The Respiratory System
On average each day we breathe 20,000 times to expel waste gases and intake oxygen.
The respiratory system brings air from the atmosphere into the lungs, transfers oxygen into the blood, removes carbon dioxide from the blood, expels heat and water vapour in air breathed out and allows the vocal cords to create speech. When we breathe air in, our nasal cavity warms, filters and moistens the intake.
From your nose to your bronchial, Cilia line your respiratory tract. Cilia are tiny hairs which filter out most of the dust and impurities. The epiglottis is a little flap at the junction of your oesophagus, trachea and pharynx. The epiglottis’ function is to cover the trachea when swallowing food and liquid to prevent the matter entering and blocking your airways. When you choke, the term ‘gone down the wrong way’ is used, what happens is food or liquid has gotten passed the epiglottis and is blocking the airway. The larynx or voice box is at the top of the trachea. The Nasal cavity – initial pathway, air warmed and moistened, layers of tissue called septa which are covered with hair like fibres called cilia, acts as a filter, smoking destroys cilia
The Pharynx – section where back of mouth and throat combine, air also warmed in this region The Larynx – more evident in males “Adams apple”, contains vocal cords The Trachea – windpipe, made up of rings of hyaline cartilage, sits behind sternum = well protected The Bronchi – two tubes that provide air to the lungs The Bronchioles – branches after bronchus The Alveoli – leaves of the tree, one cell thick, surrounded by capillaries, where gaseous exchanges occur The Pleura – membrane covering the lungs, separated by fluid to allow expanding and contracting during breathing The Diaphragm – involuntary muscle, contracts and relaxes with breathing, moves up and down chest cavity decreases and increases in size causing breathing Transfer & Transport of Gases: Most oxygen is transported by RBC combined with Hb and form oxyhaemoglobin. Most oxygen is transported by the red blood cells combined with hemoglobin (Hb) and when the two combine they form oxyhaemoglobin: Haemoglobin + Oxygen = Oxyhaemoglobin Hb + O2 = HbO2 Inspiration: Inhaling Air Expiration: Exhaling Carbon Dioxide and Water Vapour Movement of gases at the alveoli is two way: oxygen moves from the alveoli into the blood & carbon dioxide moves from the blood to the alveoli. Pulmonary Diffusion occurs in the lungs and as having two main functions: 1. To provide un-oxygenated blood oxygen before being transported to the muscles and other cells & 2. To remove carbon dioxide from returning blood. |