,
and protects deeper tissues from injury.
Synthesizes vitamin D, and houses
cutaneous (pain, pressure, etc.)
receptors and sweat and oil glands.
Skeletal
muscles
Bones
Joint
Skeletal System
Protects and supports body organs,
and provides a framework the muscles
use to cause movement. Blood cells
are formed within bones. Bones store
minerals.
(c) Muscular System
Allows manipulation of the environment,
locomotion, and facial expression.
Maintains posture, and produces heat.
Pineal gland
Brain
Pituitary
gland
Thyroid
gland
Thymus
Adrenal
gland
Pancreas
Testis
Spinal
cord
Nerves
Nervous System
As the fast-acting control system of
the body, it responds to internal and
external changes by activating
appropriate muscles and glands.
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Ovary
Endocrine System
Glands secrete hormones that
regulate processes such as growth,
reproduction, and nutrient use
(metabolism) by body cells.
Red bone
marrow
Heart
Thymus
Lymphatic
vessels
Thoracic
duct
Spleen
Lymph nodes
Blood
vessels
Cardiovascular System
Blood vessels transport blood,
which carries oxygen, carbon dioxide,
nutrients, wastes, etc. The heart
pumps blood.
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Lymphatic System/Immunity
Picks up fluid leaked from blood vessels
and returns it to blood. Disposes
of debris in the lymphatic stream.
Houses white blood cells (lymphocytes)
involved in immunity. The immune
response mounts the attack against
foreign substances within the body.
Figure 1.3h The body’s organ systems and their major functions.
Nasal
cavity
Pharynx
Larynx
Bronchus
Trachea
Lung
Respiratory System
Keeps blood constantly supplied with
oxygen and removes carbon dioxide.
The gaseous exchanges occur through
the walls of the air sacs of the lungs.
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Figure 1.3i The body’s organ systems and their major functions.
Oral cavity
Esophagus
Liver
Stomach
Small
Intestine
Large
Intestine
Rectum
Anus
Digestive System
Breaks down food into absorbable units
that enter the blood for distribution to
body cells. Indigestible foodstuffs are
eliminated as feces.
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Figure 1.3j The body’s organ systems and their major functions.
Kidney
Ureter
Urinary
bladder
Urethra
Urinary System
Eliminates nitrogenous wastes from the
body. Regulates water, electrolyte and
acid-base balance of the blood.
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Figure 1.3k–l The body’s organ systems and their major functions.
Mammary
glands (in
breasts)
Prostate
gland
Ovary
Penis
Testis
Scrotum
Ductus
deferens
Uterus
Vagina
Male Reproductive System
Overall function is production of offspring. Testes
produce sperm and male sex hormone, and male
ducts and glands aid in delivery of sperm to the
female reproductive tract. Ovaries produce eggs
and female sex hormones. The remaining female
structures serve as sites for fertilization and
development of the fetus. Mammary glands of
female breasts produce milk to nourish the newborn.
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Uterine
tube
Female Reproductive System
Overall function is production of offspring. Testes
produce sperm and male sex hormone, and male
ducts and glands aid in delivery of sperm to the
female reproductive tract. Ovaries produce eggs
and female sex hormones. The remaining female
structures serve as sites for fertilization and
development of the fetus. Mammary glands of female
breasts produce milk to nourish the newborn.
Homeostasis
• Homeostasis
– Maintenance of relatively stable internal
conditions despite continuous changes in
environment
– A dynamic state of equilibrium
– Maintained by contributions of all organ
systems
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Homeostasis
Organism in
homeostasis
Internal
change
External
change
Internal change
results in loss
of homeostasis
Organism attempts
to compensate
Compensation fails
Illness or disease
Compensation succeeds
Wellness
Components of a Control Mechanism
• Receptor (sensor)
– Monitors environment; Responds to stimuli
• Control center
– Determines set point
– Receives input from receptor
– Determines appropriate response
• Effector
– Receives output from control center
– Provides the means to respond
– Response either reduces (negative feedback) or enhances
stimulus (positive feedback)
Input
signal
Integrating
center
Output
signal
Response
Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
detects
change.
1 Stimulus
produces
change in
variable.
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Receptor
Control
Center
Afferent
pathway
Efferent
pathway
BALANCE
Slide 1
4 Output: Information sent
along efferent pathway to
effector.
Effector
5 Response
of effector
feeds back to
reduce the
effect of
stimulus and
returns
variable
to homeostatic
level.
Negative Feedback
• Most feedback mechanisms in body
• Response reduces or shuts off original
stimulus
– Variable changes in opposite direction of initial
change
• Examples
– Regulation of body temperature (a nervous
system mechanism)
– Regulation of blood glucose by insulin (an
endocrine system mechanism)
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Figure 1.5 Body temperature is regulated by a negative feedback mechanism.
Control Center
(thermoregulatory
center in brain)
Afferent
pathway
Efferent
pathway
Receptors
Effectors
Sweet glands
Temperature-sensitive
cells in skin and brain)
Sweat glands activated
Response
Evaporation of sweat
Body temperature falls;
stimulus ends
Body temperature
rises
BALANCE
Stimulus: Heat
Stimulus: Cold
Response
Body temperature
falls
Body temperature rises;
stimulus ends
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Skeletal muscles
Shivering begins
Efferent
pathway
Afferent
pathway
Control Center
(thermoregulatory
center in brain)
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Negative Feedback:
Regulation of Blood Glucose by Insulin
• Receptors sense increased blood glucose
(blood sugar)
• Pancreas (control center) secretes insulin
into the blood
• Insulin causes body cells (effectors) to
absorb more glucose, which decreases
blood glucose levels
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Positive Feedback
• Response enhances or exaggerates
original stimulus
• May exhibit a cascade or amplifying effect
• Usually controls infrequent events that do
not require continuous adjustment
– Enhancement of labor contractions by
oxytocin (chapter 28)
– Platelet plug formation and blood clotting
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Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.
1 Break or tear
occurs in blood
vessel wall.
Positive feedback
cycle is initiated.
3 Released
chemicals
attract more
platelets.
2 Platelets
Positive
feedback
loop
adhere to site and
release chemicals.
Feedback cycle ends
when plug is formed.
4 Platelet plug
is fully formed.
Figure 1.12 A positive feedback loop
Baby drops
lower in uterus to
initiate labor
Cervical
stretch
causing
stimulates
Push baby
against
cervix
Oxytocin
release
Positive feedback loop
causes
Uterine
contractions
Delivery of baby
stops the cycle
Clinical Question:
Calcium levels in Mr. X’s blood are dropping to
dangerously low levels. The hormone PTH is released
and soon blood Ca levels begin to rise. Shortly after, PTH
release slows.
Form a group and answer these questions (10 min):
•Positive or negative feedback?
•Identify the initial stimulus, receptor, afferent, integrating
center, efferent?
•Result?
The Scientific Method
• Steps:
– Make observations.
– Form a hypothesis.
– The hypothesis must be testable (educated guess).
Variables:
Independent: Factor to be changed by investigators &
Dependent: Observed factor following change
– Design and conduct experiments or make more
observations.
– Analyze the data.
Results must be replicated many times before a
conclusion is accepted. Several verified hypotheses
may become a general theory.
Interpretation of Human Experiments
• Difficult to interpret results
– Genetic and environmental variability
• Crossover studies
– Placebo effect and nocebo effect
• Blind, double-blind studies, and double-blind
crossover studies
– Ethics of humans as test subjects
Tuskegee syphilis experiment
Ethics in Germany - Nazi
Measurements, Controls, and Statistics
• Good physiological research requires:
– Quantifiable measurements
– An experimental group and a control group
– Statistical analysis
– Review and publication by a peer-reviewed
journal (pubmed.gov)
Can you form a good hypothesis?
Figure 1.14a FOCUS ON . . . Graphs (1 of 5)
Dependent variable (units)
y-axis
1 unit
1 unit
x-axis
Independent variables(units)
Legend
(Describes the information represented
by the graph)
The standard features of a graph
include units and labels on the
axes, a key, and a figure legend.
Group A
Group B
Key
Figure 1.14b FOCUS ON . . . Graphs (2 of 5)
8
Food intake (g/day)
7
6
5
4
3
2
1
A
Canaries were fed
one of the three diets
and their food intake
was monitored
for three weeks.
B
Diet
C
GRAPH QUESTION
Which food did the
canaries prefer?
Bar graph. Each bar shows a distinct variable. The bars are lined up
side by side along one axis so that they can be easily compared with
one another. Scientific bar graphs traditionally have the bars running
vertically.
Figure 1.14c FOCUS ON . . . Graphs (3 of 5)
Number of students
5
4
3
2
1
0
1
2
3
4
5
6
7
8
9
10
Quiz score
The distribution of
student scores on
a 10-point quiz
is plotted on a histogram.
GRAPH QUESTION
How many students
took the quiz?
Histogram. A histogram quantifies the distribution of one variable
over a range of values.
Figure 1.14d FOCUS ON . . . Graphs (4 of 5)
60
Body weight (g)
50
40
30
KEY
20
Males
10
Females
0
1
2
3
4
5
6
7
Day
Male and female mice were fed a standard diet
and weighed daily.
GRAPH QUESTION
When did male mice increase
their body weight the fastest?
Line graph. The x-axis frequently represents time; the points
represent average observations. The points may be connected by
lines, in which case the slope of the line between two points shows
the rate at which the variable changes.
Figure 1.14e FOCUS ON . . . Graphs (5 of 5)
100
90
Exam score (%)
80
70
Game
60
50
40
30
20
10
2
4
8
6
Time spent studying (hours)
10
12
Student scores were directly related to the amount
of time they spent studying.
GRAPH QUESTION
For graphs (d) and (e),
answer the following:
• What was the investigator
trying to determine?
• What are the independent
and dependent variables?
• What are the results or trends
indicated by the data?
Scatted plot. Each point represents one member of a test population.
The individual points of a scatter plot are never connected by lines, but a
best fit line may be estimated to show a trend in the date, or better yet,
the line may be calculated by a mathematical equation.