Comprehensive Study Guide: Foundations of Anatomy & Physiology

Survival Needs and Requirements for Life

Five Survival Needs

Organisms require certain basic needs to survive and maintain homeostasis. These needs are essential for cellular function and overall health.

• Nutrients: Chemical substances used for energy and cell building.

• Oxygen: Required for cellular respiration and energy production.

• Water: The most abundant chemical in the body, vital for chemical reactions and transport.

• Stable Body Temperature: Necessary for proper metabolic reactions.

• Atmospheric Pressure: Required for breathing and gas exchange.

Five Things Necessary for Life

In addition to survival needs, life requires certain conditions and processes to persist.

• Maintaining Boundaries: Separation between internal and external environments (e.g., cell membranes).

• Movement: Activities promoted by the muscular system, including movement of substances within the body.

• Responsiveness: Ability to sense changes and respond to stimuli.

• Digestion: Breakdown of ingested food into simple molecules.

• Metabolism: All chemical reactions within the body, including catabolism and anabolism.

Homeostasis and Feedback Loops

Definition and Maintenance

Homeostasis is the maintenance of a stable internal environment despite changes in the external environment. It is achieved through feedback mechanisms.

• Negative Feedback: Reduces or shuts off the original stimulus. Example: Regulation of body temperature, blood glucose levels.

• Positive Feedback: Enhances or amplifies the original stimulus. Example: Blood clotting, labor contractions.

Elements and Atomic Structure

Protons, Neutrons, and Electrons

An element is a substance that cannot be broken down into simpler substances. Atoms are composed of:

• Proton: Charge: +1; Weight: 1 atomic mass unit (amu); Location: Nucleus

• Neutron: Charge: 0; Weight: 1 amu; Location: Nucleus

• Electron: Charge: -1; Weight: ~0 amu; Location: Electron cloud/orbitals

Mixtures and Chemical Bonds

Types of Mixtures

Mixtures are combinations of two or more substances physically blended together.

• Solutions: Homogeneous mixtures; solute particles are very small and do not settle out.

• Colloids: Heterogeneous mixtures; larger particles that do not settle out.

• Suspensions: Heterogeneous mixtures; large particles that settle out over time.

Types of Chemical Bonds

Chemical bonds are forces that hold atoms together in molecules and compounds.

• Ionic Bonds: Transfer of electrons from one atom to another, resulting in charged ions.

• Covalent Bonds: Sharing of electron pairs between atoms.

• Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (e.g., oxygen, nitrogen).

Chemical Reactions

Patterns of Chemical Reactions

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

• Synthesis (Combination): $A + B \rightarrow AB$ Example: Formation of water from hydrogen and oxygen.

• Decomposition: $AB \rightarrow A + B$ Example: Breakdown of glycogen to glucose.

• Exchange (Displacement): $AB + C \rightarrow AC + B$ Example: ATP transfers a phosphate group to glucose.

Endergonic vs. Exergonic Reactions

Reactions can be classified based on energy changes.

• Endergonic: Absorb energy; products have more energy than reactants.

• Exergonic: Release energy; products have less energy than reactants.

Factors Influencing Reaction Rate

• Temperature: Higher temperature increases reaction rate.

• Concentration: Higher concentration increases reaction rate.

• Particle Size: Smaller particles react faster.

• Catalysts: Speed up reactions without being consumed.

Properties of Water

Water is vital for life due to its unique properties.

• High Heat Capacity: Absorbs and releases heat slowly.

• High Heat of Vaporization: Requires much energy to change from liquid to gas.

• Polar Solvent Properties: Dissolves ionic and polar substances.

• Reactivity: Participates in chemical reactions (e.g., hydrolysis).

• Cushioning: Protects organs from physical trauma.

Acids, Bases, and pH

Comparison and Measurement

Acids release hydrogen ions (H+), while bases accept H+ or release hydroxide ions (OH-).

• pH Scale: Measures hydrogen ion concentration; ranges from 0 (acidic) to 14 (basic).

• Measurement: pH meters or indicators are used to measure pH.

Buffer Systems

Buffers resist changes in pH by absorbing or releasing H+. Example: Bicarbonate buffer system in blood.

Biomolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids

Carbohydrates

• Monomers: Monosaccharides (e.g., glucose).

• Polymerization: Joined by dehydration synthesis to form disaccharides and polysaccharides.

Lipids

• Fatty Acids: Long hydrocarbon chains with a carboxyl group.

• Triglycerides: Three fatty acids bonded to glycerol.

• Phospholipids: Two fatty acids and a phosphate group attached to glycerol.

Proteins

• Monomers: Amino acids.

• Polymerization: Joined by peptide bonds through dehydration synthesis.

• Protein Folding: Process by which a polypeptide folds into its functional three-dimensional structure.

Nucleic Acids

• Monomers: Nucleotides (composed of a sugar, phosphate, and nitrogenous base).

• Polymerization: Joined by phosphodiester bonds to form DNA and RNA.

Cellular Components and Membrane Structure

Extracellular Components

• Extracellular Fluid: Includes interstitial fluid, blood plasma, and cerebrospinal fluid.

• Extracellular Matrix: Network of proteins and polysaccharides outside cells.

Plasma Membrane

The plasma membrane is a selectively permeable barrier composed of a phospholipid bilayer with embedded proteins.

• Phospholipids: Form the basic structure.

• Proteins: Serve as channels, carriers, and receptors.

• Cholesterol: Stabilizes membrane fluidity.

• Carbohydrates: Involved in cell recognition.

Specialized Junctions

• Tight Junctions: Prevent leakage between cells.

• Desmosomes: Anchor cells together.

• Gap Junctions: Allow communication between cells.

Transport Mechanisms

Diffusion

Diffusion is the movement of molecules from an area of higher concentration to lower concentration.

• Simple Diffusion: Direct movement through the membrane.

• Facilitated Diffusion: Movement via membrane proteins.

Osmosis

Osmosis is the diffusion of water across a selectively permeable membrane.

• Hypertonic Solution: Higher solute concentration outside; cell shrinks.

• Hypotonic Solution: Lower solute concentration outside; cell swells.

• Isotonic Solution: Equal solute concentration; no net movement.

Sodium-Potassium Pump

The sodium-potassium pump is an active transport mechanism that moves Na+ out of the cell and K+ into the cell against their concentration gradients, using ATP.

• Function: Maintains electrochemical gradients essential for nerve impulse transmission and muscle contraction.

• Mechanism: Pumps 3 Na+ out and 2 K+ in per ATP molecule hydrolyzed.

Summary Table: Types of Chemical Bonds

Bond Type	Description	Strength	Example
Ionic	Transfer of electrons between atoms	Strong (in dry conditions)	NaCl (table salt)
Covalent	Sharing of electron pairs	Strong	H2O (water)
Hydrogen	Weak attraction between H and electronegative atom	Weak	Between water molecules

Summary Table: Effects of Solutions on Red Blood Cells

Solution Type	Solute Concentration	Effect on RBC
Hypertonic	Higher outside cell	Cell shrinks (crenation)
Hypotonic	Lower outside cell	Cell swells (lysis)
Isotonic	Equal inside and outside	No change

Additional info: Some explanations and examples were expanded for clarity and completeness based on standard Anatomy & Physiology curriculum.