Respiratory system

• organs (dependant on species)

  • nasal chambers
  • larynx
  • trachea
  • bronchi
  • bronchioles
  • lungs
  • alveoli
  • diaphragm
  • gills
  • spiracles
  • skin
• functions of the respiratory system

  • oxygen in
  • carbon dioxide (waste) out
  • thermoregulation
  • sense of smell and taste
  • filter out pathogens and invaders
  • vocal communication
  • working with the circulatory system and heart
• nasal chamber

  • passages are separated by a wall called the septum
  • hard and soft palates separate passages from the mouth
  • three functions are to:

  - warm air through heat form blood vessels near the surface

  - humidify air through damp mucus lining

  - filter air through passages + sticky mucous lining (trapping particles that are then swept to the pharynx when swallowing because if cilia moving them along)
• larynx

  • short irregular tube connecting voice box to trachea (mainly made of segments of cartilage)
  • three ways which the larynx assists respiration:

  > protection - stops foreign materials getting into delicate tissues of trachea + lungs (when animal swallows flap called epiglottis covers opening of larynx)

  > control of airflow - small adjustments help air movement in the lungs. when glottis closed pressure builds up behind forcing foreign materials to expel through coughing

  > warming air + humidifying - further warms and moistens incoming air
• trachea

  • short wide tube extending through neck region to chest where it divides to two tubes, entering the lungs. bronchi made of fibrous tissue, held open by cartilage rings and has tissue hairs in lining
  • functions of trachea are:

  > keep airway open

  > warm + moisten air

  > trap foreign materials + move back to pharynx to be swallowed

  > when many foreign materials inhaled more mucus formed, trapping them + it is coughed up out of airways
• bronchi and bronchioles

  • trachea divides to left and right bronchi, similar structure/function to trachea
  • subdivides into smaller + smaller airways termed 'bronchial tree'
  • the 'trunk' of the tree called the bronchus
  • airways from bronchioles onwards have smooth muscle fibres in walls (these dilate/contract airway, helping move air from alveoli sacks)
• alveoli

  • tiny sacks arranged like bunches of grapes at end of alveolar ducts (group of alveoli called 'alveolar sack'
  • millions of alveoli in lungs
  • large SA, absorbing oxygen + transporting gases
  • moist surface allows oxygen to dissolve
  • thin lining (one cell) allowing easy diffusion
  • dense network of blood capillaries means easy gas exchange
• diaphragm

  • located below the lungs
  • major muscle of respiration
  • large dome shaped muscle which contracts
• respiration

  • swapping O2 for CO2
  • provides O2 to body
  • removes waste (CO2)
  • breathing O2 in - inspiration
  • breathing CO2 out - expiration
• inspiration/inhalation

  • muscles move ribs up + out
  • diaphragm contracts
  • lungs relax + draws in air
• expiration/exhalation

  • muscles move ribs down and in
  • diaphragm relaxes
  • lungs get smaller increasing pressure + push air out
• aerobic respiration

  • needs oxygen present
  • occurs in most cells most times
  • cells aerobic respiration occurs in mitochondria
• anaerobic respiration

  • no oxygen needed
  • less frequent then aerobic
  • glucose -> lactic acid
  • during exercise when not enough oxygen
  • releases less energy