Define respiratory system in human beings.5marks

Asked by akhileshsingh.future | 18th Nov, 2018, 03:29: PM

Expert Answer:

Respiratory system in human beings:

The respiratory system in human beings consists of the nose, pharynx, larynx, trachea, bronchi and lungs.

  • Air is taken in through the nostrils.
  • Nostrils further continue into the nasal cavity.
  • There is a bony plate called the palate, which separates the oral cavity from the nasal cavity.
  • Nasal cavity opens into the pharynx.
  • The pharynx is a muscular chamber acting as a common passage for the windpipe or trachea and the food pipe or oesophagus.
  • It is connected to the larynx through a slit-like opening called the glottis.
  • The larynx connects the pharynx to the trachea.
  • The trachea shows the presence of cartilaginous rings.
  • The cartilaginous rings provide flexibility thus, facilitating continuous air flow.
  • The inner wall of the trachea is lined by a mucous membrane consisting of ciliated columnar epithelium.
  • The trachea divides into two branches or tubes called bronchi, one of which enters the right lung and the other enters the left lung.
  • The bronchi have cartilaginous rings for distention.
  • Each bronchus divides into fine secondary bronchi. These bronchi further divide into finer tertiary bronchi. In the lungs, each bronchus finally divides into finer and smaller branches called bronchioles.
  • The bronchioles further divide to form smaller terminal bronchioles.
  • The bronchioles divide repeatedly to form a cluster of tiny air chambers called air sacs or alveoli.
  • Alveoli have thin and moist walls which enable gaseous diffusion with blood capillaries.
  • The lungs are a pair of spongy and elastic respiratory organs protected by a bony rib cage.
  • The base of the lungs rests on the diaphragm.
  • Each lung is covered by two membranes. The inner membrane is called the inner or visceral pleura and the outer membrane is called the outer or parietal pleura.
  • The diaphragm is a curved, musculo-fibrous sheath which separates the thoracic cavity from the abdominal cavity.
  • The diaphragm plays a major role during respiration.

Answered by Sheetal Kolte | 19th Nov, 2018, 11:55: AM