Biology Take-Home Assignment
Describe the process of respiration in man and toad using suitable diagrams
BY: Nwaezeigwe Franklin
The Process of Respiration in Man
The Respiratory system in Man: The human respiratory system is typical of the respiratory systems of mammals in general. It includes the nasal passages or nostrils, the pharynx, the larynx, the bronchi and the lungs.
The respiratory system starts with the nose that encloses the nasal cavity. The nasal cavity opens outside through the openings called the nostrils. The nasal cavity is divided into two portions by a cartilaginous septum and is lined by fine hairs that filter the dust particles from the air. The nasal cavity is separated from the mouth by hard and soft palate that forms its floor. It opens into the region called the pharynx. The pharynx leads into the larynx or the voice box. The larynx is held open with the help of cartilages. 'Adam 's apple ' is a prominent cartilage of larynx. The larynx leads into the trachea or wind pipe. The trachea is held open with the help of C-shaped cartilaginous rings. The open ends of the rings are towards the oesophagus also known as the food pipe, it lies just behind the trachea and it prevents food particles from falling into the larynx and trachea when food is being swallowed. The trachea then branch into two main branches called bronchi.
Each bronchus is also supported by the cartilaginous rings. The bronchus then branches into smaller tubes called bronchioles. The bronchioles progressively lose the cartilages as they become narrower. The bronchioles end as fine tubules called the alveolar ducts. The alveoli communicates with the atmosphere through a continuous air passage leading from them to the bronchioles, bronchi, trachea, larynx, pharynx, nostrils, and mouth.
The mass of each lung consists mainly of numerous air sacs and the small tubes (bronchioles) which lead into them. The alveoli are richly supplied with blood
References: * F.O.C NDU etal, Senior Secondary Biology 2, Longman * Respiratory system - Wikipedia, the free encyclopedia * respiration (biology)-- Britannica Online Encyclopedia