Respiration and Breathing

• Plants and the lower members of the animal kingdom can obtain their O2 and eliminate

  their CO2 by diffusion.
• Higher animals, including humans, require a breathing apparatus in order to exchange these gases.
• Artificial Respiration’ (also known as ‘The Kiss of Life’) you can help save someone’s life by helping them to breathe, but you can’t do their respiration for them.
• Also in a dusty or dangerous atmosphere/ underwater you might use a respirator to help you to breathe more easily, but it doesn’t do your respiration for you.
• Breathing happens in your lungs, and your diaphragm help with this. Your lungs are part of the respiratory system.
• Respiration happens in every cell in your body (and in fact every living cell in plants and animals).
• In unicellular organisms, gases exchange with the surrounding medium by diffusion across the moist cell membrane of the cell.
• The membrane must be moist. It is more difficult for gases to diffuse across a dry membrane.
• Gases enter and exit the air spaces of leaves via the stomates. The openings of stomates are controlled by guard cells.
• Older stems are usually impermeable to gases. Some trees have lenticels that let air into the cambium.
• In many large trees, there are enough cracks in the bark so that air is available for the cambium and living phloem cells.
• Roots can exchange gases with the soil. This is done via the moist cell membranes of the cells in the lower parts of the roots.
• Hydra does not have any specialized breathing apparatus. It only has two cell layers and therefore does not need one.
• Gills are used by marine worms, molluscs (clams), and fishes. The gill lamellae (layers) have a large area for exchange of gases.
• The afferent vessel carries blood toward the gill. This blood is high in CO2

  and low in O2.
• The blood in the gill exchanges gases with the water. The CO2 leaves the gill and enters the water while the O2 leaves the water and enters the gill
• Then, the efferent vessel carries blood away from the gill. This blood is high in O2 and low in CO2
• Each cell in the body of an insect or spider is in contact or near a breathing tube known as a trachiole. A group of trachioles will be combined to form a larger breathing tube called a trachea.
• Grasshoppers have numerous tracheas that exit through holes on the side of the body called spiracles. These spiracles are used for gas exchange, the "spir" part is also found in the word "respiration.
• Frog and other amphibians, about half of the gas exchange takes place across the skin. The other half of the respiration is done using lungs.
• Frogs do not have a diaphragm so they must force air into the lungs. This is called positive pressure breathing. Humans have a diaphragm so their breathing is by negative pressure.
• Birds have a complicated respiratory system consisting of lungs and air sacs in the bones. Air is cycled through the air sacs in the hollow spaces in the bones.
• The human respiratory system consists of the lungs, bronchi and trachea. The lungs are located in the thoracic (chest) cavity, the area in the chest above the diaphragm. The heart is also located in the chest cavity.
• In humans, the diaphragm contracts and makes the chest cavity larger. The air that enters the lungs from the outside is high in O2 and low in CO2.
• Inspiration is the term used for inhaling air. When the diaphragm relaxes, the pressure in the chest

  increases and forces the air out. Expiration is term used for exhaling air The

  air that leaves the lungs is low in O2

  and high in CO2.
• Control of breathing is done by the nervous system. When CO2 increases as a result of exercise, for example, the breathing rate and heart rate increase. When there is little CO2 in the blood, the nervous system slows the breathing rate.
• Gases are exchanged in the alveoli of the lungs. Air makes its way down to the air sacs where O2 passes through the capillary walls by diffusion, and into the blood stream where it enters the red blood cells. Blood leaving the alveoli is high in O2 and low in CO2.
• Simultaneously, CO2 and some water leave the blood stream and enter the alveoli of the lungs.
• Diffusion process

  
• How diffusion works

  It work through higher concentration to a lower concentration
• Insects and spiders respiratory system

  • Tracheoles
  • Spiracles
  • Tracheae
  • Air sacs