ANAPHY CHAPTER 1

• Anatomy


  The scientific discipline that investigates the body's structures—for example, the shape and size of bones. In addition, anatomy examines the relationship between the structure of a body part and its function.
• Anatomy at different levels

  • Developmental anatomy
  • Embryology
  • Cytology
  • Histology
  • Gross anatomy
  • Systemic anatomy
  • Regional anatomy
  • Surface anatomy
• Developmental anatomy


  Studies the structural changes that occur between conception and adulthood
• Embryology


  Subspecialty of developmental anatomy, considers changes from conception to the end of the eighth week of development
• Cytology


  Examines the structural features of cells
• Histology


  Examines tissues, which are composed of cells and the materials surrounding them
• Gross anatomy


  Study of structures that can be examined without the aid of a microscope, can be approached either systemically or regionally
• Systemic anatomy


  The body is studied area by area, used in this and most other introductory textbooks
• Regional anatomy


  Within each region, such as the head, abdomen, or arm, all systems are studied simultaneously, taken in most graduate programs at medical and dental schools
• Surface anatomy


  Involves looking at the exterior of the body to visualize structures deeper inside the body
• Anatomical anomalies


  Physical characteristics that differ from the normal pattern, can vary in severity from relatively harmless to life-threatening
• Physiology


  The science of the normal function of living systems, the major goals are to understand and predict the body's responses to stimuli and to understand how the body maintains conditions within a narrow range of values in a constantly changing environment
• Physiology at different levels

  • Cell physiology
  • Systemic physiology
  • Neurophysiology
  • Cardiovascular physiology
• Cell physiology


  Examines the processes occurring in cells
• Systemic physiology


  Considers the functions of organ systems
• Neurophysiology


  Focuses on the nervous system
• Cardiovascular physiology


  Deals with the heart and blood vessels
• Anatomical imaging


  Uses radiographs (X-rays), ultrasound, magnetic resonance imaging (MRI), and other technologies to create pictures of internal structures
• Anatomical imaging has revolutionized medical science, with the past 20 years seeing as much progress in clinical medicine as occurred in all of medicine's previous history
• Anatomical imaging allows medical personnel to look inside the body with amazing accuracy and without the trauma and risk of exploratory surgery
• Wilhelm Roentgen became the first medical scientist to use X-rays to see inside the body

  1895
• 1. ray


  Extremely shortwave electromagnetic radiation that moves through the body, exposing a photographic plate to form a radiograph
• Ultrasound


  Uses high-frequency sound waves, which are emitted from a transmitter-receiver placed on the skin over the area to be scanned, sound waves strike internal organs and bounce back to a receiver on the skin
• Computed tomographic scan


  Developed in 1972 and originally called computerized axial tomographic (CAT) scans, are computer analyzed X-ray images
• Digital subtraction angiography


  A 3-D radiographic image of an organ, such as the brain, is made and stored in a computer, then a radiopaque dye is injected into the blood, and a second radiographic computer image is made, the first image is subtracted from the second one, greatly enhancing the differences revealed by the injected dye
• Magnetic resonance imaging


  Directs radio waves at a person lying inside a large electromagnetic field, the magnetic field causes the protons of various atoms to align, and the time it takes the hydrogen atoms to realign is different for various body tissues, these differences can be analyzed by computer to produce very clear sections through the body
• Positron emission tomography


  Can identify the metabolic states of various tissues, particularly useful in analyzing the brain, when cells are active they take up radioactively treated glucose, as the radioactivity decays, positrons are emitted and annihilate with electrons, giving off gamma rays that can be detected to pinpoint metabolically active cells
• Whenever the human body is exposed to X-rays, ultrasound, electromagnetic fields, or radioactively labeled substances, a potential risk exists, this risk must be weighed against the medical benefit
• Positron Emission Tomography (PET)


  • Can identify the metabolic states of various tissues
  • Particularly useful in analyzing the brain

  
• How PET works


  1. Radioactively treated ("labeled") glucose is given to a patient

  2. Active cells take up the labeled glucose

  3. As the radioactivity in the glucose decays, positrons are emitted

  4. Positrons collide with electrons and annihilate each other, emitting gamma rays

  5. Gamma rays can be detected, pinpointing the metabolically active cells
• When cells are active, they are using energy supplied by the breakdown of glucose (blood sugar)
• Whenever the human body is exposed to X-rays, ultrasound, electromagnetic fields, or radioactively labeled substances, a potential risk exists
• Risk vs medical benefit


  The risk must be weighed against the medical benefit
• Numerous studies have been conducted and are still being done to determine the effects of diagnostic and therapeutic exposure to X-rays
• The risk of anatomical imaging is minimized by using the lowest possible doses providing the necessary information
• No known risks exist from ultrasound or electromagnetic fields at the levels used for diagnosis
• Both surface anatomy and anatomical imaging provide important information for diagnosing disease
• Life is characterized by a high degree of order, and the biological organization is based on this order
• Levels of biological organization

  • Each level is more complex compared with the level preceding it
  • The higher degree contains all the characteristics of the one on its lower level, and it usually has other characteristics, called an emergent property, in addition to what the former level has
• Chemical level


  • Involves interactions between atoms, which are tiny building blocks of matter
  • Atoms combine to form molecules, such as water, sugar, lipids, and proteins
  • The function of a molecule is intimately related to its structure