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Levels of Organization

Levels of Organization. The structures of the human body are organized into levels of increasing complexity. Chemical  Cellular  Tissue  Organ  System  Organism. Feedback Systems. Aka feedback loop

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Levels of Organization

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  1. Levels of Organization • The structures of the human body are organized into levels of increasing complexity. Chemical  Cellular  Tissue  Organ  System  Organism

  2. Feedback Systems • Aka feedback loop • A cycle of events in which the status of a body condition is continually monitored, evaluated, changed, re-monitored, re-evaluated, changed, re-monitored, re-evaluated…

  3. Stimulus • Any disruption that causes a change in the controlled condition • Can be internal or external

  4. Controlled Condition • Each monitored condition in the body • Ex – heart rate, BP, BGL, temperature…

  5. Receptor • A body structure that sends information (input) to the control center in the form of nerve impulses or chemical signals

  6. Control Center • Sets the range of values within which a controlled condition should be maintained, evaluated input from the receptors and send output to the effector

  7. Effector • A body structure that receives output from the control center and produces a response or effect that changes the controlled condition

  8. Negative Response Systems • Reverses a change in the controlled condition • Ex – If blood pressure is too high, your body works to lower it

  9. Blood Pressure Baroreceptors Brain Heart Decrease Heart rate

  10. Positive Feedback System • Operates to reinforce the initial change in the controlled condition • Ex – Contractions of the uterus increase during childbirth

  11. Abdominopelvic Regions • 9 smaller divisions of the abdominopelvic cavity to help describe the precise location of organs

  12. Trace Elements • The remaining 0.2% of the body’s mass is made of these 14 elements: • Al, B, Cr, Co, Cu, F, I, Mn, Mo, Se, Si, Sn, V and Zn • Even though they are present in REALLY small amounts, they are still essential to maintain homeostasis!

  13. Cation – a positive ion • Anion – a negative ion

  14. Free Radicals • An electrically charged ion or molecule that has an unpaired electron in its outermost shell • A free radical is unstable and destructive to nearby molecules • They break apart other molecules in the body by either giving up their unpaired electron or by taking an electron from another molecule.

  15. Antioxidants • Substances that inactivate oxygen associated free radicals. • Consumption of antioxidants is though to slow the pace of damage caused by free radicals. • Dietary sources of antioxidants include selenium, beta-carotene and vitamins C and E. “The antioxidants will protect me…”

  16. Electrolytes • An ionic compound that breaks apart into cations and anions when dissolved is called an electrolyte because the resulting solution can conduct an electric current • Critical in controlling water movement, maintaining acid/base balance and producing nerve impulses

  17. Hydrogen Bonds • A VERY VERY strong interaction between some polar molecules containing hydrogen • A hydrogen atom in one molecule with a partial positive charge attracts a partial negative atom (F, O or N) from another molecule. • About 5% as strong as an actual covalent bond

  18. Inorganic Compounds Usually small Lack carbon and/or hydrogen Many contain ionic bonds Examples: Water, oxygen, carbon dioxide, many acids, bases and salts

  19. Acids dissociate into H+ ions • Bases dissociate into OH- ions • Salts form ions that are not H+ or OH-

  20. Buffer Systems Consist of a weak acid and a weak base that function to prevent drastic changes in the pH of body fluid by rapidly changing strong acids and bases into weak acids and bases

  21. Body’s pH The pH range of blood is 7.35-7.45 (you need to know these exact numbers!) The body maintains pH through the use of buffer systems

  22. Dehydration Synthesis • 2 smaller molecules join together to form a larger molecule by removing a molecule of water

  23. Hydrolysis • Large molecules are broken down into smaller molecules by the addition of water

  24. Review of Organic Compounds • Carbohydrates • Building blocks = monosaccharides • Lipids (Triglycerides) • Building Blocks = glycerol and fatty acids • Proteins • Building Blocks = amino acids

  25. Carbohydrates • Include sugars, glycogen, starches and cellulose • Made from Carbon, Hydrogen and Oxygen • Usually 1:2:1 ratio (CH2O) • Divided into groups based on size

  26. Lipids (Fats) • Made of Carbon, Hydrogen and Oxygen • Proportion of Oxygen is usually lower than in carbohydrates • Not as many polar bonds so they are not soluble in water • Include triglycerides, phospholipids, steroids, fatty acids and fat soluble vitamins (A, D, E and K)

  27. Protein • Large molecules containing Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulfur • Building Blocks are Amino Acids

  28. Amino Acids

  29. Protein Structures • Primary • Secondary • Tertiary • Quaternary

  30. Denaturation • If temperature, pH or ion concentration is altered, a protein may unravel and lose it shape • If a protein changes shape (is denatured) it is no longer functional because… • SHAPE DETERMINES FUNCTION!

  31. Enzymes • Protein Catalyst • A substance that can speed up a chemical reaction without themselves being altered • Names of enzymes generally end in -ase • Ex. Kinase, dehydrogenase, amylase

  32. Nucleic Acids • Named because they were first found in the nucleus of cells • VERY VERY BIG • Contain C, H, O, N and P • DNA and RNA

  33. The Plasma Membrane • Flexible yet sturdy barrier composed mainly of phospholipids and proteins. • Called the “Fluid Mosaic Model”

  34. Selective Permeability • The plasma membrane allows some substances to move into and out of the cell but restricts the passage of other substances • Permeable to: lipid soluble molecules such as fatty acids, vitamins, steroids. Also small molecules such as water, oxygen and carbon dioxide • NOT permeable to ions and charged or polar molecules such as glucose and amino acids

  35. Communication Structures • Receptors • Integral proteins that recognize and bind to specific molecules governing some cellular function • Enzymes • Membrane proteins that speed up chemical reactions in the cell • Cell Identity Markers • Molecules that allow the cell to recognize cells of its own kind or to recognize and respond to potentially dangerous foreign cells.

  36. Passive Processes • Transport of materials without the addition of extra cellular energy (ATP)

  37. Tonicity of Body Fluids • Sodium Chloride concentration [NaCl] in body cells is 0.9%

  38. Active Processes • Cellular energy is used to transport substances up a concentration gradient

  39. Sodium Potassium Pumps • Remove Na+ from the cell and transport K+ into the cell • Maintain concentration gradients necessary for osmotic balance and to generate electrical signals

  40. Organelles • Specialized structures inside the cell with characteristic shapes and functions

  41. Nucleus • Most cells have 1 nucleus • Mature Red Blood Cells have no nucleus • Skeletal Muscles are multinucleated

  42. Gene Action: Protein Synthesis • 2 basic steps: • Transcription – the genetic information in DNA base triplets is copied into a complementary sequence of codons in a strand of mRNA • Translation – mRNA codons associated with ribosomes direct the order of amino acids in a polypeptide

  43. Nuclear Division • The duplicated chromosomes become exactly segregated (one set into each new nucleus). • Divided into 4 continuous stages: • Prophase, Metaphase, Anaphase, Telophase http://www.cellsalive.com/mitosis.htm

  44. Types of Tissues • Epithelial Tissue • Covers body surfaces; lines body cavities, hollow organs and ducts; forms glands • Connective Tissue • protect and supports the body and its organs, binds organs together, stores energy reserves as fat, provides immunity • Muscular Tissue • Generates the force needed to make body structures move • Nervous Tissue • Detects changes inside and outside the body and initiates and transmits nerve impulses that coordinate body activities to help maintain homeostasis

  45. Epithelial Tissue • AKA Epithelium • 2 types: • Covering and Lining Epithelium • Forms the outer covering of the skin and some internal organs. It also lines body cavities, blood vessels, ducts, and the interiors of many of the body systems. • Glandular Epithelium • Makes the secreting portion of glands

  46. Covering and Lining Epithelium – Cell Shapes • Squamous – flat cells that attach to each other like tiles • Allows for rapid passage of substances through them • Cuboidal – cells are as tall as they are wide, sometimes contain microvilli • Function in Secretion and Absorption • Columnar – Taller than they are wide, sometimes contain microvilli or cilia • Function in Secretion, Absorption and Protection

  47. Simple Epithelium • A single layer of cells found in areas where diffusion, osmosis, filtration, secretions and absorption occur

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