Anatomy Notes Week 1 PDF

Anatomy of the Human Body Anatomy – study of the internal and external body structures, and their relationships to one another  e.g. nerves, bone, and muscle Physiology – studies the function of these structures  e.g. nerve impulses and muscle contraction Gross (macroscopic) Anatomy Study of large...

Anatomy of the Human Body Anatomy – study of the internal and external body structures, and their relationships to one another  e.g. nerves, bone, and muscle Physiology – studies the function of these structures  e.g. nerve impulses and muscle contraction Gross (macroscopic) Anatomy Study of large body structures visible to the naked eye  e.g. bone, heart, and lung morphology Microscopic Anatomy Study of structures too small too be seen with the eye a) cytology – internal structures of cells b) histology – study of tissues (groups of cells/cell types) Levels of structural organization molecules 1. Chemical  atoms join together to form molecules H2O, fats, amino acids, proteins, and carbohydrates (CHOs)  e.g. 2. Cellular the organelles, which make up cells – the basic unit unit of structure and function atom amino acid (many atoms) protein (many aa’s) organelle (many proteins, lipids & CHOs)  molecules form  vary widely in size, shape, makeup, and function  e.g. red blood cells, neurons, muscle cells cell (many organelles, proteins, lipids, CHOs & water) Levels of structural organization 3. Tissues  group of structurally similar cells with a common function Four basic types: i) epithelium – covers body surface and lines its cavities ii) muscle – provides force, enabling movement iii) connective – protect, connect, and support organs/tissues iv) nervous – transmits electrical impulses within body (“internal communication”) Levels of structural organization 4. Organs  discrete structures composed of two to four tissues that work together to perform one or more specific functions e.g. lungs (possess all 4 tissue types); gas exchange 5. Organ systems  related organs working together to perform a common task e.g. larynx, trachea, bronchus, and lungs = respiratory system  supply blood with O2 and remove CO2  pH (acid/base) balance  immunity 6. Organism  all organ systems working together to maintain life This structural organization is a hierarchy: each level contains those below it Atoms 1 Organelle Molecule Smooth muscle cell Chemical level 2 Cellular level 3 Tissue level e.g. Smooth Muscle Tissue 4 6 Organismal level The human organism. 5 Organ system level e.g. Cardiovascular System Organ level e.g. Blood Vessel Chemical level of organization Knowledge of basic chemistry needed for understanding: a) anatomy and physiology b) difference between health and disease Atoms, elements, and molecules Atoms – composed of a nucleus containing neutrons (n0) and protons (p+), with associated electrons (e–) ‘orbiting’ this nucleus e.g. helium nucleus – + + – 2 neutrons (no charge) 2 protons (+ charge) 2 electrons (– charge) Atoms, elements, and molecules Atoms with differing numbers of neutrons, protons, and electrons are organized into 92 naturally occurring elements e.g. hydrogen (1 p+, 1 e-) carbon (6 n0 , 6 p+, 6 e-) oxygen (8 n0 , 8 p+, 8 e-) Atom and element terminology is used interchangeably  i.e. the element oxygen = an oxygen atom Atoms, elements, and molecules Elements are electrically neutral (# of p+ = # of e-), each having unique physical and chemical properties However, some elements can lose or gain electrons (thus are no longer electrically neutral), becoming ions  e.g. element sodium (Na) can lose an e- → Na+ ion (cation) element chlorine (Cl) can gain an e- → Cl- ion (anion) transfer e- sodium atom chlorine atom sodium ion + – chloride ion sodium chloride (NaCl; salt) Important ions (electrolytes) are: calcium (Ca2+), sodium (Na+), potassium (K+), hydrogen (H+), and chloride (Cl-) Molecules Two types of chemical bonds (ionic or covalent) can bind two or more atoms together to form molecules Ionic bonds – transfer of an e- from 1 atom (ion) to another  e.g. Na+ + Cl- → NaCl (see last slide) Covalent bonds – sharing of electrons between atoms  e.g. an oxygen molecule (O2) + oxygen atom oxygen atom oxygen molecule When two or more different kinds of atoms bind, they form molecules of a compound Two types of compounds: inorganic and organic A) Inorganic compounds  typically lack carbon atoms (but include CO2, CO, and HCO3-) e.g. H2O, NaCl, HCl, NaOH 1. Water – the most important, abundant compound in cells  60-80% by volume H2O is a polar molecule  unequal charge distribution over the molecule hydrogen bonds The slightly positive and negative charges of each H2O molecule creates weak hydrogen bonds with other H2O molecules, holding them together A) Inorganic compounds The charged ends of H2O are also attracted to anions and cations in compounds, thus separating them  i.e. it breaks their ionic bonds H2O is thus known as the universal solvent, as many important compounds dissolve and dissociate (ionize) in water e.g. table salt separates into Na+ and Cl- ions + water NaCl A) Inorganic compounds H2O plays many other critical roles in the body: i) many biological molecules only react if dissolved in H2O ii) prevents large charged molecules (e.g. proteins) from settling out of solution iii) transports chemicals and nutrients within and between cells iv) its high heat capacity helps minimize temperature fluctuations within the body v) helps lubricate joints and organs (e.g. heart) A) Inorganic compounds 2. Salts – compounds containing cations (except H+) and anions (except OH-)  are bound together by ionic bonds, thus dissolve in water to form ions All ions can conduct an electrical current in H2O, and hence, are also known as electrolytes (e.g. Ca2+, Na+, K+, Cl-) Salts (and electrolytes) play vital roles in body function e.g. Na+ and K+ (from NaCl and KCl) are critical for nerve impulse transmission and muscle contraction e.g. calcium phosphate salts help make bones and teeth hard + Na+ Na + Na ATP ADP K+ K+ +P Acids and Bases: May be either inorganic (e.g. HCl, NaOH) or organic molecules (e.g. RNA, DNA) 3. Acids – dissociate in H2O and release H+ ions (‘proton donors’) e.g. HCl → H+ + Cl(proton) 4. Bases – take up (or buffer) H+ ions (‘proton acceptors’) e.g. NaOH → Na+ + OH(hydroxyl ion) then OH- + H+ → H2O Like salts, acids and bases are electrolytes, though they also play a critical role in maintaining the pH balance of cells, organs, and blood within narrow ranges  helps optimize the rate of chemical reactions (pH of most body fluids = 7.35 – 7.45) Basic pH = measure of the “free” [H+]  i.e. based on the number of hydrogen ions in solution A pH of 7.0 is neutral Neutral = [OH-] Logarithmic scale  a solution with a pH of 5 has a H+ concentration that is ten times higher than a solution with a pH = 6 more protons  [H+] less protons Acids and Bases: pH scale Acidic B) Organic compounds Carbon containing compounds; often very large molecules  carbon is electroneutral, thus can only share electrons 1. Carbohydrates – (C1H2O1)n; n = # of CH2O units e.g. glucose (C6H12O6) Functions:  source of energy for cells  small amounts used for structural support e.g. DNA/RNA backbone, ATP B) Organic compounds: carbohydrates i) monosaccharides – ‘simple sugars’  basic building blocks of carbohydrates e.g. glucose, fructose, galactose, dioxyribose, ribose ii) disaccharides – ‘double sugars’ 2 monosaccharides covalently bound together e.g. glucose + fructose = sucrose + H2O H2O iii) polysaccharides – energy storage products  many monosaccharides bound together e.g. glycogen (animals), starch (plants) Together, these three forms constitute 1–2% of the total cell mass 2. Proteins Composed of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) atoms (some have sulphur (S) too) Functions:  primary structural material of the body (collagen)  play vital roles in cell function and communication e.g. contractile proteins of muscle (actin and myosin) e.g. form enzymes, antibodies, transporters, and hormones i) amino acids – basic building blocks of all proteins  20 common types glycine cysteine lysine 2. Proteins ii) dipeptides peptide bond C amino acid #1 amino acid #2 N H2O  two amino acids joined by a peptide (C–N) bond peptide bond iii) polypeptides  chain of >10 amino acids iv) proteins  1 or more polypeptides in their final conformation (‘folded’ or in ‘sheets’) lysozyme -globin -globin -globin -globin hemoglobin 3. Lipids Fats, oils, waxes, cholesterol, and fatty acids  contain C, H & O (& P), but in different ratio than CH2Os  non-polar and hence insoluble in H2O Functions:  build cell membranes, source of stored energy, protect organs i) glycerides (acylglycerols) – fats and oils  most common lipid in diet; the body’s major energy source  composed of a glycerol backbone and 1 to 3 fatty acids i.e. monoglycerides diglycerides 1 fatty acid glycerol triglycerides 3 fatty acids 2 fatty acids 3. Lipids ii) phospholipids – main component of cell membranes a hydrophilic ‘head’ containing a phosphate group (PO4-) a glyercol ‘backbone’  a hydrophobic ‘tail’ formed by two fatty acids PO4glycerol phosphate containing group 2 fatty acids (polar, water soluble ‘head’) (non-polar, hydrophobic ‘tail’) 3. Lipids iii) cholesterol – found in cell membranes  synthesized in liver, but most comes from diet iv) steroids – derived from cholesterol e.g. sex hormones – testosterone, estrogen bile salts – aid lipid digestion vitamin D – maintains proper blood levels of Ca+ & P 4. Nucleic Acids Contain C, H, O, N, and P Basic building block is the nucleotide acidic PO4- group organic base monosaccharide (ribose/deoxyribose) RNA DNA (Adenine, Thymine/Uracil, Cytosine, Guanine) i) deoxyribonucleic acid (DNA) – organic bases: A, T, C, G Double-stranded helix  ‘spiral ladder’ – A always binds T; C binds G 4. Nucleic Acids ii) ribonucleic acid (RNA) Single stranded – organic bases: A, U, G, C Functions: DNA → stores “blueprint” of organism ↓ genes → “instructions” for building proteins ↓ RNA → carries out instructions for protein synthesis 4. Nucleic Acids Adenosine triphosphate (ATP) Adenosine RNA nucleotide with three bound phosphate groups high energy covalent bonds adenosine ribose adenine from food catabolism released for cell use adenosine diphosphate (ADP)  primary  energy source of cellular reactions catabolism of food used to re-synthesize ATP The Cell Basic structural and functional unit of the body  can perform all basic functions of life 1. Cell (plasma) membrane – outer boundary of cell; it is selectively permeable to molecules inside the body  divides intracellular fluid (ICF) from extracellular fluid (ECF) a) phospholipid bilayer Extracellular fluid (outside cell) phosphate ‘heads’ (hydrophilic) cholesterol (adds stability) fatty acid ‘tails’ (hydrophobic) Intracellular fluid (inside cell) 1. Cell membrane b) membrane proteins i) integral proteins – have hydrophobic and hydrophilic regions  most span the membrane completely (transmembrane)  form ion channels, transporters, hormone receptors peripheral protein ii) peripheral proteins  attached to transmembrane ion channel integral proteins integral proteins on inner or outer surface of the bilayer  aid in the support and function of the cell membrane 1. Cell membrane c) membrane carbohydrates (‘glycocalyx’)  only on outer surface, bound to proteins or lipids  used to ‘anchor’ cells together and for cell-to-cell recognition (e.g. egg and sperm) d) microvilli  tiny fingerlike projections of the cell membrane (prominent in small intestine and kidney)  increase cell surface area enormously Fluid mosaic model of the cell membrane:  the cell surface is constantly changing, as the phospholipids and some proteins are free to ‘float’ around