gen bio 2 l3

• Produce the chemical insulin


  • Pancreas
• Homeostasis is the maintenance of relatively stable conditions
• Organ system that allows us to exchange oxygen to carbon dioxide

  • Respiratory system
• Allows blood to travel throughout the body

  • Circulatory system
• Nervous control of homeostasis

  The nervous system detects changes from the normal state and sends out nerve impulses to organs to counteract the change
• Examples of maintaining homeostasis

  • Keeping body temperature around 37 degrees
  • Maintaining blood glucose level
  • Keeping oxygen concentration steady
• Feedback system


  Cycle of events in which the status of a body condition is continually monitored, evaluated, changed, remonitored, reevaluated, and so on
• Every body structure contains homeostatic devices that work to keep the internal environment within normal limits
• Stimulus


  Any disruption that causes a change in a controlled condition
• Negative feedback systems reverse the change in a controlled condition
• Disorder: Any disturbance of the structure or function of the body
• Examples of positive feedback systems


  • Childbirth
  • Ovulation
  • Blood clotting
• This is where the digestion starts

  • Digestive system
• Allows control for the body through communication within certain parts

  • Nervous system
• Homeostasis ensures the body’s internal environment remains steady despite changes both inside and outside the body
• Homeostasis


  Maintaining relatively stable conditions
• Body systems controlling most homeostatic devices

  • Endocrine
  • Nervous
• Endocrine control of homeostasis


  Corrects changes by secreting hormones into the blood. Hormones affect specific body cells causing responses that restore homeostasis
• Homeostasis and disease: If components of the body lose their ability to contribute to homeostasis, the normal balance among all the body’s processes may be disturbed, resulting in a disease, disorder, or even death
• Components of a feedback system

  1. Receptor – monitors change

  2. Control center – sets a range of acceptable values, evaluates input from the receptor and sends output to an effector

  3. Effector – a body structure that receives output from the control center and produces a response or effect that changes the controlled condition
• Positive feedback systems enhance or reinforce the initial change in the controlled condition
• Controlled condition

  Each condition in the body that is monitored in a feedback system
• Dynamic equilibrium

  Homeostasis can fluctuate over a narrow range compatible with life. Death may result if certain levels fall outside this range for a prolonged period of time
• If 1 or more components of the body lose their ability to contribute to homeostasis, the normal balance among all the body's processes may be disturbed. This may result in a disease, disorder, or even death
• Controlled conditions happen in stimuli that do not happen very often
• Disorders

  • Diabetes
  • Graves' disease
  • Hypothermia or Hyperthermia
  • Dehydration
  • Hypertension
  • Hemochromatosis
  • Parathyroid disorders (calcium levels in blood)
  • Myocardial infarction (heart attack)
• Local disease

  Affects one part or region of the body
• Pathology


  The science that deals with the nature, causes, and development of abnormal conditions that occur from the disease process
• Symptoms

  Subjective changes in the body function that are not apparent to an observer
• Pharmacology


  The science that deals with the effects and uses of drugs in the treatment of disease
• Aging is a normal process characterized by a progressive decline in the body's ability to restore homeostasis. It produces observable changes in structure and function and increases vulnerability to stress and disease
• Signs


  Objective changes that a clinician can observe and measure
• Disease is a more specific term for an illness that is characterized by a specific set of signs and symptoms
• Homeostasis


  The body's ability to maintain internal stability and balance despite external changes
• Disorder is any disturbance of the structure or function of the body
• Epidemiology


  The science that deals with the why, when, and where diseases occur and how they are transmitted in a human body
• Systemic disease


  Affects several body parts or the whole body
• Infectious disease occurs when pathogens invade a host and cause a disease
• Diagnosis


  The identification of a disease or disorder based on a scientific evaluation of a patient's signs and symptoms, medical history, physical examination, and sometimes lab tests