Respiratory System

• Human Respiratory System


  sustains tissue functions in the human body by facilitating exchange of gases or oxygen and carbon dioxide with external environment
• Pulmonary Ventilation


  "breathing" ; process of air flowing into the lungs during inspiration & out of the lungs during expiration
• External Respiration


  process that moves oxygen from lungs to blood & carbon dioxide from blood to the air spaces in the lungs (between alveoli pulmonary capillaries)
• Transport of Gases


  involves movement of oxygen from lungs to tissues of the body & carbon dioxide from tissues to lungs removal
• Internal Respiration

  • exchange of gases with the internal environment and occurs in the tissues
  • oxygen diffuses from blood to the tissues & carbon dioxide from tissues to the blood
• Conducting Zone


  passageway of air into lungs
• Respiratory Zone


  consists of structures that facilitate the actual gas exchange
• Parts of Upper Respiratory Tract

  • Nose
  • Nasal Cavity
  • Pharynx
  • Epiglottis
  • Larynx
• Nose

  • primary entrance of air into the respiratory tract
  • helps moisten, warm, and filter incoming air
  • nostrils (primary opening) lead to nasal cavity (inner chamber)
• Nasal Cavity

  • consists of nasal hairs, vibrissae & cilia, both filter air
  • lined with the mucous membrane with cells that produce mucus (help trap particles from the air)
• Pharynx

  • throat
  • connects mouth and nasal cavity to the esophagus
  • passageway for air & food into esophagus
• Nasopharynx

  • top of throat
  • connects nose to respiratory system
• Oropharynx

  • middle of throat
  • contains tonsils at base of the tongue & connects to oral cavity
• Hypopharynx

  • bottom of throat
  • regulates movement of food to esophagus
• Epiglottis

  • small-leaf shaped sheet of elastic cartilage that protects larynx and helps in swallowing
  • located behind tongue, above & infront larynx
• Larynx

  • "voice box"
  • hollow tube in middle of neck, above trachea & behind esophagus
  • helps in sound production & protects trachea from food aspiration
• Parts of Lower Respiratory Tract

  • Trachea
  • Bronchi
  • Lungs
  • Diaphragm
• Trachea

  • windpipe ; connects larynx to the rest of the lungs
  • consists of cilia that help propels debris-containing mucus back into esophagus
  • primary function: allow passage of inspired & expired air into & out of lungs
  • midline structure & lies just anterior the esophagus
  • after it originates from larynx, divides into L & R mainstem bronchi
• Bronchi

  • large tubes, connect to trachea, & direct air you breathe to L & R lungs
  • moisturize air we breathe & screen out foreign particles
  • lined with cilia (helps move mucus & particles out lungs)
  • branches into smaller bronchi & even smaller tubes called bronchioles
• Left Bronchus

  • carries air to left lung
• Right Bronchus

  • carries air to right lung
• Lungs

  • primary respiratory organ
  • elastic, can expand to change air pressure
  • makes oxygen avail. to body & removes other gases (carbon dioxide), process 12 - 20 mins
  • both R & L lungs are covered with pleural tissue
• Right Lung

  • 3 lobes
  • superior, middle, inferior
  • shorter but wider
• Left Lung

  • 2 lobes
  • superior, interior
  • smaller , bc heart is where the middle lobe on your L Lung would be
  • 2 parts: cardiac notch & lingula
• Diaphragm

  • thin dome-shaped muscle that helps inhale and exhale
  • sits below lungs & heart, attached to sternum, bottom of rib cage. & spine
  • separates chest from abdominal cavity
  • inc. pressure inside abdomen & helps with other important functions:
  • remove urine & feces
  • prevent acid reflux, by putting pressure on esophagus
• General Mechanism of Breathing

  Respiratory muscle contraction -> volume inc. in lungs -> air pressure dec. in lungs -> AIR IN

  Respiratory muscle relaxation -> volume dec. in lungs -> air pressure inc. in lungs -> AIR OUT