Unit 2

Unit 2Organization of the Body

Hierarchy of Human StructureGuided Reading:1. List the levels of organization, starting

with molecules.2. What are stem cells?

Hierarchy: a series of ordered groupings within a systemAlpha 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 EnvironmentGuided 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 homeostasisHomeostasis ≠ 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.

XX 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: tissues deprived of water

Diarrhea Sweating Vomiting Indicators: extreme thirst, stop sweating, nausea

& exhaustion Water intoxication?

Body takes in more water than it loses at a given period of time.

Upsets natural balance of ions, mineralsA Fraternity Hazing Gone Wrong : NPR

TissuesGuided 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 SquamousCuboidalColumnar

FlatCube-shaped; produce secretionsTall, column-shaped; secretions, uptakeSimple: Single-layerStratified: Multi-layered; subject to wear and tearPseudostratified: False-stratification

Connective MatrixProtein: CollagenProtein: ElastinProtein: ReticulumLoose

Dense

Made of gel, liquid, protein, saltsStrengthFlexibilitySupportMost abundant; attachment, stabilization, structure, supportStrength, storage, flexibility

Muscle Smooth

CardiacSkeletal

Spindle-shaped; no visible fibers; weak contractions; line organsHeart; visible striations; intercalated disksLarge cells; distinct striations; (in)voluntary

Nervous NeuronsNeuroglia

Motor, Sensory, InterneuronAssist Neuron functions (astrocytes, oligodendites, ependymal cells)

Organs, and SystemsGuided Reading1. 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 SpanGuided 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 PathologyPrefixes Dys: bad, abnormal A: not Hyper: over, above, exceedingly, in excess Meta: changed; alteredRoots Trophy: make to thrive Plasia: formation Stasis: place

Cell Pathology Terms Atrophy: Wasting or decrease in size of a cell,

tissue or organ. 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.

Not cancerous Has significant impact on body structure

Hyperplasia: abnormal multiplication in the number of normal cells in a tissue 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 damagecell 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 intakeincreased 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 tasksaffect tissues, organs, etc. Caused by environmental factors, stress Cells can die early or undergo programmed death

protect the nearby cells