Chapter 1: The Human Body – An Orientation

Definitions of Anatomy and Physiology

Anatomy and physiology are foundational sciences in understanding the human body.

• 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; how the body parts work and carry out their life-sustaining activities.

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

Organ Systems: Identification and Functions

The human body is organized into organ systems, each with specific functions and major organs.

• Examples:

  • Cardiovascular System: Heart, blood vessels; transports blood.

  • Digestive System: Stomach, intestines; breaks down food.

  • Nervous System: Brain, spinal cord, nerves; controls responses.

Anatomical Terms and Body Position

Standard anatomical terms describe the locations and relationships of body parts.

• Proximal: Closer to the point of attachment.

• Superficial: Toward or at the body surface.

• Medial: Toward the midline of the body.

• Anatomical Position: Body erect, feet slightly apart, palms facing forward, thumbs pointing away from the body.

Body Cavities and Contained Organs

The body contains several major cavities, each housing specific organs.

• Dorsal Body Cavity: Contains the central nervous system (brain and spinal cord).

• Ventral Body Cavity: Includes thoracic and abdominopelvic cavities.

• Thoracic Cavity: Contains heart and lungs.

• Abdominopelvic Cavity: Contains digestive organs, urinary bladder, reproductive organs.

Homeostasis and Feedback Systems

Homeostasis is the maintenance of a stable internal environment.

• Definition: The body’s ability to maintain relatively stable internal conditions despite changes in the environment.

• Components of Homeostatic Control:

  1. Receptor: Detects changes (stimuli).

  2. Control Center: Processes information and determines response.

  3. Effector: Carries out the response.

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

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

Abdominopelvic Regions and Anatomical Landmarks

The abdominopelvic cavity is divided into nine regions for anatomical reference.

• Regions: Right/left hypochondriac, epigastric, right/left lumbar, umbilical, right/left iliac (inguinal), hypogastric.

Chapter 2: Chemistry

Forms of Energy and Subatomic Particles

Understanding basic chemistry is essential for studying physiology.

• Forms of Energy: Chemical, electrical, mechanical, and radiant energy.

• Subatomic Particles:

  • Proton: Positive charge (+1)

  • Neutron: No charge (0)

  • Electron: Negative charge (-1)

• Atomic Number: Number of protons in the nucleus.

• Atomic Weight: Sum of protons and neutrons.

Elements and Chemical Properties

• Element: A substance that cannot be broken down into simpler substances by ordinary chemical means.

• Atomic Symbol: One- or two-letter abbreviation for each element (e.g., H for hydrogen, O for oxygen).

• 13 Principal Elements in the Human Body: C, H, O, N, Ca, P, K, S, Na, Cl, Mg, I, Fe.

• Electrons determine an element’s chemical properties.

Chemical Bonds and Reactions

• Chemical Bonds:

  • Ionic Bonds: Transfer of electrons.

  • Covalent Bonds: Sharing of electrons.

  • Hydrogen Bonds: Weak attractions between polar molecules.

• Chemical Reactions: Synthesis, decomposition, and exchange reactions.

Properties of Water

• Unique Properties: High heat capacity, high heat of vaporization, universal solvent, reactivity, cushioning.

• Hydrogen Bonds: Responsible for water’s unique properties.

Organic Compounds and Macromolecules

• Organic Compounds: Contain carbon; include carbohydrates, lipids, proteins, nucleic acids.

• Carbohydrates:

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

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

  • Polysaccharides: Many monosaccharides (e.g., glycogen).

• Lipids: Fats and oils; saturated (no double bonds, solid at room temp) vs. unsaturated (one or more double bonds, liquid at room temp).

• Proteins: Made of amino acids; function as enzymes, structural components, etc.

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

DNA, RNA, and Enzymes

• DNA Base Pairing: Adenine–Thymine, Cytosine–Guanine.

• Differences between DNA and RNA: DNA is double-stranded, contains deoxyribose; RNA is single-stranded, contains ribose.

• Enzyme: A protein that acts as a biological catalyst, speeding up reactions by lowering activation energy.

pH Scale and Acids/Bases

• pH Scale: Measures hydrogen ion concentration; ranges from 0 (acidic) to 14 (basic), with 7 as neutral.

• Acid: pH < 7; Base: pH > 7; Neutral: pH = 7.

• Strength: Lower pH = stronger acid; higher pH = stronger base.

Chapter 3: Cells

Cell Structure and Organelles

The cell is the basic structural and functional unit of all living organisms.

• Cell (Plasma) Membrane: Phospholipid bilayer with embedded proteins; selectively permeable.

• Phospholipid: Hydrophilic (water-attracting) head and hydrophobic (water-repelling) tails.

• Cytoplasm: The liquid interior material of the cell, containing organelles.

• Nucleus: Contains DNA; includes nuclear envelope, nucleolus, chromatin.

• Organelles: Specialized structures (e.g., mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes).

Cellular Transport Mechanisms

• Diffusion: Movement of molecules from high to low concentration.

• Osmosis: Diffusion of water across a selectively permeable membrane.

• Active Transport: Movement of substances against concentration gradient, requires energy (ATP).

Cell Cycle and Mitosis

• Cell Cycle: Series of events that cells go through as they grow and divide.

• Phases: Interphase (cell spends most of its life here), Mitosis (division of nucleus), Cytokinesis (division of cytoplasm).

• Mitosis Stages (in order): Prophase, Metaphase, Anaphase, Telophase.

Solutions and Effects on Cells

• Isotonic: Same solute concentration as cell; no net water movement.

• Hypertonic: Higher solute concentration than cell; cell shrinks (crenates).

• Hypotonic: Lower solute concentration than cell; cell swells (may lyse).

Tissues: Types and Characteristics

• Tissue: A group of similar cells performing a common function.

• Four Types:

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

  • Connective: Supports, protects, binds other tissues.

  • Muscle: Produces movement.

  • Nervous: Transmits electrical impulses.

• Features of Epithelial Tissue: Cellularity, polarity, attachment, avascularity, regeneration, specialized contacts.

• Endocrine vs. Exocrine Glands: Endocrine secrete hormones into blood; exocrine secrete onto surfaces or into ducts.

• Connective Tissue: Tendons and ligaments are dense regular connective tissue; cartilage lacks blood vessels.

• Muscle Tissue: Skeletal (voluntary, striated), cardiac (involuntary, striated), smooth (involuntary, non-striated).

• Nervous Tissue: Contains neurons and supporting cells; specialized for communication.

Tissue Repair

• Steps of Tissue Repair (in order):

  1. Inflammation

  2. Organization (restores blood supply)

  3. Regeneration and fibrosis (permanent repair)