1. Biology 211 Anatomy & Physiology I Orientation to Anatomy

2. Throughout this course, we will focus on three "major concepts" which are central to the understanding of anatomy and physiology: a) b) c)

3. First major concept: All complex animals share a number of basic physiological functions for which anatomical structures are specifically adapted, including: - Protection of internal body environment from external environment - Maintenance of stable internal environment - Responsiveness - Ingestion, digestion, elimination - Metabolism - Excretion - Reproduction

4. Second major concept: The structures and functions of all complex animals are based on a “structural heirarchy” These are interdependent. Abnormalilties at one level will affect all higher levels

5. Example #1: Your body consists of trillions of cells of at least 400 different types About a dozen types: Lymphocytes One type of lymphocyte: CD4 cell Suppose a virus attacks and destroys your CD4 cells, while all other cells (including all other lymphocytes) remain healthy.

6. Example #2: Your body consists of trillions of cells of at least 400 different types Four types found in pancreatic islets One type of islet cell: beta cell, which produces insulin Suppose your body attacks and destroys the beta cells, while all other cells (including other islet cells) remain healthy.

7. Example #3: Your body consists of trillions of cells of at least 400 different types One type of cell in nervous system: oligodendrocyte Oligodendrocytes: dozens of organelles One organelle: plasma membrane Plasma membrane: hundreds of types of molecules One type of molecule: myelin Suppose your body attacks and destroys the myelin in the plasma membranes of oligodendrocytes, while all molecules and all other cells remain healthy.

8. Third major concept: Homeostasis: A state of "dynamic (changing) equilibrium (balance)" in which the body's internal environment is maintained within narrow limits even when the external environment changes significantly. For example: You must maintain a steady internal body temperature of approximately 37 o C even if the external temperature changes from -20 o C to over 100 o C. Homeostasis requires communication among many different organelles, cells, tissues, and organs

9. Homeostasis involves feedback mechanisms: Positive Feedback: Examples: Negative Feedback: Examples:

10. Positive Feedback Blood Clotting

11. Negative Feedback: Temperature Regulation

12. Negative Feedback: Concentration of glucose in blood Eating increases blood glucose. Blood glucose stimulates pancreatic islets to secrete insulin. Insulin stimulates muscle cells and liver cells to absorb glucose from blood. Absorption of glucose by liver & muscle lowers its concentration in blood. This returns blood glucose to original level

13. Negative Feedback: Concentration of glucose in blood Fasting lowers blood glucose. Blood glucose stimulates pancreatic islets to secrete glucagon. Glucagon stimulates muscle cells and liver cells to release glucose back into blood. Release of glucose by liver & muscle increases its concentration in blood. This returns blood glucose to original level

14. Approximate normal ranges for selected blood measurements: Arterial pH7.35 - 7.43 Bicarbonate21.3 - 28.5 mEq/L Sodium136-151 mEq/L Calcium4.6 - 5.2 mEq/L Oxygen17.2 - 22 ml / 100 ml Urea12 - 35 mg / 100 ml Amino acids3.3 - 5.1 mg / 100 ml Protein6.5 - 8 g / 100 ml Total lipids350 - 850 mg / 100 ml Glucose75 - 110 mg / 100 ml

15. Next: A few basic concepts of anatomy which we will use throughout this course 1) Planes or sections 2) Terms indicating relative positions 3) Regions of the body 4) Primary and secondary body cavities 5) Three-dimensional relationships

16. 1)

18. How a structure appears depends on the plane in which you view it:

20. 2) In discussing parts of the human body, we also use a number of terms of relative position: Superior (cranial): Inferior (caudal): Superficial: Deep: Proximal: Distal: Anterior (ventral): Posterior (dorsal): Medial: Lateral:

21. 3) Various regions of body have specific names: Anterior

22. Various parts of body have specific names: Posterior

23. You should be able to identify the regions shown on these diagrams. For example: The region of the upper limb between the shoulder and elbow is the_________ region For example: The _________ region is immediately distal to the antebracheal region

24. 4) Primary Body Cavities (Formed by folding of the embryo)

25. Secondary Body Cavities (Formed in place as organs develop) Examples: -

26. 5) Finally: As we discuss the human body, get your brain to think three-dimensionally and focus on relationships...