Unit 2
Organization of the Body
Hierarchy of Human Structure
Guided Reading:
1. List the levels of organization, starting
with molecules.
2. What are stem cells?
Hierarchy: a series of ordered
groupings within a system
Alpha male &
female
Pups & adults
Outcasts / Dispersers
Levels of Organization
Stem Cells
 Undifferentiated


cells
have the potential to develop into many different
cell types during early life & growth
Can be induced to become specialized cells
 brain
cells, red blood cells, skin cells, etc.
 Embryonic
stem cells: derived from fertilized eggs
 Induced pluripotent stem cells: adult specialized
cells that can be “reprogrammed” to become a
different kind of cell
 Blastocyst (early stage of development)

stem cells differentiate into specialized cells
 Adults:
stem cells still exist (in organs & bone
marrow) to replace old/damaged cells
The Human Physiological
Environment
Guided Reading:
1. If humans live on land, why does the
author say that the human physiological
environment is “aqueous”?
2. What does it mean when people say
that something acts as a “solvent”?
The Human Physiological
Environment
 All
the internal conditions that allow cells to
perform their functions effectively & efficiently.
This positively impacts body organization
 Involves internal & external cellular conditions.
 Both rely on water.

Needs specific conditions to maintain homeostasis:
 pH,
ions, chemical reactions, transport of molecules
between internal & external environments
 Allows
us to maintain homeostasis…
More on homeostasis
 Homeostasis
≠ balance.
 Allows us to adapt to changing
environments. Maintained by negative
feedback loops
 Maintain constant conditions inside the
body when the external environment
fluctuates.
 “Set
point”
 Often
utilizes chemical messengers (e.g.
hormones)
Negative Feedback Systems
Negative Feedback:
Maintaining Homeostasis
 “System”
has a set point (ideal level) and
“sensors” that detect changes…
 If it drops below set point, something is
produced…
 If it exceeds that level, production stops…
 Examples:


Thermostat
Toilet
Body Temperature Example
Negative Feedback Loop
Generic Example:
Gland
X releases hormone X…
 This
stimulates target cells to
release hormone Y.
 Eventually, an excess of hormone
Y exists
 Gland X "senses" this… and inhibits
its release of hormone X.
X
X
Y
Positive Feedback
Defined…
 “Feedback
in which the system responds
so as to increase the magnitude of any
particular perturbation”
 Results
in amplification of the original
signal instead of stabilization.
 Any system where there is a net positive
feedback will result in a runaway
situation.
 Requires a feedback loop to operate.
 Examples: Fruit ripening, childbirth,
breastfeeding
The Human Physiological
Environment
 The
human physiological environment is aqueous.
 Water is contained in the cells, the blood, body
cavities, organ systems, and tissue.

Not just sloshing around under the skin!!
 Water’s
atomic structure provides it with all the
properties that make it useful for the body.
The universal solvent. . . .
 Water
is polar  can dissolve most materials
needed for human survival
 Solvent = dissolves other chemicals & forms a
solution
 Solute = a particle that is dissolved in a solvent
 Water is a good bio solvent b/c it is polar (charged)
 Most chemical reactions require an aqueous
environment
 Water
is a natural solvent for ions, needed for
cellular functions
 Adhesion & cohesion  won’t evaporate quickly
(so we won’t become easily dehydrated)
 High specific heat  water absorbs much heat
energy when it evaporates
Living in a balance
 Dehydration:




Diarrhea
Sweating
Vomiting
Indicators: extreme thirst, stop sweating, nausea &
exhaustion
 Water


tissues deprived of water
intoxication?
Body takes in more water than it loses at a given
period of time.
Upsets natural balance of ions, minerals
A Fraternity Hazing Gone Wrong : NPR
Tissues
Guided Reading:
1. What are the four types of tissue found in
humans?
2. What are the major
characteristics/functions of the four
types of tissue? (Recommend you make
a chart)
Stem cells again!!!!
 Retain
ability to undergo cell division
 Assist further body development and
healing later in life
 Stem cells from bone can produce a
variety of human tissues
 Brain stem cells can develop into many
types of cells
Embryological germ layers
 Ectoderm
 skin and brain
 Mesoderm  Bone and muscle
 Endoderm  Digestive organs
 Lay
down the 4 human tissue types into
the hierarchy that eventually forms a
human
Create a Concept Map (aka
Mind Map) for One Type of
Tissue…
 How
to create a concept map
 Constructing a concept map
 Example
 For each cell type…..





Names of cells & structures
Characteristics
Locations
Functions
Examples
Four Types of Tissues




Connective: forms the
supportive framework
of the organs & body
Epithelial: covers
internal & external
body surfaces; forms
layers of cells that line
body cavities
Muscle: provides body
w/ movement &
support
Nervous: conducts &
coordinates body info;
highly specialized cells
Tissue Type
Types of
Cells/structures
Characteristics of these cells
Epithelial
Squamous
Cuboidal
Columnar
Flat
Cube-shaped; produce secretions
Tall, column-shaped; secretions, uptake
Simple: Single-layer
Stratified: Multi-layered; subject to wear and
tear
Pseudostratified: False-stratification
Connective
Matrix
Protein: Collagen
Protein: Elastin
Protein: Reticulum
Loose
Made of gel, liquid, protein, salts
Strength
Flexibility
Support
Most abundant; attachment, stabilization,
structure, support
Strength, storage, flexibility
Dense
Muscle
Smooth
Cardiac
Skeletal
Nervous
Neurons
Neuroglia
Spindle-shaped; no visible fibers; weak
contractions; line organs
Heart; visible striations; intercalated disks
Large cells; distinct striations; (in)voluntary
Motor, Sensory, Interneuron
Assist Neuron functions (astrocytes,
oligodendites, ependymal cells)
Organs, and Systems
Guided Reading
1. What is the relationship between tissues
and organs/systems?
2. What are the various organ systems
found in humans?
Organs and Systems










Cardiovascular  regulates blood flow
Digestive  regulates nutrition
Integumentary  provides protection
Lymphatic  regulates body fluids, helps fight disease
Muscular  provides structure and movement
Skeletal  provides support and movement
Endocrine  regulates body function and
development
Reproductive  regulates sexual function
Respiratory  regulates atmospheric gasses and
certain body wastes
Urinary  regulates production, storage, and removal
of urine
Wellness and Illness over the
Life Span
Guided Reading:
1. What does this statement mean? “Cell
pathology causes hierarchy dysfunctions of
the body”?
2. What is the purpose of a biopsy?
3. Make a chart describing the major types of
cell pathology.
4. What is “molecular decay”?
5. What does “telomere shortening” cause for
a cell?
Cell Pathology
 The
basis of understanding dysfunction of the
body’s hierarchy
 Dysfunction: Abnormal, impaired, or incomplete
functioning of an organism, organ system, organ,
tissue or cell. All gross diseases.
 Cell pathology: examining cells microscopically

Biopsy: Removal of diseased cells for study
Types of Cell Pathology
Prefixes
 Dys: bad, abnormal
 A: not
 Hyper: over, above, exceedingly, in excess
 Meta: changed; altered
Roots
 Trophy: make to thrive
 Plasia: formation
 Stasis: place
Cell Pathology Terms
 Atrophy:
or organ.


Wasting or decrease in size of a cell, tissue
Caused by malnutrition / blood flow problems
Lack of muscle use / nerve damage  muscle
atrophy
 Dystrophy:
“ill growth.” progressive changes in a
tissue that is almost always due to long-term
malnutrition, decreased blood flow.

Muscular dystrophy: general weakening of muscles
 Hypertrophy:
Enlargement of a tissue or organ due
to an increase in cell size, NOT CELL NUMBER.
Cell Pathology Terms

Dysplasia: disorderly growth pattern in a tissue or organ.



Hyperplasia: abnormal multiplication in the number of
normal cells in a tissue



Not cancerous
Has significant impact on body structure
Increases the risks of certain cancers
Distorts the function of the tissue/organ
Metaplasia: A change in cell and tissue function from
normal to abnormal.




Can be reversible
Can produce inappropriate functioning of the tissue or
organ
Cause: DNA damage, exposure to certain chemicals
Can lead to cancer or breakdown in cell communication /
tissue organization
Cell Pathology Terms
 Metastasis:
Diseased cells break away from
the original location and establish themselves
in new areas of the body


Can carry out functions in new location
Reserved from cancerous or highly abnormal
cells
Cell Pathology: Amyloid deposition
 Amyloid:
protein-like material
 Disagreement: do they cause disease or are they
the result of disease?

Intended to help but cause harm when build up in
cytoplasm
 Indicators
of cell damagecell senses & corrects
 Cell death is the result usually
Cell Pathology: Fatty Change
 Accumulation
of lipids in the cell in
response to cellular injury.
 Excessive alcohol intakeincreased fat in
liver cells, disrupting cell function & thus
tissue function
Cell Pathology: Necrosis
 Localized
tissue death
 Blood flow decrease (bed sores!) burns,
chemical damage, infections, injury
 Results in diminished functioning of the
tissue, organ & organ system.
Cellular Aging: Non-mitotic cells
 Occurs
because of accumulated molecular
damage





Especially in cells that cannot undergo mitosis: fat
cells, skeletal muscle, nervous tissue.
They can’t fix the damage
Fail at tasksaffect tissues, organs, etc.
Caused by environmental factors, stress
Cells can die early or undergo programmed death
protect the nearby cells