6.8.2011 Anatomy- The study of the structure of body parts and their relationships to one another (Body architecture) Physiology- Concerns the functioning of the body?s structural machinery, how the parts of the body work and carry out life-sustaining activities Levels of Structural Organization: Chemical- atoms (& their parts) and molecules. Cellular- Cells are the basic structural & functioning units of life. Tissue-groups of similar cells with intercellular material that work together toward a specific function. *Common embryological origin. EX: blood, muscle, nerves Organ- Structure composed of 2 or more tissue types that work together to perform a function System Level (Organ system level) - an association of organs that cooperate to accomplish some purpose. (There are 12 principle systems in humans). Organismal Level- Sum total; a collection of structurally and functionally integrated systems The 12 principle systems found in humans: Integumentary system- External body covering Protects deeper tissues Synthesizes vitamin D Site of cutaneous (pain, pressure, etc.) receptors, and sweat and oil glands Temperature control Skeletal system Protects/supports body organs Framework for the muscles use to cause movement Location of blood cell formation Stores minerals Muscular system Allows manipulation of the environment, locomotion and facial expression Maintains posture Produces heat Nervous system Fast acting control system of the body Responds to internal and external changes Activates (or inhibits) appropriate muscles and glands Endocrine system Various glands that secrete hormones that regulate processes such as growth, reproduction and nutrient use (metabolism) by body cells Cardiovascular system Heart and blood vessels Blood vessels transport blood which carries oxygen, carbon dioxide, nutrients, wastes Heart pumps blood Lymphatic system/immunity Picks up fluid leaked from blood vessels and returns it to blood Disposes of debris in the lymphatic stream Houses white blood cells (lymphocytes) involved in immunity. (immune response is an attack against foreign substances within the body.) Respiratory system Lungs Oxygenates blood Removes C0? from blood Exchange of 0? and C0? occurs through the walls of the air sacs (alveoli) of the lungs Digestive system Breaks down food into the absorbable units that enter the blood for distribution to the body cells Indigestible foodstuffs are eliminated as feces Urinary System Eliminates nitrogenous waste from the body (urea) Regulates water, electrolyte, and acid base balance of the blood Male reproductive System Female Reproductive system Overall function is production of offspring Testes produce sperm and male sex hormone Ducts and glands aid in delivery of sperm to the female reproductive tract Ovaries produce eggs and female sex hormones Remaining structures (ducts) serve as sites for fertilization and development of the fetus Mammary glands of female breasts produce milk to nourish the newborn Characteristics of life Metabolism- sum of all the chemical reactions occurring within an organism Catabolism Break down large molecules to smaller molecules Release energy stored in the chemical bonds Anabolism- Build or synthesize large molecules from smaller units Consume energy Movement (or contractility) Capacity to shorten, change, shape or move Maintenance of boundaries Keep internal environment distinct from external Responsiveness (or irritability) Ability to sense & adjust to environmental change Reproduction Ability to produce offspring Asexual- replication (copy) of existing cells Sexual- production of new organisms Growth Hypertrophy- increase cell size Hyperplasia-increase cell number 6.9.2011 Homeostasis Homeo=within; same Stasis= not changing; standing still Homeostasis- maintenance of near constant internal environment in face of external change Homeostatic control mechanisms: Operate as feedback control systems Control center receives input & adjusts output Positive Feedback Change in one direction accelerates change in same direction Rare Examples: blood clotting, muscle and neuron action potential, labor contractions, orgasm Negative Feedback Change in one direction produces adjustment in the opposite direction (i.e. thermostat) Most common Examples: body temperature, pH, blood pressure, blood sugar Chemistry Matter Anything that occupies space and has mass (mass ~ weight) States of matter: gas, liquid, solid Energy Capacity to do work Forms of energy Mechanical Electrical Thermal Chemical Elements Basic substance that cannot be broken down to simpler substances by chemical means Composed of atoms There are over 100 elements? but 99% of our body?s mass is made up of 6 elements. (atoms) Oxygen- 65% Carbon- 18% Hydrogen- 10% Nitrogen- 3% Calcium- 2% Phosphorous- 1% Table 2.1. Names & atomic symbols of 13 elements very important to physiological function. Oxygen- O Nitrogen- N Potassium- K Carbon- C Calcium- Ca Sulfur- S Hydrogen- H Phosphorous- P Sodium- Na Chlorine- Cl Magnesium- Mg Iodine- I Iron- Fe Atoms Smallest unit of element that displays element?s unique chemical and physical properties. Composed of smaller particles & a lot of empty space Atomic Structure Protons (p+) positively charged particles Neurons(no) neutral (no charge) particles Electrons (e+) negatively charged particles Atomic nucleus consists of p+ and no Electrons orbit the nucleus as a ?cloud? organized into energy levels Neutral atom: Electron Number = proton number, making the overall atom neutral in charge Each element has a unique number of protons Atomic number- number of protons Example: 8O (8 is the atomic number of Oxygen) 7N (7 is the atomic number of Nitrogen) *Annotated as a subscript to the left of the symbol * You can?t change the number of protons or you will change the element Atomic weight (mass) ? the sum of proton and neutron # in an atom # of protons + # of neutrons = Atomic mass Protons & Neutrons contribute most of the mass of an atom Protons & Neutrons are ~2000 times the mass of electrons. Proton= 1 atomic mass unit (a.m.u.) Neutron= 1 a.m.u. Electron= 0.0005 a.m.u. Isotopes Atomic variants Nearly all elements have 2 or more isotopes Have same atomic number but varies in the number of neutrons (thus varies in atomic mass) Some isotopes are radioactive Atomic Stability/Instability An atom strives for stability by having its outermost energy level full of electrons Each energy level can hold a specific number of electrons 1st level: 2e_ 2nd level: 8e- 3rd level: 8e- Innermost levels fill up first, if there are vacancies they are in the outer energy levels To achieve stability (a full outer shell level) an atom will give up, steal, or share electrons with other atoms. Valence shell refers to outermost energy level. Valence refers to combining capacity of an atom (number indicating the number of extra or deficient electrons in an atom?s valence shell. Inert elements are stable due to a full outer shell; chemically inactive Chemical reactions occur when atoms combine or break apart from other atoms Chemical bond is a force of attraction between atoms due to their outer level electrons (valence electrons) Molecule- 2 or more atoms joined by a chemical bond. (More than one atom bonded together) Example: Water= H2O Compound- a molecule with more than 1 element in it Example: Glucose= C6H12O6 Ion- Charged particle resulting from gain or loss of an electron Anion Negatively charged ion Atom that gained 1 or more electrons Cation Positively charged ion Atom has lost 1 or more electrons Ions are represented by a (+) or (-) after the chemical symbol, i.e. Na+ = the sodium ion or sodium cation Chemical Bonds Ionic bond- a chemical bond due to a transfer of electrons (one loses, one gains) resulting in oppositely charged ions are attracted to each other (see figure 2.6) Covalent bond- involves sharing of valence electrons (1, 2, or 3). These bonds are stronger, more stable & more common. If there is one shared electron it?s a single bond symbol: H-H If there are two shared electrons it is a double bond: O=O If there are three shared electrons it is a triple bond: N=N The sharing of e_ in a covalent bond is not necessary in a polar covalent bond creates a charged molecule?not necessarily equal, one atom may have more ?pull?; this creates polar covalent bonds (H20) if the sharing is equal you have a non-polar covalent bond (CO2). The unequal sharing of electrons in a polar covalent bond creates a charged molecule? meaning one end is slightly negative and the other slightly positive (like a bar magnet or dipole) 6.10.2011 Hydrogen bond- a type of bond which is too weak to bind atoms into molecules but important in creating relationships between molecules and in causing them to fold into 3 dimensional shapes Hydrogen bonds are due to polar covalent bonds involving hydrogen atoms, creating a dipole or charged portion which is attracted to other charged portions (H20 to H20) Even though Hydrogen bonds are individually weak they are often so numerous that they have a strength due to numbers, consequently they are very important (amongst other things hydrogen bonds cause most of the properties of water; used in DNA) Chemical reactions- simply the making/breaking of bonds or rearranging bonds, possibly into a new molecule with new properties Associated with making and breaking bonds is an energy change Forming bonds requires (uses) varying amounts of energy Breaking bonds releases this energy Therefore, a chemical bond is stored energy Types of Chemical Reactions Synthetic (anabolic) reactions- combining of 2 or more atoms (molecules) Decomposition (catabolic) reactions- breaking down of a molecule into separate atoms, different molecules, or combinations Exchange reactions- a combination of both Essentially all reactions are reversible How/why do chemical reactions occur? Atoms and molecules must collide with enough force to overcome the repulsion of their mutual electrons? if this happens the interaction between valence electrons is possible. The energy necessary to disrupt one configuration and allow for rearrangement is called activation energy To increase reaction rates you can: Increase temperature (collisions speed up) Increase concentration level of reactants or pressure (increase frequency/chance of collision) Introduce a catalyst (enzyme) (lowers amount of activation energy needed for reaction) 2 Classifications of chemical compounds Inorganic compounds are generally small molecules ionically bonded and do not include carbon. Most dissolve in water. (Water, salts, acids, bases). Exceptions: CO and CO2 Organic Compounds are generally large, almost always covalently bonded and include carbon and hydrogen; they dissolve poorly if at all in water. Solvent- liquid (or gas) in which some other material is dissolved. The solvent is the material present in the greater amount. Solute- the dissolved material. Present in lesser amounts Solution- combination of solvent and solute. A solute will not settle out of a solution without some chemical reaction or physical intervention Suspension- as contrast to solution, solute will settle out over time Inorganic Compounds Water is the most abundant and important inorganic compound in living material (70% of a human?s weight) Key uses/characteristics: Very good solvent and suspension medium; called the universal solvent; serves as a major transport medium in the body. An important reactant involved in many reactions. Serves as a temperature buffer; prevents rapid fluctuation due to a high heat capacity. Means it absorbs or releases a lot of heat before changing temperature (insulator) Has high vaporization heat; means it absorbs a lot of heat before its hydrogen bonds break and it turns to gas (vapor). Why sweat cools when it evaporates (coolant). Since water is polar and forms hydrogen bonds, it is both cohesive and adhesive. Gives lubricant and cushioning properties. Salts, Acids, Bases-molecules of salts, acids, and bases are readily dissolved in water (ionize or dissociate into their constituent cations and anions). Often called electrolytes because the positive and negative charges conduct electricity Acids- substances that when dissolved dissociates into hydrogen ions (H+) and some negative ions (anion) Since hydrogen ions are simply protons, acids are often called ?proton donors? Bases-substance that when dissolved dissociates, forming hydroxyl ions (OH-) are strongly attracted to protons (H+) bases are often called ?proton acceptors? (the words base and alkaline mean the same thing) Acids and bases will react with each other in an exchange reaction to form salt and water. We call this neutralization Salt- a substance that when dissolved dissociates into anions and cations that are neither H+ or OH- pH scale (percent hydrogen scale) The more hydrogen ions in a solution the more acidic it is. The more hydroxyl is in a solution the more basic it is. If H+>OH- then it?s acidic. If OH->H+ then it?s basic. When H+=OH- then it?s water. pH scale ranges from 0-14 at pH 7 the concentration of H+ and OH- A pH<7 is basic Egg white =8.0 Bleach= 9.5 Oven cleaner= 13.5 Living organisms and their reactions are very sensitive to even small pH changes. Our blood must remain in the range of 7.35 and 7.45 Organic Compounds Carbon has 4e- in valence shell. Needs 4e- to achieve stability. Can form up to 4 single covalent bonds. Near infinite complexity and diversity of molecules. Carbohydrates (sugars) Fuel for body (energy source) and form storage molecules (glycogen) Composed of C H O (CH20) Sometimes used structurally, often as backbone for complex molecules (carbs) 3 classes of carbs (based on size) Monosaccharides (glucose, fructose, ribose)- simple sugars, energy source Disaccharides- 2 simple sugars bonded together. During this reaction, an H20 is removed, thus called dehydration synthesis Polysaccharides- longer chain of simple sugars used as storage molecules Examples: Starch- storage carb found and made by plants Glycogen- storage molecule found and made by animals Disaccharides and polysaccharides are what we usually eat but in order to pass through a cell membrane (and get into our body) they are first broken down to monosaccharides 6.13.2011 polar molecules (like water) can form weak bonds with other polar molecules Non-polar molecules do not form bonds with polar ones? in fact the two won?t mix. They exclude each other if you try to mix them (oil and water) Hydrophobic (water fearing) - non-polar molecules are insoluble in a polar solvent e.g. water- thus it?s called hydrophobic Hydrophilic (water loving) - polar molecules do dissolve in polar solvents 2. Lipids- a diverse group of organic compounds. They are non-polar and insoluble in water? but soluble in a non-polar solvent such as alcohol function: structural and insulating, long term energy storage, hormones and vitamin precursors neutral fats (fats and oils) storage and insulations saturated fats- have no double bonds in the fatty acid chain (saturated with Hs) unsaturated fats- have one or more double bond (if more than one it?s polyunsaturated) phospholipids- modified fats containing a polar phosphate group in place of one fatty acid important in forming membranes phospholipids are polar at one end and therefore they always assume a certain orientation in water (plasma membrane) steroids- instead of hydrocarbon chains they have a ring structure in spite of a bad press due to heart disease and athletic misuse, they are essential for life -e.g. cholesterol, vitamin D and hormones 3. Proteins: very complex molecules made up of chains of sub units called amino-acids (AA) Varied functions: Structural- hair tendons? Contractile- muscle Regulating- hormones, enzymes Oxygen transport- hemoglobin Immunity- antibodies There are 20 different AAS that all contain C, H, O, and N & sometimes S. they are bonded together in chains of varying length and number of AAs. Bonds are formed by dehydration and called peptide bonds. (dipeptide, tripeptide, polypeptide chains or simply proteins). Most AAs are synthesized by our body. Those we cannot make are called ?essential? AAs Levels of Organization in Proteins Primary structure: the sequence of the AAs in polypeptide chain Secondary structure: when primary chain coils or folds into some shape. It is held into shape by its hydrogen bonds Tertiary structure: any further coiling or folding of the secondary structure. Quaternary structure: refers to 2 or more proteins bonded together The overall shape of a protein is determined by the primary structure or sequence since the type/sequence of AAs determines where other bonds can be. Shape of a protein determines its functional activity Denaturation- changing a single AA or heating or altering pH of a protein will alter its shape because bonds get changed. This will also alter or destroy the protein?s function 4. Nucleic Acids- large organic molecules containing C, H, O, N & P Nucleic acids are composed of chains of sub-units called nucleotides, each nucleotide consists of a : 5 carbon sugar Phosphate Nitrogen base 3 Types of Nucleic Acids Ribonucleic Acid (RNA)- formed from DNA template in nucleus but shuttled to cytoplasm where it is involved in protein synthesis RNA is a single stranded molecule (single nucleotide chain). ?Backbone? of RNA is the 5 carbon sugar is ribose with alternating phosphate groups The nitrogen base of RNA can be 1 of 4 types: Guanine- G Cytosine- C Adenine- A Uracil- U Deoxyribonucleic Acid (DNA) Found in nucleus Carries genetic code (chromosomes are made of DNA). The 5 carbon sugar is deoxyribose Is a double helix (twisted ladder) formed by 2 parallel strands of nucleotides that are hydrogen bonded together by bases (so the bases are the rungs of the ladder). DNA?s nitrogen bases are: guanine, cytosine, adenine & thymine-T (instead of uracil) The bases of double helix always pair up to form the ?rungs? such that A pairs with T and G pairs with C The sequence of these bases is the genetic code Adenosine triphosphate (ATP)- temporary storage and transfer of energy throughout a cell Often called ?energy currency? Energy released by catabolism of glucose ?captured? and stored in high energy phosphate bonds Cytology Cyt=cell Ology=study of Plasma(cell) membrane Functions: Enclose/separate cell from external environment ?contact? surface Receptors for chemicals Regulates entrance/exit of materials Structure: Known as ?fluid mosaic model? Phospholipid bilayer arranged with polar heads on the surface and nonpolar tails inside Protein molecules are embedded in membrane (mosaic appearance). Types of proteins include: Integral membrane proteins- transport pores or channels; strongly attached to membrane Peripheral proteins- loosely attached to external or internal surface of the membrane Glycocalyx proteins (sugar halo)- proteins which have branching carbohydrate chains ?hanging off? membranes surface. These ?flags? serve as cellular recognition and/or receptor sites Membrane transport- phospholipid membrane is a selectively permeable barrier. Means it allows some things through some things but not others (due to their size or charge or solubility) Movement across the p-membrane occurs either actively or passively (spends energy or not). Passive processes- movement without assistance or expenditure of energy? occurs ?down hill?, down a concentration or pressure gradient (from high to low) Types of passive transport: Simple diffusion- movement of particles from high to low concentration; will continue until equilibrium (same concentration) is reached. Generally only small, nonpolar lipid soluble particles diffuse Facilitated diffusion- some substances (polar and/or insoluble) can diffuse faster by combining with a ?carrier? or transport protein. (it ?facilitates? or assists diffusion) Osmosis- the diffusion of water through a selectively permeable membrane. Water diffuses from areas of low solute concentration to areas of high solute concentration until equilibrium is reached. This will generate what is called an osmotic pressure. The extracellular fluid (ECF) surrounding a cell can be: Isotonic- having the same solute/solvent concentration as the intracellular fluid cell Hypotonic (under concentrated)- having lower concentration of solutes and higher concentration of solvents than the cell. Water enters the cell by osmosis until either equilibrium is reached or the cell bursts (burst=lyse) Hypertonic (over concentrated)- higher solute and lower solvent outside the cell. Water leaves the cell by osmosis, which causes the cell to shrink. (crenation=cell shrinking) Active process- involves spending energy (ATP) to move things that are either too big to diffuse or that need to move against a concentration gradient (low-> high; uphill) Active transport- movement of (mostly) ions or small molecules through protein pumps (revolving doors) against a concentration gradient Bulk transport Endocytosis (into a cell)-plasma membrane surrounds something and pinches itself off by bringing it inside the cell Phagocytosis- solids? cell eating Pinocytosis- liquids? cell drinking Exocytosis (leaving a cell)- vesicle merges with plasma membrane, dumps contents outside (secretion); wastes, hormones, mucus Cytology Part II Cytoplasm- matrix between plasma membrane and nuclear membrane. Is a gel-like solution with many molecules and/or organelles suspended in it Organelles- ?little organs?- specialized compartments (membrane bound) that performs specific metabolic functions. Types of organelles: Nucleus- large almost spherical almost central part of the cell- controls cell activity and contains genetic info. Parts of the nucleus: Nuclear envelope Nucleoplasm Nucleolus- ribosome synthesis site Chromosomes- DNA Ribosome- made of ribosomal RNA; involved in synthesis of proteins (protein factory); located either loose in the cytoplasm or attached to the endoplasmic reticulum Endoplasmic Reticulum (ER)- a membranous network that is involved in protein 2 types: Rough ER- has ribosomes attached to it. Involved in producing proteins destined for export (secretion or use in the cell. Smooth ER- no ribosomes, some lipid synthesis and is mainly an extensive tubular support/transport network Golgi Complex- flattened sacks; process and package proteins into vesicles for storage or export Vesicle- membrane enclosed package of ?something?. Ex: pinocytic vesicle, phagocytic vesicle, secretory vesicle Lysosome- vesicle full of digestive enzymes Mitochondria- double membrane enclosed organelle where ATP is produced. The ?powerhouse? of a cell Cytoskeleton- system of microfilaments and microtubules. Protein scaffolding that structurally supports cell; some involved in cell movement Centrioles- pairs of organelles which play a role in cell division by producing the mitotic spindle Flagella- whip like cellular projections that move the cell (humans only on sperm) Cilia- smaller hair like projections that do not move the cell but create currents that move substances along the outside of a cell Extracellular materials (outside the cell) Materials secreted by cells into their surroundings ranging from saliva, gastric juice, blood plasma, bone, cartilage etc
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