Respiratory system:

• Respiration = uptake, transportation and release by an organism involving O2 and CO2.
• Upper respiratory tract components = nose, throat, sinuses, larynx, trachea and guttural pouches.
• Lower respiratory tract components = bronchi and lungs (thoracic cavity and diaphragm have a close connection).
• The respiratory centre in the medulla oblongata controls breathing.
• Breathing can also be consciously controlled.
• Flared/contracted nostrils allow greater inspiration.
• Nasal cavity = divided in half by a nasal septum, nasal conchae divides each half into 3 nasal passages and there is a hard palate at the bottom with a mucous membrane.
• Olfactory mucous membrane = back of the nasal cavity where smell is detected.
• Frontal sinuses = small and sit in front of the brain.
• Maxillary sinuses = upper jaw above the molar teeth.
• Eustachian tubes = connect respiratory section of the throat to the middle ear.
• Guttural pouches = air filled chambers, they regulate the temperature of blood flowing into the brain during exercise.
• Empyema = pus accumulation in the guttural pouches which can lead to discharge.
• Recurrent pharyngeal nerve = controls the larynx muscles and is susceptible to damage (sound distorts).
• The trachea is lined with mucous and cilia.
• Lymph nodes = produce WBCs and antibodies.
• Immune cells are found in the lung connective tissue and alveoli.
• Pleura = smooth cell layer to reduce friction during breathing. A thin membrane that surrounds the thoracic cavity and diaphragm.
• Pulmonary emphysema = small air volume remains in the lungs causing it to distend.
• Gas exchange SA on the lungs = 1,300 m2.
• Tidal volume = 6 litres at rest.
• Minute ventilation = 70-95 litres/minute at rest and 2000 litres/minute during exercise.
• Paranasal sinuses = protect + insulate the head and allow for large skull regions regardless of weight.
• Nasopharynx = caudal to the choanae.
• Oropharynx = caudal to the mouth.
• Laryngopharynx = surround the larynx.
• Phonation = vocalisation in the larynx.
• Hilus = medial lung aspect with an indent where the: bronchi, pulmonary vessels, lymphatics and nerves enter/exit the lung.
• Ventilation = air is inspired into and expired out of the lungs.
• Alveolar ventilation = air in and out of the alveoli.
• Tidal volume = volume of air inspired and expired per breath.
• Boyle's law = inverse relationship between volume and pressure of gas.
• Eupnea = normal, quiet breathing.
• Obligate nasal breather = only breaths through their nose.
• The soft palate near the epiglottis prevents breathing through the mouth.
• Upper respiratory tract = airways in the head and neck.
• Lower respiratory tract = airways supplying the lungs and lung tissues.
• Dead space = nasal cavity to bronchioles where there is no gaseous exchange.
• Extra thoracic portion = nostrils to bronchi - dead space.
• Intrathoracic portion = lungs and the site of gaseous exchange.