Unit 1

1. Introduction to Anatomy and Physiology Unit 1

2. Introduction to Anatomy and Physiology Relationship Between Anatomy and Physiology

3. Relationship between Anatomy and Physiology • Anatomy • The study of internal and external structures of the body and the physical relationships among body parts • Physiology • The study of how living organisms perform their vital functions • Someone studying anatomy might examine how and where a particular muscle attaches to the skeleton, whereas someone studying physiology might consider how a muscle contracts or what forces a contracting muscle exerts on the skeleton

4. Relationship between Anatomy and Physiology • Anatomical info provides clues about functions (physiology), and physiological mechanisms can be explained only in terms of the underlying anatomy • ALL SPECIFIC FUNCTIONS ARE PERFORMED BY SPECIFIC STRUCTURES!!!!!

5. Relationship between Anatomy and Physiology • Anatomy can be divided into gross (macroscopic) anatomy and microscopic anatomy • Gross Anatomy • Examination of relatively large structures • Usually visible with unaided eye • 5 different forms of gross anatomy • Surface anatomy • Study of general form and superficial markings • Regional anatomy • Anatomical organization of specific areas of body (head, neck, trunk)

6. Relationship between Anatomy and Physiology • 5 different forms of gross anatomy (con’t) • Systemic anatomy • Study of the structure of organ systems (skeletal system, muscular system, cardiovascular system, etc.) • Developmental anatomy • Describes the changes in form that occur between conception and physical maturity • Embryology – study of early developmental processes • Clinical anatomy • Subspecialities important in clinical practice • Medical anatomy (anatomical features that change during illness) • Radiographic anatomy (anatomical structures seen using imaging techniques)

7. Relationship between Anatomy and Physiology • Microscopic Anatomy • Study of structures that cannot be seen without magnification • Has 2 major divisions • Cytology – analysis of the internal structure of individual cells • Histology – examination of tissues

8. Relationship between Anatomy and Physiology • Physiology • The study of the function of anatomical strucures • Can be divided into 4 major specialties • Cell physiology – study of the function of cells • Chemical processes within cells and chemical interactions between cells • Special physiology – study of the physiology of specific organs • Systemic physiology – study of the functioning of specific organ systems • Pathological physiology – study of the effects of diseases on organ or system fuctions

9. Introduction to Anatomy and Physiology Levels of Organization

10. Levels of Organization • The Chemical (or Molecular) Level • Atoms can combine to form molecules with complex shapes • The functional properties of a particular molecule are determined by its unique 3D shape • The Cellular Level • Molecules interact to form organelles, each of which has specific functions. • Organelles are grouped to form cells • The Tissue Level • Groups of cells working together to perform specific functions • Heart muscle cells interact with other types of cells and extracellular materials to form cardiac muscle tissue

11. Levels of Organization • The Organ Level • Two or more tissues working in combination to perform several functions • Cardiac muscle tissue, in combination with connective tissue from the bulk of the heart. • The Organ System Level • Two or more organs interacting • The heart and blood vessels work together to form the cardiovascular system. • The Organism Level • Highest level of organization • All organ systems working together

13. Homeostasis Introduction to Anatomy and Physiology

14. Homeostasis • One of the roles of the organ systems in an organism is to maintain homeostasis. • Homeostasis – maintaining a stable internal environment. • Absolutely vital to survival • Homeostatic regulation – adjustment of physiological systems to preserve homeostasis.

15. Homeostasis • 2 mechanisms of homeostasis • Autoregulation (intrinsic regulation) – when a cell, tissue, organ or organ system adjusts its activities automatically in response to an environmental change • Ex: when blood oxygen levels decrease in a tissue, the cells release a chemical that dilate local blood vessels. This increases blood flow and, therefore, oxygen.

16. Homeostasis • 2 mechanisms of homeostasis (con’t) • Extrinsic regulation – from activities of the nervous and/or endocrine systems. • Ex: During exercise, your nervous system increases heart rate so that blood will circulate faster. Will also decrease blood flow to less active organs.

17. Homeostasis • The nervous system directs rapid, short-term, and very specific responses • Response to placing hand on a hot stove • Endocrine system releases hormones that affect tissues and organs throughout the body. • Not immediate, not specific, may be long-term

18. Homeostasis • Homeostatic regulatory mechanism consists of 3 parts • Receptor – sensor that is sensitive to a particular change in environment • Control center – receives and processes info from receptor and sends out commands • Effector – cell or organ that responds to the commands from control center. • Similar to thermostat in your house

19. Homeostasis • Negative feedback • Most regulatory mechanisms involve this opposition to changing conditions • Example is body temperature control (thermoregulation) • Control center is the hypothalamus region of the brain • Hypothalamus receives info from two receptors: skin receptors and one in hypothalamus • Normal body temp is 98.6o. If temp increases, the control center targets two effectors: • muscles in the walls of the blood vessels supplying the skin • sweat glands

20. Homeostasis • Negative feedback (con’t) • The muscles in the skin blood vessels relax, increasing blood flow to skin. • Sweat glands increase their secretion • The skin acts like a radiator by losing heat to the environment • Evaporation of sweat speed the process • As temp returns to normal, temp at hypothalamus declines, and the control center becomes less active • Blood flow and sweat production return to normal.

21. Homeostasis • There are variations in normal homeostatic levels between individuals • 95% of population has body temp between 36.7oC and 37.2oC • Physicians must keep this in mind when treating patients.

22. Homeostasis • Positive feedback • Produces a response that enhances the change in the original conditions. • Usually produces extreme responses • What if your thermostat was connected to your heater instead of your air conditioner? • What would occur if the temp in your house increased? • When temp exceeds set point, thermostat would turn on the heater, and it would continue to run until someone turned off the thermostat, heater, or intervened in some other way. • This escalating cycle is called a positive feedback loop

23. Homeostasis • Positive feedback (con’t) • In your body, these loops are found when a potentially dangerous process must be completed quickly before homeostasis can be restored. • Ex: immediate danger from a severe cut will decrease blood pressure and reduce efficiency of the heart • The response is to clot the blood. • Each step in the process accelerates the process until a clot is formed • Labor and delivery of a baby is another example

25. Frames of Reference for Anatomical Studies Introduction to Anatomy and Physiology

26. Frames of Reference for Anatomical Studies • Early anatomists faced communication problems. • A “bump on the back” doesn’t give very precise info about its location • Prominent anatomical structures serve as landmarks, distances are measured in centimeters, and specialized directional terms are used

27. Frames of Reference for Anatomical Studies • Superficial Anatomy • Anatomical landmarks are used in reference to the anatomical position • Anatomical position – hands at side, palms facing forward, and feet together • ALL descriptions given are in reference to the anatomical position, unless otherwise noted • Prone – lying face down in the anatomical position • Supine – lying face up in the anatomical position

29. Frames of Reference for Anatomical Studies • Anatomical Regions • Abdominopelvic quadrants • Formed by a pair of lines that intersect at the umbilicus (naval) • Used by physicians to help determine possible cause of aches, pains, injuries. • Internal organs can be found in different quadrants • Abdomiopelvic regions • More specific than quadrants • Preferred by anatomists

31. Frames of Reference for Anatomical Studies • Anatomical Directions • The terms left and light always refer to the left and right sides of the subject, NOT of the observer

32. Frames of Reference for Anatomical Studies • Sectional Anatomy • Sometimes the best way to understand anatomy is to slice through it and look at the internal organization • Useful with imaging techniques • Radiologists use these when looking at films

33. Frames of Reference for Anatomical Studies • Planes and Sections • Transverse plane – right angle to long axis of object, dividing it into superior and inferior • A cut in this plane is called a transverse section • Frontal plane – parallel to long axis; extends from side to side, dividing the body into anterior and posterior • A cut in this plane is called a frontal section • Sagittal plane – parallel to long axis; extends from front to back, dividing the body in to left and right • A cut down the midline is called a midsagittal section • Parallel cuts are called parasagittal sections

34. Frames of Reference for Anatomical Studies • Body cavities • Internal chambers where many vital organs can be found • 2 functions • Protect organs • Permit change of size and shape of the organs • Your diaphragm divides your torso into two cavities • Thoracic cavity • Abdominopelvic cavity • Viscera – organs enclosed (fully or partially) by these cavities

35. Frames of Reference for Anatomical Studies • Body cavities (con’t) • Thoracic cavity • Contains lungs and heart, associated organs of respiratory, cardiovascular, and lymphatic system; lower esophagus; thymus • Boundaries are the ribs and diaphragm • Subdivided into left and right pleural cavities, which each contain a lung. • Contains pericardial cavity, which surrounds the heart

36. Frames of Reference for Anatomical Studies • Body cavities (con’t) • Abdomiopelvic cavity • Extends from diaphragm to pelvis • Divided into a superior abdominal cavity and an inferior pelvic cavity • The peritoneal cavity surrounds the abdominal and pelvic cavities

37. Frames of Reference for Anatomical Studies • Body cavities (con’t) • Abdominal cavity contains the liver, stomach, spleen, small intestine, and most of the large intestine • The kidneys and pancreas lie posteriorly between the peritoneal cavity and the muscles of the abdominal cavity • The pelvic cavity contains distal large intestine, urinary bladder, and various reproductive organs