Introduction to Anatomy & Physiology and The Chemistry of Life: Study Notes

Chapter 1: Introduction to Anatomy and Physiology

Differences Between Anatomy and Physiology

Anatomy and physiology are closely related fields that form the foundation of medical science. Understanding their distinctions and subdisciplines is essential for further study.

• Anatomy: The study of the structure of body parts and their relationships to one another. Subdisciplines include gross anatomy (visible to the naked eye), microscopic anatomy (cells and tissues), and developmental anatomy (changes throughout life).

• Physiology: The study of the function of body parts and how they work to carry out life-sustaining activities. Subdisciplines include cell physiology, systemic physiology, and pathophysiology (disease states).

• Example: Studying the structure of the heart (anatomy) versus understanding how it pumps blood (physiology).

Levels of Organization

The human body is organized in a hierarchical manner, from the simplest to the most complex structures.

• Chemical Level: Atoms and molecules

• Cellular Level: Cells and their organelles

• Tissue Level: Groups of similar cells performing a common function

• Organ Level: Two or more tissue types performing specific functions

• Organ System Level: Organs working together for a common purpose

• Organismal Level: The complete living being

Organ Systems of the Body and Their Functions

The body consists of several organ systems, each with specific functions vital to survival.

• Integumentary System: Protects the body, regulates temperature, and provides sensory information.

• Skeletal System: Provides support, protection, and stores minerals.

• Muscular System: Produces movement and generates heat.

• Nervous System: Directs immediate responses to stimuli, coordinates activities of other systems.

• Endocrine System: Directs long-term changes via hormones.

• Cardiovascular System: Distributes blood, nutrients, gases, and waste.

• Lymphatic System: Defends against infection and disease.

• Respiratory System: Delivers air to sites of gas exchange.

• Digestive System: Processes food and absorbs nutrients.

• Urinary System: Eliminates waste and regulates water balance.

• Reproductive System: Produces sex cells and hormones.

Homeostasis

Homeostasis is the maintenance of a stable internal environment despite external changes.

• Definition: The body's ability to maintain relatively constant internal conditions.

• Example: Regulation of body temperature, blood glucose, and pH.

Mechanisms of Homeostatic Regulation

Homeostatic regulation involves feedback systems that detect and respond to changes.

• Intrinsic Regulation: Local, automatic adjustment by a cell, tissue, or organ.

• Extrinsic Regulation: Regulation by the nervous or endocrine system.

• Negative Feedback: The response reduces or shuts off the original stimulus (e.g., body temperature regulation).

• Positive Feedback: The response enhances the original stimulus (e.g., blood clotting, labor contractions).

Basic Anatomical Terminology

Standardized terms describe body directions and regions for clear communication.

• Directional Terms: Anterior/posterior, superior/inferior, medial/lateral, proximal/distal, superficial/deep.

• Body Regions: Cephalic (head), cervical (neck), thoracic (chest), abdominal, pelvic, upper limb, lower limb, etc.

Chapter 2: The Chemistry of Life

Atomic Structure and Subatomic Particles

Atoms are the basic units of matter, composed of subatomic particles with specific charges.

• Protons: Positive charge (+1), found in the nucleus.

• Neutrons: No charge (0), found in the nucleus.

• Electrons: Negative charge (-1), orbit the nucleus.

• Atomic Number: Number of protons; Mass Number: Protons + neutrons.

Chemical Bonds

Atoms combine via chemical bonds to form molecules.

• Ionic Bonds: Transfer of electrons; forms ions (e.g., NaCl).

• Covalent Bonds: Sharing of electrons; can be polar or nonpolar (e.g., H2O, O2).

• Hydrogen Bonds: Weak attractions between polar molecules (e.g., between water molecules).

Cations and Anions

Ions are charged atoms or molecules.

• Cation: Positively charged ion (e.g., Na+).

• Anion: Negatively charged ion (e.g., Cl-).

Distribution of Sodium and Potassium

• Sodium (Na+): Predominantly outside cells (extracellular).

• Potassium (K+): Predominantly inside cells (intracellular).

Exergonic and Endergonic Reactions

• Exergonic: Release energy (e.g., cellular respiration).

• Endergonic: Require energy input (e.g., protein synthesis).

Catabolic and Anabolic Reactions

• Catabolic: Break down molecules, releasing energy (e.g., hydrolysis).

• Anabolic: Build complex molecules, requiring energy (e.g., dehydration synthesis).

Types of Chemical Reactions

• Decomposition (Hydrolysis): Breaks molecules into smaller units; water is added.

• Synthesis (Dehydration Synthesis): Combines molecules; water is removed.

Factors Affecting Reaction Rates

• Temperature, concentration, particle size, catalysts (enzymes).

Enzymes and Catalysis

• Enzymes: Biological catalysts that speed up reactions by lowering activation energy.

• Mechanism: Bind substrates at the active site, facilitate reaction, release products.

• Metabolic Pathways: Series of enzyme-catalyzed reactions; allow regulation and efficiency.

Properties and Distribution of Water

• High heat capacity, solvent properties, reactivity, cushioning.

• Major component of cells and body fluids.

Solutions, Solvents, and Solutes

• Solution: Homogeneous mixture of solute dissolved in solvent.

• Solvent: Substance present in greatest amount (usually water).

• Solute: Substance dissolved in solvent.

Solutions, Colloids, and Suspensions

Type	Particle Size	Appearance	Example
Solution	Small	Clear	Salt water
Colloid	Intermediate	Cloudy	Milk
Suspension	Large	Settles out	Blood cells in plasma

Electrolytes

• Substances that dissociate into ions in water and conduct electricity (e.g., NaCl).

Hydrophobic and Hydrophilic Compounds

• Hydrophobic: Water-fearing; do not dissolve in water (e.g., lipids).

• Hydrophilic: Water-loving; dissolve in water (e.g., salts, sugars).

Acids, Bases, and Salts

• Acid: Releases H+ ions in solution (e.g., HCl).

• Base: Releases OH- ions or accepts H+ (e.g., NaOH).

• Salt: Ionic compound formed from acid-base reaction (e.g., NaCl).

pH Scale and H+/OH- Concentrations

• pH measures hydrogen ion concentration: $\mathrm{pH} = -\log_{10}[\mathrm{H}^+]$

• pH < 7: Acidic; pH = 7: Neutral; pH > 7: Basic

• As [H+] increases, pH decreases; as [OH-] increases, pH increases.

Buffers

• Compounds that resist changes in pH by absorbing or releasing H+ ions.

• Important for maintaining homeostasis (e.g., bicarbonate buffer system in blood).

Macromolecules: Carbohydrates, Proteins, Lipids, Nucleic Acids

• Carbohydrates: Sugars and starches; energy source (e.g., glucose).

• Proteins: Chains of amino acids; structural, enzymatic, regulatory roles (e.g., hemoglobin).

• Lipids: Fats, oils, steroids; energy storage, membrane structure (e.g., triglycerides).

• Nucleic Acids: DNA and RNA; genetic information storage and transfer.

Denaturation

• Loss of protein structure (and function) due to heat, pH, or chemicals.

• Example: Cooking an egg denatures albumin protein.

ATP: Energy Storage and Release

• Adenosine Triphosphate (ATP): Main energy currency of the cell.

• Energy is stored in high-energy phosphate bonds; released when ATP is hydrolyzed to ADP:

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$

• ATP powers cellular processes such as muscle contraction, active transport, and biosynthesis.