Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
13 Cards in this Set
- Front
- Back
|
Surface area |
The total number of cells in direct contact with the environment |
|
|
Mass flow |
Brough about by pressure differences. High pressure at SOURCE low pressue at SINK. the pressure gradent causes substances to move from source to sink. |
|
|
Xylem Tissue |
Water evaporating from leaf creates a negative pressure that pulls water through the xylem as part of the transpiration stream. It transprots watre and mineral ons from the roots to the leaves |
|
|
Phloem tissue |
Energy expended here is involved in moving the sucrose into the phloem. ATP is used to move sucrose from te companion cells to the phloem sieve tube. Transport of sucrose (Translocation) to roots and growing regions |
|
|
Fick's Law |
Surface Areax Difference in cncentration Thickness of Exchange Surface |
|
|
Gas Exchange in Mammals |
Short diffusion distance- wall of each alveoli very thin (squamous endothelium- twin cells). red blood cells have o squeeze their way through the narrow capillaries, ensuring that they are in contact with the endothelial wall) Surface area-large, more diffusion of gases, alveoli are sacculated Steep concentration gradient Macrophages-Originate from monocytes. Protects the alveoli against infection by digesting mocrobes through phagocytosis |
|
|
Compensation point |
Rate of respiration= Rate of photosynthesis |
|
|
Inspiration |
1. External intercoastal muscles contract 2. Ribcage is pulled upwards and outwards 3. Diaphragm contracts and flattens 4. The volume in the thorax increases, reducing pressure around the lungs 5. Pressure in the thorax is below atmospheric pressure 6. Air is drawn into the lungs Expiration vice versa Additionally, the natural elasticity of the lungs produces an elastic recoil, which helps force air out of the lungs during expiration |
|
|
Tar |
General name given to the collection of toxic chemicals in cigarette smoke Causes lung cancer by damaging the DNA in the epithelial lining of the lungs. Some cells divide uncontrollably causing a tumour to form |
|
|
Nicotine |
Highly addictive drug |
|
|
Carbon monoxide |
Combines with haemoglobin in red blood cells, reducing their ability to carry O2 around the body |
|
|
Emphysema |
Irritation fron tar damages the lining of the alveoli The walls of the alveoli break down This reduces surface area of the lungs, therefore less diffusion of respiratory gases Also reduces elasticity of the lungs meaning it can recoil less during expiration Air cannot be expelled effectively, leaving a layer of residual air in alveoli which prevents inhaled fresh air reahing the gas exchange surface |
|
|
Bronchitis |
Caused by inflammation of the bronchioles Narrower bronchial tubes and increased mucus production reduces air flow Tar also paralyses cillia, which helps remove mucus from the respiratory tract People with bronchitis suffer from breathlessness, coughing, and increased risk of infection |
