Essential Concepts in Anatomy & Physiology: Structured Study Notes

1. Homeostasis and Feedback Mechanisms

Negative Feedback & Positive Feedback

Homeostasis refers to the maintenance of a stable internal environment. Feedback mechanisms regulate physiological processes to maintain equilibrium.

• 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 equilibrium. Example: Blood clotting, childbirth.

2. Levels of Organization

Hierarchical Structure in the Human Body

The human body is organized into increasing levels of complexity.

• Chemical Level: Atoms and molecules

• Cellular Level: Cells and their organelles

• Tissue Level: Groups of similar cells

• Organ Level: Structures composed of different tissues

• Organ System Level: Groups of organs working together

• Organism Level: The complete living being

3. Anatomical Position and Body Planes

Standard Reference and Sectional Views

Anatomical position is the standard reference for describing body locations and directions.

• Anatomical Position: Standing upright, facing forward, arms at sides, palms facing forward.

• Sagittal Plane: Divides the body into left and right parts.

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

• Transverse Plane: Divides the body into superior and inferior parts.

4. Serous Membranes

Pleura and Pericardium

Serous membranes line body cavities and cover organs, reducing friction.

• Pleura: Surrounds the lungs.

• Pericardium: Surrounds the heart.

5. Abdominal Pelvic Regions

Division of the Abdomen

The abdomen is divided for anatomical study and clinical reference.

• Regions: Nine regions (e.g., epigastric, umbilical, hypogastric, etc.)

• Quadrants: Four quadrants (right upper, left upper, right lower, left lower)

6. Characteristics of Life

Defining Living Organisms

Life is characterized by several essential properties.

• Organization

• Metabolism

• Responsiveness

• Growth

• Development

• Reproduction

7. Anatomy vs. Physiology

Structure and Function

Anatomy studies the structure of body parts; physiology studies their function.

• Anatomy: Focuses on form and location.

• Physiology: Focuses on processes and mechanisms.

8. Elements in the Body

Major Elements and Their Roles

Several elements are essential for life and biological processes.

• Major Elements: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N)

• Roles: Form biomolecules, participate in metabolism

9. Carbohydrates

Glucose and Glycogen

Carbohydrates are organic molecules that provide energy.

• Glucose: Main energy source for cells

• Glycogen: Storage form of glucose in animals

10. Electron Numbers and Energy Levels

Atomic Structure

Electrons occupy energy levels (shells) around the nucleus.

• Valence Electrons: Electrons in the outermost shell, important for chemical bonding

• Calculating Electrons: Atomic number equals number of protons and electrons in a neutral atom

11. Organic vs. Inorganic Molecules

Classification of Compounds

Organic molecules contain carbon and hydrogen; inorganic molecules do not.

• Organic: Carbohydrates, lipids, proteins, nucleic acids

• Inorganic: Water, salts, acids, bases

12. Chemical Reactions in Biology

Anabolic vs. Catabolic Reactions

Biological reactions build up or break down molecules.

• Anabolic (Synthesis): Build larger molecules from smaller ones (e.g., dehydration synthesis)

• Catabolic (Hydrolysis): Break down molecules into smaller units

13. Chemical Formulas and Valence Electrons

Understanding Chemical Notation

Chemical formulas represent the composition of molecules.

• Example: $H_2O$ has 2 hydrogen atoms and 1 oxygen atom

• Valence Electrons: Determine bonding and reactivity

14. DNA and RNA

Genetic Material

DNA and RNA are nucleic acids that store and transmit genetic information.

• DNA: Double-stranded, contains deoxyribose, bases A-T, G-C

• RNA: Single-stranded, contains ribose, bases A-U, G-C

15. Solutions and Tonicity

Effects on Red Blood Cells

Cells respond differently to various solution types.

• Isotonic: No net movement of water; cell remains unchanged

• Hypotonic: Water enters cell; cell swells

• Hypertonic: Water leaves cell; cell shrinks

16. Plasma Membrane Components

Structure and Function

The plasma membrane controls entry and exit of substances.

• Lipids: Phospholipids, cholesterol

• Proteins: Channels, carriers, receptors

• Carbohydrates: Glycoproteins, glycolipids

17. Biological Macromolecules

Types and Functions

Macromolecules are large, complex molecules essential for life.

• Carbohydrates: Energy source (monosaccharides, disaccharides, polysaccharides)

• Proteins: Structure, enzymes, transport (amino acids)

• Lipids: Energy storage, membranes (triglycerides, phospholipids)

• Nucleic Acids: Genetic information (DNA, RNA; nucleotides)

18. Cell Division

Mitosis and Interphase

Cells divide to grow and repair tissues.

• Mitosis: Division of the nucleus; stages include prophase, metaphase, anaphase, telophase

• Interphase: Period of cell growth and DNA replication

19. Cell Organelles

Structure and Function

Organelles perform specialized functions within cells.

• Nucleus: Contains genetic material

• Mitochondria: Produce ATP

• Golgi Apparatus: Modifies and packages proteins

• Ribosomes: Protein synthesis

• Endoplasmic Reticulum: Synthesis and transport of proteins/lipids

20. Cellular Processes

Key Functions

Cells perform various processes to maintain life.

• Creation: Formation of new molecules

• Lysis: Breakdown of molecules

• Phagocytosis: Engulfing particles

• Exocytosis: Expelling substances

• Endocytosis: Taking in substances

21. Cellular Transport

Movement Across Membranes

Cells move substances using passive and active mechanisms.

• Active Transport: Requires ATP to move substances against a gradient

• Passive Transport: Diffusion, osmosis (no energy required)

22. Atomic Structure

Atoms and Molecules

Atoms are the basic units of matter, composed of protons, neutrons, and electrons.

• Atomic Number: Number of protons

• Atomic Mass: Sum of protons and neutrons

• Molecule: Two or more atoms bonded together

23. Body Cavities

Major Cavities and Their Contents

Body cavities house and protect organs.

• Dorsal Cavity: Contains brain and spinal cord

• Ventral Cavity: Contains thoracic and abdominopelvic cavities

24. Table: Comparison of Solution Types

Solution Type	Effect on Red Blood Cell
Isotonic	No change
Hypotonic	Cell swells
Hypertonic	Cell shrinks

25. Table: Major Biological Macromolecules

Macromolecule	Monomer	Function
Carbohydrate	Monosaccharide	Energy source
Protein	Amino acid	Structure, enzymes
Lipid	Fatty acid, glycerol	Energy storage, membranes
Nucleic Acid	Nucleotide	Genetic information

26. Key Equations

• Atomic Mass: $\text{Atomic Mass} = \text{Number of Protons} + \text{Number of Neutrons}$

• ATP Hydrolysis: $\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$

27. Example: Calculating Valence Electrons

• Oxygen (O): Atomic number 8; electron configuration 2,6; 6 valence electrons

• Hydrogen (H): Atomic number 1; 1 valence electron

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