Anatomy & Physiology: Foundational Concepts and Key Principles

1. Homeostasis and Feedback Mechanisms

Negative Feedback & Positive Feedback

Homeostasis is the maintenance of a stable internal environment. Feedback mechanisms regulate physiological processes:

• Negative Feedback: A process that reverses a change to keep a variable within a set range. Example: Regulation of body temperature.

• Positive Feedback: A process that amplifies a change, moving the system away from its starting state. Example: Blood clotting, childbirth contractions.

2. Structural Organization of the Human Body

Levels of Organization

The human body is organized into hierarchical levels:

• 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

3. Anatomical Terminology

Anatomical Position

• Standard reference position: standing upright, facing forward, arms at sides, palms facing forward.

Body Cavities

• Dorsal cavity: Cranial and vertebral cavities

• Ventral cavity: Thoracic and abdominopelvic cavities

Serous Membranes

• Pleura: Surrounds the lungs

• Pericardium: Surrounds the heart

Abdominal Pelvic Regions

• Divided into nine regions (e.g., epigastric, umbilical, hypogastric) or four quadrants (RUQ, LUQ, RLQ, LLQ).

4. Planes and Sections of the Body

• Sagittal Plane: Divides body into left and right

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

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

5. Characteristics of Life

• Organization, metabolism, responsiveness, growth, development, reproduction

6. Anatomy vs. Physiology

• Anatomy: Study of structure

• Physiology: Study of function

7. Chemistry in Physiology

Atoms, Ions, and Molecules

• Atom: Smallest unit of matter

• Ion: Atom with a charge (gained or lost electrons)

• Molecule: Two or more atoms bonded together

Carbohydrates

• Monosaccharides: Glucose

• Polysaccharides: Glycogen (storage form in animals)

Energy Levels and Electron Numbers

• Electrons occupy energy levels (shells) around the nucleus.

• Valence electrons are in the outermost shell and determine chemical reactivity.

Organic vs. Inorganic Molecules

• Organic: Contains carbon and hydrogen (e.g., glucose, proteins)

• Inorganic: Does not contain both carbon and hydrogen (e.g., water, salts)

8. Chemical Reactions in Physiology

Dehydration Synthesis and Hydrolysis

• Dehydration Synthesis (Anabolic): Builds larger molecules by removing water.

• Hydrolysis (Catabolic): Breaks down molecules by adding water.

Chemical Formulas

• H2O: 2 hydrogen atoms, 1 oxygen atom

• CO2: 1 carbon atom, 2 oxygen atoms

Calculating Valence Electrons

• Valence electrons = group number for main group elements

• Example: Oxygen (group 16) has 6 valence electrons

9. Solutions and Tonicity

Types of Solutions

• Isotonic: Same solute concentration as the cell; no net water movement

• Hypotonic: Lower solute concentration than the cell; water enters cell

• Hypertonic: Higher solute concentration than the cell; water leaves cell

Reading Red Blood Cell Responses

• In isotonic solution: cell remains normal

• In hypotonic solution: cell swells (may burst)

• In hypertonic solution: cell shrinks

10. DNA, RNA, and Nucleotides

• DNA: Deoxyribonucleic acid; double helix; stores genetic information

• RNA: Ribonucleic acid; single-stranded; involved in protein synthesis

• Nucleotide: Building block of nucleic acids; consists of a sugar, phosphate group, and nitrogenous base

11. Plasma Membrane and Transport

Components of the Plasma Membrane

• Lipids: Phospholipids, cholesterol

• Proteins: Integral and peripheral

• Carbohydrates: Glycoproteins, glycolipids

Transport Mechanisms

• Passive: Diffusion, osmosis (no energy required)

• Active: Requires ATP (e.g., sodium-potassium pump)

• Endocytosis/Exocytosis: Bulk transport into/out of cell

12. Macromolecules

Major Classes and Their Building Blocks

Macromolecule	Building Block	Example
Carbohydrates	Monosaccharides	Glucose
Proteins	Amino acids	Hemoglobin
Lipids	Glycerol, fatty acids	Triglycerides
Nucleic Acids	Nucleotides	DNA, RNA

13. Cellular Structures and Functions

Organelles

• Nucleus: Contains genetic material

• Mitochondria: ATP production

• Golgi Apparatus: Modifies and packages proteins

• Ribosomes: Protein synthesis

• Endoplasmic Reticulum: Protein and lipid synthesis

14. Cell Cycle and Division

Mitosis

• Division of somatic cells for growth and repair

• Phases: Prophase, metaphase, anaphase, telophase

• Interphase: Cell grows and DNA replicates

15. Cellular Processes

• Phagocytosis: Cell engulfs large particles

• Receptor-mediated endocytosis: Specific uptake of molecules

• Exocytosis: Release of substances from cell

16. Atomic Structure and Chemistry

• Atomic number: Number of protons

• Atomic mass: Protons + neutrons

• Labeling a DNA molecule: Identify sugar-phosphate backbone and nitrogenous bases

17. Summary Table: Key Concepts

Concept	Definition	Example/Application
Homeostasis	Stable internal environment	Body temperature regulation
Negative Feedback	Reverses change	Blood glucose control
Positive Feedback	Amplifies change	Labor contractions
Isotonic Solution	Equal solute concentration	IV fluids
Active Transport	Requires ATP	Sodium-potassium pump

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