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Unit 2. Organization of the Body. Hierarchy of Human Structure. Guided Reading: List the levels of organization, starting with molecules. What are stem cells?. Hierarchy: a series of ordered groupings within a system. Alpha male & female Pups & adults Outcasts / Dispersers.
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Unit 2 Organization of the Body
Hierarchy of Human Structure Guided Reading: • List the levels of organization, starting with molecules. • What are stem cells?
Hierarchy: a series of ordered groupings within a system Alpha male & female Pups & adults Outcasts / Dispersers
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: • If humans live on land, why does the author say that the human physiological environment is “aqueous”? • 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: 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
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. Y X X
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, minerals A Fraternity Hazing Gone Wrong : NPR
Tissues Guided Reading: • What are the four types of tissue found in humans? • 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
Organs, and Systems Guided Reading • What is the relationship between tissues and organs/systems? • 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: • What does this statement mean? “Cell pathology causes hierarchy dysfunctions of the body”? • What is the purpose of a biopsy? • Make a chart describing the major types of cell pathology. • What is “molecular decay”? • 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: 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