Anatomy & Physiology Lecture #1 - Introduction

1. Anatomy & PhysiologyLecture #1 - Introduction Fall 2009

2. Overview • Anatomy & Physiology Subdivisions • Requirements of Life & Survival Needs • Homeostasis • Cell Transport • Biochemistry & Metabolism

3. Definitions • Anatomy - the structure of body parts and their relationships to one another • Physiology - the function of the body

4. Anatomy Subdivisions • Gross Anatomy • Regional Anatomy • Systemic Anatomy • Surface Anatomy

5. Anatomy Subdivisions • Microscopic Anatomy • Cytology • Histology

6. Anatomy Subdivisions • Developmental Anatomy

7. Physiology Subdivisions • Most subdivisions focus on the operation of specific organ systems • Disease states can be thought of physiology gone wrong

8. Physiology SubdivisionsLevels of Organization • Simple to Complex • Chemical Level • Cellular Level • Four large groups of cells in the body • Activities of cells fall into two categories

9. Physiology SubdivisionsLevels of Organization • Simple to Complex • Tissue Level • Organ Level

10. Physiology SubdivisionsLevels of Organization • Simple to Complex • Organ Systems • Organismal Level

12. Requirements of Life • Maintain Boundaries • Single Cell • Humans • Movement • Responsiveness

13. Requirements of Life • Digestion • Metabolism • Catabolism • Anabolism • Cellular Respiration • Excretion

14. Survival Needs • Nutrients • Oxygen

15. Requirements of Life • Reproduction • Growth

16. Survival Needs • Survival Needs • Water • 60-80% of the body by weight • Is the base for body secretions and excretions • Obtained from ingested food and liquids • Lost from evaporation and excretion • Divided into • Intracellular • Interstitial • Plasma

17. Survival Needs • Maintain normal body temperature • Atomospheric Pressure - the force that air exerts on the surface of the body

18. Homeostasis The ability of the body to maintain relatively stable internal conditions even though the outside world changes; indicates a dynamic state of equilibrium

19. Homeostatic Control Mechanisms • Communication is essential to maintain homeostasis • Communication signals in three categories: • Endocrine • Paracrine • Autocrine

21. ICF ISF plasma organs external environment internal environment

23. Homeostatic Control Mechanisms • All homeostatic control mechanisms have at least three interdependent components

24. Homestatic Control Components • Receptor • Control center • Effector

26. To Identify a Homestatic System • Identify the internal environmental variable. • Establish the “set point” value for that variable. • Identify the inputs and outputs affecting the variable. • Examine the balance between the inputs and outputs. • Determine how the body monitors/senses the variable. • Identify effectors that restore the variable to its set point.

27. Negative Feedback Hypothalamus targets two different effectors Afferent Nerves Efferent Nerves Body temperature rises above 37.2 C Receptors: Information comes from sensors in the skin and hypothalamus • Effectors • Muscle tissue in the walls of blood vessels dilate • Sweat glands increase activity Heat Loss Decreases the Body Temperature to Acceptable Levels, Hypothallamus is turned off

28. Positive Feedback Endocrine Center of the Brain Afferent Nerves Efferent Nerves Uterus is Distorted by the growing fetus and uterine oxytocin levels increase • Effectors • Increased Oxytocin Release leads to increased contraction of the uterine wall Contraction and further distortion of the uterus

29. How do things get in and out of cells?

30. Overcoming the Cell Barrier • The cell membrane is a barrier, but: • nutrients must get in • products and wastes must get out

31. Permeability • Permeability determines what moves in and out of a cell: • A membrane that: • lets nothing in or out is impermeable • lets anything pass is freely permeable • restricts movement is selectivelypermeable

32. Selective Permeability • Cell membrane is selectivelypermeable: • allows some materials to move freely • restricts other materials

33. Restricted Materials • Selective permeability restricts materials based on: • size • electrical charge • molecular shape • lipid solubility

34. Transport • Transport through a cell membrane can be: • active • passive

35. 3 Categories of Transport • Diffusion & Osmosis • Carrier-mediated transport • Vesicular transport

36. Concentration Gradient • Concentration is the amount of solute in a solvent • Concentration gradient:

37. Diffusion • Diffusion: • molecules mix randomly • solute spreads through solvent

38. Factors Affecting Diffusion Rates • Distance • Molecule size: • Temperature:

39. Factors Affecting Diffusion Rates • Gradient size: • Electrical forces:

40. Diffusion and the Cell Membrane • Diffusion can be simple or channel-mediated Figure 3–15

41. Simple Diffusion • Materials which diffuse through cell membrane: • lipid-soluble compounds • dissolved gases

42. Channel-Mediated Diffusion • Materials which pass through transmembrane proteins (channels): • are water soluble compounds • are ions

43. Factors in Channel-Mediated Diffusion • Passage depends on: • size • charge • interaction with the channel

44. Osmosis • Osmosis is the diffusion of water across the cell membrane Figure 3–16

45. How Osmosis Works • More solute molecules, lower concentration of water molecules • Membrane must be freely permeable to water, selectively permeable to solutes

46. Osmosis Water Movement • Water molecules diffuse across membrane toward solution with more solutes • Volume increases on the side with more solutes

47. Osmotic Pressure • Is the force of a concentration gradient of water • Equals the force needed to block osmosis

48. Tonicity • The osmotic effect of a solute on a cell: • 2 fluids may have equal osmolarity, but different tonicity Figure 3–17a

49. Isotonic Solutions • A solution that does not cause osmotic flow of water in or out of a cell • iso = same, tonos = tension

50. Hypotonic Solutions • hypo = below • Has less solutes • Loses water through osmosis