Anatomy & Physiology: Foundational Concepts and Cellular Structure

Introduction to Anatomy & Physiology

Anatomy and Physiology (A&P) are foundational sciences in understanding the structure and function of the human body. This guide covers essential terminology, concepts, and processes relevant to introductory college-level A&P courses.

Key Terminology

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of the body’s structural machinery.

• Directional Terms: Terms such as cranial, caudal, dorsal, ventral, medial, lateral, proximal, distal, superior, inferior, anterior, posterior, etc., describe locations and relationships of body parts.

• Body Planes: Sagittal, coronal (frontal), and transverse planes divide the body for anatomical study.

• Homeostasis: The maintenance of a stable internal environment.

• Feedback Mechanisms: Processes that maintain homeostasis, including positive and negative feedback.

Chapter 1: Introduction to Anatomy & Physiology

Distinguishing Anatomy and Physiology

• Anatomy focuses on body structure, while physiology examines function.

• Example: Studying the heart’s chambers (anatomy) vs. understanding how the heart pumps blood (physiology).

Structure and Function Relationship

• Structure determines function; the shape and composition of a body part enable its role.

• Example: The thin walls of alveoli in the lungs facilitate gas exchange.

Levels of Organization

• From simplest to most complex: chemical, cellular, tissue, organ, organ system, organism.

• Example: Muscle cell (cellular) → muscle tissue → biceps brachii (organ) → muscular system.

Directional Terms and Body Planes

• Directional terms describe positions (e.g., medial vs. lateral, proximal vs. distal).

• Body planes:

  • Sagittal: Divides body into left and right.

  • Coronal (frontal): Divides body into anterior and posterior.

  • Transverse: Divides body into superior and inferior.

Body Cavities and Membranes

• Body cavities: Dorsal (cranial and vertebral) and ventral (thoracic and abdominopelvic).

• Serous membranes: Line body cavities and cover organs; include parietal (lines cavity) and visceral (covers organ) layers.

• Example: The pericardium surrounds the heart.

Homeostasis and Feedback

• Homeostasis: Maintains internal stability (e.g., temperature, pH).

• Negative feedback: Reverses a change (e.g., body temperature regulation).

• Positive feedback: Enhances a change (e.g., blood clotting).

Anatomical Landmarks

• Recognize key surface features and regions for orientation and clinical reference.

Chapter 2: Basic Chemistry for Anatomy & Physiology

Key Chemical Terminology

• Covalent bond: Atoms share electrons.

• Ionic bond: Transfer of electrons between atoms.

• Hydrogen bond: Weak attraction between polar molecules.

• Hydrophilic vs. Hydrophobic: Water-loving vs. water-fearing substances.

• Isotopes: Atoms with the same number of protons but different neutrons.

Chemical Bonds and Water

• Covalent bonds are strong and form molecules like water ($H_2O$).

• Hydrogen bonds are weaker but crucial for properties of water and DNA structure.

• Example: Water’s high heat capacity and solvent properties are due to hydrogen bonding.

Acids, Bases, and pH

• Acid: Releases $H^+$ ions in solution.

• Base: Accepts $H^+$ ions or releases $OH^-$.

• pH scale: Measures hydrogen ion concentration; $pH = -\log[H^+]$.

• Example: Blood pH is tightly regulated around 7.4.

Organic Molecules and Functional Groups

• Organic molecules contain carbon; key groups include hydroxyl, carboxyl, amino, phosphate, methyl, etc.

• Functional groups determine chemical reactivity and biological function.

Chapter 3: The Cell and Its Environment

Cell Structure and the Fluid Mosaic Model

• Plasma membrane: Phospholipid bilayer with embedded proteins; selectively permeable.

• Fluid mosaic model: Describes the dynamic arrangement of lipids and proteins.

Cellular Organelles

• Nucleus: Contains DNA, controls cell activities.

• Mitochondria: Site of ATP production.

• Endoplasmic reticulum, Golgi apparatus, lysosomes: Involved in synthesis, modification, and transport of biomolecules.

Transport Across Membranes

• Passive transport: Diffusion, osmosis, facilitated diffusion (no energy required).

• Active transport: Requires ATP to move substances against gradients.

• Endocytosis/Exocytosis: Bulk transport into/out of cells.

Osmosis and Tonicity

• Osmosis: Diffusion of water across a semipermeable membrane.

• Tonicity: Effect of solution on cell volume:

  • Isotonic: No net water movement.

  • Hypotonic: Water enters cell; cell swells.

  • Hypertonic: Water leaves cell; cell shrinks.

Macromolecules: Proteins, Nucleic Acids, Carbohydrates, Lipids

• Proteins: Polymers of amino acids; structure (primary, secondary, tertiary, quaternary) determines function.

• Carbohydrates: Energy source; includes monosaccharides, disaccharides, polysaccharides.

• Lipids: Fats, phospholipids, steroids; important for membranes and energy storage.

• Nucleic acids: DNA and RNA; store and transmit genetic information.

Enzymes and Metabolism

• Enzymes: Biological catalysts that speed up chemical reactions.

• Factors affecting enzyme activity: Temperature, pH, substrate concentration.

• ATP: Main energy currency of the cell.

Summary Table: Types of Transport Across Cell Membranes

Type	Energy Required?	Direction	Example
Simple Diffusion	No	High to Low	Oxygen, CO2
Facilitated Diffusion	No	High to Low	Glucose via carrier proteins
Osmosis	No	High to Low (water)	Water movement
Active Transport	Yes (ATP)	Low to High	Sodium-potassium pump
Endocytosis/Exocytosis	Yes (ATP)	Bulk transport	Phagocytosis, neurotransmitter release

Additional info:

• Some content was expanded for clarity and completeness, such as definitions and examples of feedback mechanisms, membrane transport, and macromolecule structure.