Gas Exchange Surfaces M3 Flashcards
Describe the movement of inhalation - inspiration
ACTIVE PROCESS. External intercostal muscles contract and ribcage is pulled up and out. The diaphragm contracts and volume of the thorax increase and pressure decrease. Air is drawn into the lungs down the pressure gradient.
Describe the movement of exhalation - expiration
PASSIVE PROCESS. External intercostal muscles relax and ribcage moves down and in and the diaphragm relaxes. The volume of thorax decrease, the pressure increases and the air is forced out fo the lungs down the pressure gradient.
What precautions should you take when selecting a volunteer for spirometer?
they are not asmatic. check it os work correctly with no leaks. there is sufficient soda lime.
Over time what happens to the volume of air in spirometer and what would this look like on a graph?
It would decrease and show a negative correlation.
Explain how an insect pumps air in and out of its body?
It changes the volume of its body with abdominal movements, which changes the pressure in te body so that air is drawn and out of the spiracles.
Describe how you would dissect a bony fish to see its gill filaments.
- remove the OPERCULLUM. 2. Take the GILL ARCH out, and rinse will water thoroughly and gently. 3. Cut off the singular gill filaments to examine, put onto to a microscope slide and observe.
What is countercurrent flow?
water and blood move in opposite directions across the lamella so equilibrium is not reached and a concentration gradient can be maintained along the gill filament
Explain one way the gill filament has adapted to its function
- Made of squamous epthilium, that is one cell thick. 2. Makes a short diffusion pathway to gases diffuse faster.
Explain how changes in the buccal cavity of a bony fish allow the gills to be ventilated.
When the mouth opens, the volume of the buccal cavity increases ad the pressure decrease and therefore water goes in. When the mouth closes the volume decrease and pressure increase therefore water flows out under the operculum.
Structural adaptations for gaseous exchnage
Large surface area means more oxygen can be absorbed and the rate of diffusion is better. Short diffusion pathway, means oxygen can diffuse much more quickly. Good blood supply means the blood is constantly being replaced meaning it’s able to maintain its concentration gradient.
Describe the differences in insect trachea and mammalian trachea.
M - C-shaped rings of cartilage to stop it collapsing die to changes in pressure. They have 1 trachea, with a larger diameter. Cillia. I - rings of chitin lining the trachea. They also have many trachea, that is much smaller in diameter.
FICKS LAW
RATE OF DIFFUSION = (SA x concentration gradient) / thickness of exchange surface
What is the vital capacity
The maximum volume of air that can be exchanged in one breath.
How have alveoli adapted
- Many of them makes a large SA. 2. Squamous epithelium, on cell thick, means a short diffusion pathway. 4. Blood is constantly ventilated to maintain a concentration gradient. 5. Elastic fibres allows alveoli to stretch and recoil without bursting when filled with oxygen.
Describe the stricture and function of the goblet cells and ciliated epithelium cells.
Goblet cells secret mucus that traps microorganism and dust, the cilia on the ciliated epithelium cells waft this down airways to be swallowed and eliminated.
