Physiology Overview

1. Physiology Overview

2. OpeningCase Physiology Overview

3. Opening Case • An 18-year-old male patient is unconscious. • He has taken his grandmother’s morphine pills. • His respiratory rate is slow.

4. Sick or Not-yet-sick? SICK? Why? or NOT YET SICK?

5. Case (continued) • Upon arrival you find an 18-year-old male lying supine on the kitchen floor. • Pupils are pinpoint, and respiratory rate is 6/min. • Prior to your arrival, police on scene confirmed that one 30 mg pill of morphine was missing from grandma’s pill bottle.

6. How does knowledge of physiology help predict this patient’s problems? • Cardiovascular effects of vasodilation • Respiratory insufficiency (acidosis/hypoxia/anaerobic metabolism) • CNS depression from opiates (sympathetic and parasympathetic responses)

7. Introduction

8. Introduction • Physiology • the study of the functions of living organisms

9. Regulation and Maintenance

10. Tissues • Proper function: • Need adequate nutrients and oxygen • Eliminate waste and carbon dioxide • Live in an environment that provides • Stable pH • Temperature • Fluid and electrolyte balance

11. Nutrients • Serve as energy for cells to: • Grow • Synthesize proteins • Transport molecules and ions through membranes • Move • Divide • Change shape

12. Nutrients • Cells use nutrients to synthesize more complex molecules • Proteins • Complex carbohydrates • Lipids • Nucleic acids like DNA and RNA

13. Metabolism • Chemical reactions that take place in an organism • Catabolic • Anabolic • Aerobic • Anaerobic

14. ATP: Adenosine triphosphate ATP is ENERGY • Cellular respiration creates ATP • ATP acts as a “carrier molecule” for energy

15. Metabolism • Oxygen-reduction reactions • Most common energy transfer reactions • One molecule loses electrons (H+) • One molecule gains electrons (H+)

16. Glycolysis • Glucose is broken down into energy • Catabolic (energy releasing) reactions • Pyruvic acid is generated and creates • Two ATP molecules • Two molecules of NADH+H+ • Anaerobic process

17. Aerobic Metabolism • One glucose molecule produces: • CO2 • H2O • 30–32 ATP

18. Hypoxia O2 consumption exceeds O2 delivery

19. Hypoxia • Consequences of Hypoxia • Cells generate ATP by anaerobic methods • Seizure • Coma • Death

20. Which of the following is an example of hypoxia caused by an inability of cells to utilize oxygen? • Cyanide poisoning • Carbon dioxide poisoning • Thrombosis • Hemorrhage

21. Which of the following is an example of hypoxia caused by an inability of cells to utilize oxygen? • Cyanide poisoning • Carbon dioxide poisoning • Thrombosis • Hemorrhage

22. Hypoxemia • Abnormally low arterial oxygen • Occurs with low cardiac output

23. Hypoxia leads to free radicals • Dangerous chemicals • Partially reduced molecules • Contain an unpaired electron • Unstable and highly reactive • Quickly react with other molecules in cells

24. Free Radicals • Attempt to “steal” electrons to complete their pair • Cells become damaged • Membrane integrity • Changes in C+ homeostasis • Cancer • Premature cell death

25. Which of the following patients is most likely to be hypoxic, but NOT hypoxemic? A. A patient suffering from altitude illness B. A patient with a chronic lung disease C. A patient with carbon monoxide poisoning D. A patient with a traumatic abdominal injury

26. Which of the following patients is most likely to be hypoxic, but NOT hypoxemic? A. A patient suffering from altitude illness B. A patient with a chronic lung disease C. A patient with carbon monoxide poisoning D. A patient with a traumatic abdominal injury

27. Homeostasis

28. Homeostasis • Healthy, well-balanced state • Physiology • Monitors • Adjusts as needed • Variables have “setpoint” • Vascular autoregulation

29. Homeostasis • Examples of setpoints maintained by control mechanisms

30. Homeostasis • Elements of a control mechanism: • Receptors • Control center • Effectors

31. Homeostasis

32. Homeostasis • Afferent pathways • Efferent pathways • Negative feedback mechanisms • Positive feedback mechanisms

33. Negative Feedback

34. Positive Feedback

35. Integration and Control

36. Homeostatic Control • Endocrine system control of homeostasis • Serving as a control center • Produce hormones

37. Hormones • Five major classes: • Amino acid derivatives • Small neuropeptides • Large proteins • Steroid hormones • Vitamin derivatives • Functions of hormones

38. Nervous System Control • Composed of the brain and spinal cord • Control centers in the nervous system regulate: • Water balance • Skeletal muscle tone • Digestion • Heart rate • Blood pressure • Ventilation

39. Nervous System Control • Efferent division of nervous system • Somatic • Control of skeletal muscles • Autonomic • Controls cardiac muscle, smooth muscle, and glands

40. CNS Control

41. Synapses • Exist between afferent neurons and CNS neurons • Examples based on the molecular structure

42. The Cardiovascular System

43. The Cardiovascular System • Properties of cardiac muscle • Contractility • Extensibility • Automaticity • Irritability • Inherent contraction rate • Cardiac cycle • Systole • Diastole

44. The Cardiovascular System • Stroke Volume • Average stroke volume • Influences • Preload • Afterload

45. Cardiac Output CO = SV x HR • Average blood volume • Cardiac reserve • End diastolic volume • End systolic volume

46. The Cardiovascular System • Mean arterial pressure • Frank Starling’s Law • Contractility • Inotropic effect

47. The Cardiovascular System • Impact of heart rate on cardiac output • Chronotropic • Heart rate and venous return • Mean arterial pressure

48. The Cardiovascular System • Frictional Resistance to Blood Flow • Resistance • Hypertension • Hypotension • The Vasomotor Center • Baroreceptors • Cranial nerves IX & X

49. Frictional Resistance to Blood Flow

50. The Cardiovascular System • Chemoreceptors • Function