gas exchange in insects + fish Flashcards
(24 cards)
What needs to be exchanged between organisms and environment?
Respiratory gases, nutrients, excretory products, heat
Why do bigger organisms need a respiratory system?
They have a small SA:V ratio, making it difficult for oxygen to reach the most active cells.
What are the features of specialised exchange surfaces?
Large SA:V ratio, short diffusion pathway, partially permeable, movement of the environmental medium.
How can the SA:V ratio be increased?
Folding in the surface of the cell membrane, longer thinner shape, presence of large vacuoles.
What is the gas exchange process in insects?
Oxygen enters through spiracles, travels through tracheoles and trachea to muscles or air sacs.
What are tracheae?
An internal network of tubes separated by strengthened rings to prevent collapsing.
What are tracheoles?
Smaller divisions from the trachea that extend throughout the body of the insect.
What are spiracles?
Tiny pores on the surface of the insect’s body that contain valves to regulate airflow.
What are air sacs?
Temporary stores of air within the body located at the end of tracheoles.
Why can’t a fish obtain oxygen like a single-celled organism?
Fish have a larger SA:V ratio, a waterproof outer covering, and live in water with lower oxygen concentration.
What is the counter current system in fish?
The flow of blood and water over the gill lamellae occurs in opposite directions to maintain a concentration gradient.
How is a fish adapted for gas exchange?
Thin lamellae, many lamellae for increased surface area, constant mouth movement for ventilation, high water pressure, and counter current flow.
How does gas exchange in insects occur along a concentration gradient?
As cells respire, oxygen concentration decreases towards the end of tracheoles, creating a concentration gradient.
What is insect mass transport?
Contraction of muscles can squeeze the trachea, allowing mass movements of air in and out.
What happens at the ends of tracheoles during major activity?
Muscle cells respire anaerobically, producing lactate which decreases water potential, causing water to move into cells.
How do insects limit water loss?
Small SA:V ratio, waterproof covering, and spiracles that can close to prevent water loss.
Why are lungs located inside the body?
To protect delicate structures from air density and to prevent excessive water loss.
What is ventilation?
The process of air constantly moving in and out of the lungs.
What is inspiration?
When atmospheric pressure is greater than lung pressure, forcing air into the alveoli.
What is expiration?
When lung pressure is greater than atmospheric pressure, forcing air out of the alveoli.
What is the process of inspiration?
External intercostal muscles contract, internal intercostal muscles relax, diaphragm flattens, thorax volume increases, and air is forced in.
What is the process of expiration?
External intercostal muscles relax, internal intercostal muscles contract, diaphragm relaxes, thorax volume decreases, and air is forced out.
What is the pulmonary ventilation equation?
Tidal volume x breathing rate
What is pulmonary ventilation?
The total volume of air moved into the lungs in one minute.
