Overview of the Human Body

1. Overview of the Human Body Chapter 1

2. Overview • Anatomy and physiology: definitions • Form and Function • Homeostasis • Levels of organization

3. What is “Anatomy and Physiology”? • Anatomy- • Physiology-

4. Form (Structure) Fits Function • Principle of Complementarity- • You need to understand the parts and how they are put together before you can truly understand how they work • If you know what a body structure does, you can usually predict how it is organized/structured to do its job

5. Homeostasis • Homeostasis- • The nervous system and endocrine system (hormones) play important roles in communication that promotes homeostasis throughout the body. • Every cell of the body must also maintain homeostasis

6. Homeostasis and Feedback Loops • All systems involve three components: a ‘receptor’, a control center and an effector Stimulus(input into the system) RECEPTOR (ie. free nerve ending in the skin) CONTROL CENTER(such as the brain) EFFECTOR(such as a muscle, or a gland) Response(system’s output) The response to the stimulus leads to change. The change is ‘fed back’ to the receptor.

7. Homeostasis and Feedback Loops • In negative feedbacka stimulus causes a response which works to reduce/counteract the stimulus • Examples? • In positive feedbacka stimulus causes a response which further increases the stimulus, so that output is accelerated • Examples?

8. ~ 10,000,000 atoms lined up side by side to measure 1 mm Levels of Organization • How big is an atom?

9. Organelle Atoms Molecule Smooth muscle cell Cellular level 2 Chemical level 1 Smooth muscle tissue Tissue levelTissues consist of similartypes of cells. 3 Heart Bloodvessels Blood vessel (organ) Smooth muscle tissue Connective tissue Epithelialtissue Organ levelOrgans are made up of different typesof tissues. 4 Organismal level Organ system level 6 5

10. Chemistry Chapter 2

11. Chemistry Basics • Element: unique substance that cannot be broken down into a more simple substance by ordinary chemical methods.

12. Chemistry Basics • Atom: building block of an element • Proton • Neutron • Electron • Atomic Number • Atomic Mass

13. Chemistry Basics • Isotope: different # of neutrons (from a standard atom of the same element) • Ion: different # of electrons (from the standard atom of the same element)

14. Chemical Bonds • Chemical bonds: energy relationships between electrons of reacting atoms • Electrons in valence shell (outermost electron shell) • chemically reactive electrons • Octet rule (rule of eights) • Except for the first shell (full with two electrons) atoms interact to have eight electrons in their valence shell • 3 major bond types • Ionic • Covalent • Hydrogen

15. Ionic Bonds + — Sodium ion (Na+) Sodium atom (Na) (11p+; 12n0; 11e–) Chloride ion (Cl–) Chlorine atom (Cl) (17p+; 18n0; 17e–) Sodium chloride (NaCl) Sodium gains stability by losing one electron, and chlorine becomes stable by gaining one electron. After electron transfer, the oppositely charged ions formed attract each other. Figure 2.6a–b Formation of an ionic bond.

16. Covalent Bonds Figure 2.7a Formation of covalent bonds. Reacting atoms Resulting molecules + or Structural formula shows single bonds. Molecule of methane gas (CH4) Carbon atom Hydrogen atoms Formation of four single covalent bonds: Carbon shares four electron pairs with four hydrogen atoms.

17. Types of Covalent Bonds • Non-Polar: Electrons shared equally • Produces electrically balanced, nonpolar molecules • Polar: unequal sharing of electrons produces polar • Atoms in bond have different electron-attracting abilities

18. Electrons and chemical bonds H2 H2O • Which molecule above is polar? Non-polar? How do you know? • Which molecule above has covalent bonds? Polar covalent bonds? • Are either of these molecules ions?

19. Other important terms • Hydrophilic- • Hydrophobic- GLYCEROL A triglyceride H2O

20. pH- Acids and Bases • Acids • Have a sour taste • Release hydrogen ions, protons (H+) into solution • HCl, HC2H3O2, H2CO3 • Bases • Have a bitter taste, feel slippery • Are proton acceptors (they take up H+s from solution) • NaOH, HCO3-, NH3

21. pH- Acid-Base Concentration • The concentration of H+ ions in solution is measured in units of pH • The pH scale is logarithmic and runs from 0 to 14, with a pH value of 7 indicating a neutral solution • Acidic solutions have pH values from 0-6 • Neutral solutions = pH 7 • Basic (alkaline) solutions have pH values from 8-14 • The more hydrogen ions in a solution, the more acidic it is, but the lower its pH value.

22. Thought Question • The presence of hydrogen ions stimulates the brain to increase respiration rate. • Johnny’s blood pH is 7.25. Normal blood pH is 7.4. • Will Johnny likely be breathing faster or slower than normal? Why?

23. Chemical Reactions • Synthesis or Anabolic reactions • Decomposition or Catabolic reactions • Exchange reactions (swapping partners)

24. Chemical Reactions • Synthesis or Anabolic reactions A + B → AB • Decomposition/Catabolic Reactions AB → A + B • Exchange reactions AB + CD → AD + CB

25. Fructose Fructose What type of reaction is this? Sucrose Glucose Glucose Fructose Fructose & O Products Reactant • Synthesis Reaction • Decomposition Reaction • Exchange Reaction • All of the above

26. Chemical Reactions, Energy & Enzymes • Most chemical reactions do not occur spontaneously, or they occur so slowly that they would be of little value to cells • Activation energy- • Enzymespromote chemical reactions by lowering activation energy • Enzymes are biological catalysts, they are usually protein molecules

27. Mechanism of enzyme action Product (P) e.g., dipeptide Substrates (S) e.g., amino acids Energy is absorbed; bond is formed. Water is released. Peptide bond + Active site Enzyme-substrate complex (E-S) Enzyme (E) Enzyme (E) 1 2 Substrates bind at active site. Enzyme changes shape to hold substrates in proper position. Internal rearrangements leading to catalysis occur. 3 Product is released. Enzyme returns to original shape and is available to catalyze another reaction. Link- Enzyme animation

28. Fructose Fructose Sucrase is the enzyme that catalyzes this decomposition reaction Sucrose sucrase Glucose Glucose Fructose Fructose & O Products Reactant What do you think? -Does the reverse reaction ever occur?-Is sucrose ever formed (synthesized) from glucose and fructose?

29. What are organic compounds? ? • In chemistry, an organic compound must contain carbon and hydrogen • Most biologically relevant, organic compounds are soluble in water • Why? • What group might be the exception? • Many are polymers (large molecules) built from monomers (small subunits)

30. What are examples of inorganic compounds in the body?

31. What are some examples of these organic compounds in the body? • Carbohydrates • Lipids • Proteins • Nucleic acids Can you identify an example of each?

32. Carbohydrates • Group of molecules that includes sugars, starches and fiber • Account for less then 1-2% of body weight • In the body, primary function is as a readily usable energy source (glucose) • Also as energy storage (glycogen) • Cellular surface markers • Forms of carbohydrates • Monosaccharides, Disaccharides, Polysaccharides

33. Glucose is a monosaccharide = Fuel C6H12O6 = = glucose • Glucose is a ‘single’ sugar. • Note that it is a ring structure with 6 carbon atoms. • Other monosaccharides- fructose, galactose

34. Fructose Sucrose is a disaccharide Glucose Fructose O Other disaccharides- maltose, lactose

35. Polysaccharides • Starch/Amylose • Glycogen • Cellulose Linear chain

36. Polysaccharides Glucose monomer Starch granules in potato tuber cells (a) Starch Glycogen Granules In muscle tissue (b) Glycogen Cellulose fibril in a plant cell wall Cellulose molecules (c) Cellulose Monomer + Monomer + Monomer = Polymer

37. Lipids • Lipids, as a class, are a very diverse group of molecules • What do you think is the unifying characteristic of lipids? • Lipids are important energy stores • Lipids form essential structures in cells ?

38. Major types of lipids • Triglycerides - Comprised of fatty acids and glycerol; what we usually call ‘fats’ or ‘oils’ • Steroids -Cholesterol derivatives • Eicosanoids-Cell signaling molecules • Phosopholipids - Amphipathic molecules that form cell membranes

39. F A T T Y A C I D GLYCEROL F A T T Y A C I D F A T T Y A C I D Triglycerides • Triglycerides are threefatty acids linked to one glycerol molecule. • Fatty acids are long, linear chains of carbon and hydrogens (hydrocarbon chains).

40. Triglycerides FATTY ACID #1 GLYCEROL • In different triglycerides, the glycerol is the same, but the fatty acid chains vary, resulting in different types of fats and oils. • All fatty acid (hydrocarbon chains) are non-polar.

41. F A T T Y A C I D GLYCEROL F A T T Y A C I D F A T T Y A C I D Functions and locations of triglycerides in the body • Functions of triglycerides? • Where can we find stores of triglycerides? 1. 2. 3.

42. Steroids • All consist of a complex ring structure • Cholesterol is the precursor for all steroid hormones • Estrogen • Testosterone • Cortisol • Signaling molecules • Sexual function • Tissue metabolism • Component of animal cell membranes cholesterol estrogen testosterone

43. Eicosanoids • Diverse group of lipids derived from fatty acids of cell membranes • Prostaglandins • Powerful signaling molecules, synthesized by nearly all tissues of the body • Tend to act locally • Pain/inflammation • Labor Cell membranae Cell • Non-Steroidal Anti-Inflammatory Drugs(NSAIDs) inhibit prostaglandin synthesis

44. Phospholipids Phospholipids are modified triglycerides. Phospholipids have TWO fatty acids chains, and a phospho-group in place of the third! Non-lipid Group A phospholipid A triglyceride PhosphateGroup GLYCEROL GLYCEROL = F A T T Y A C I D F A T T Y A C I D F A T T Y A C I D F A T T Y A C I D F A T T Y A C I D

45. Phospholipid Chemist’s version Anatomist/Biologist’s version Yikes! Phospholipid molecules are amphipathic. One part of the molecule is polar, while the other end is non-polar. Which end interacts readily with water?

46. Phospholipid bilayer Chemist’s version Biologist’s version Sesame Street version H20 Two layers of phospholipids, stacked on each other, with the hydrophobic tails of each layer facing one another. Phospholipid animationhttp://telstar.ote.cmu.edu/biology/MembranePage/index2.html

47. All cell membranes are a phosophlipid bilayer • Forms the boundary between a cell and its environment • Hydrophobic core, with hydrophilic ends

48. Proteins • Proteins are polymers (chains) of amino acids (AA) • A single, generalizedamino acid

49. Peptide bonds Heidi’s Protein Cartoon- Each shape in the chain represents one amino acid + - + - • Amino acids are linked together via peptide bonds. • Two linked amino acids = dipeptide • 10-50 linked together = polypeptide • 50+ = protein

50. Protein Functions The over 2 million proteins in our bodies do an amazing variety of tasks • Enzymes (control metabolism) • Support • Movement • Transport • Cell Receptors for communication • Buffering • Hormonal Regulation • Defense