Human Respiratory System By: D. Reis
The Respiratory System • Air enters the respiratory system through both the nasal cavity and mouth. • The nasal cavity is lined with tiny hairs and mucus to trap foreign particles. • The air is warmed and moistened.
The Respiratory System • Pharynx – where the nasal cavity and oral cavity meet • Epiglottis – flap that closes over the top of the trachea(glottis) due to reflexive action while eating • Trachea – the windpipe through which air passes Supported by cartilage rings
The Respiratory System • Larynx – voicebox located in the trachea containing vocal cords. The vocal cords vibrate producing sounds. • Adam’s Apple – thick band of cartilage protecting larynx.
The Respiratory System • Bronchi – extend from the trachea also contains cartilage • Bronchioles – the smallest passageways of the respiratory tract • Alveoli – tiny air sacs where gas exchange occurs between the air and the blood
Alveoli • Each lung is made up of 150 million alveoli. • Capillaries surround each cluster of alveoli and ensure gas diffusion between the air and blood occurs. • Oxygen moves from the air inside the lungs to the alveoli while carbon dioxide moves from the alveoli into the air inside the lungs. • Lipoprotein prevents alveoli from sticking together
Goblet cells • Goblet cells – mucus secreting cells lining the trachea, bronchi and bronchioles to trap foreign particles. • Cilia- hair like structures that sweep the foreign particles up towards the mouth
Thoracic Cavity • External intercostal muscles – muscles between the ribs that raise the rib cage, increasing volume and reducing air pressure in chest. • Diaphragm – muscle that separates organs of the chest from abdominal cavity.
Pleural membrane – thin fluid-filled membrane surrounding lungs and inner wall of chest cavity that reduces friction during inhalation.
The Movement of Air • Air moves from an area of high pressure to an area of low pressure. • Air will move into the lungs when the air pressure inside the lungs is less than the air pressure outside the body. • Air will move out of the lungs when the air pressure inside the lungs is______ than the air pressure outside the body.
Inspiration (Inhaling) • The diaphragm contracts and moves down • External intercostal musclesexpand rib cage upward and outward • Volume of thoracic cavityincreases therefore air pressure decreases. • Movement of air into the lungs.
Expiration (Exhaling) • The diaphragm relaxes and moves up • External intercostal muscles move rib cage inward and downward. • Volume of thoracic cavitydecreases therefore air pressure increases. • Movement of air out of the lungs.