Anatomy & Physiology Study Guide: Chapters 1–4

Chapter 1: Organization of the Human Body

Levels of Organization

The human body is organized into hierarchical levels, each building upon the previous one to form a complete organism.

• Atom: The smallest unit of matter.

• Molecule: Two or more atoms bonded together.

• Cell: The basic structural and functional unit of life.

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

• Organ: Structures composed of two or more tissue types working together.

• Organ System: Groups of organs that perform related functions.

• Organism: The complete living being.

Example: Muscle cell → muscle tissue → biceps brachii (organ) → muscular system → human organism.

Major Organ Systems and Their Functions

The body contains several organ systems, each with specific functions essential for survival.

Organ System	Main Functions
Cardiovascular	Transports oxygen, nutrients, hormones, and waste products throughout the body.
Respiratory	Facilitates gas exchange (oxygen in, carbon dioxide out) through the lungs.
Digestive	Breaks down food into nutrients for energy, growth, and cell repair.
Nervous	Controls body activities with electrical signals; processes sensory information.
Muscular	Contracts to enable movement, maintains posture, and generates heat.
Skeletal	Provides structure, protects organs, and produces blood cells.
Endocrine	Regulates body functions through hormones (growth, metabolism, reproduction).
Urinary	Removes metabolic waste, maintains water and electrolyte balance.
Reproductive	Enables reproduction and production of sex hormones.
Lymphatic	Returns fluid to the bloodstream and supports immune function.
Integumentary	Protects the body, regulates temperature, and provides sensory information.

Homeostasis

Homeostasis is the maintenance of relatively stable internal conditions necessary for normal body functioning and survival.

• Receptor: Detects changes.

• Control Center: Determines the set point.

• Effector: Produces a response.

Feedback mechanisms:

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

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

Body Cavities and Membranes

• Dorsal cavity: Cranial and vertebral cavities.

• Ventral cavity: Thoracic and abdominopelvic cavities.

• Serous membranes: Line body cavities and cover organs (pleura, pericardium, peritoneum).

Chapter 2: Introductory Chemistry

Atoms and Elements

Atoms are the smallest units of matter, composed of protons, neutrons, and electrons.

• Protons: Positively charged, found in the nucleus.

• Neutrons: No charge, found in the nucleus.

• Electrons: Negatively charged, orbit the nucleus.

Ions and Chemical Bonds

• Ions: Atoms with a charge due to loss or gain of electrons.

• Ionic bonds: Transfer of electrons (e.g., NaCl).

• Covalent bonds: Sharing of electrons.

• Polar covalent: Unequal sharing, creating partial charges (e.g., H2O).

• Nonpolar covalent: Equal sharing of electrons.

Water, Acids, Bases, and Salts

• Water: Most abundant inorganic compound; high heat capacity, solvent, cushioning.

• Acids: Release H+ ions. $\text{Acid} \rightarrow \text{H}^+ + \text{Anion}$

• Bases: Bind H+ or release OH-. $\text{Base} \rightarrow \text{Cation} + \text{OH}^-$

• Salts: Dissociate into ions other than H+ or OH-.

pH scale: 0–14; Acidic < 7, Neutral = 7, Basic > 7

Organic Molecules

• Carbohydrates: Store energy (e.g., glucose, starch).

• Lipids: Energy storage, insulation, cell membranes (e.g., triglycerides, phospholipids).

• Proteins: Structure, enzymes, hormones.

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

DNA, RNA, and ATP

• DNA: Double-stranded, contains genetic instructions. Bases: adenine (A), thymine (T), cytosine (C), guanine (G). A pairs with T, C pairs with G.

• RNA: Single-stranded, involved in protein synthesis. Bases: adenine (A), uracil (U), cytosine (C), guanine (G). A pairs with U, C pairs with G.

• ATP: Main energy currency of the cell. Energy is released by breaking high-energy phosphate bonds. $\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$

Chapter 3: Cells and Tissues

Cell Structures and Functions

• Mitochondria: Produce ATP (energy).

• Ribosomes: Protein synthesis.

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

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

• Lysosomes: Digestive enzymes, breakdown of waste.

Plasma Membrane and Transport

The plasma membrane is selectively permeable, controlling the movement of substances in and out of the cell.

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

• Active transport: Requires ATP (e.g., sodium-potassium pump).

• Endocytosis: Engulfing substances into the cell (phagocytosis, pinocytosis).

• Exocytosis: Expelling substances from the cell.

Protein Synthesis

• Transcription: DNA → mRNA (in nucleus).

• Translation: mRNA → protein (at ribosome).

• DNA replication: Copying DNA before cell division.

Cell Cycle and Division

• Interphase: Cell grows, DNA replicates.

• Mitosis: Division of the nucleus (prophase, metaphase, anaphase, telophase).

• Cytokinesis: Division of the cytoplasm, forming two daughter cells.

Example: During mitosis, chromosomes condense, align at the cell equator, separate, and move to opposite poles, resulting in two genetically identical cells.

Chapter 4: Integumentary System

Skin and Body Membranes

The integumentary system includes the skin and its associated structures, providing protection, temperature regulation, and sensory information.

• Epidermis: Outer layer, provides a barrier.

• Dermis: Middle layer, contains blood vessels, nerves, glands.

• Hypodermis: Subcutaneous layer, stores fat and insulates.

• Functions: Protection, sensation, thermoregulation, vitamin D synthesis.

Body Membranes

• Serous membranes: Line body cavities not open to the outside (pleura, pericardium, peritoneum).

• Mucous membranes: Line cavities open to the exterior (digestive, respiratory tracts).

• Cutaneous membrane: The skin.

• Synovial membranes: Line joint cavities.

Homeostatic Imbalances

• Burns, infections, and skin cancers are examples of conditions affecting the integumentary system.

Additional info: For exam preparation, focus on understanding definitions, processes (such as homeostasis and protein synthesis), and the functions of each organ system. Practice applying concepts to scenarios, such as predicting the movement of substances across membranes or identifying the effects of pH changes on biological molecules.