Presentation on theme: "Gas Exchange in Vertebrates"— Presentation transcript:
1Gas Exchange in Vertebrates Gas exchange refers to the physical methods that organisms have for obtaining oxygen from their surroundings and removing excess carbon dioxide.
2C6H12O6 +O2 (g) CO2 (g) + H2O(l) + Energy Gas ExchangeWhy must organisms carryout gas exchange?Organisms that carry out the process of aerobic respiration require oxygen to break down and obtain energy from nutrients like glucose.C6H12O6 +O2 (g) CO2 (g) + H2O(l) + Energy
3Respiratory SurfacesIn order for oxygen to enter an organism it must first pass through a respiratory surface. Respiratory surfaces have several characteristics:The surface must be very thinThe surface must be moist. This is due to the fact both oxygen and carbon dioxide must be dissolved in water.
4Respiratory Surfaces3. It must be in contact with a source of oxygen in the environment4. In large multicellular organisms such as humans, the surface, must be in contact with a transport system that will be able to carry these gases to and from the cells.5. Land living, air breathing organisms such as humans, have their respiratory surfaces inside the body. This internal surface is important for protection and the reduction of evaporation of the moist surface.
5Respiratory Surfaces How do gases cross the respiratory surfaces? The external side of the respiratory surface has a high concentration of oxygen compared to the internal side. Therefore Oxygen will diffuse across the surface and into the transport system. The opposite is true of carbon dioxide.The larger the surface area of the respiratory surface, the faster the rate of diffusion of gases across it.
6The Human Respiratory System The human respiratory system consists of the lungs and the systems of air tubes that carry air to and from the lungs.Air PathwayNose Pharynx Larynx Trachea Bronchi Bronchiole Tubes Bronchioles Alveoli
7NoseAir normally enters the respiratory tract through the nostrils, it then enters spaces called the nasal passages.
8The Nose The nose has three main functions: Filters the air - hair at the opening of the nasal passages traps foreign particles.- nasal passages are lined with mucus producing cells and cilia that work to trap foreign particles.
9Nose Moistens the air Warms the Air - Mucous works to moisten the air (moist air will diffuse faster into the blood stream than colder airWarms the Air- Just below the mucous membranes of the nasal passages are many tiny capillaries. The blood flow through the capillaries works to warm the air.Warm air diffuses across the surface of the lungs at a faster rate than cold air
11Pharynx and the LarynxFrom the nasal passages the air enters the pharynx which is also called the throat.air leaving the pharynx enters the larynx (also called the voice box). The larynx contains the vocal cords. The vocal cords are membranes stretched over the pharynx that vibrate as air passes over them.The epiglottis prevents food from entering the larynx when we swallow
13Trachea Also called the windpipe 12 cm long, 2.5 cm in diameter composed of rings of cartilage that ensure that the windpipe always remains open.Lined with ciliated mucous membrane. The sweeping action of the cilia move debris upwards into the pharynx, here they are either swallowed or coughed out.
15Bronchi Two bronchi branch from the trachea Composed or cartilage rings and are lined with ciliated mucous membranesBranch in a tree-like fashion into numerous bronchiole tubes located with in the lungs
16BronchiolesBronchi tubes branch into increasingly smaller and thinner tubes called bronchioles
18Alveoli Each bronchiole ends in tiny air sacs called alveoli There are thought to be 300 million alveoli in the lungsAlveoli are one cell thick and surrounded by many capillariesThe alveoli are the structures through which gases are exchanged between the lungs and the bloodTremendous surface area = tennis court