Topic 2 The Respiratory System: Invertebrate Respiration

Question 1

• What we rely on for gas exchange mechanisms
• External respiration is the entry of air into lungs and subsequent gas exchange between alveoli and blood
• Internal respiration is gas exchange between blood cells and intracellular respiration processes

Answer 1

The Respiratory System

Question 2

• Protozoa and Hydra
• Direct with environment: have large surface areas and cell is exposed or closed to environment -> simple diffusion of gases directly with outside environment (flatworms and some small animals exhibit this respiration)

Answer 2

Invertebrate Respiration

1. Cnidaria

Question 3

• Mucus secreted by earthworms provides moist surface for gas exchange via diffusion
• Circulatory system brings oxygen to cells, and waste products back to skin for excretion

Answer 3

Invertebrate Respiration

2. Annelids

Question 4

• 80% of all living species; insects, spiders, crustaceans
• Grasshopper: series of chitin-lined respiratory tubules called trachea that open to surface via openings called spiracles, through which oxygen enters and carbon dioxide exits
  a. Oxygen carriers such as hemoglobin are not needed due to direct distribution and removal of gases
  b. Moistened tracheal endings ease rat of diffusion
• Spider: have book lungs: stacks of flattened membranes enclosed in internal chambers

Answer 4

Invertebrate Respiration

3. Arthropods

Question 5

• Water: enters mouth and passes over gills (structures that create a large surface area and take in oxygen and out carbon dioxide
• Gills: external/unprotected or internal/protected
• Water exits via operculum (gill cover)
• Countercurrent exchange: exchange between opposing movements of water and underlying blood that maximizes diffusion of oxygen into blood and CO2 into water

Answer 5

Invertebrate Respiration

4. Fish