Basic Principles of Anatomy & Physiology

Introduction to Homeostasis and Organization

Understanding the foundational concepts of anatomy and physiology is essential for studying the human body. This section covers homeostasis, levels of organization, and anatomical terminology.

• Homeostasis: The process by which the body maintains a stable internal environment despite changes in external conditions.

• Levels of Organization: The human body is organized into hierarchical levels: atoms & molecules, cells, tissues, organs, organ systems, and the organism.

• Anatomical Terminology: Key directional terms include medial, lateral, proximal, distal, anterior, and posterior. Sectional terms include transverse, sagittal, and frontal.

• Example: The heart is medial to the lungs and anterior to the vertebral column.

Biological Molecules Section – Chemistry

Kinetic and Potential Energy

Energy is fundamental to biological processes. Understanding the difference between kinetic and potential energy is crucial.

• Kinetic Energy: Energy of motion; e.g., movement of molecules.

• Potential Energy: Stored energy; e.g., energy stored in chemical bonds.

• Example: ATP stores potential energy that is released during cellular work.

Types of Chemical Reactions

Chemical reactions are central to metabolism and cellular function.

• Anabolism: Building up complex molecules from simpler ones.

• Catabolism: Breaking down complex molecules into simpler ones.

• Exchange Reactions: Parts of molecules are exchanged to form new products.

• Examples: Protein synthesis (anabolism), glycolysis (catabolism).

ATP and Chemical Bonds

ATP is the primary energy currency of the cell, and chemical bonds store energy used in biological processes.

• ATP: Adenosine triphosphate, a molecule that stores and transfers energy within cells.

• Covalent, Ionic, and Hydrogen Bonds: Three major types of chemical bonds discussed in class.

• Example: Hydrolysis of ATP releases energy for cellular activities.

Biological Molecules Section – General Features of Biomolecules

Structure and Function of Biomolecules

Biomolecules are essential for life and include carbohydrates, lipids, proteins, and nucleic acids.

• Carbohydrates: Provide energy and structural support; building blocks are monosaccharides.

• Lipids: Store energy, form cell membranes; building blocks are fatty acids and glycerol.

• Proteins: Perform a wide range of functions; building blocks are amino acids.

• Nucleic Acids: Store and transmit genetic information; building blocks are nucleotides.

• Functions: Energy storage, structural support, catalysis, information storage.

• Example: Enzymes are proteins that catalyze biochemical reactions.

Biological Molecules Section – Enzymes

Enzyme Structure and Function

Enzymes are biological catalysts that speed up chemical reactions in the body.

• Enzyme: A protein that lowers the activation energy of a reaction.

• Substrate: The molecule upon which an enzyme acts.

• Enzyme Activity: Influenced by substrate concentration, temperature, pH, and inhibitors.

• Example: Lactase breaks down lactose in the digestive system.

Equation:

Biological Molecules Section – Nucleic Acids

DNA and RNA Structure

Nucleic acids are polymers that store and transmit genetic information.

• DNA: Double helix structure; base pairing rules (A-T, C-G).

• RNA: Single-stranded; base pairing (A-U, C-G).

• Central Dogma: DNA → RNA → Protein.

• Example: mRNA carries genetic code from DNA to ribosomes for protein synthesis.

Equation:

Cells Section – Introduction and Cell Membrane Structure

Plasma Membrane and Transport

The plasma membrane controls the movement of substances into and out of the cell.

• Phospholipid Bilayer: Composed of hydrophilic heads and hydrophobic tails.

• Membrane Proteins: Integral and peripheral proteins serve as channels, receptors, and enzymes.

• Transport: Includes passive (diffusion, osmosis) and active (pumps, endocytosis) mechanisms.

• Example: Sodium-potassium pump maintains cellular ion balance.

Cells Section – Organelles

Major Cell Organelles and Their Functions

Organelles perform specialized functions within the cell.

• Mitochondria: Site of ATP production.

• Endoplasmic Reticulum (SER, RER): SER synthesizes lipids; RER synthesizes proteins.

• Ribosomes: Site of protein synthesis.

• Golgi Apparatus: Modifies, sorts, and packages proteins.

• Nucleus: Contains genetic material (DNA).

• Example: Insulin is synthesized in the RER and processed in the Golgi apparatus.

Cells Section – Cell Cycle

Phases of the Cell Cycle

The cell cycle consists of a series of phases that lead to cell division.

• G1 Phase: Cell growth.

• S Phase: DNA replication.

• G2 Phase: Preparation for mitosis.

• M Phase: Mitosis and cytokinesis.

• Example: During S phase, each chromosome is duplicated.

Cells Section – Cell Membrane Transport and Osmosis

Transport Mechanisms Across the Membrane

Cells use various mechanisms to move substances across the plasma membrane.

• Simple Diffusion: Movement of molecules from high to low concentration without energy input.

• Facilitated Diffusion: Movement via membrane proteins.

• Active Transport: Movement against concentration gradient using energy (ATP).

• Osmosis: Diffusion of water across a semipermeable membrane.

• Endocytosis/Exocytosis: Bulk transport mechanisms.

• Example: Glucose enters cells via facilitated diffusion.

Key Terms: Hypertonic, hypotonic, isotonic, solute, solvent, molarity, osmotic pressure.

Equation:

Where: = van 't Hoff factor, = molarity, = gas constant, = temperature in Kelvin.

Cells Section – Cell Junctions and Specialized Structures

Cell Junctions and Specialized Cell Types

Cells are connected and communicate via specialized junctions and structures.

• Tight Junctions: Prevent leakage between cells.

• Desmosomes: Provide mechanical strength.

• Gap Junctions: Allow communication between cells.

• Microvilli and Cilia: Increase surface area and aid movement; found in the intestines and respiratory tract, respectively.

• Example: Cilia in the respiratory tract help move mucus.

Summary Table: Major Cell Organelles and Functions

Additional info: Some explanations and examples have been expanded for clarity and completeness.