Study of Respiratory System

  • The respiratory system consists of the nose, pharynx, trachea, bronchi and lungs. They act with the cardio- vascular system to supply oxygen  and remove carbon dioxide from the blood.
  • The external portion of the nose made of cartilage , skin and these is line with a mucous membrane . Opening to the exterior are the external nacres.
  • The internal portion of the nose communicate with the par nasal sinfns and nasopharynx.
  • The nasal cavity is divided into septum. The interior portion of the cavity is called vestibule. The nose warms, moisten and filter air.
  • The pharynx (throat) is a muscular tubes line by a mucous membrane. The anatomy resions are nasopharynx , oropharynx and larynopharynx function both is digestion and respiration.
  • The larynx (voice box) is a passage way that connect the pharynx with the trachea. It contain the light thyroid cartilage (Adam apple) the epiglottis, which prevent food from entry the larynx.
  • The larynx contains vocal folds , which produce sound as a vibrate.
  • The trachea extends  from the larynx to the primary bronchi. It is composed of C- shaped of cartilage and smooth muscles and lined with pseudo stratified ciliated columnar epithelium.
  • The bronchioles tree consists of trachea ,primary bronchioles, secondary bronchioles, tertiary bronchioles and terminal bronchioles (Alveoli).
  • Lungs are paired organ in the thoracic cavity and closed by the pleural membrane. Which are divided two layers outer is visceral pleura and inner is parletal pleura.
  • The right lungs is three lobes and left lung is two lobes.
  • Secondary bronchioles give to branches called segmental bronchi , which supply segment of lungs tissue called bronchi pulmonary segments.
  • Each bronchi pulmonary segments consists of lobules which contain lymphatic , atrobules ,alveolar ducts, alveolar sacs and alveoli.
  • Gases excess occurs across the respiratory membrane.

Transport of Oxygen and Carbon dioxide:

  • In each 100 ml of oxygenated blood 1.5% of oxygen is dissolve into blood plasma and 98.5% is bound to haemoglobin and as oxyhaemoglobin.
  • The binding of oxygen to haemoglobin is affected by PO2, acidity PH, PCo2 and temperature.
  • Fetal haemoglobin differ from adult haemoglobin in structure and as a higher affinity for oxygen.
  • In each 100 ml of deoxygenated blood, 9% of carbon dioxide is dissolved into blood plasma ,13% of carbon dioxide combined with haemoglobin and formed card amino haemoglobin and 78% carbon dioxide is transported by converting into bicarbonates ion (HCo-3).
  • In an acitic environment haemoglobin affinity for oxygen is lower and oxygen dissociated more radily.
  • In the presence of oxygen the carbon dioxide is less bind from carbon dioxide.

Pulmonary Ventilialus (P.V):

  • P.V are breathing consists of inhalation and exhalation. The moment of air into and out of lungs depend on the pressure.
  • Inhalation occurs when alveolar pressure falls below atmosphere pressure.
  • Contraction of diaphragm and external intercostals .
  • There bind decrease the intra pleural pressure . So, that the lungs expand. Expansion of lungs decrease as alveolar pressure . So, that air moves down a pressure radiant from the atmosphere into lungs.
  • During forceful inhalation accessory muscles of inhalant are used.
  • Exhalation occurs when alveolar pressure is higher than atmosphere pressure.
  • Relaxation of diaphragm and external inter costal muscle recoil of the chest wall and lungs , which increase intra pleural pressure.
  • Lungs volume decrease alveolar pressure increase . So, air moves from the lung to atmosphere pressure.
  • Forceful exhalation involve contraction of the intercostal muscle and abdominal muscles .

Bhanu Pratap Singh


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