Overview
This lecture introduces the major themes of Anatomy & Physiology, key properties of life, levels of biological organization, and the concept of homeostasis.
Introduction to Biology and Life
- Biology is the study of life.
- Life cannot be defined in one sentence; it is recognized by shared properties.
- Living things exhibit 8 properties: cellular composition, reproduction, development, metabolism, homeostasis, organization, evolution, and responsiveness/movement.
Properties of Life
- All living things are made of cells.
- Reproduction passes genetic information to new generations.
- Development includes growth and differentiation of cells.
- Metabolism is the sum of chemical reactions in the body.
- Homeostasis maintains stable internal conditions.
- Organization means living things maintain an ordered structure.
- Evolution involves changes in DNA, leading to species adaptation.
- Responsiveness/movement allows living things to react and adapt to their environment.
Anatomy & Physiology: Definition and Connection
- Anatomy is the study of structure (form).
- Physiology is the study of function.
- Structure and function are interdependent; each influences the other.
- Always ask how structure and function relate in the body.
Levels of Biological Organization
- Atoms are the building blocks of matter and life.
- Molecules are formed from atoms; structure determines function (e.g., morphine fitting body receptors).
- Compounds are molecules with different atoms bonded together.
- Macromolecules (large, important molecules) will be studied in detail.
- Cells are the smallest units of life; diverse cell types have specialized structures/functions.
- Tissues consist of similar cells working together; four major types: connective, epithelial, muscle, nervous.
- Organs are made of at least two tissue types performing complex functions.
- Organ systems consist of organs working together toward a common purpose.
- The organismal level is the sum of all structural levels, representing a living being.
Homeostasis and Feedback Mechanisms
- Homeostasis is maintaining stable internal conditions with constant, small fluctuations (dynamic equilibrium).
- Communication is done through the nervous and endocrine systems.
- Homeostatic systems have three parts: receptor, control center (set point), and effector.
- Negative feedback mechanisms reverse changes to restore balance (e.g., temperature and blood pressure regulation).
- Positive feedback mechanisms enhance or amplify changes, moving the body further from equilibrium (e.g., blood clotting, labor contractions).
- Positive feedback is less common and, if uncontrolled, can be harmful.
Key Terms & Definitions
- Biology â the study of life.
- Cell â the basic unit of life.
- Metabolism â all chemical reactions in an organism.
- Homeostasis â maintaining stable internal conditions.
- Anatomy â study of a structure's form.
- Physiology â study of a structure's function.
- Emergent properties â new characteristics arising at higher levels of organization.
- Reductionism â studying complex systems by examining simpler components.
- Holism â viewing systems as wholes, more than the sum of parts.
- Negative feedback â response that reverses the direction of the initial change.
- Positive feedback â response that amplifies the initial change.
Action Items / Next Steps
- Focus reading on sections 1.1, 1.5, and 1.6 of the textbook.
- Complete the Learn Smart Assignment for this chapter.
- Review and ensure understanding of chapter objectives before the exam.
- Post questions in the discussion forum or email the instructor as needed.