Gas Exchange Flashcards

Flashcards about gas exchange in humans and fish.

List the structures involved in gas exchange in humans.

Trachea, bronchi, bronchiole, alveoli

What structures are involved in ventilation during exercise?

Diaphragm, internal and external intercostal muscles, ribs forming the thorax.

Describe the process of inhalation.

Diaphragm contracts, external intercostal muscles contract, thorax volume increases, pressure decreases, air forced into lungs.

Describe the process of exhalation.

Diaphragm relaxes, internal intercostal muscles contract, thorax volume decreases, pressure increases, air forced out of lungs.

Describe the structure of an alveolus.

Thin layer of epithelial cells forming the epithelium of the alveolus.

What are the essential features of alveoli that maximize the rate of diffusion?

Shortened diffusion path, large surface area, steep concentration gradient of O2 and CO2.

Where do fish get their oxygen?

Fish extract O2 from water.

Describe the appearance of gills.

Gills look like fleshy pink feathers.

List the main components of a gill structure.

Gill arch, gill filaments, lamellae.

What are lamellae?

Thin plates on gill filaments containing a network of capillaries.

What are the three key adaptations that make gills efficient at gas exchange?

Short diffusion pathway, large surface area, counter-current flow.

What two structural features contribute to the short diffusion pathway in fish gills?

Network of capillaries in each lamella and a single layer of flattened cells.

How is a large surface area achieved in fish gills?

Multiple gill arches with numerous long, thin filaments and lamellae.

What is counter-current flow?

Water flows over gills in the opposite direction of blood flow.

What is the significance of counter-current flow in gas exchange?

Maintains a steep O2 concentration gradient along the length of each lamella.

What adaptation would a fish living in water with a low O2 concentration likely have?

Larger surface area of gills.