Anatomy and Physiology: Foundations, Chemistry, and Biomolecules Study Guide

Anatomy and Physiology: Foundations

Define Anatomy and Physiology and Their Subdivisions

Anatomy and physiology are two closely related branches of biology that study the structure and function of the human body.

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

  • Gross (macroscopic) anatomy: Visible to the naked eye (e.g., regional, systemic, surface anatomy).

  • Microscopic anatomy: Requires a microscope (e.g., cytology—cells, histology—tissues).

  • Developmental anatomy: Changes from conception to adulthood (embryology).

• Physiology: The study of the function of body parts.

  • Subdivisions are often based on organ systems (e.g., cardiovascular physiology, neurophysiology).

Principle of Complementarity

Structure and function are closely related; the function of a body part depends on its structure, and vice versa.

• Key Point: Anatomical structure enables physiological function.

• Example: The thin walls of alveoli in the lungs facilitate gas exchange.

Levels of Structural Organization in the Human Body

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

Level	Description
Chemical	Atoms and molecules
Cellular	Cells, the smallest living units
Tissue	Groups of similar cells performing a function
Organ	Structures composed of two or more tissue types
Organ System	Organs that work closely together
Organismal	The whole living body

Each level builds on the previous one; cells make tissues, tissues make organs, organs make systems, systems make the organism.

Functional Characteristics Necessary to Maintain Life

Several essential functions are required for life.

• Maintaining boundaries: Separation between internal and external environments (e.g., skin).

• Movement: Of body parts and substances within the body.

• Responsiveness: Ability to detect and respond to stimuli.

• Digestion: Breakdown of food.

• Metabolism: All chemical reactions in the body.

• Excretion: Removal of wastes.

• Reproduction: Production of offspring.

• Growth: Increase in size and number of cells.

Interdependence of Cells

Cells rely on each other to function properly.

• Example: Muscle cells need nutrients delivered by blood cells; red blood cells carry oxygen, which is essential for all other cells' metabolism.

The 11 Organ Systems and Their Major Organs

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

System	Major Organs	Function
Integumentary	Skin, hair, nails	Protection, temperature regulation
Skeletal	Bones, joints	Support, protection, blood formation
Muscular	Skeletal muscles	Movement, posture, heat production
Nervous	Brain, spinal cord, nerves	Control and communication
Endocrine	Glands (pituitary, thyroid, adrenal, pancreas)	Hormone production and regulation
Cardiovascular	Heart, blood vessels	Transport of nutrients and wastes
Lymphatic	Lymph nodes, lymphatic vessels, spleen	Immunity, fluid balance
Respiratory	Lungs, trachea, bronchi	Gas exchange
Digestive	Stomach, intestines, liver, pancreas	Breakdown and absorption of food
Urinary	Kidneys, bladder	Waste elimination, fluid balance
Reproductive	Ovaries, testes, uterus, prostate	Production of offspring

Survival Needs of the Body

Several factors are necessary for survival.

• Nutrients: Chemicals for energy and cell building.

• Oxygen: For energy production (cellular respiration).

• Water: Essential for chemical reactions and transport.

• Appropriate atmospheric pressure: Needed for breathing and gas exchange.

Homeostasis and Its Significance

Homeostasis is the ability to maintain a stable internal environment despite external changes.

• Significance: Vital for survival and function of cells; imbalance can lead to disease or death.

Negative and Positive Feedback in Homeostasis

• Negative Feedback: The output reduces the original stimulus (e.g., body temperature regulation, blood sugar control). Most common.

• Positive Feedback: The output enhances or amplifies the original stimulus (e.g., childbirth contractions, blood clotting).

Homeostatic Imbalance and Disease

• When homeostasis fails, it results in illness or disease.

• Example: Diabetes results from failure to regulate blood sugar.

Anatomical Position and Directional Terms

Standard anatomical position and directional terms are used to describe locations and relationships in the body.

• Anatomical Position: Standing upright, feet parallel, arms at sides, palms facing forward, thumbs pointing away from the body.

• Directions:

  • Superior (above), Inferior (below)

  • Anterior (front), Posterior (back)

  • Medial (towards midline), Lateral (away from midline)

  • Proximal (near origin), Distal (far from origin)

  • Superficial (towards surface), Deep (away from surface)

• Regions: Head, neck, trunk (thorax, abdomen, pelvis), upper limbs, lower limbs.

• Planes:

  • Sagittal (left/right)

  • Frontal (anterior/posterior)

  • Transverse (top/bottom)

Major Body Cavities, Subdivisions, and Membranes

Cavity	Subdivisions	Membranes	Major Organs
Dorsal	Cranial and vertebral	Meninges	Brain, spinal cord
Ventral	Thoracic and abdominopelvic	Pleura, pericardium, peritoneum	Lungs, heart, digestive organs

Abdominopelvic Quadrants and Regions

• Four Quadrants:

  • Left Upper Quadrant (LUQ): Stomach, spleen

  • Right Upper Quadrant (RUQ): Liver, gallbladder

  • Right Lower Quadrant (RLQ): Appendix, intestines

  • Left Lower Quadrant (LLQ): Intestines, reproductive organs

• Nine Regions:

  • Right Hypochondriac, Epigastric, Left Hypochondriac

  • Right Lumbar, Umbilical, Left Lumbar

  • Right Iliac (inguinal), Hypogastric, Left Iliac (inguinal)

Chemistry and Biomolecules

Matter, Energy, Potential Energy, and Kinetic Energy

Understanding matter and energy is essential for studying biological processes.

• Matter: Anything that occupies space and has mass (e.g., solids, liquids, gases).

• Energy: The capacity to do work or cause change; does not have mass or occupy space.

• Potential Energy: Stored energy based on position or chemical structure (e.g., energy stored in bonds).

• Kinetic Energy: Energy of motion (e.g., moving molecules, heat).

Major Forms of Energy

• Chemical energy: Stored in chemical bonds.

• Electrical energy: Movement of charged particles (ions).

• Mechanical energy: Energy of movement or physical work.

• Radiant energy: Energy carried by electromagnetic waves (light, X-rays).

Chemical Elements and Body Composition

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

• Four elements making up ~96% of body matter:

  • Oxygen (O)

  • Carbon (C)

  • Hydrogen (H)

  • Nitrogen (N)

Atom and Subatomic Particles

• Atom: Smallest unit of an element retaining its chemical properties.

• Subatomic Particles:

  • Protons: Positive charge (+1), mass ~1 amu, located in nucleus.

  • Neutrons: No charge, mass ~1 amu, located in nucleus.

  • Electrons: Negative charge (-1), negligible mass, orbit the nucleus in electron shells.

Atomic Number, Atomic Mass, Atomic Weight, Isotope, Radioisotope

• Atomic Number: Number of protons in an atom (defines the element).

• Atomic Mass: Total number of protons + neutrons.

• Atomic Weight: Average mass of all isotopes of an element.

• Isotope: Atoms of the same element with different numbers of neutrons.

• Radioisotope: Isotopes that emit radiation due to instability.

Molecule, Compound, and Mixture

• Molecule: Two or more atoms chemically bonded.

• Compound: Two or more different elements bonded together.

• Mixture: Two or more substances physically combined (can be separated physically).

Solutions, Colloids, and Suspensions

Type	Particle Size	Appearance	Example
Solution	Small (ions, molecules)	Clear, transparent	Salt dissolved in water
Colloid	Medium (protein clusters)	Cloudy, opaque	Gelatin in water
Suspension	Large particles	Cloudy, particles settle	Blood cells in plasma

Electrons in Chemical Bonding & Octet Rule

• Electrons in the outermost shell (valence electrons) determine bonding.

• Octet Rule: Atoms tend to gain, lose, or share electrons to have 8 electrons in their valence shell (stability).

Ionic, Covalent, and Hydrogen Bonds

• Ionic Bond: Transfer of electrons from one atom to another, resulting in oppositely charged ions attracted to each other (e.g., NaCl).

• Covalent Bond: Sharing of electrons between atoms (single, double, triple bonds).

• Hydrogen Bond: Weak attraction between a hydrogen atom in one molecule and an electronegative atom in another (important in water and protein structure).

Polar vs Nonpolar Compounds

• Polar: Unequal sharing of electrons, molecules have partial charges (e.g., water).

• Nonpolar: Equal sharing of electrons, no partial charges (e.g., oils, fats).

Major Types of Chemical Reactions

• Synthesis: Two or more atoms/molecules combine to form a larger molecule ($A + B ightarrow AB$).

• Decomposition: Breakdown of a molecule into smaller parts ($AB ightarrow A + B$).

• Exchange: Parts of molecules are swapped ($AB + CD ightarrow AD + CB$).

• Oxidation-Reduction Reactions: Involve the transfer of electrons; oxidation is loss of electrons, reduction is gain. Crucial in energy production.

Exergonic vs Endergonic Reactions

• Exergonic: Release energy (e.g., decomposition).

• Endergonic: Require energy input (e.g., synthesis).

Factors Affecting Chemical Reaction Rates

• Temperature (higher increases rate)

• Concentration of reactants (higher increases rate)

• Particle size (smaller increases rate)

• Catalysts (enzymes) speed up reactions without being consumed.

Salts and Homeostasis

• Salts dissociate into ions (electrolytes) important for nerve impulses, muscle contraction, and fluid balance.

Acids, Bases, and pH

• Acid: Substance that releases H+ ions in solution (pH < 7).

• Base: Substance that accepts H+ or releases OH- ions (pH > 7).

• pH Scale: Measures hydrogen ion concentration; 7 is neutral.

Buffer Systems

• Buffers maintain pH by neutralizing excess acids or bases to keep bodily fluids stable.

Carbohydrates

• Building Blocks: Monosaccharides (simple sugars).

• Structure: Carbon, hydrogen, oxygen in 1:2:1 ratio.

• Function: Primary energy source; structural components.

Lipids

• Building Blocks: Glycerol and fatty acids.

• Structure: Mostly hydrocarbons, hydrophobic.

• Function: Energy storage, membrane structure, signaling molecules.

Protein Structure Levels

• Primary: Sequence of amino acids.

• Secondary: Alpha helices and beta sheets (folding patterns).

• Tertiary: 3D shape of single polypeptide.

• Quaternary: Arrangement of multiple polypeptides.

Enzyme Action

• Enzymes lower activation energy and speed up reactions by binding substrates.

• Highly specific and reused.

ATP and Cellular Metabolism

• ATP (Adenosine Triphosphate): The cell's energy currency.

• Stores and releases energy for metabolic processes.

• Energy is released by breaking high-energy phosphate bonds. $ATP ightarrow ADP + P_i + ext{energy}$

Nucleic Acids: DNA vs RNA

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Bases	A, T, G, C	A, U, G, C
Structure	Double helix	Single strand
Function	Stores genetic information	Protein synthesis, gene regulation