Introduction to Anatomy & Physiology

This study guide covers foundational concepts, terminology, and systems relevant to a college-level Anatomy & Physiology course. It is organized by major topics and subtopics, providing definitions, examples, and key facts essential for exam preparation.

Cellular and Organismal Functions

Basic Life Processes

• Cell: The smallest unit capable of carrying out the functions of life.

• Metabolism: The sum of all chemical reactions in the body.

• Growth: Increase in size of individual cells or in the number of cells.

• Excretion: Removal of waste products from the body.

• Responsiveness: Sensing and reacting to changes in the environment.

• Movement: Ability of an organism or its parts to move.

• Reproduction: Production of new cells within an organism or the production of offspring.

Levels of Structural Organization

• Chemicals → Cells → Tissues → Organs → Organ Systems → Organism

• Each level builds upon the previous, increasing in complexity.

Major Organ Systems

Overview of Organ Systems

• Integumentary System: Skin and accessory organs; protects the body, retains water, regulates temperature, and produces vitamin D.

• Skeletal System: Bones and associated cartilages; supports the body, protects organs, provides leverage, produces blood cells, and stores calcium salts.

• Muscular System: Skeletal muscles and associated connective tissues; produces movement, controls body openings, and generates heat.

• Lymphatic System: Lymph nodes, vessels, spleen, tonsils, thymus; returns excess fluid to the cardiovascular system and provides immunity.

• Respiratory System: Delivers oxygen to blood, removes carbon dioxide.

• Digestive System: Alimentary canal and accessory organs; digests food, absorbs nutrients, removes waste.

• Nervous System: Brain, spinal cord, nerves; regulates body functions, sensation, movement, and higher mental functions.

• Endocrine System: Glands that secrete hormones influencing other cells and tissues.

• Cardiovascular System: Heart and blood vessels; delivers and drains blood, transports nutrients and wastes.

• Urinary System: Kidneys, ureters, bladder, urethra; removes metabolic wastes, regulates fluid, electrolytes, acid-base balance, and stimulates red blood cell production.

• Reproductive System: Sex organs; produces gametes and hormones, allows for offspring production.

Anatomical Terminology

Fields of Study

• Gross Anatomy: Study of structures visible to the naked eye.

• Microscopic Anatomy: Study of structures only visible with a microscope.

• Histology: Study of tissues.

• Cytology: Study of cells.

Body Positions and Directions

• Anatomical Position: Standing upright, feet shoulder-width apart, arms at sides, palms facing forward.

• Anterior (ventral): Toward the front.

• Posterior (dorsal): Toward the back.

• Superior (cranial): Toward the head.

• Inferior (caudal): Toward the tail.

• Proximal: Closer to the point of origin (usually the trunk).

• Distal: Farther from the point of origin.

• Medial: Toward the midline.

• Lateral: Away from the midline.

• Superficial: Closer to the surface.

• Deep: Farther from the surface or more internal.

Body Planes and Sections

• Sagittal Plane: Divides body into right and left portions.

• Midsagittal Plane: Divides body into equal right and left halves.

• Parasagittal Plane: Divides body into unequal right and left portions.

• Frontal (Coronal) Plane: Divides body into anterior and posterior portions.

• Transverse (Horizontal) Plane: Divides body into superior and inferior portions.

Body Cavities and Membranes

Major Body Cavities

• Cavity: Any fluid-filled space within the body.

• Dorsal Body Cavity: Includes cranial and vertebral (spinal) cavities.

• Cranial Cavity: Houses the brain.

• Spinal Cavity: Houses the spinal cord.

• Ventral Body Cavity: Includes thoracic and abdominopelvic cavities.

• Thoracic Cavity: Includes pleural, mediastinum, and pericardial cavities.

• Pleural Cavities: Surround each lung.

• Mediastinum: Central thoracic cavity between the lungs.

• Pericardial Cavity: Potential space between parietal and visceral pericardial membranes; contains serous fluid and surrounds the heart.

• Abdominopelvic Quadrants: Used to localize problems; include upper right, upper left, lower right, lower left.

Membranes

• Serous Membranes: Thin sheets of tissue that envelope organs and produce serous fluid.

• Parietal Layer: Lines the cavity wall.

• Visceral Layer: Covers the organ.

Homeostasis and Feedback Mechanisms

Homeostasis

• Homeostasis: Maintenance of a stable internal environment.

• Homeostatic Imbalances: Disturbances that can lead to disease or death if uncorrected.

Feedback Loops

• Negative Feedback Loop: Response reverses the initial change, maintaining homeostasis. Example: Regulation of body temperature.

• Positive Feedback Loop: Response amplifies the initial change. Example: Blood clotting, childbirth.

Basic Chemistry for Anatomy & Physiology

Atoms and Elements

• Matter: Anything with mass and volume.

• Chemistry: Study of matter and its interactions.

• Atom: Smallest unit of matter retaining its properties.

• Protons: Positively charged subatomic particles in the nucleus.

• Neutrons: Neutrally charged subatomic particles in the nucleus.

• Electrons: Negatively charged subatomic particles in electron shells.

• Electron Shells: First shell holds 2 electrons, second holds 8, third holds up to 18.

• Atomic Number: Number of protons.

• Mass Number: Number of protons plus neutrons.

• Isotope: Element with same number of protons but different number of neutrons.

• Major Elements in Human Body: Carbon, Hydrogen, Oxygen, Nitrogen (CHON).

Mixtures and Solutions

• Suspension: Large, unevenly distributed particles that settle out.

• Colloid: Small, evenly distributed particles that do not settle out.

• Solution: Extremely small, evenly distributed particles that do not settle out.

Chemical Bonds

• Molecule: Two or more atoms bonded together.

• Compound: Two or more atoms of different elements bonded together.

• Inert Element: Unreactive due to a full outer shell of electrons.

• Ionic Bond: Electrons transferred from a metal to a nonmetal atom.

• Ion: Charged particle (cation: positive, anion: negative).

• Covalent Bond: Sharing of electrons.

• Nonpolar Covalent Bond: Equal sharing of electrons.

• Polar Covalent Bond: Unequal sharing of electrons.

• Hydrogen Bond: Weak attraction between partially positive and negative ends of dipoles; responsible for water's surface tension.

Chemical Reactions and Energy

• Chemical Reaction: Bonds are formed, broken, or rearranged; electrons are transferred.

• Reactants: Substances entering a reaction.

• Products: Substances produced by a reaction.

• Energy: Capacity to do work.

• Kinetic Energy: Energy of motion.

• Potential Energy: Stored energy.

• Endergonic Reaction: Requires input of energy.

• Exergonic Reaction: Releases excess energy.

• Anabolic Reaction: Builds up molecules (synthesis).

• Oxidation-Reduction (Redox) Reaction: Electrons are transferred; oxidation is loss, reduction is gain of electrons.

• Enzyme: Biological catalyst that lowers activation energy and is not consumed in the reaction.

Inorganic and Organic Compounds

• Inorganic Compounds: Generally do not contain carbon bonded to hydrogen (e.g., water, acids, bases, salts).

• Organic Compounds: Contain carbon bonded to hydrogen.

• Water: Makes up 60-80% of body mass; high heat capacity, evaporative cooling, cushioning, solvent properties.

• Hydrophilic: Water-loving.

• Hydrophobic: Water-fearing.

• Acid: Releases hydrogen ions in solution (pH < 7).

• Base: Accepts hydrogen ions or releases hydroxide ions (pH > 7).

• pH Scale: Measures hydrogen ion concentration; scale from 0-14, 7 is neutral. Blood pH is 7.35-7.45.

• Buffer: Resists changes in pH.

Macromolecules

• Monomers: Single subunits that can combine to form polymers.

• Dehydration Synthesis: Builds polymers from monomers by removing water.

• Hydrolysis: Breaks down polymers by adding water.

• Carbohydrates: Organic molecules composed of carbon, hydrogen, and oxygen (often in a 1:2:1 ratio).

• Monosaccharide: Simple sugar monomer.

• Polysaccharide: Large carbohydrate made of many monosaccharides.

*Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard Anatomy & Physiology curricula.*