Respiratory System in animals

  

The respiratory system begins at the nose and ends at the distal alveoli. It is comprised of the upper and lower airways. The upper airway includes the nose, sinuses, and pharynx. The nose provides olfaction and temperature regulation in hyperthermic patients. The nasal turbinates initially humidify and warm air, and filter particulate matter. The lower airways include the trachea, bronchi, bronchioles, and alveoli. The primary function of the respiratory system is to deliver oxygen to the lungs to be exchanged with carbon dioxide.

Gas exchange occurs in the alveoli, which are comprised of one-cell-layer-thick membranes in which oxygen moves into the capillary and where carbon dioxide moves into the alveoli from the blood in the capillary. Failure or major dysfunction of gas transfer due to disease leads to respiratory distress or failure. Additional functions of the respiratory system include maintaining acid-base balance, acting as a blood reservoir, filtering and probably destroying emboli, metabolizing some bioactive substances (eg, serotonin, prostaglandins, corticosteroids, and leukotrienes), and activating some substances (eg, angiotensin).

Large, inhaled airborne particles enter the nose and are deposited along the mucous lining of the nasal passages. Cilia move these particles along the mucosal barrier to the pharynx to be swallowed or expectorated. Small particles may not be filtered on inhalation and may be deposited in the alveoli, where they are phagocytized by macrophages. Defense against invasion by microorganisms and other foreign particles is provided by this mucociliary "blanket" and by cellular and humoral immunity. These factors determine species and individual susceptibility to disease and may be manipulated through various management techniques, vaccines, antimicrobials, and other agents, such as interferons and lymphokines. Mechanical factors include the tortuosity of nasal passages; presence of hairs, cilia, and mucus; the cough reflex; and bronchoconstriction. Cellular defenses include neutrophils and macrophages. The latter phagocytize invaders and present them (or at least their important antigens) to lymphocytes for stimulation of an immune response. Secretory defenses include interferon for antiviral defense, complement for lysis of invaders, surfactant lining the alveoli to prevent their collapse and to facilitate macrophage function, fibronectin to modulate bacterial attachment, antibodies, and mucus.  

The functions of Respiratory System in animals

• The major functions of the respiratory system are providing oxygen to tissues and cells and removing carbon dioxide from the body. Other important functions include, and.
• It provides oxygen to tissues and cells 
• It delivers oxygen to the cardiovascular system (for distribution to the body) 
• It removes carbon dioxide from the body
• It controls body temperature
• It eliminates water (as vapor)
• It aids in voice production
• It maintains acid-base balance
• It acts as a blood reservoir
• It filters and destroys emboli 
• It metabolizes some bioactive substances 
• It activates some substances 
• It protects its own delicate airways by warming and humidifying inhaled air and by filtering out particulate material. The upper airways also provide for the sense of smell and play a role in temperature regulation in panting animals.