Introduction to Anatomy and Physiology

Definitions and Core Concepts

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

• Physiology: The study of the function of the body and how its parts work together to carry out life-sustaining activities.

• Structure supports function: The form of a body part is directly related to its function. For example, the thin walls of alveoli in the lungs facilitate gas exchange.

Levels of Organization

• 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

The 11 Organ Systems

• Integumentary: Skin, hair, nails; protection, temperature regulation

• Skeletal: Bones, joints; support, movement, protection

• Muscular: Skeletal muscles; movement, heat production

• Nervous: Brain, spinal cord, nerves; control, communication

• Endocrine: Glands (pituitary, thyroid, etc.); hormone production

• Cardiovascular: Heart, blood vessels; transport of nutrients and gases

• Lymphatic/Immune: Lymph nodes, spleen; defense, fluid balance

• Respiratory: Lungs, airways; gas exchange

• Digestive: Stomach, intestines; nutrient breakdown and absorption

• Urinary: Kidneys, bladder; waste elimination, water balance

• Reproductive: Ovaries/testes; production of offspring

Anatomical Terminology and Body Cavities

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

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

• Membranes: Serous membranes (pleura, pericardium, peritoneum) line body cavities and cover organs

Homeostasis

• Definition: The maintenance of a stable internal environment despite external changes

• Components: Receptor, control center, effector

Feedback Mechanisms

• Negative feedback: Reduces the effect of the stimulus (e.g., body temperature regulation)

• Positive feedback: Enhances the effect of the stimulus (e.g., blood clotting, labor contractions)

The Chemistry of Life

Basic Chemistry Concepts

• Mass: The amount of matter in an object

• Element: A substance that cannot be broken down by chemical means

• Atom: The smallest unit of an element

• Molecule: Two or more atoms bonded together

• Compound: A molecule containing two or more different elements

Atomic Structure

• Proton: Positive charge, located in nucleus

• Neutron: No charge, located in nucleus

• Electron: Negative charge, orbits nucleus

• Atomic number: Number of protons

• Mass number: Protons + neutrons

• Valence electrons: Electrons in the outermost shell, determine chemical reactivity

• Ions: Atoms with a charge (cations: positive, anions: negative)

Types of Chemical Bonds

• Ionic bonds: Transfer of electrons between atoms

• Covalent bonds: Sharing of electrons between atoms

• Hydrogen bonds: Weak attractions between polar molecules

Forms of Energy in the Body

• Chemical energy: Stored in bonds of molecules

• Electrical energy: Movement of charged particles

• Mechanical energy: Directly involved in moving matter

• Potential energy: Stored energy

• Kinetic energy: Energy of motion

Properties of Water

• High heat capacity, solvent properties, reactivity, cushioning

Inorganic vs. Organic Compounds

• Inorganic: Usually lack carbon (e.g., water, salts, acids, bases)

• Organic: Contain carbon and hydrogen (e.g., carbohydrates, lipids, proteins, nucleic acids)

Major Biological Molecules

• Carbohydrates: Sugars and starches; energy source

• Lipids: Fats, oils, steroids; energy storage, membrane structure

• Proteins: Chains of amino acids; structure, enzymes, signaling

• Nucleic acids: DNA and RNA; genetic information

Salts/Electrolytes, Acids, Bases, and Buffers

• Salts/electrolytes: Dissociate into ions in water; important for nerve and muscle function

• Acids: Release H+ ions; Bases: Accept H+ ions

• Buffers: Resist changes in pH

• pH scale: Measures hydrogen ion concentration; 0 (acidic) to 14 (basic), 7 is neutral

The Cell

Cell Structures and Organelles

• Plasma membrane: Selective barrier, regulates entry/exit

• Cytoplasm: Fluid and organelles inside the cell

• Nucleus: Contains DNA, controls cell activities

• Ribosomes: Protein synthesis

• Rough ER: Protein modification, has ribosomes

• Smooth ER: Lipid synthesis, detoxification

• Golgi apparatus: Modifies, sorts, packages proteins/lipids

• Mitochondria: ATP production (cellular respiration)

• Lysosomes: Digestive enzymes, breakdown waste

• Peroxisomes: Detoxify harmful substances

• Cytoskeleton: Structural support, cell movement

• Centrioles: Organize cell division

• Cilia: Move substances across cell surface

• Flagella: Cell movement (e.g., sperm)

Membrane Transport

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

• Active transport: Requires energy (ATP); moves substances against concentration gradient

• Osmosis: Diffusion of water across a membrane

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

Protein Synthesis

• Transcription: DNA → mRNA (in nucleus)

• Translation: mRNA → protein (at ribosome)

• mRNA: Messenger RNA, carries code from DNA

• tRNA: Transfer RNA, brings amino acids

• rRNA: Ribosomal RNA, part of ribosome structure

• Central Dogma:

Cell Cycle and Mitosis

• Cell cycle: G1 (growth), S (DNA replication), G2 (preparation), Mitosis, Cytokinesis

• Mitosis stages: Prophase, Metaphase, Anaphase, Telophase (PMAT)

• Dysregulation: Can lead to uncontrolled cell division (cancer)

Histology: The Study of Tissues

The Four Basic Tissue Types

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

• Connective tissue: Supports, protects, binds other tissues

• Muscle tissue: Movement, contractility

• Nervous tissue: Communication, control

Classification of Epithelial Tissues

• By layers: Simple (one layer), Stratified (multiple layers)

• By shape: Squamous (flat), Cuboidal (cube-shaped), Columnar (tall)

Major Tissue Subtypes: Structure, Location, Function

• Simple squamous epithelium: Thin, allows diffusion (e.g., alveoli)

• Stratified squamous epithelium: Protection (e.g., skin, mouth)

• Areolar connective tissue: Loose, supports organs

• Adipose tissue: Stores fat, insulates

• Dense regular connective tissue: Tendons, ligaments

• Cartilage: Flexible support (e.g., nose, ears)

• Bone: Rigid support, mineral storage

• Blood: Transport of gases, nutrients

• Skeletal muscle: Voluntary movement

• Cardiac muscle: Heart contraction

• Smooth muscle: Involuntary movement (e.g., digestive tract)

• Neurons: Transmit electrical signals

• Neuroglia: Support neurons

Exocrine vs. Endocrine Glands

• Exocrine glands: Secrete products into ducts (e.g., sweat, saliva)

• Endocrine glands: Secrete hormones into blood

Muscle Types and Tissue Repair

• Skeletal muscle: Striated, voluntary

• Cardiac muscle: Striated, involuntary, intercalated discs

• Smooth muscle: Non-striated, involuntary

• Tissue repair stages: Inflammation, organization, regeneration/fibrosis

Body Membranes

• Mucous membranes: Line body cavities open to exterior

• Serous membranes: Line closed body cavities, secrete serous fluid

• Cutaneous membrane: The skin

• Synovial membranes: Line joint cavities