Transcript The Hierarchy of Structural Organization

Chapter 1
Introduction to Anatomy &
Physiology
• Expected Learning Outcomes
– Define anatomy and physiology and relate
them to each other.
– Describe several ways of studying human
anatomy.
– Define a few subdisciplines of human
physiology.
Anatomy
• Describes the structures of the body:
– what they are made of
– where they are located
– associated structures
Physiology
• Is the study of:
– functions of anatomical structures
– individual and cooperative functions
Specialties of Anatomy (1 of 3)
• Gross anatomy, or macroscopic
anatomy examines large, visible
structures:
– surface anatomy:
• exterior features
– regional anatomy:
• body areas
Specialties of Anatomy (2 of 3)
– systemic anatomy:
• groups of organs working together
– developmental anatomy:
• from egg (embryology) to maturity
– clinical anatomy:
• medical specialties
Specialties of Anatomy (3 of 3)
• Microscopic anatomy examines cells
and molecules:
– cytology:
• cells and their structures
• cyt = cell
– histology:
• tissues and their structures
Specialties of Physiology
• Cell physiology:
– processes within and between cells
• Special physiology:
– functions of specific organs
• Systemic physiology:
– functions of an organ system
• Pathological physiology:
– effects of diseases
Scientific Method
• Expected Learning Outcomes
– Describe the inductive and hypothetico–
deductive methods of obtaining scientific
knowledge.
– Describe some aspects of experimental
design that help to ensure objective and
reliable results.
– Explain what is meant by hypothesis, fact,
law, and theory in science.
1-9
The Scientific Method: A powerful
way of “knowing”.
1.
Starts with a question or problem, based on observations of the
natural world.
2.
Propose a hypothesis, a possible answer that presents a
reasonable explanation or solution.
3.
Make a prediction that tests the hypothesis.
4.
Design an experiment to see if the prediction is correct.
Example:
1.
Problem: The computer cannot connect to the internet.
2.
Hypothesis: The cable is faulty.
3.
Prediction: If I use the cable from my roommate’s laptop, which
is working, I should be able to connect.
4.
Experiment: Connect the known good cable and try to connect.
5.
(Using a cable that is known to be good and changing just that
one thing while keeping the rest the same provides a “control”)
The Inductive Method
• Described by Francis Bacon
– Making numerous observations until one becomes
confident in drawing generalizations and predictions from
them
– Knowledge of anatomy obtained by this method
• Proof in science
– Reliable observations
– Tested and confirmed repeatedly
– Not falsified by any credible observation
• In science, all truth is tentative
– “Proof beyond a reasonable doubt”
1-11
The Hypothetico–Deductive Method
• More physiological knowledge gained by this method
• Investigator asks a question
• Formulates a hypothesis—an educated speculation or
possible answer to the question
– Characteristics of a good hypothesis
• Consistent with what is already known
• Testable and possibly falsifiable with evidence
1-12
The Hypothetico–Deductive Method
• Falsifiability—if we claim something is scientifically
true, we must be able to specify what evidence it would
take to prove it wrong
• Hypothesis—to suggest a method for answering
questions: written as “if–then” statements
1-13
Facts, Laws, and Theories
• Scientific fact
– Information that can be independently verified by a trained
person
• Law of nature
– Generalization about the predictable way matter and
energy behave
• Results from inductive reasoning and repeated observations
• Written as verbal statements or mathematical formulae
• Theory
– An explanatory statement or set of statements derived
from facts, laws, and confirmed hypotheses
• Summarizes what we know
• Suggests direction for further study
1-14
Human Origins and
Adaptations
• Expected Learning Outcomes
– Explain why evolution is relevant to
understanding human form and function.
– Define evolution and natural selection.
– Describe some human characteristics that can
be attributed to the tree-dwelling habits of
earlier primates.
– Describe some human characteristics that
evolved later in connection with upright
walking.
1-15
Human Origins and Adaptations
• Charles Darwin
– On the Origin of Species by Means of Natural
Selection (1859)—‟the book that shook the world”
– The Descent of Man (1871)—human evolution,
anatomy and behavior, relationship to other animals
• Theory of natural selection
– How species originate and change through time
– Changed prevailing view of our origin, nature and
our place in the universe
– Increases understanding of human form and
function
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Evolution, Selection,
and Adaptation
• Evolution
– Change in genetic composition of population of
organisms
• Development of bacterial resistance to antibiotics
• Appearance of new strains of AIDS virus
• Natural selection
– Some individuals within a species have hereditary
advantage over their competitors
• Better camouflage
• Disease resistance
• Ability to attract mates
– Selection pressures—natural forces that promote the
reproductive success of some individuals more than
others
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Evolution, Selection,
and Adaptation
• Adaptations—features of an organism’s
anatomy, physiology, or behavior that have
evolved in response to these selection pressures
and enable the organism to cope with the
challenges of its environment
– Model—animal species selected for research on
a particular problem
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Evolution, Selection,
and Adaptation
• Closest relative: chimpanzee
– Difference of only 1.6% in DNA structure
– Chimpanzees and gorillas differ by 2.3%
• Study of evolutionary relationships
– Help us chose animals for biomedical
research (the animal model)
– Rats and mice used extensively due to issues
involved with using chimpanzees
1-19
Vestiges of Human Evolution
• Vestigial organs—remnants of organs that
apparently were better developed and more
functional in the ancestors of a species, and
now serve little or no purpose
– Piloerector muscle
– Auricularis muscles
1-20
Our Basic Primate Adaptations
• Primates—order of mammals to which humans,
monkeys, and apes belong
• Earliest primates
– Squirrel-sized, arboreal, insect-eating African mammals
– Moved to trees due to safety, food supply, and lack of
competition
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Our Basic Primate Adaptations
• Adaptations for arboreal (treetop) lifestyle
– Mobile shoulders
– Opposable thumbs made hands prehensile to grasp
branches and encircle them with the thumb and finger
– Forward-facing eyes (stereoscopic vision)
• Depth perception for leaping and catching prey
– Color vision
• Distinguish ripe fruit and young, less toxic foliage
– Larger brains and good memory
• Remember food sources and improved social
organization
1-22
Our Basic Primate Adaptations
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Monkey
Human
Figure 1.5
Figure 1.6
1-23
Walking Upright
• African forest became grassland 4 to 5 million
years ago
– Producing more predators and less protection
• Bipedalism—standing and walking on two legs
– Helps spot predators, carry food or infants
• Adaptations for bipedalism
– Skeletal and muscular modifications
– Increased brain volume
– Family life and social changes
1-24
Walking Upright
• Australopithecus—oldest bipedal primate
• Homo genus (appeared 2.5 million years ago)
– Taller, larger brain volume, probable speech, toolmaking
• Homo erectus (appeared 1.8 million years ago)
– Migrated from Africa to parts Asia
1-25
Walking Upright
• Other Homo species discovered recently still
matter of considerable debate
• Homo sapiens originated in Africa 200,000
years ago
– Sole surviving hominid species
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Human Structure
• Expected Learning Outcomes
– List the levels of human structure from the most
complex to the simplest.
– Discuss the value of both reductionistic and
holistic viewpoints to understanding human form
and function.
– Discuss the clinical significance of anatomical
variation among humans.
1-27
The Hierarchy
of Structural
Organization
The Hierarchy of Complexity
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• Organism is composed of organ
systems
Organism
• Organ systems composed of
organs
• Organs composed of tissues
• Tissues composed of cells
Organ system
Tissue
Organ
• Cells composed of organelles
Cell
• Organelles composed of
molecules
• Molecules composed of atoms
Macromolecule
Organelle
Atom
Molecule
Figure 1.7
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Organizing a Muscle
•
•
•
•
•
Protein molecules (chemical level)
Protein filaments (organelle level)
Muscle cells (cellular level)
Cardiac muscle tissue (tissue level)
Heart (organ level)
Anatomical Variation
• No two humans are exactly alike
– 70% most common structure
– 30% anatomically variant
– Variable number of organs
• Missing muscles, extra vertebrae, renal arteries
– Variation in organ locations (situs solitus, situs
inversus, dextrocardia, situs perversus)
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Anatomical Variation
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Normal
Pelvic kidney
Horseshoe kidney
Figure 1.8
Normal
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Variations in branches of the aorta
Human Function
• Expected Learning Outcomes
– State the characteristics that distinguish living
organisms from nonliving objects.
– Explain the importance of defining a reference
man and woman.
– Define homeostasis and explain why this
concept is central to physiology.
– Define negative feedback, give an example of
it, and explain its importance to homeostasis.
– Define positive feedback and give examples of
its beneficial and harmful effects.
1-33
Homeostasis and Negative Feedback
• Homeostasis—the body’s ability to detect change,
activate mechanisms that oppose it, and thereby
maintain relatively stable internal conditions
• Claude Bernard (1813–78)
– Constant internal conditions regardless of external
conditions
• Internal body temperature ranges from 97°–99°F despite
variations in external temperature
1-34
Mechanisms of Regulation
• Autoregulation (intrinsic):
– automatic response in a cell, tissue, or
organ
• Extrinsic regulation:
– responses controlled by nervous and
endocrine systems
Negative Feedback Loop
• Body senses a change and activates mechanisms to reverse it—
dynamic equilibrium
• Because feedback mechanisms alter the original changes that triggered
them (temperature, for example), they are called feedback loops
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1
Room temperature
fallsto66°F(19°C)
C10°
15°
20°
25°
6 Room cools down
F50°
60°
70°
80°
2
C10°
15°
20°
25°
Thermost atactivates
furnace
F50°
60°
70°
80°
Figure 1.9a
5 Thermostat shuts
off furnace
4 Room temperature
rises to 70°F (21°C)
3 Heat output
(a)
1-36
Negative Feedback
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Room temperature (oF)
75
(b)
Furnace turned
off at 70 oF
70
Set point 68 oF
65
Furnace turned
on at 66 oF
60
Figure 1.9b
Time
• Example: Room temperature does not stay at set point of
68°F—it only averages 68°F
1-37
Negative Feedback
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Core body temperature
Sweating
37.5 oC
(99.5
oF)
Vasodilation
37.0 oC
(98.6
oF)
36.5 oC
(97.7
oF)
Set point
Vasoconstriction
Figure 1.10
Time
Shivering
• Example: Brain senses change in blood temperature
– If too warm, vessels dilate (vasodilation) in the skin and sweating
begins (heat-losing mechanism)
– If too cold, vessels in the skin constrict (vasoconstriction)
and shivering begins (heat-gaining mechanism)
1-38
Homeostasis and Negative
Feedback
• Sitting up in bed causes a drop in blood pressure in
the head and upper torso region (local imbalance in
homeostasis); detected by baroreceptors
• Baroreceptors (sensory nerve endings) in the
arteries near the heart alert the cardiac center in
the brainstem. They transmit to the cardiac center
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Homeostatis and Negative Feedback
• Sitting up in bed causes a drop in blood pressure in the
head and upper torso region (local imbalance in
homeostasis); detected by baroreceptors
• Baroreceptors (sensory nerve endings) in the arteries
near the heart alert the cardiac center in the brainstem.
They transmit to the cardiac center
1-40
Homeostatis and Negative Feedback
• Cardiac center sends nerve signals that increase the
heart rate and return the blood pressure to normal;
regulates heart rate
• Failure of this to feedback loop may produce dizziness in
the elderly
1-41
Postural Change in Blood Pressure
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Person rises
from bed
Blood pressure rises
to normal; homeostasis
is restored
Cardiac center
accelerates heartbeat
Blood drains from
upper body, creating
homeostatic imbalance
Baroreceptors above
heart respond to drop
in blood pressure
Figure 1.11
Baroreceptors send signals
to cardiac center of brainstem
Homeostasis and Negative Feedback
• Receptor—senses change in the body (e.g.,
stretch receptors that monitor blood pressure)
• Integrating (control) center—control center that
processes the sensory information, “makes a
decision,” and directs the response (e.g., cardiac
center of the brain)
• Effector—carries out the final corrective action
to restore homeostasis (e.g., cell or organ)
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Positive Feedback and Rapid Change
• Self-amplifying cycle
– Leads to greater change in the same direction
– Feedback loop is repeated—change produces more
change
• Normal way of producing rapid changes
– Occurs with childbirth, blood clotting, protein
digestion, fever, and generation of nerve signals
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A positive feed
back mechanism:
blood clotting and
wound healing
Positive Feedback and Rapid Change
• During birth, the head of the fetus pushes
against the cervix and stimulates its nerve
endings
– Hormone oxytocin is secreted from the pituitary gland
– Oxytocin travels through the bloodstream to the uterus
stimulating it to contract
– This action pushes the fetus downward toward cervix,
thus stimulating the cervix more, causing the positive
feedback loop to be repeated
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Positive Feedback Loops
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3 Brain stimulates
pituitary gland to
secrete oxytocin
4
Oxytocin stimulates uterine
contractions and pushes
fetus toward cervix
2 Nerve impulses
from cervix
transmitted
to brain
1 Head of fetus
pushes against cervix
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Positive Feedback and Rapid Change
• Fever > 104°F
–
–
–
–
Metabolic rate increases
Body produces heat even faster
Body temperature continues to rise
Further increasing metabolic rate
• Cycle continues to reinforce itself
• Becomes fatal at 113°F
1-48
Integration
means working together
• Systems integration:
– systems work together to maintain
homeostasis
The History of
Anatomical Terminology
• Standard international anatomical terminology
– Terminologia Anatomica (TA) was codified in 1998
by professional associations of anatomists
• About 90% of medical terms from 1,200
Greek and Latin roots
1-50
Analyzing Medical Terms
• Terminology based on word elements
– Lexicon of 400 word elements on the inside back
cover of textbook
• Scientific terms
–
–
–
–
One root (stem) with core meaning
Combining vowels join roots into a word
Prefix modifies core meaning of root word
Suffix modifies core meaning of root word
1-51
Analyzing Medical Terms
• Acronyms formed from first letter, or first few
letters, of series of words
– Calmodulin comes from the phrase “calciummodulating protein”
1-52
The Importance of Precision
• Be precise in your terms
• Spell correctly
• Health-care professions demand the same
type of precision
• People’s lives will be in your hands
1-53
Review of Major Themes
• Cell theory
– All structure and function result from the activity of cells
• Homeostasis
– The purpose of most normal physiology is to maintain stable
conditions within the body
• Evolution
– The human body is a product of evolution
• Hierarchy of structure
– Human structure can be viewed as a series of levels of complexity
• Unity of form and function
– Form and function complement each other; physiology cannot be
divorced from anatomy
1-54
Anatomical Landmarks
Figure 1–6
Positional terms
• Anatomical position:
– hands at sides, palms forward
• Supine:
– lying down, face up
• Prone:
– lying down, face down
Quadrants and Regions
• 4 abdominopelvic quadrants around umbilicus
• 9 abdominopelvic regions
Figure 1–7b
• Internal organs associated with
abdominopelvic regions
Figure 1–7c
Which Direction?
• Lateral:
– side view
• Frontal:
– front view
• Anatomical direction:
– refers to the patient’s left or right
Which Direction?
3 Dimensions
• Plane:
– a 3-dimensional axis
• Section:
– a slice parallel to a plane
3 Dimensions
• Coelom:
– divided by the
diaphragm into
the thoracic
cavity and the
abdominopelvic
cavity
The Ventral Body Cavity
Serous membranes
The pericardium
The 11 organ systems Some structural associations
1. Integumentary - skin
2. Skeletal - bones, cartilage, joints
3. Muscular - skeletal cardiac and smooth
4. Nervous - central & peripheral, voluntary & involuntary
5. Endocrine - glands & hormones
6. Cardiovascular - blood, blood vessels & the heart
7. Lymphatic & Immune - lymph vessels, organs, tissues & cells
8. Respiratory - nasal structures, larynx, airways & lungs
9. Digestive - alimentary canal & accessory organs
10. Urinary - kidneys, ureters & urethra
11. Reproductive - gonads, accessory organs (primary and
secondary structures)
The 11 organ systems Some general functions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Integumentary - protection, water regulation, endocrine
Skeletal - protection, support, movement
Muscular - movement, transportation, heat
Nervous - communication & control, rapid to intermediate
Endocrine - communication & control, short to long term
Cardiovascular - transportation, thermal regulation, defenses, water
Lymphatic & Immune - water balance, absorption, immunity
Respiratory - gas exchange
Digestive - absorption, energy storage & production, filtration
Urinary - water & pH balance, blood pressure, toxin removal
Reproductive -makin’ babies!
Some main points:
•
Scientific method
•
•
Complementarity of structure and function
Hierarchy of structural organization
•
Homeostasis - the balancing act of living systems
– Hypothesis
– Theory
– law
–
–
–
–
–
–
–
–
–
–
–
Atoms
Molecules
Compounds
Biochemical
Organelles
Cells
Tissues
Organs
Organ systems (we organize them into distinct 11 systems)
Organisms
Populations
– Negative feedback
– Positive feedback
Fin