Introduction to Anatomy & Physiology

Key Definitions and Concepts

• Physiology: The study of how living organisms function, including processes and mechanisms in the body.

• Anatomy: The study of the structure of organisms and their parts.

• Gross Anatomy: Examination of structures visible to the naked eye.

• Histology: The study of tissues at the microscopic level.

Levels of Organization

• Human body organization proceeds from chemical (atoms, molecules) to cellular, tissue, organ, organ system, and organism levels.

• Example: Muscle cell (cellular) → Muscle tissue (tissue) → Heart (organ) → Cardiovascular system (organ system) → Human (organism).

Body Cavities and Membranes

• Major body cavities: Dorsal (cranial, vertebral) and Ventral (thoracic, abdominopelvic).

• Membranes (e.g., serous, mucous) line cavities and organs, providing protection and reducing friction.

Homeostasis and Feedback Mechanisms

• Homeostasis: Maintenance of a stable internal environment.

• Feedback loops regulate physiological processes:

  • Negative feedback: Counteracts changes (e.g., blood sugar regulation).

  • Positive feedback: Amplifies changes (e.g., childbirth contractions).

• Components of feedback loop: Stimulus, receptor, control center, effector, response.

Chemistry of Life

Elements and Atoms

• Atom: Smallest unit of matter, composed of protons, neutrons, electrons.

• Major elements in the human body: Oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus.

• Example: Water molecule (H2O) contains hydrogen and oxygen atoms.

Chemical Bonds

• Covalent bonds: Atoms share electrons; can be polar (unequal sharing) or nonpolar (equal sharing).

• Ionic bonds: Atoms transfer electrons, forming charged ions (e.g., NaCl).

• Hydrogen bonds: Weak attractions between polar molecules.

Hydrophilic vs. Hydrophobic

• Hydrophilic: Water-loving, polar molecules.

• Hydrophobic: Water-fearing, nonpolar molecules.

Macromolecules

• Carbohydrates: Monosaccharides, disaccharides, polysaccharides; main energy source.

• Lipids: Triglycerides, phospholipids; energy storage, cell membrane structure.

• Proteins: Polymers of amino acids; structure, enzymes, transport.

• Nucleic acids: DNA, RNA, ATP; genetic information and energy transfer.

Table: Properties of Selected Molecules

Cell Structure and Function

Cell Organelles

• Nucleus: Contains genetic material (DNA).

• Mitochondria: Site of ATP production.

• Endoplasmic reticulum (ER): Protein and lipid synthesis.

• Golgi apparatus: Modifies, sorts, and packages proteins/lipids.

• Lysosomes: Digestive enzymes for breakdown of waste.

• Peroxisomes: Detoxification of harmful substances.

Plasma Membrane Structure

• Phospholipid bilayer: Hydrophilic heads face outward, hydrophobic tails inward.

• Proteins: Channels, carriers, receptors for transport and signaling.

• Carbohydrates: Cell recognition and adhesion.

Transport Across Membranes

• Channels: Allow specific ions/molecules to pass.

• Carriers: Bind and transport substances.

• Receptors: Bind signaling molecules.

Energy and Chemical Reactions

Potential and Kinetic Energy

• Potential energy: Stored energy (e.g., chemical bonds).

• Kinetic energy: Energy of motion.

Reactants, Products, and Reaction Types

• Reactants: Substances entering a reaction.

• Products: Substances formed by a reaction.

• Catabolic reactions: Break down molecules, release energy.

• Anabolic reactions: Build molecules, require energy.

Activation Energy and Enzymes

• Activation energy: Minimum energy required to start a reaction.

• Enzymes: Biological catalysts that lower activation energy and increase reaction rate.

• Enzyme specificity: Each enzyme acts on specific substrates.

Factors Affecting Reaction Rates

• Concentration of reactants

• Temperature

• pH

• Presence of catalysts (enzymes)

• Particle size

Histology: Tissues and Their Functions

Major Tissue Types

• Epithelial tissue: Covers surfaces, lines cavities, forms glands.

• Connective tissue: Supports, binds, protects organs (e.g., bone, cartilage, blood).

• Muscle tissue: Movement (skeletal, cardiac, smooth).

• Nervous tissue: Transmits electrical signals.

Extracellular Matrix (ECM)

• Composed of protein fibers (collagen, elastin) and ground substance.

• Provides structural support and influences cell behavior.

Structure-Function Relationships

• Structure of tissues determines their function (e.g., simple squamous epithelium allows rapid diffusion).

• Connective tissue ECM varies by tissue type, affecting properties (e.g., bone vs. cartilage).

Regeneration and Fibrosis

• Regeneration: Replacement of damaged tissue with the same type of cells.

• Fibrosis: Replacement with scar tissue; may impair function.

Sample Exam Questions and Applications

• Feedback loops: Blood sugar regulation is an example of negative feedback.

• Bond types: KF is ionic and hydrophilic.

• Enzyme function: Enzymes lower activation energy and increase reaction rates.

• Plasma membrane: Nonpolar lipids pass through easily; channel proteins facilitate passage of polar molecules.

• Muscle tissue: Binds, supports, and protects the body.

• Simple squamous epithelium: Thickening would reduce gas diffusion efficiency.

Key Equations

• Rate of chemical reaction:

• First Law of Thermodynamics:

• ATP hydrolysis:

Additional info: Academic context and examples have been expanded for clarity and completeness.