Chapter 1 – The Human Body: An Orientation

1. Chapter 1 – The Human Body: An Orientation J.F. Thompson, Ph.D.

2. Anatomy and Physiology Overview • Anatomy and Physiology • Anatomy – structure – how it is constructed • Physiology – function - how it works • Topics of Anatomy • Gross anatomy • Regional anatomy • Systemic anatomy* • Surface anatomy • Microscopic anatomy • cytology – internal cell structure • histology – tissues composed of different cell types* • Developmental anatomy

3. Anatomy and Physiology Overview Topics of Physiology at the System Level Neurophysiology Renal Cardiovascular Respiratory Endocrine Muscle Gastrointestinal Reproductive Topics of Physiology at various Organizational Levels Cellular Physiology Animal Physiology Pathophysiology

4. Essential Concepts: The Complimentarity of Structure and Function • Function dependent on Structure: • mineral deposits harden – bones & teeth • valves in heart – keep blood flow unidirectional • Function is also specific to Location • cartilage is flexible and smooth– ears, nose, joints • actin/myosin interacts in muscle fibers • hairs – skin, scalp, axillae, nose, etc.

5. Essential Concepts: The Hierarchy of Structural Organization • Chemical • Cellular • Tissue • Organ • Organ System • Organismal

6. Essential Concepts: The Hierarchy of Structural Organization • Chemical • Atoms & bonds • Carbon, oxygen, hydrogen, etc. I. Molecules small inorganic small organic proteins carbohydrates lipids nucleic acids II. Cells: cytoplasm and organelles assembled from various molecules

7. Essential Concepts: The Hierarchy of Structural Organization GnRH cells • Cellular level – • Cells – the basic structural and functional units of the organism • Cells are specialized for particular functions, e.g., muscle cells are specialized for contracting • Cell organelles are subcompartments with specialized tasks

8. Essential Concepts: The Hierarchy of Structural Organization skeletal muscle tissue • Tissue level Groups of different cell types cooperate to perform specific functions • Organ level - two or more different tissue types are organized to perform specific functions

9. Essential Concepts: The Hierarchy of Structural Organization • Organ system level - connected organs that cooperate in related function(s) The Digestive System

10. Essential Concepts: The Hierarchy of Structural Organization • Organismal level - all of the organ systems working together to maintain life constitute the living organism

11. Necessary Life Functions • Maintaining Boundaries - keeping the inside separate/different from the outside • Movement - motion of the whole body, individual cells, organelles or material inside the body/cells • walking/running • food moving from the mouth throughout the GI tract • white blood cells patrolling the body to fight infection • mitochondria moving in the cell in response to oxygen • Responsiveness – detecting and responding to changes in the internal/external environments • nerve cells • muscle cells • endocrine cells

12. Necessary Life Functions • Digestion - breaking down ingested food to simple molecules to be absorbed • Metabolism - all biochemical processes in the body • catabolism – breakdown reactions • anabolism – synthetic reactions • Excretion - removing wastes from the body • Reproduction - formation of new cells for growth, repair, replacement or a new organism • Growth • increase in size, complexity • due to increased cell number or increased cell size

13. Survival Needs • Things required for an organism’s survival • Nutrients • Oxygen • Water • Normal body temperature • Atmospheric pressure – for gas exchange • All, except E above, must be maintained within fairly narrow ranges

14. Essential Concept: Homeostasis • Homeostasis is the ability to maintain relatively stable internal conditions even though the outside world changes continuously • Important for maintaining physiological limits • multiple organs and systems are working all the time • cells and organs need a relatively constant internal environment for survival • the internal environment stays within those limits due to the stability of body fluid composition

15. Homeostatic Systems Three Basic Components: • Receptor • detects change in a variable (stimulus/stress) • sends input (information) to a control center • Control Center • assesses input; sends output to effector(s) • Effector • causes response, i.e., an “effect” which is triggered by output

16. Negative Feedback Control • Results in a return to homeostatic equilibrium because the response reduces stimulus (stress) • Examples: • Regulation of blood glucose • Regulation of body temperature • Most other physiological mechanisms

17. Positive Feedback Control • Results in a shift to a new homeostatic equilibrium because the response increases the stimulus level (stress) [“snowball effect”] • Examples: • Blood clotting • Pregnancy/Childbirth • Immune responses • A few others • Most are responses to special conditions resulting in a new, temporary physiologic state

18. Homeostatic Imbalances • Pathological processes with a particular set of characteristics in which some or all parts of the body are not functioning correctly • diseases or injuries may be local or systemic • different systemic changes are present and may suggest a cause • symptoms - subjective changes in body function, not observable; reported by the individual, e.g., pain • signs - objective changes which are observable, e.g., temperature, pulse

19. The Language of Anatomy • Anatomical position: a constant reference point • Directional terms: Table 1.1, pg. 13 • Regional terms: Figure 1.7, pg. 14 • Axial • Appendicular

20. Body Planes and Sections • Sagittal • Frontal • Transverse (cross)

21. Body Cavities • Dorsal body cavity • cranial • vertebral or spinal • Ventral body cavity • thoracic • pleural • mediastinum • Abdominopelvic • abdominal • pelvic

22. Functions of the Body Cavities • They house and separate body organs • They protect and cushion organs from external impact • They allow considerable freedom for movement of internal organs without disrupting the functions of other organs - The heart, lungs, and small intestine all require the relatively uninhibited ability to move • They enable different pressures to be developed within the body without disrupting other organs - Lung cavity: breathing results from changes in pressures within the thoracic cavity

23. Serous Membranes • Line body cavities that are closed to the exterior - exceptions are the dorsal cavity and joint cavities II. Occur in pairs • The parietal layer lines a specific portion of the wall of the ventral cavity. • The parietal layer folds in on itself to form the visceral layer, which covers the outside of the organs in that cavity. • Between these layers is a very thin, fluid filled space – a cavity

24. Membranes in the Ventral Cavity • Like a “Fist in a balloon” • Membrane inside a membrane with a narrow enclosed space in between • parietal • the outer membrane • on the body wall • visceral • the inner membrane • on the organ wall • space filled with watery fluid • Body cavity lined with serous membrane (serosa) which produces the serous fluid • Membrane named depending on its position, and the cavity’s organs inside • parietal pericardium • visceral pericardium

26. The Language of Anatomy • The following slides and tables from your text are part of the subject matter of Lab 1 – be familiar with them • See your Lab Guide (on the web) and your Lab Manual as well

27. Figure 1.7A Regional terms for body areas

28. Figure 1.7B Regional terms for body areas

29. Abdominopelvic Regions

30. Table 1.1A Orientation & Directional Terms

31. Table 1.1B Orientation & Directional Terms

32. Table 1.1C Orientation & Directional Terms

33. End of Chapter 1