Module 3

• What adaptations do exchange surfaces in organisms have to facilitate efficient substance exchange?

  • Large surface area
  • Short diffusion distance
  • Maintained concentration gradient
• Why do small organisms like amoeba not require special adaptation organs for transport?

  They have a large surface area to volume ratio, allowing simple diffusion to meet their metabolic needs.
• How does the surface area to volume ratio differ between large and small organisms?

  Large organisms have a smaller surface area to volume ratio compared to their volume, leading to a longer diffusion distance.
• What is the significance of higher metabolic rates in larger organisms?

  Higher metabolic rates require more oxygen for respiration to create ATP.
• What are the adaptations found in fish, humans, and insects for gas exchange?

  • Gills in fish
  • Alveoli in humans
  • Tracheal system in insects
• What are the three features to comment on regarding gas exchange surfaces?

  The features are large surface area, short diffusion distance, and maintained concentration gradient.
• What is the function of the trachea in the mammalian gas exchange system?

  The trachea, or windpipe, supports air flow and prevents collapse with its C-shaped cartilage rings.
• What role do ciliated epithelial cells play in the trachea?

  Ciliated cells sweep mucus away from the trachea to prevent pathogens from reaching the lungs.
• What is the function of goblet cells in the trachea?

  Goblet cells produce thick and sticky mucus that traps pathogens and dust particles.
• How does smooth muscle in the trachea respond to harmful substances in the air?

  Smooth muscle contracts, constricting the lumen and reducing airflow to the lungs.
• What are the structures that the trachea splits into?

  The trachea splits into two bronchi, which further divide into bronchioles.
• What is the primary function of alveoli in the lungs?

  Alveoli are the site of gas exchange where oxygen diffuses into the blood and carbon dioxide diffuses out.
• What are the three features of alveoli that facilitate gas exchange?

  • Large surface area due to millions of alveoli
  • Short diffusion distance with squamous epithelial cells
  • Maintained concentration gradient by surrounding capillary network
• How does ventilation maintain the concentration gradient in the alveoli?

  Ventilation brings in fresh air and removes carbon dioxide, maintaining the concentration gradient for gas exchange.
• What muscles are involved in the process of ventilation?

  The diaphragm and the external and internal intercostal muscles are involved in ventilation.
• What happens to the thorax volume during inhalation?

  The volume of the thorax increases, causing a decrease in pressure that allows air to flow into the lungs.
• What occurs during exhalation in terms of thorax volume and pressure?

  During exhalation, the thorax volume decreases, increasing pressure and forcing air out of the lungs.
• What is the vital capacity in terms of lung function?

  Vital capacity is the maximum volume of air an individual can inhale and exhale during a deep breath.
• What is tidal volume?

  Tidal volume is the amount of air inhaled and exhaled when at rest.
• What is residual volume in lung function?

  Residual volume is the volume of air that remains in the lungs to prevent collapse.
• How can breathing rates be calculated using a spirometer graph?

  Breathing rates can be calculated by counting the number of peaks over a specific period of time on the graph.
• What is the formula for ventilation rate?

  Ventilation rate is calculated as tidal volume times breathing rate.
• What challenge do fish face regarding oxygen in water?

  Fish face the challenge of less oxygen being dissolved in water compared to the atmosphere.
• How do fish ventilate their gills?

  Fish ventilate their gills by swimming with their mouth open to allow water to flow over the gills.
• What is the role of the operculum in fish ventilation?

  The operculum valve closes to create a pressure difference that helps water flow over the gills.
• What are the features of gills that facilitate gas exchange in fish?

  • Large surface area due to numerous gill filaments
  • Short diffusion distance with thin gill lamellae
  • Maintained concentration gradient through counter current flow mechanism
• What is the counter current flow mechanism in fish?

  The counter current flow mechanism allows water to flow over gill lamellae in the opposite direction to blood flow, maintaining a concentration gradient for oxygen diffusion.
• What is the tracheal system in insects and its components?

  • Made up of spiracles, trachea, and tracheoles
  • Spiracles are valve-like structures for gas exchange
  • Trachea branch into many tracheoles for efficient gas exchange
• How do insects maintain a concentration gradient for gas exchange?

  Insects maintain a concentration gradient by respiring, using up oxygen and producing carbon dioxide, and by pumping air in and out through muscle contractions.
• What happens to tracheal fluid during insect flight?

  During flight, lactate production lowers water potential, causing tracheal fluid to move into abdominal cells by osmosis, decreasing liquid volume and pressure, allowing air to enter.
• What are the characteristics of open and closed circulatory systems?

  Open Circulatory System:

  • Found in invertebrates like insects
  • Hemolymph pumped directly to body cavity
  • Low pressure and few transport vessels

  
  

  Closed Circulatory System:

  • Found in vertebrates and some invertebrates
  • Blood remains in vessels
  • High pressure and efficient gas transport
• What is the difference between single and double closed circulatory systems?

  In a single closed circulatory system, blood passes through the heart once per cycle, while in a double closed system, blood passes through the heart twice per cycle.
• Which type of circulatory system do fish have?

  Fish have a single closed circulatory system.
• How does the single closed circulatory system in fish facilitate gas exchange?

  In fish, the blood passes through two sets of capillaries, allowing for efficient oxygenation in the gills and delivery to the body.
• What is the role of hemoglobin in the closed circulatory system?

  • Hemoglobin transports oxygen in the blood
  • It binds to oxygen in the lungs and releases it in tissues
  • It helps in the transport of carbon dioxide as well
• What is an example of a pigmented protein mentioned in the study material?

  Hemoglobin
• What is the difference between single closed and double closed circulatory systems?

  • Single closed: Blood passes through the heart once per cycle (e.g., fish).
  • Double closed: Blood passes through the heart twice per cycle (e.g., birds and most mammals).
• How does blood flow in a single closed circulatory system?

  Blood flows through two sets of capillaries after being pumped out of the heart.
• Why does the single closed circulatory system work for fish?

  Because fish have a counter current flow mechanism that enables efficient gas exchange.
• What is the function of the double closed circulatory system?

  It allows blood to pass through the heart twice per cycle.