Flashcards in Gas Exchange Deck (126)
What is the total oxygen requirement of an organism proportional to?
Its total volume
What is proportional to the organisms surface area?
The rate of absorption of oxygen
What has an organism done if it has increased in size?
Developed different adaptations to overcome these problems
What are the 5 common features of surface areas?
1. Large surface area relative to volume
4. Moist - potential region of water loss
5. Mechanism to maintain diffusion gradients
How can large surface area be obtained in small organisms?
The large surface area can be formed by the folding of the exchange surface
Why is being permeable important to an exchange surface?
This allows easy diffusion of gases
Why is being thin important to an exchange surface?
It creates a short diffusion pathway, as diffusion is only effective across less than 1mm.
How far is diffusion effective?
Less than 1mm
Why is being moist important to an exchange surface?
O2, CO2 and nutrients diffuse in solution
Why is having a mechanism to maintain diffusion gradients important to an exchange surface?
Transport system, ventilation mechanism or creation of currents across surface allows for exchange.
What are the 3 mechanisms to maintain diffusion gradients?
1. Transport System
2. Ventilation Mechanism
3. Creation of currents across a surface
What adaptation have terrestrial vertebrates made for gas exchange with air?
What is the epiglottis?
a flap of cartilage behind the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe.
What are the similarities and differences between the trachea and bronchi?
Similar in structure
Different in size
What is the inner surface of the trachea and bronchi covered in?
What is the function of ciliated cells?
Rhythmic wave like movement moves mucus to top of trachea where it is swallowed
What are the 3 functions of goblet cells?
1. Secrete sticky mucus containing glycoprotein
2. Protects from dehydration, traps microbes and dust
3. Lysozyme also present which causes bacterial lysis
What is the function of cartilage ?
Holds the airway open during inhalation and exhalation throughout the pressure changes to prevent collapse.
Where is cartilage found?
In the trachea and bronchi
What shape is the cartilage found in the trachea?
C- shaped rings
What shape is the cartilage found in the bronchi?
In irregular blocks
What is found on the inside of the cartilage?
What is the function of the smooth muscle in cartilage during exercise?
Relax during exercise to allow more air into the lungs
What causes asthma attacks?
Contracts during asthma which causes constriction and breathlessness
What recoils during exhalation?
What are the three features of the alveoli that make them good for gaseous exchange?
1. They provide an enormous surface area
2. Their surface is moist so gases can dissolve in the moisture and diffuses through the epithelial lining
3. The walls are thin providing a short diffusion pathway
Why is it important that alveoli are well ventilated?
Because ventilation movement ensure air is inhaled and exhaled from the lungs
Why do alveoli have a good blood supply?
Because they are covered with an extensive network of capillaries
Why do the alveoli have a maintained diffusion gradient?
Because blood is always moving taking oxygen away and bringing carbon dioxide