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• Homeostasis


  The ability to maintain a relatively stable internal environment in an ever-changing outside world
• Internal environment of the body

  • In a dynamic state of equilibrium
  • Chemical, thermal and neural factors interact to maintain homeostasis
  • Maintaining balance in relation to its environment
• Set temperature


  If the body detects the environment is too hot or too cold, it will make mechanisms to maintain the temperature inside
• Body fluids


  Dilute, watery solutions<|>Intracellular fluid (ICF) is inside cells<|>Extracellular fluid (ECF) is outside cells<|>Plasma is the ECF within blood vessels<|>Interstitial fluid is the ECF that fills spaces between tissue cells
• Disruptions of homeostasis


  Come from external and internal stimuli and psychological stresses<|>When mild and temporary, responses of body cells quickly restore balance<|>If disruption is extreme, regulation of homeostasis may fail
• Nervous and endocrine systems

  • Act together or separately to regulate homeostasis
  • Nervous system detects body changes and sends nerve impulses to counteract changes
  • Endocrine system regulates homeostasis by secreting hormones
• Components of a homeostatic control system

  1. Receptors

  2. Afferent

  3. Control Center

  4. Efferent

  5. Effector
• Receptors


  Respond to environmental changes via stimulus (change in environment)
• Afferent


  Delivers the information from the receptors to the control center
• Control Center


  Gives out the response<|>Maintains and analyses information
• Efferent


  Delivers the response from the control center to the effector
• Effector


  Response to stimulus
• Feedback system or feedback loop


  A cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated, and so on
• Controlled condition


  Any monitored variable, such as body temperature, blood pressure, or blood glucose level
• Stimulus


  Any disruption that changes a controlled condition
• Negative feedback mechanism


  One of the mechanisms to maintain balance<|>It does the other way (high to low - low to high)<|>It includes most homeostatic controls<|>Shuts off the original stimulus or reduces its intensity
• Negative feedback mechanism


  • Temperature regulation
  • Blood pressure regulation
  • Water imbalance regulation
• Positive feedback mechanism


  Intensifies the stimuli<|>Not homeostatic in nature<|>Can lead to a person's death
• Positive feedback mechanism


  • Blood pressure and heart rate drop
  • Extreme blood loss
  • Uterine contraction
• Homeostatic imbalance


  Disturbance in homeostasis<|>As we age, body organs become less efficient and internal conditions become less stable, increasing risk of illness and aging changes
• Factors in health balance

  Environment and own behavior<|>Genetic makeup<|>Air, food, and thoughts
• Disorder


  Any abnormality of structure or function
• Disease


  A more specific term for an illness characterized by a recognizable set of signs and symptoms<|>Local disease affects one part or a limited region<|>Systemic disease affects either the entire body or several parts of it
• Symptoms


  Subjective changes in body functions not apparent to an observer
• Signs


  Objective changes that a clinician can observe and measure<|>Anatomical, such as swelling or a rash<|>Physiological, such as fever, high blood pressure, or paralysis
• Epidemiology


  The science that deals with why, when, and where diseases occur and how they are transmitted among individuals in a community
• Pharmacology


  The science that deals with the effects and uses of drugs in the treatment of disease
• Anatomical position


  Standard position of the body<|>Body erect<|>Feet slightly apart<|>Palms facing forward<|>Thumbs point away from the body
• Directional terms


  • Superior (cranial or cephalad)
  • Inferior (caudal)
  • Ventral (anterior)
  • Dorsal (posterior)
  • Medial
  • Lateral
  • Bilateral
  • Intermediate
  • Contralateral
  • Ipsilateral
  • Proximal
• Superior (cranial or cephalad)


  Upward. Toward the head end or upper part of a structure or the body
• Inferior (caudal)


  Downward. Away from the heard end or toward the lower part of a structure or the body; below
• Ventral (anterior)


  Front. Toward or at the front of the body
• Dorsal (posterior)


  Toward or the backside of the body
• Medial


  Middle. Toward or at the midline of the body. On the inner side of
• Lateral


  Side. Away from the midline of the body. On the outer side of
• Bilateral


  Refers to paired structures, one of which is on each side of midline
• Intermediate


  Between a more medial or a more lateral structure, in-between (compares 3 parts)
• Contralateral


  Refers to structures on the opposite side
• Ipsilateral


  Same side
• Proximal


  Near the point of attachment. Close to the origin of the body part or the point of attachment of a limb to the body trunk