B4 Flashcards
Name two substances transported by plasma in the blood:
-Soluble products of digestion from the SI to other organs
-Urea from the liver to the kidneys
-Carbon dioxide to the lungs
Why is the wall of the heart muscle thicker on the left?
Because it has to pump blood around the whole body
Where is the sinoatrial node?
In the right atrium
What happens in your chest when you breathe in?
-The intercostal muscles contract, moving the ribcage up and out
-The muscles of the diaphragm contracts causing it to flatten
-The volume of the thorax increases
-The pressure in the thorax decreases and air is drawn into your lungs
How are the alveoli adapted to carry out their function?
-They have a large surface area
-Thin walls create a short diffusion path
-Have a good blood supply
-Ventilated to maintain a steep concentration gradient
What direction do xylem vessels transport substances?
From the roots to the rest of the plant
What is the function of guard cells?
They control movement of water vapour out of the cell- they can close stomata to prevent excessive water loss.
What factors affect the rate of transpiration?
-Temperature- warmer= more evaporation so diffusion rate increases+ more photosynthesis
-Humidity- rate of diffusion is faster in dry air
-Air flow- windy conditions maintain steep concentration gradient by blowing away vapour
-Light intensity- more light= more photosynthesis
Where are most of the stomata located?
On the underside of the leaf
Explain why having more red blood cells is an advantage to an athlete.
-More haemoglobin
-More oxygen can be
carried / transported
-More aerobic respiration of muscle cells
What part of the plant carries dissolved sugars?
Phloem
List 2 types of cardiovascular disease:
-Coronary heart disease
-Heart failure
-Faulty valves
What happens in coronary heart disease?
Build-up of fatty plaque can narrow the lumen of the coronary arteries, restricting blood supply to the heart. This means that the heart receives less oxygen, so cardiac cells cannot aerobically respire as effectively.
List the advantages and drawbacks of using stents as a treatment for CHD:
Advantages:
-surgery is relatively quick
-lasts a long time
Disadvantages:
-surgery risks, i.e. infection
-blood clots could form near stents
List the advantages and drawbacks of using statins as a treatment for CHD:
Advantages:
-lowers LDL cholesterol
-increases HDL cholesterol
-less invasive than stents
Disadvantages:
-must be taken every day
-side effects, i.e. headaches, kidney failure
