Chemical Foundations of Anatomy & Physiology

Atoms & Elements

Atoms are the basic units of matter, composed of subatomic particles. Elements are pure substances consisting of only one type of atom.

• Proton (p+): Positively charged particle, found in the nucleus, determines atomic number and element identity.

• Neutron (n): Neutral particle, found in the nucleus, contributes to atomic mass.

• Electron (e-): Negatively charged particle, orbits the nucleus, involved in chemical bonding.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Valence Electrons: Electrons in the outermost shell, determine chemical reactivity.

Compounds & Bonds

Compounds are substances formed by the chemical combination of two or more elements. Chemical bonds hold atoms together in compounds.

• Ionic Bonds: Formed when electrons are transferred from one atom to another, creating charged ions (e.g., NaCl).

• Covalent Bonds: Formed when atoms share electrons. Can be single, double, or triple bonds.

• Polar Covalent Bonds: Electrons are shared unequally, resulting in partial charges (e.g., H2O).

• Non-Polar Covalent Bonds: Electrons are shared equally between atoms of similar electronegativity.

Electronegativity

Electronegativity is the tendency of an atom to attract electrons in a chemical bond.

• Atoms with higher electronegativity attract electrons more strongly.

• Common polar molecules: H2O, NH3, HF.

Water Molecule

Water is essential for life and exhibits unique properties due to its polar covalent bonds and hydrogen bonding.

• Structure: Two hydrogen atoms covalently bonded to one oxygen atom (H2O).

• Hydrogen Bonds: Weak attractions between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another.

• Properties: High heat capacity, solvent abilities, cohesion, and adhesion.

Acids, Bases, and pH

Acids and bases are substances that alter the concentration of hydrogen ions (H+) in a solution.

• Acid: Releases H+ ions, lowers pH.

• Base: Accepts H+ ions or releases OH-, raises pH.

• Neutral: pH 7.

Biomolecules in Anatomy & Physiology

Proteins

Proteins are polymers of amino acids and perform a wide range of functions in the body.

• Monomer: Amino acid.

• Polymer: Polypeptide/protein.

• Functions: Enzymatic (speed up reactions), structural (collagen, keratin), communication, transport, immune defense.

• Structure: Determined by amino acid sequence and folding; denaturation (by heat, pH changes) disrupts function.

Carbohydrates

Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen, serving as energy sources and structural components.

• Monosaccharides: Simple sugars (e.g., glucose, fructose).

• Disaccharides: Two monosaccharides joined (e.g., sucrose).

• Polysaccharides: Long chains for energy storage (e.g., glycogen in animals).

Lipids

Lipids are hydrophobic molecules important for energy storage, membrane structure, and insulation.

• Types: Triglycerides (energy storage), phospholipids (cell membranes), steroids (hormones).

• Structure: Glycerol backbone with fatty acid chains.

Nucleic Acids & ATP

Nucleic acids (DNA and RNA) store and transmit genetic information. ATP is the primary energy carrier in cells.

• Monomer: Nucleotide (phosphate, sugar, nitrogenous base).

• ATP: Adenosine triphosphate, releases energy by breaking phosphate bonds.

Cellular Structure and Function

Cell Membrane

The cell membrane is a phospholipid bilayer that controls the movement of substances in and out of the cell.

• Structure: Phospholipids, proteins, cholesterol, carbohydrates.

• Function: Selective permeability, communication, structural support.

Fluid Compartments

Body fluids are distributed in various compartments.

• Intracellular Fluid (ICF): Fluid within cells.

• Extracellular Fluid (ECF): Fluid outside cells (plasma, interstitial fluid).

Organelles

Organelles are specialized structures within cells that perform distinct functions.

• Nucleus: Contains DNA, controls cell activities.

• Mitochondria: Site of ATP production via cellular respiration.

• Rough ER: Protein synthesis (ribosomes attached).

• Golgi Apparatus: Modifies, sorts, and packages proteins.

Cell Junctions

Cell junctions connect cells together and facilitate communication.

• Gap Junctions: Allow passage of ions and small molecules between cells.

• Tight Junctions: Prevent leakage between cells.

• Desmosomes: Anchor cells together, provide mechanical strength.

Tissues of the Human Body

Epithelial Tissue

Epithelial tissue lines body surfaces and cavities, providing protection, secretion, and absorption.

• Simple Epithelium: Single layer, allows exchange (lungs).

• Stratified Epithelium: Multiple layers, protects against abrasion (skin).

• Glandular Epithelium: Forms glands, secretes substances.

Connective Tissue

Connective tissue supports, protects, and binds other tissues.

• Loose Connective Tissue: Areolar (protects organs), adipose (stores fat).

• Dense Connective Tissue: Tendons (muscle to bone), ligaments (bone to bone).

• Bone: Osteocytes, collagen fibers, rigid support.

• Cartilage: Firm, flexible support.

Muscle Tissue

Muscle tissue enables movement through contraction.

• Types: Skeletal (voluntary movement), cardiac (heart), smooth (internal organs).

Nervous Tissue

Nervous tissue transmits electrical signals for communication and control.

• Neurons: Conduct impulses.

• Neuroglia: Support and protect neurons.

Cell Death and Stem Cells

Cell Death

Cells may die due to injury, lack of oxygen, or programmed processes.

• Necrosis: Death due to trauma or damage.

• Hypoxia: Lack of oxygen.

• Ischemia: Lack of blood supply.

• Apoptosis: Programmed cell death for development and maintenance.

Stem Cells

Stem cells are undifferentiated cells capable of dividing and developing into specialized cell types.

• Function: Tissue repair, regeneration, development.

Key Table: Types of Chemical Bonds

Key Equations

• pH Calculation:

• ATP Hydrolysis:

Additional info: Some explanations and examples have been expanded for clarity and completeness.