Chapter 1 – The Human Body: An Orientation

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Chapter 1 The Human Body An Orientation

• J.F. Thompson, Ph.D.

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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

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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

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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.

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Essential Concepts The Hierarchy of Structural
Organization

• Chemical
• Cellular
• Tissue
• Organ
• Organ System
• Organismal

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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

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Essential Concepts The Hierarchy of Structural
Organization

• 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

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Essential Concepts The Hierarchy of Structural
Organization

• 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

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Essential Concepts The Hierarchy of Structural
Organization

• Organ system level - connected organs that
  cooperate in related function(s)

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Essential Concepts The Hierarchy of Structural
Organization

• Organismal level - all of the organ systems
  working together to maintain life constitute the
  living organism

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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

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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

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Survival Needs

• Things required for an organisms survival
• Nutrients
• Oxygen
• Water
• Normal body temperature
• Atmospheric pressure for gas exchange
• All, except E above, must be maintained within
  fairly narrow ranges

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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

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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

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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

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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

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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

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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

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Body Planes and Sections

• Sagittal
• Frontal
• Transverse (cross)

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Body Cavities

• Dorsal body cavity
• cranial
• vertebral or spinal
• Ventral body cavity
• thoracic
• pleural
• mediastinum
• Abdominopelvic
• abdominal
• pelvic

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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
  cavitys organs inside
• parietal pericardium
• visceral pericardium

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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

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Figure 1.7A Regional terms for body areas
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Figure 1.7B Regional terms for body areas
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Abdominopelvic Regions
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Table 1.1A Orientation Directional Terms
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Table 1.1B Orientation Directional Terms
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Table 1.1C Orientation Directional Terms
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End of Chapter 1