Overview
This lecture introduces the foundations of human anatomy and physiology, explains course expectations, and covers essential concepts such as the history of the field, definitions, levels of biological organization, characteristics and needs of life, and the principles of homeostasis.
Course Structure & Expectations
- Lecture content is the main source for exam questions; lab and lecture materials are assessed separately.
- Students are required to watch lecture videos, take thorough notes, and use the textbook for additional visuals, figures, and tables.
- Lecture videos may contain embedded questions that could appear in discussions or homework.
- The course lectures generally follow the textbook but may include extra information or present topics in a different order.
- Student lecture guides are provided to help organize notes and pull information from the textbook.
- Lab activities focus mainly on anatomy (identifying and naming structures), while lectures emphasize physiology (understanding functions and mechanisms).
- Face-to-face students can use recorded lectures for review; online students can pause and revisit lectures as needed.
History & Language of Anatomy and Physiology
- The formal study of human anatomy began in 1543 with Andreas Vesalius’ publication of "De Humani Corporis Fabrica Libri Septem" (On the Fabric of the Human Body in Seven Books).
- Early anatomical knowledge was often gained through illegal means, such as grave robbing, to obtain bodies for dissection.
- Advances in medicine, such as anesthetics and sterilization, were developed over time, sometimes through controversial methods.
- Scientific terminology in anatomy and physiology is based on Greek and Latin, the languages of early scholars, to ensure standardized and universal communication.
- Standardized terms are essential for clear understanding across languages and regions, especially in medical and scientific contexts.
- Using scientific names avoids confusion caused by regional or common names for organisms or body parts.
Anatomy vs. Physiology & Their Interrelationship
- Anatomy: The study of structure (morphology), including naming and identifying body parts. Most anatomy is covered in lab, focusing on structures like bones, muscles, and organs.
- Physiology: The study of function, focusing on how anatomical structures work and interact. Most physiology is covered in lecture, discussing mechanisms and processes.
- Anatomy and physiology are closely linked; changes in structure (form) affect function, and vice versa.
- Example: If a bone is malformed or deteriorates with age, its function is impaired.
- This relationship applies to all levels, from whole organs to cells (e.g., cell differentiation and specialization).
- In lab, students make observations and perform dissections (in-person or virtually), while physiology often involves experimentation and understanding mechanisms.
Levels of Biological Organization
- The human body is organized into hierarchical levels:
- Atoms: Basic units of matter (e.g., hydrogen, oxygen).
- Molecules: Atoms bonded together (e.g., water).
- Macromolecules: Large molecules (e.g., proteins, carbohydrates, lipids, nucleic acids).
- Organelles: Specialized structures within cells (e.g., mitochondria, nucleus).
- Cells: Basic units of life, composed of organelles.
- Tissues: Groups of similar cells working together (four main types).
- Organs: Structures made of multiple tissues performing specific functions (e.g., heart, stomach, bones, muscles).
- Organ Systems: Groups of organs working together (e.g., digestive, cardiovascular).
- Organism: The complete living being, with all systems integrated.
- Each level builds on the previous, and systems interact to maintain overall function.
- While systems are studied individually, it is important to understand their interdependence (e.g., how the nervous system affects the muscular system).
Characteristics of Life
- All living organisms share fundamental characteristics that distinguish them from non-living things:
- Organization: Structured interactions among molecules, cells, tissues, organs, and systems are essential for proper function.
- Metabolism: The sum of all chemical reactions in the body, including the production of ATP (adenosine triphosphate) for energy.
- Responsiveness: The ability to sense and respond to internal and external changes (e.g., temperature regulation, plants growing toward light).
- Growth: Increase in cell size or number; occurs during development and throughout life.
- Development: Includes growth and differentiation, where cells become specialized for specific functions.
- Reproduction: Formation of new cells (for growth and repair) or new organisms (e.g., through egg and sperm cells in humans).
- These characteristics are used to determine if something is living or non-living.
Basic Needs for Life
- All living organisms, including humans, require certain basic needs to maintain life:
- Water: Essential for chemical reactions and transport.
- Food: Provides nutrients and energy.
- Oxygen: Required for cellular respiration and energy production.
- Heat: Necessary to maintain body temperature; generated by metabolism and muscle activity.
- Pressure: Includes atmospheric pressure (important for breathing) and hydrostatic pressure (important for blood flow and other bodily functions).
- Both the amount (quantity) and quality of these needs are important for survival (e.g., clean water, adequate oxygen).
Homeostasis & Feedback Mechanisms
- Homeostasis: The process of maintaining a stable internal environment despite constant external and internal changes.
- The body uses control systems to monitor and adjust variables to stay within normal ranges.
- Components of control systems:
- Receptors: Detect changes (stimuli) in the environment.
- Control Center: Usually the brain; processes information and determines the response.
- Effectors: Carry out the response to restore balance (e.g., sweat glands, muscles).
- Feedback Mechanisms:
- Negative Feedback: The most common mechanism; reverses a change to bring conditions back to normal (e.g., regulating body temperature, blood glucose).
- Example: When body temperature rises, receptors signal the brain, which activates sweat glands to cool the body.
- Example: High blood glucose triggers insulin release to lower glucose levels.
- Positive Feedback: Less common; amplifies a change until a specific outcome is achieved (e.g., childbirth, blood clotting).
- Example: During childbirth, contractions trigger the release of oxytocin, which causes more contractions until delivery.
- Example: Platelet plug formation in blood clotting.
- Most homeostatic regulation in the body is through negative feedback; positive feedback occurs in specific situations.
- Normal ranges for physiological variables can vary between individuals; textbooks present values typical for the majority of the population, but individual variation is expected.
Key Terms & Definitions
- Anatomy: The study of the structure and naming of body parts.
- Physiology: The study of how body parts function and the mechanisms involved.
- Homeostasis: The maintenance of a stable internal environment.
- Negative Feedback: A mechanism that reverses a change to maintain balance.
- Positive Feedback: A mechanism that amplifies a change toward a specific outcome.
- ATP (Adenosine Triphosphate): The main energy-carrying molecule in cells.
- Differentiation: The process by which immature cells become specialized for specific functions.
Action Items / Next Steps
- Complete pre-lab activities and review key terminology from chapter 1.
- Refer to textbook visuals and figures on positive and negative feedback mechanisms for further understanding.
- Use the student lecture guide and textbook as resources for review and clarification.
- Reach out to the instructor with any questions about the material.