1. Overview of Anatomy and Physiology Anatomy –the study of the structure of body parts and their relationships to one another Gross (macroscopic) Microscopic Molecular Physiology –the study of the function of the body’s structural machinery which strives to keep the body working at peak efficiency –focuses on the functions of the body, often at the cellular or molecular level –understanding physiology requires a knowledge of anatomy and physics (chemistry), to explain how the heart works, how we breathe, how we regulate blood glucose…

2. Function versus Process Function explains the “why” –Teleological approach Process or mechanism describes the “how” –Mechanistic approach For example: –Why do we have red blood cells? because the cells of the body require oxygen and red blood cells bring it to them –How do red blood cells carry oxygen to the cells? oxygen binds to hemoglobin molecules contained in the red blood cells

3. Principle of Complementarity The anatomy of a part of the body reflects the physiology of that part –form determines function –all the parts of the body are designed to create an extremely efficient and effective machine

4. Levels of Structural Organization

5. Levels of Organization BiosphereAtomsMoleculesCellsTissuesOrgans Organ systems Organisms Populations of one species Ecosystem of different species CHEMISTRY MOLECULAR BIOLOGY CELL BIOLOGY ANATOMY and PHYSIOLOGY ECOLOGY

6. Levels of Structural Organization All matter is made from atoms Groups of atoms bonded together form molecules Certain molecules can be linked together to form macromolecules (proteins, polysaccharides, nucleic acids and lipids) Groups of molecules and macromolecules form subcellular machinery are called organelles The structural and functional unit of life composed of many different organelles are cells Groups of cells form tissues (muscular, epithelial, connective and nervous) Structures formed by the combination of different types of tissues are referred to as organs Groups of organs that function together towards a common goal is called an organ system The total collection of all organ systems in a biological entity is called the organism

7. Homeostasis Homeostasis is the ability to maintain a relatively constant internal environment in order to function optimally For the body to work as efficiently as possible, there are hundreds of variables that must remain relatively constant (at a set point) –body temperature, blood glucose levels, blood pressure, body CO 2 levels, body pH… –these variables are constantly changing due to stimuli presented to the body (scents, stress, heat, pain, pressure, light…) The body uses control systems (loops) to maintain these variables at their respective set point

8. Homeostatic Control Mechanisms There are three interdependent components of a control system: –Receptor monitors the variable and responds to changes (stimuli). The receptor sends information regarding the changed variable to the… –Control center determines the set point at which the variable is maintained. Then the control center sends information to the… –Effector provides the means to respond to the stimulus (creates an effect) to bring the variable back to the set point

9. Homeostatic Control Systems

10. Homeostatic Control Systems (Loops) There are 2 different types of control systems Most (over 99%) of them are referred to as negative feedback loops where the output of the system (effector) causes a change in the variable which opposes the original stimulus –If the original stimulus caused a increase in a variable, the effector will cause the variable to decrease back to the set point –Function like the heating/cooling system in a house to maintain a constant room temperature

11. Negative Feedback

13. Homeostatic Control Systems (Loops) The minority (less than 1%) of the systems are referred to as positive feedback systems where the output of the system causes a change in the variable which reinforces the original stimulus –If the original stimulus caused a increase in a variable, the effector will cause the variable to further increase

14. Positive Feedback