Module 3 Flashcards
Describe the structures of the human gas exchange system and their functions
Goblet Cells - secretes mucus that traps microorganisms.
Cilia - beat the mucus towards the throat to be swallowed to prevent lung infections
Elastic fibres - help the process of breathing out
Smooth muscle - controls the diameter of the tubes
Cartilage - provide support and prevent collapse when breathing in.
Describe the process of inhalation
External intercostal and diaphragm contract.
Rib cage moves up and out
Lung pressure decreases
Air flows into lungs because pressure outside is higher than inside
Is an active process that needs energy
Describe the process of exhalation
External intercostal and diaphragm relax
Rib cage moves down and in
Air pressure increases in lung so air is forced out
It’s assume and doesn’t require energy
Forced expiration can occur when the internal intercostal muscles contract and pull the rib cage in.
What absorbs carbon dioxide in a spirometer?
Soda lime
Describe a fish’s exchange system
- Fish opens mouth
- Buccal cavity floor lowered
- Volume of buccal cavity increases
- Pressure in cavity decreases
- Water sucked into cavity
- Fish closes its mouth and floor of buccal cavity is raised.
- Volume inside cavity increases and water is forced out of the cavity and across the gill filaments
- Increased pressure forces the operculum flap to open and water leaves the gills.
Describe the blood and water graph for fish.
Blood is first the arrow points up. Water is second the arrow points down.
How do you dissect fish gills
Push back the operculum
Use scissors to cut each gill arc at the bone
Remove and submerge in water to fully see the gills.
Describe insect gas exchange system
Air moves into trachea from spiracles on the surface of the insects body. Oxygen travels down the concentration gradient towards the cells and vice versa for carbon dioxide. The tracheoles also contain fluid for the oxygen to dissolve in. Insects use rhythmic abdominal movements to change the volume of their bodies to move air. When flying, wing movements helps with this.
How can you dissect insects to see their gas system
Fix the insect to the dissecting board
Cut and remove a piece of the exoskeleton from along the length of the insects abdomen
Use a syringe and fill the abdomen with saline solution. You’ll see a network of thin silver-grey tubes (trachea). They look silver because they’re filled with air.
Examine further under a light microscope.
Describe the structures that are present in arteries, capillaries and veins.
Artery:
- elastic tissue in walls - for stretch and recoil
- thick muscle layer - helps maintain high pressure
- lumen - smaller lumen to maintain high pressure
- folded endothelium - allows artery to expand
Capillary:
- endothelium - one cell thick for a short diffusion distance
Vein:
- large lumen - for lower pressure
- thin muscle wall - for lower pressure
- endothelium - allows it to expand
- valves - to prevent back flow
Describe the formation of tissue fluid
At the arteriole end, the hydrostatic pressure is greater than in the tissue fluid outside so fluid is forced out. The opposite is true of the venule end.
The arteriole end has a lower oncotic pressure and the venule end has a higher oncotic pressure.
Describe the lymphatic system
Excess tissue fluid gets returned to the blood via the lymphatic system.
Valves in the lymph vessels prevent the lymph from going backwards and it returns the lymph back to the blood near the heart.
What is an electrocardiograph and describe what it can show
It’s produced by an electrocardiogram. There is a bunch of different letters.
P wave comes first: caused by depolarisation of atria.
QRS complex comes second: caused by depolarisation of ventricles.
T wave comes last: due to repolarisation (relaxing) of ventricles.
What is oxygen carried around as in the body. Write the equation for that.
It’s carried as oxyhaemoglobin.
Hb + 4O2 <—> HbO8
Why is the partial pressure curve for oxygen affinity an s shape?
Once haemoglobin binds to the first O2, it gets progressively easier for the other O2’s to join. But as the Hb gets more saturated, it gets harder for more oxygen to join.
Foetal haemoglobin has a higher affinity for oxygen. It’s to the left of the adult haemoglobin graph. It must have a higher affinity so that it can survive.
