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Lecture 1

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  1. Lecture 1 The Human Body: An Orientation: Part A

  2. Overview of Anatomy and Physiology • Anatomy: The study of structure • Subdivisions: • Gross or macroscopic (e.g., regional, surface, and systemic anatomy) • Microscopic (e.g., cytology and histology) • Developmental (e.g., embryology)

  3. Overview of Anatomy and Physiology • Essential tools for the study of anatomy: • Mastery of anatomical terminology • Observation • Manipulation • Palpation (to examine by touch) • Auscultation (listening to internal sounds of the body)

  4. Overview of Anatomy and Physiology • Physiology: The study of function at many levels • Subdivisions are based on organ systems (e.g., renal or cardiovascular physiology)

  5. Overview of Anatomy and Physiology • Essential tools for the study of physiology: • Ability to focus at many levels (from systemic to cellular and molecular) • Basic physical principles (e.g., electrical currents, pressure, and movement) • Basic chemical principles

  6. Principle of Complementarityof Structure and Function • Anatomy and physiology are inseparable • Function always reflects structure • What a structure can do depends on its specific form • Function and structure complement each other

  7. Structure determines Function • Function always reflects structure • What a structure can do depends on its specific form

  8. Levels of Structural Organization • Chemical: atoms and molecules • Cellular: cells and their organelles • Tissue: Groups of similar cells • Organ: contains two or more types of tissues • Organ system: organs that work closely together • Organismal: all organ systems

  9. Levels of Structural Organization

  10. Review: What is A&P? Anatomy – the study of the structure of living organisms Physiology – the study of the function of living organisms

  11. Levels of Organization ORGAN SYSTEM – a group of organs that work together to perform a vital body function TISSUE – Group of similar cells & intercellular substances that have a common function ORGAN – 2 + tissues performing a specific function

  12. Body Systems • What is their role? • What are the major organs that perform this job/role?

  13. Homework: Make a table like this in your journal – complete for 11 body systems

  14. Organ Systems Interrelationships • All cells depend on organ systems to meet their survival needs • Organ systems work cooperatively to perform necessary life functions

  15. Necessary Life Functions 1. Maintaining boundaries between internal and external environments Plasma membranes Skin 2. Movement (contractility) Of body parts (skeletal muscle) Of substances (cardiac and smooth muscle)

  16. Necessary Life Functions 3. Responsiveness: The ability to sense and respond to stimuli - Withdrawal reflex - Control of breathing rate 4. Digestion - Breakdown of ingested foodstuff - Absorption of simple molecules into blood

  17. Necessary Life Functions 5. Metabolism: All chemical reactions that occur in body cells - Catabolism and Anabolism 6. Excretion: The removal of wastes from metabolism and digestion - Urea, carbon dioxide, feces

  18. Necessary Life Functions 7. Reproduction - Cellular division for growth or repair - Production of offspring 8. Growth: increase in size of a body part or of organism

  19. Survival Needs 1. Nutrients - Chemicals for energy and cell building - Carbohydrates, fats, proteins, minerals, vitamins 2. Oxygen - Essential for energy release (ATP production)

  20. Survival Needs 3. Water - Most abundant chemical in the body - Site of chemical reactions 4. Normal body temperature - Affects rate of chemical reactions 5. Appropriate atmospheric pressure - For adequate breathing and gas exchange in the lungs

  21. Homeostasis - Maintenance of a relatively stable internal environment despite continuous outside changes - A dynamic state of equilibrium

  22. Homeostasis Control Mechanisms - Involve continuous monitoring and regulation of many factors (variables) - Nervous and endocrine systems accomplish the communication via nerve impulses and hormones

  23. Components of a Control Mechanism 1. Receptor (sensor) - Monitors the environment - Responds to stimuli (changes in controlled variables) 2. Control center - Determines the set point at which the variable is maintained - Receives input from receptor - Determines appropriate response

  24. Components of a Control Mechanism 3. Effector - Receives output from control center - Provides the means to respond - Response acts to reduce or enhance the stimulus (feedback)

  25. Homeostatic Control Mechanisms

  26. Components of Feedback Loop Receptor monitors a controlled condition Control center determines next action Effector receives directions from the control center produces a response that changes the controlled condition

  27. Negative Feedback - The response reduces or shuts off the original stimulus Examples: - Regulation of body temperature (a nervous mechanism) - Regulation of blood volume by ADH (an endocrine mechanism)

  28. Negative Feedback:Regulation of Blood Volume by ADH - Receptors sense decreased blood volume - Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH) - ADH causes the kidneys (effectors) to return more water to the blood

  29. Eg. Homeostasis of Blood Pressure Pressure receptors in walls of certain arteries detect an increase in BP Blood Pressure = force of blood on walls of vessels Brain receives input and signals heart and blood vessels Heart rate slows and arterioles dilate (increase in diameter) BP returns to normal

  30. Positive Feedback - The response enhances or exaggerates the original stimulus - May exhibit a cascade or amplifying effect - Usually controls infrequent events e.g.: - Enhancement of labor contractions by oxytocin (Chapter 28) - Platelet plug formation and blood clotting

  31. Eg. Positive Feedback during Childbirth Stretch receptors in walls of uterus (cervix) send signals to the brain Brain releases hormone (oxytocin) into bloodstream Uterine smooth muscle contracts more forcefully More stretch, more hormone, more contraction etc. Cycle ends with birth of the baby & decrease in stretch of the cervix

  32. Homeostatic Imbalance Disturbance of homeostasis - Increases risk of disease - Contributes to changes associates with aging - May allow destructive positive feedback mechanisms to take over (e.g., heart failure)

  33. % of blood flow to body regions • What changes occurred here? • What might this person have done between these measurements? • Why did these changes occur?

  34. Remainder of Class • Finish Poster