Topic 3 A Flashcards
(19 cards)
What is the relationship between surface area:volume and size?
The smaller the organism the larger the surface area: volume ratio
How does exchange occur in single celled organisms?
It can diffuse directly across the membrane
How does exchange occur in multicellular organisms?
A mass transport system is used
What is the structure of gills in fish?
Gill filaments that have lamella on its surface to increase the surface area. Good blood supply
How does the counter-current system work in fish?
Water with relatively high oxygen flows next to blood with a lower conc of water, maintaining a steep conc gradient
How does gas exchange work in insects?
Air moves into the trachea through the spiracles on the side of the insect, oxygen flows down conc gradient. The trachea branch off into tracheoleswhich have thin permeable walls allowing oxygen to diffuse through
How are xerophytes adapted to prevent water loss?
Sunken stomata and hairs to trap water vapour, reduced number of stomata fewer places for water to evaporate from, thick waxy cuticle to reduce evaporation
How does inspiration work in humans?
External intercostal and diaphragm muscles contract, causing the ribcage to move out and upwards, the diaphragm flattens which increases the volume in the thoracic cavity and the lung pressure to decrease. Air flows in from high to low pressure, flowing down the trachea into lungs. Requires energy
How does expiration work in humans?
External intercostal muscles and diaphragm relax, causing the ribcage to move downward and inward. The diaphragm curves upward. Volume in thoracic cavity decreases and air pressure increases. Air is forced down pressure gradient and out of the lungs
What happens during forced expiration?
External intercostal muscles relax and internal intercostal muscles contract pulling the ribcage further down and in (antagonistic()
How does gas exchange occur ion the alveoli?
Oxygen diffuses across the alveolar epithelium and the capillary endothelium into haemoglobin.
What is tidal volume?
the volume of air in each breath
What is ventilation rate?
The number of breaths per minute
What is forced expiratory volume?
Maximum vol of air that can be breathed out in one second
What is forced vital capacity?
The max vol of air possible to breathe forcefully out of the lungs after a deep breath
What is tuberculosis and how does it effect the lungs?
Immune system build walls around the bacteria forming small hard lumps. Infectious tissue in lungs dies. Reduced tidal volume causes less air to be inhaled in. Symptoms= coughing, mucus, coughing up blood
What is fibrosis and how does it effect the lungs?
Scar tissue forms due to an infection or exposure to e.g dust. It gets thicker and less elastic so the lungs cant expand an cant hold as much air. Tidal volume decreased. Symptoms= chest pain, shortness of breath, fatigue
What is asthma and how doe sit effect the lungs?
Airways become inflamed and irritated. Smooth muscle lining contracts and large amounts of mucus is produced, constricting the airway. Airflow reduced and so is FEV. Symptoms= wheezing, tight chest, shortness of breath
What is emphysema and how does it effect the lungs?
Foreign particles become trapped in alveoli causing inflammation. Phagocytes then produce enzyme which breaks down the elastin (cant return to normal shape) Symptoms= shortness of breath and wheezing
