Week 3-4 (Generated)

• 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


  The process where water vapor, and Carbon Dioxide leave and enters plant leaves. This activity takes place during the respiration and photosynthesis.
• Respiration


  The process of taking up oxygen from air with simultaneous release of carbon dioxide
• Photosynthesis


  The process 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. Photosynthesis takes place only in the presence of sunlight; thus it ceases at night.
• LESSON 1: GAS EXCHANGE, TRANSPORT AND CIRCULATION IN PLANTS AND ANIMALS
• Breathing


  A physical process of bringing air in and releasing gaseous material into and out of the body
• Respiration


  The whole cycle of taking oxygen into the body and releasing the carbon dioxide as waste product
• Respiratory structures in animals


  • Gills
  • Tracheal system
  • Skin
  • Lungs

  
• Gills


  • Used by fish and other marine species to absorb oxygen trapped in water and filter carbon dioxide out of the bloodstream
  • Fish and other marine species have gills that are used in water to absorb dissolved oxygen
• Gill function in fish


  1. When the oral valve opens in their mouth, the water draws into the buccal cavity

  2. The opercular cavity, which contains the gills, then closes

  3. When the oral valve is closed, the operculum (gill cover) opens the gills to force the water out

  4. The blood in the capillaries flows into the gill filament in a direction contrary to the flow of water

  5. This opposite flow allows countercurrent movement, the movement of materials moving in opposite directions between two fluids

  6. The oxygen molecules thus diffuse from water (higher concentration of O2) into the blood (lower concentration of O2)

  7. This mechanism maximizes the efficiency of gas exchange, since all fluids flow in the same direction, the difference in concentration will rapidly decrease

  
• Tracheal system in insects

  • 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
  • Once the oxygen enters the tracheoles it diffuses into a neighboring body cell's cytoplasm
  • At the other side, CO2 that is produced as a waste product diffuses through the tracheal system out of the cell and ultimately out of the body
  • The air sac which serves as an air reservoir is another part of the tracheal system

  
• Cutaneous respiration


  • Amphibians, earthworms, and some turtles respire 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
  • Some animals, including amphibians and earthworms, may use their skin to pass gasses between the outside environment and the circulatory system due to the capillary network below the skin
• Respiratory system in mammals

  • The lungs are the main respiratory organs
  • Before entering the lungs, the air must go through different organs during respiration
  • The air travels into a windpipe called trachea when air is inhaled
  • The trachea separates the air into channels called bronchial tubes or bronchi at the lungs
  • The air travels into smaller airways called the bronchioles with tiny balloon-like air sacs at their ends before they enter the lungs
  • Surrounding the alveoli are capillaries, a network of tiny blood vessels
  • These vessels are the gas-exchange sites
  • After the deoxygenated blood in the capillaries absorbs the oxygen from the walls of the alveoli, it travels to the heart which in effect pumps it across the body to supply the cells with oxygen
  • The blood carries CO2 released by the cells back to the lungs where it is eliminated by exhalation
• Animals need oxygen for their metabolism. 21% of air is made up of oxygen. Respiration requires oxygen.
• Function of the respiratory system

  To supply oxygen for the metabolic needs to the cells to remove one of the waste materials for cellular metabolism, carbon dioxide
• Gas exchange in animals

  The exchange of respiratory gases-absorption of molecular oxygen and carbon dioxide discharge
• Mechanism of gas exchange in animals

  1. Air first enters the body through the mouth or nose, quickly moves to the pharynx (throat), passes through the larynx (voice box), enters the trachea, which branches into left and right bronchi within the lungs and further divides into smaller and smaller branches called bronchioles

  2. The smallest bronchioles end in tiny air sacs, called alveoli, which inflate during inhalation, and deflate during exhalation

  3. Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs

  4. It occurs between the alveoli in the lungs and network of blood vessels called capillaries located in the walls of the alveoli

  5. The walls of the alveoli share a membrane with the capillaries in which oxygen and carbon dioxide move freely between the respiratory system and the bloodstream

  6. Oxygen molecules attach to red blood cells, which travel back to the heart

  7. At the same time, the carbon dioxide molecules in the alveoli are blown out of the body with the next exhalation
• Oxygen and Carbon Dioxide Transport

  • Oxygen diffuses down a pressure gradient from the lungs into the blood plasma to red blood cells to binds to hemoglobin
  • 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; these four conditions occur in tissues with high metabolisms
  • Carbon Dioxide diffuses down its partial pressure gradient from the tissues into the blood plasma and red blood cells to air in alveoli
  • 7% is dissolved plasma, 23% binds with hemoglobin to form carbaminohemoglobin and 70% is in bicarbonate form
  • Bicarbonate and carbonic acid formation are enhanced by the enzyme carbonic anhydrates, which is in the red blood cells
• Respiratory Problems


  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Emphysema
  • Lung Cancer
  • Cystic fibrosis
  • Pneumonia
  • Pleural effusion
  • COVID-19
• Asthma


  A severe, chronic respiratory condition due to inflammation of the airways causing difficulty breathing. Symptoms include dry cough, wheezing, tightness in the chest and shortness of breath.
• COPD


  An umbrella term that encompasses several respiratory illnesses that cause breathlessness, or the inability to exhale normally. People usually develop symptoms, including shortness of breath, and usually cough up sputum (lung mucus), particularly in the morning.
• Chronic bronchitis


  A form of COPD emphasized by a chronic cough. Usually people cough up sputum (mucus from the lungs), especially in the morning.
• Emphysema


  A severe respiratory disease, usually caused by smoking. Many suffering from emphysema have difficulty breathing out oxygen from their lungs. Cigarette smoke destroys the air sacs in the lungs to the point that they cannot repair themselves anymore.
• 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. Within the lungs, DNA mutations allow irregular cells to multiply, causing unchecked development of abnormal cells or tumors. These tumors interact with normal lung functions.
• Cystic fibrosis


  A genetic respiratory disease caused by a defective gene which produces thick and sticky mucus which obstructs tubes and passages. This mucus induces frequent and harmful lung infections as well as pancreatic obstructions that block vital enzymes from breaking down the body's nutrients.
• Pneumonia


  A common lung disease caused by an infection in the air sacs in the lungs. The infections can be bacterial, viral or fungal. Most people can recover in one to three weeks, but for certain people, pneumonia can be extremely serious and even life-threatening.
• Pleural effusion


  A collection of fluid between the lung and the chest wall in what is called the pleural space. The fluid can collect for a variety of reasons, including pneumonia, cancer or congestive heart failure. Patients notice symptoms of increasing chest discomfort and shortness of breath.
• COVID-19


  A respiratory illness that belongs to a large family of viruses called coronaviruses. This type of virus infects humans and animals, but this new strain has not been seen in humans before 2019. The virus seems to have originated in Wuhan, China. The virus spread mainly from person-to-person between people who are in close contact with one another (within about 6 feet). Like other viruses, COVID-19 spreads through droplets released when an infected person coughs, sneezes or talks. The primary symptoms are cough, shortness of breath and fever.
• Green plants require a supply of carbon dioxide and a way of disposing of oxygen to carry on the photosynthesis. Plant cells need oxygen and a means of disposing of carbon dioxide (just like animal cells do) to carry on cellular respiration.
• Unlike animals, plants have no specialized organs for gas exchange.
• Gas exchange in small plants


  • In small plants such as mosses, leaves and other structures are very thin, and gases can move in and out via diffusion
• Gas exchange in 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
  • Stomata are most abundant on the leaves of the plant
  • The opening and closing of stomata can be in response to water moving in or out of the cell
  • When water moves into the cell, the turgor of the cell increases causing them to lengthen and open the stomata
  • Opening and closing of the stomata can also be in response to light and low internal carbon dioxide levels
• Gas exchange in aquatic plants

  • Water plants will have special adaptations that allow them to exchange gases within their moist environment
  • Some plants such as lily pads have leaves that float giving them ready access to air
  • Mangroves have pneumatophores also known as aerial roots that grow above the water's surface
• Gas exchange in plants

  Plants exchange oxygen and carbon dioxide through the stomata on leaves, stems and roots
• Stomata


  • Can regulate gas exchange by controlling when they are open and when they are enclosed
  • Most abundant on the leaves of the plant
  • Bordered by two cells known as guard cells which control when the stomata is opened and closed
• Opening and closing of stomata

  1. In response to water moving in or out of the cell

  2. When water moves into the cell, the turgor of the cell increases causing them to lengthen and open the stomata

  3. Also in response to light and low internal carbon dioxide levels
• Aquatic plants


  • Have special adaptations that allow them to exchange gases within their moist environment
  • Some plants such as lily pads have leaves that float giving them ready access to air
  • Mangroves have pneumatophores also known as aerial roots that grow above the water's surface
  • Submerged aquatic plants can exchange gases with water across their epidermis
• Xylem


  Transports water and minerals extracted from the roots to the rest of the plant body
• Phloem


  Transports the food manufactured in the leaves to all parts of the plant