Week 3-4

• All living organisms need gases to survive.
• Gases are the most important nonliving thing for the living organisms.
• Exchanging of gases on earth facilitates all living organisms to live, grow, develop and perform their specific functions.
• Gas exchange is the process where water vapor, and Carbon Dioxide leave and enters plant leaves. This activity takes place during the respiration and photosynthesis.
• Respiration is process of taking up oxygen from air with simultaneous release of carbon dioxide together, while photosynthesis is where plants use carbon dioxide and water to produce carbohydrates and release oxygen as the waste product.
• Respiration happens during day and night, supplying a source of energy for the plant.
• Breathing is a physical process of bringing air in and releasing gaseous material into and out of the body.
• Respiration is the whole cycle of taking oxygen into the body and releasing the carbon dioxide as waste product.
• Important respiratory structures include the gills, the tracheal system, the skin, and the lungs.
• Gills are used by fish and other marine species to absorb oxygen trapped in water and filter carbon dioxide out of the bloodstream.
• When the oral valve opens in their mouth, the water draws into the buccal cavity. The opercular cavity, which contains the gills, then closes. When the oral valve is closed, the operculum (gill cover) opens the gills to force the water out. The blood in the capillaries flows into the gill filament in a direction contrary to the flow of water. This opposite flow allows countercurrent movement, the movement of materials moving in opposite directions between two fluids.
• The oxygen molecules thus diffuse from water (higher concentration of O2) into the blood (lower concentration of O2). This mechanism maximizes the efficiency of gas exchange, since all fluids flow in the same direction, the difference in concentration will rapidly decrease.
• Among insects the tracheal system is normal. This mechanism does not require the direct intervention of the circulatory system for transportation of O2 and CO2 because the air will pass directly to the cells.
• There are pairs of openings called spiracles in each segment of the insect's abdomen, where air enters and exits the body.
• These openings connect to the tubular trachea network which eventually branches into tracheoles.
• Moreover, Amphibians, earthworms, and some turtles respire through a process called cutaneous respiration and breathe through their skin. When submerged in water or damp areas they breathe through their skin.
• Keeping their skin moist is essential for them to enable effective cutaneous respiration. Its skin secretes mucus through the mucus glands to prevent desiccation.
• Cutaneous respiration also occurs through concurrent exchange, where the direction of the absorbed oxygen is directly opposite the circulation of the blood in the skin.
• In mammals the lungs are the main respiratory organs. Before entering the lungs, the air must go through different organs during respiration.
• Windpipe - Trachea - Bronchial Tubes - Bronchioles - Alveoli - Capillaries - Heart
• Animals need oxygen for their metabolism. 21% of air is made up of oxygen. Respiration requires oxygen.
• The function of the respiratory system of the animals is to supply oxygen for the metabolic needs to the cells to remove one of the waste materials for cellular metabolism, carbon dioxide.
• This method follows the concept of diffusion, by moving molecules from a high concentration region to a low concentration region.
• Mechanism o Gas Exchange in Animals

  • Mouth
  • Pharynx
  • Larynx
  • Trachea
  • Left and Right Bronchi
  • Bronchioles
  • Alveoli
  • Heart
• Hemoglobin gives up its oxygen in tissues where partial pressure of oxygen is low, blood is warmer, partial pressure of carbon dioxide is higher and pH is lower;
• 7% is dissolved plasma, 23% binds with hemoglobin to form

  carbaminohemoglobin and 70% is in bicarbonate form.
• Asthma - characterized as a severe, chronic respiratory condition due to inflammation of the airways causing difficulty breathing.
• Chronic obstructive pulmonary disease (COPD) - an umbrella term that encompasses several respiratory illnesses that cause breathlessness, or the inability to exhale normally.
• Emphysema - another type of COPD which is a severe respiratory disease. Smoking the most common cause. Many suffering from emphysema have difficulty breathing out oxygen from their lungs.
• Lung Cancer - this cancer is difficult to detect, with the ability to develop in any part of the lungs. The cancer most often develops near the air sacs in the main portion of the lungs.
• Cystic fibrosis - a genetic respiratory disease caused by a defective gene which produces thick and sticky mucus which obstructs tubes and passages.
• Pneumonia - a common lung disease caused by an infection in the air sacs in the lungs.
• Pleural effusion - a collection of fluid between the lung and the chest wall in what is called the pleural space.
• COVID-19 - a respiratory illness that belongs to a large family of viruses called coronaviruses.
• Green plants require a supply of carbon dioxide and a way of disposing of oxygen to carry on the photosynthesis.
• plants have no specialized organs for gas exchange.
• In small plants such as mosses, leaves and other structures are very thin, and gases can move in and out via diffusion. In more complex plants oxygen and carbon dioxide is exchanged through the stomata on leaves, stems and roots.
• Stomata can regulate gas exchange by controlling when they are open and when they are enclosed.
• This pore is bordered by two cells known as guard cells which control when the stomata is opened and closed.
• The opening and closing of stomata can be in response to water moving in or out of the cell.