Topic 3: organisms exchange substances with environment

• What is ventilation?

  Ventilation is the process of moving air in and out of the lungs for gas exchange.
• What happens during inspiration?

  During inspiration, the diaphragm contracts, the external intercostal muscles contract, the internal intercostal muscles relax , the thoracic volume increases which lowers pressure, allowing air in.
• What occurs during expiration?

  During expiration, the diaphragm and external intercostal muscles relax, the internal intercostal muscles contract decreasing thoracic volume which increases pressure, pushing air out.
• How is ventilation varied?

  Ventilation is varied by altering the relationship between pressure and volume.
• What is the relationship between pressure and volume in ventilation?

  Pressure and volume are inversely proportional; high pressure means low volume and vice versa.
• What must happen for gas pressure in the lungs to equal atmospheric pressure?

  The gas pressure of the lungs must equal the gas pressure of the atmosphere for breathing to occur.
• How does the body facilitate breathing?

  The body facilitates breathing by changing the shape and volume of the lungs.
• What happens to muscle volume in the lungs during breathing?

  Muscle volume in the lungs increases to stretch and allow air in.
• What is the purpose of moving air from higher pressure to lower pressure?

  The purpose is to facilitate gas exchange by allowing air to flow into the lungs.
• What is the role of the diaphragm and intercostal muscles in respiration?

  The diaphragm and intercostal muscles pull and push air to exchange gases with the blood.
• How do the lungs act as an integral fluid in gas exchange?

  The lungs move gases to low pressure, facilitating gas exchange with the blood.
• What are bronchi?

  Bronchi are the branches that carry air into the lungs and to the alveoli.
• What structural feature do bronchi have to facilitate airflow?

  Bronchi contain many C-shaped rings of cartilage to prevent collapse and facilitate airflow.
• What is the lumen in the context of bronchi?

  The lumen is the space within the bronchi where air flows.
• What is the glottis?

  The glottis is a mix of structures that facilitates gas exchange in the airway tube.
• How does smooth muscle affect the airway?

  Smooth muscle alters the diameter of the airway to accommodate pressure or volume changes.
• What type of epithelium lines the walls of the airways?

  The walls are lined with ciliated columnar epithelium containing goblet cells.
• What is the function of goblet cells in the respiratory tract?

  Goblet cells secrete mucus onto the passage to trap particles.
• How does ciliated epithelium protect the lungs?

  Ciliated epithelium beats mucus out of the respiratory tract to prevent harm to the lungs.
• What is the extracellular layer of mucus composed of?

  The extracellular layer of mucus is composed of glycoprotein.
• Why is a large surface area of tissue important in the respiratory system?

  A large surface area is important for maximizing gas exchange with epithelial cells.
• What is the role of glands in the respiratory system?

  Glands secrete substances and are surrounded by capillaries to enhance blood supply.
• What is a key feature of the epithelium near the gut passage?

  The epithelium near the gut passage is very thin, allowing for short diffusion distances.
• Why is a short diffusion distance important in the respiratory system?

  A short diffusion distance allows particles to travel quickly for efficient gas exchange.
• How does a good blood supply benefit the respiratory system?

  A good blood supply helps remove secreted goods and increases oxygen delivery.