Chapter 1: Introduction to Anatomy & Physiology

Selected Branches of Anatomy & Physiology

Anatomy and physiology are broad fields with several specialized branches, each focusing on different aspects of 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.

• Branches: Examples include gross anatomy, microscopic anatomy, developmental anatomy, and systemic physiology.

Levels of Organization

The human body is organized into hierarchical levels, each building upon the previous one.

• Chemical level: Atoms and molecules

• Cellular level: Cells and their organelles

• Tissue level: Groups of similar cells

• Organ level: Contains two or more types of tissues

• Organ system level: Organs that work closely together

• Organismal level: All organ systems combined to make the whole organism

Body Systems

The body is composed of several systems, each with specific components and functions.

• Examples: Integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive systems.

• Function: Each system contributes to homeostasis and overall health.

Basic Life Processes

Life processes are essential functions carried out by living organisms.

• Examples: Metabolism, responsiveness, movement, growth, differentiation, reproduction.

Homeostasis

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

• Control of Homeostasis: Involves receptors, control center, and effectors.

• Feedback Loops:

  • Negative feedback: Reverses a change to keep a variable within a normal range (e.g., body temperature regulation).

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

Basic Anatomical Terminology

Standardized terms are used to describe body positions, regions, and directions.

• Anatomical position: Body erect, facing forward, arms at sides, palms forward.

• Regional names: Specific areas of the body (e.g., brachial for arm).

• Directional terms: Describe positions (e.g., superior, inferior, anterior, posterior).

• Body planes: Sagittal, frontal, transverse, and oblique planes.

• Body cavities: Spaces within the body that contain organs (e.g., cranial, thoracic, abdominal cavities).

Serous Membranes

Serous membranes line body cavities and cover organs, producing serous fluid to reduce friction.

• Examples: Pleura (lungs), pericardium (heart), peritoneum (abdominal organs).

Chapter 2: Chemical and Molecular Basis of Life

Elements of the Human Body

The human body is composed of a limited number of chemical elements, with four making up about 96% of body mass: oxygen, carbon, hydrogen, and nitrogen.

Atoms & Subatomic Particles

Atoms are the smallest units of matter, consisting of subatomic particles.

• Atomic number: Number of protons in the nucleus.

• Mass number: Sum of protons and neutrons.

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

Ions, Molecules & Compounds

Ions are charged atoms or molecules; compounds are substances formed from two or more elements.

• Ions: Cations (positive), anions (negative).

• Molecules: Two or more atoms bonded together.

• Compounds: Molecules composed of different elements.

Chemical Bonds & Octet Rule

Chemical bonds hold atoms together in molecules and compounds.

• Ionic bonds: Transfer of electrons from one atom to another.

• Covalent bonds: Sharing of electron pairs between atoms.

• Hydrogen bonds: Weak attractions between hydrogen and electronegative atoms.

• Octet Rule: Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.

Chemical Reactions

Chemical reactions involve the making or breaking of bonds between atoms.

• Forms of energy: Kinetic, potential, chemical, electrical, etc.

• Energy transfer: Exergonic (release energy), endergonic (require energy).

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

Inorganic Compounds: Water

Water is the most abundant inorganic compound in the body and is essential for life.

• Properties of water:

  • Excellent solvent

  • Participates in chemical reactions (e.g., hydrolysis, dehydration synthesis)

  • High heat capacity and heat of vaporization

Acids, Bases, & Salts

Acids, bases, and salts are important inorganic compounds in the body.

• pH: Measure of hydrogen ion concentration; scale from 0 (acidic) to 14 (basic).

• Electrolytes: Substances that dissociate into ions in solution and conduct electricity.

Organic Compounds

Organic compounds contain carbon and are essential for structure and function in living organisms.

• Carbohydrates: Monosaccharides, disaccharides, polysaccharides; provide energy.

• Lipids: Fatty acids, triglycerides, phospholipids; important for energy storage and membrane structure.

• Proteins: Made of amino acids; serve as enzymes, structural components, and signaling molecules.

  • Structural organization: primary, secondary, tertiary, quaternary structures.

  • Enzymes: Biological catalysts that speed up reactions.

• Nucleic acids: DNA, RNA (three types: mRNA, tRNA, rRNA), and ATP; store and transfer genetic information and energy.

Chapter 3: The Cell

Parts of a Cell

Cells are the basic structural and functional units of life, composed of various parts with specialized functions.

• Plasma membrane: Encloses the cell, regulates entry and exit of substances.

• Structure & function: Phospholipid bilayer with embedded proteins.

• Membrane proteins: Serve as channels, receptors, enzymes, and anchors.

• Membrane permeability: Selective; allows some substances to pass more easily than others.

Transport Across the Plasma Membrane

Substances move across the plasma membrane by various mechanisms.

• Concentration gradient: Difference in concentration of a substance across a space.

• Passive transport: Does not require energy.

  • Osmosis: Movement of water across a membrane.

  • Diffusion: Movement of molecules from high to low concentration (simple and facilitated).

  • Tonicity: Effect of solution on cell volume (isotonic, hypotonic, hypertonic).

• Active transport: Requires energy (ATP).

  • Primary active transport: Direct use of ATP (e.g., sodium-potassium pump).

  • Secondary active transport: Uses energy from ion gradients.

• Vesicular transport: Movement of substances in vesicles (endocytosis, exocytosis).

Structures of a Cell

Cells contain various organelles, each with specific functions.

• Cytoplasm: Jelly-like fluid inside the cell containing organelles.

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

Protein Synthesis

Protein synthesis is the process by which cells build proteins based on genetic instructions.

• Transcript: The process of copying DNA to mRNA.

• Translation: The process of assembling proteins from mRNA at the ribosome.

• Modification after translation: Proteins may undergo folding and chemical modifications.

DNA Replication and Cell Division

Cells reproduce by duplicating their DNA and dividing into two daughter cells.

• DNA replication: The process of copying DNA before cell division.

• Cell division: Includes mitosis (nuclear division) and cytokinesis (cytoplasmic division).

• Cell cycle: Series of events that cells go through as they grow and divide (interphase, mitosis, cytokinesis).

• Interphase: Period of cell growth and DNA replication.

Additional info: These notes are based on a course outline or syllabus, summarizing the foundational topics in Anatomy & Physiology, including chemical, cellular, and systemic organization. For detailed mechanisms, refer to the relevant textbook chapters or lecture materials.